Vegetables & Fruit May/June 2020

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MAY • JUNE 2020

Citrus industry working hard to assure record exports R40,00

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21 36 Nr 195

ISSN 1015-85 37

8

Cover

Naval oranges makes up 19% of this years citrus exports.

12

NEWS 4 4 5 5 6 6 6

Agri’s got talent 2020 Avocado ambassadors announced Fruit SA announces acting CEO Kaap Agri invests in manufacturing Fruit and vegetable supply steady Sagtevrugte toekennings Plaasvars e-Mark vir boere

EDITORIAL Willie Louw (Group editor)

CITRUS 8 Citrus industry working hard to assure record exports 11 Fostering confidence in South African produce for

over 90 years 12 Protect crops with suitable shade nets 14 Focus points for drip on citrus 16 Impact of clogged irrigation systems on citrus 18 Optimising citrus fertilizer applications with science

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ROOT VEGETABLES 21 From good to great 25 Bereik volle potensiaal met BASF se oplossings vir aartappels 26 Swartvrot op uie - neem kennis van Aspergillus niger 28 Bemesting van groente

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GROENTE & VRUGTE | MEI • JUNIE 2020

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3

NEWS

Agri’s got talent 2020 It is time for the annual Agri’s got talent competition. Industry representatives are working to ensure that various agricultural industries and the people within them are both protected from the Covid-19 pandemic and financial turmoil.

A

CCORDING TO A statement by the organisers, Agri’s got talent 2020 has an opportunity to be more than a singing and skills development competition this year. It has the opportunity to be a form of encouragement, a tool to

uplift one another, a means through which agri communities all over South Africa can unify under joyous song, and together, sing of a better and brighter tomorrow.

Caroline Poole, from The Vinpro Foundation, states: “We believe in ‘Because People Matter’ and it is with this belief that we whole heartedly support Agri’s Got Talent and the change that it brings about in the lives of the contestants, their families and their communities.”

Agricultural workers everywhere are encouraged to enter this year’s Agri’s got talent.

For more information, WhatsApp a sound clip of no longer than three minutes to 082 372 1557 or e-mail: agrisgottalent@gmail.com.

Avocado ambassadors announced The third Avo ambassador competition, introduced in 2017 by the South African Avocado Growers’ Association (SAAGA), has been won by Nomvuselelo Mncube, cooking assistant at Food & Home Entertaining, and Karen Hart, food writer for Kuier and LitNet.

T

HE AWARDS WERE presented at Mexican themed lunches held recently to launch the 2020 local avocado season at the La Rosa and El Burro restaurants situated in Johannesburg and Cape Town respectively.

The Avo ambassador competition aims to recognise South African food and health writers for their overall promotion of the South African avocado.

“I wasn’t expecting this, so I am so excited to be chosen as SA’s avocado ambassador. I enjoy working with avocados as they are so versatile and such a nutritious fruit,” said Mncube.

Hart, the second Avo ambassador, commented that being given this award was not only humbling but also the ultimate accolade. “I have always loved avocados, I love the rich texture and can never get enough of the taste. I love avos plain and simple, seasoned with salt and freshly

Derek Donkin, CEO Subtrop, and Karen Hart, food writer for Kuier and LitNet.

4

Nomvuselelo Mncube, cooking assistant at Food & Home Entertaining and Derek Donkin, CEO Subtrop.

ground black pepper, on a piece of freshly baked bread.

My favourite breakfast is soft white bread, stacked with avocado, boiled egg and ripe red tomato. To be honest, I can have that for breakfast, lunch and supper,” said Hart.

The judging panel included Derek Donkin, CEO of SAAGA; Hans Boyum from Westfalia; Leandre Mynhart from Afrupro; Leigh Green from Halls and Clive Garrett from ZZ2.

“Once again, it was a difficult task to choose the two winners from amongst the many entries received from print, online and electronic media. On behalf of SAAGA I would like to thank all the media for their continued support of the local avocado industry. Due to the changing media landscape we will be making slight changes to the way the 2020 Avocado ambassador runs, including the fact that this years’ eligible submissions will be will from January to December,” said Donkin.

MAY • JUNE 2020 | VEGETABLES & FRUIT

NUUS

Fruit SA announces acting CEO Fhumulani Ratshitanga has been appointed acting CEO of Fruit South Africa.

H

ER APPOINTMENT FOLLOWS the resignation of Dr Konanani Liphadzi, after a six-year tenure as the first CEO of Fruit South Africa. Fhumulani’s career spans over 18 years in the agricultural sector. She has worked for the Southern African Confederation of Agricultural Unions, the Department of Agriculture, Land Reform and Rural Development and the Perishable Products Export Control Board. She has served as Fruit South Africa’s Industry Affairs Manager

since July 2019.

Currently completing her BCom Honours degree in Economics with the University of South Africa, Fhumulani also holds a Master’s degree in agriculture (MInstAgrar), specialising in plant protection from the University of Pretoria.

Fruit South Africa wishes Fhumulani success and will announce a permanent CEO once the position has been filled.

Kaap Agri invests in manufacturing Kaap Agri, the JSE-listed group trading in agricultural, fuel and related retail markets, has unveiled its first major investment of more than R150 million to further bolster its manufacturing capabilities.

T

HE INVESTMENT the establishment of TEGO Plastics (Pty) Ltd, a new subsidiary of the Kaap Agri Group, based in Brackenfell, Cape Town. TEGO Plastics specialises in the manufacturing of large format, injection moulded plastic products for the agricultural market, using state-of-the-art robotics and machinery. For this purpose, one of the largest injection moulding machines available in the global market was commissioned.

Set to provide 33 new job opportunities at the facility, TEGO Plastics will initially produce high-quality, food grade bulk bins for the agricultural market with the opportunity to manufacture additional solid form products at a later stage.

The TEGO Bulk Bin is a robust, versatile, food safe, bulk bin which is used in the harvesting and post-harvesting processes of fresh fruit and vegetables.

Bulk bins are essential to the pome, citrus and stone fruit sectors.

During a media tour of the facility, Kaap Agri CEO Sean Walsh, said that the launch of TEGO Plastics is in line with the group’s strategy to diversify its manufactured product range and to offer more value to its agricultural customer base.

“With limited availability of new bins and product options it became clear to us that we could help address challenges producers face with the storage and transportation of fresh produce.

“Furthermore, Kaap Agri provides the ideal platform from which to launch

such a product, not least of all because of its already-established infrastructure and the relationships built up with farmers over more than a century.

“The TEGO Bulk Bin has unique design features that takes into account the specific requirements of the agricultural end-users who need cost-effective, food grade, and durable bins that perform well under different environmental conditions in various locations - under the blazing sun in an orchard, on a transport truck, in cold storage or in a packhouse,” Walsh said.

Leading operations at Kaap Agri’s new manufacturing plant in Brackenfell, TEGO Executive Manager Edward Smith explained that injection moulding is the process whereby molten material (in this case plastic) is injected into a mould. This then hardens into a shape that has conformed to the contours of the mould to shape the bin.

Some of the challenges producers face face include: damage to produce due to limited air flow, bruising because of the shape of the inside of the bins, sun damage, as well as compatibility issues when moving bins with forklifts and pallet jacks.

Added to this, a strained availability of new bins means that farmers are resorting to using old bins that could potentially damage the produce.

“The transportation of fruit or vegetables from the field to the packhouse is possibly the most important part of the farming process. The difference between losing 6% and losing 10% of produce

GROENTE & VRUGTE | MEI • JUNIE 2020

TEGO Bulk Bins are also designed to accommodate a transport support brace across the top of the bin, which minimises damage to bin and contents during transportation.

due to bruising or heat damage is huge, and it translates to a big difference on the bottom line,” Smith said.

Design features of the TEGO Bulk Bin include a smoother inside to help eliminate bruising, a centre support structure to prevent warping and bulging associated with heavy loads, unique drenching slots to ensure better ventilation and draining, and a higher base for use of a standard pallet jack. The footprint of the TEGO Bulk Bin is compatible with the existing plastic and wooden bins in the market, and therefore it integrates seamlessly with existing customer stock.

TEGO Bulk Bins are also designed to accommodate a transport support brace across the top of the bin, which minimises damage to bin and contents during transportation.

5

NEWS

Fruit and vegetable supply steady As an essential part of the country’s food security network, South Africa’s fresh fruit and vegetable supply channels remains active and efficient.

“F

RESH FRUIT AND vegetables are an essential part of the food security network and South Africa is filled with world class producers, big and small, who produce fresh produce of the highest quality and pack and transport it, adhering to required international hygiene standards,” says Jaco Oosthuizen, CEO of the RSA Group.

To ensure this high level of adherence, RSA Group’s business unit heads are running ongoing briefing sessions on hygiene protocols at all of its fresh produce markets of operation. This ongoing programme will allow it to keep on servicing the crucial local retail sector effectively and safely, while also ensuring that its Freshworld export operation continues to do business for all of its producers and their customers.

“We trust that market management and relevant local authorities will be taking, matching and supporting health and safety actions,” says Oosthuizen. “It’s crucial that all industry players coordinate their efforts to protect local businesses and ensure consumer safety and national food security at this time.”

Jaco Oosthuizen, CEO of the RSA Group.

South Africa’s fresh produce market system is robust and able to adjust to sudden changes in supply and demand.

Markets remain the primary reference point for fresh produce prices, and the country’s markets are currently fully stocked.

Sagtevrugte toekennings Die Suid-Afrikaanse sagtevrugtebedryf vereer jaarliks mense wat ‘n verskil maak en die bedryf deur harde werk en prestasies bevorder.

H

IERDIE UITBLINKERS ONTVANG later vanjaar hulle toekennings tydens die sagtevrugtebedryf se gala-aand, wat die bedryf se 45ste geleentheid vir sulke toekennings is.

Daar kan vir die volgende kategorieë ingeskryf word: algemene landbouwerker, spesialislandbouwerker, gevorderde

landbouwerker en nuwe toetreder in die sagtevrugtebedryf.

Toekennings word ookgegee vir navorsing en tegnologie en die Izethelo-toekenning vir uitnemendheid in joernalistiek.

Besoek Hortgro se webtuiste vir meer inligting.

Plaasvars e-Mark vir boere TLU SA het onlangs die Plaasvars e-Mark bekendgestel om boere en verbruikers met mekaar te verbind.

“T

LU SA HET LANKAL reeds gesien dat boere ‘n platform nodig het om direk by die verbruiker uit te kom,” sê Louis Meintjes. “So kan hulle voortgaan om ‘n bestaan te maak gedurende uitdagende tye.”

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6

enige landbouproduk wat hulle wil verkoop, aanbied. Met TLU SA se Plaasvars e-Mark kan die verbruiker direk met die boer oor produkte onderhandel.

Die platform werk eenvoudig: die produsent laai die inligting en beskikbare produkte met ‘n foto of twee. Die verbruiker besoek die mark en kies die produkte waarin hy of sy belangstel, en die produsent en verbruiker praat direk met mekaar om ‘n transaksie te beklink.

MAY • JUNE 2020 | VEGETABLES & FRUIT

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CITRUS

Citrus industry working hard to assure record exports The soft citrus and lemon categories are expected to show the highest growth in 2020.

Southern Africa is expected to export a record 143,3 million cartons of citrus fruit to over 100 countries in 2020.

This is a 13% increase when compared to 2019, which saw 126,7 million cartons being exported, generating R20 billion in export revenue and creating 120 000 jobs.

V

EGETABLES & FRUIT spoke to Justin Chadwick and John Edmonds to hear what is currently happening in the industry and how the Covid-19 pandemic is influencing what was believed to be a record breaking export year.

Commentating on why the citrus industry in South Africa is doing so well, even with challenges that were faced during the last season, Justin said that the industry covers a lot of geographical areas, grown from KZN in the east to Northern Cape in the west, and from Robertson in the south to Zimbabwe in the north. As such, poor climatic conditions in one area are offset by good conditions in another.

In addition, given the good returns to citrus over the past few years, there has been significant new plantings, which means additional export volumes. Citrus research International is continuously researching new farming technologies and better solutions. Growers invest heavily in research which leads to new and better farming techniques each year.

This increase should translate into more job opportunities, foreign exchange revenue and will contribute towards national government’s goal of increased agricultural exports over the next few years.

John Edmonds says that the Citrus Growers’ Association of Southern Africa variety focus group representatives recently compiled their estimate of Southern African citrus exports for 2020, see Table 1. Valencia oranges make up the biggest portion of the citrus export market at 35%, followed by navel oranges (19%), lemons (18%), soft citrus (16%) and grapefruit (12%).

Valencias The Southern African Valencia export crop estimate is 50,36 million 15 kg equivalent cartons in 2020, a normal volume 2% higher than the average for the last 10 years and 8% up on last year. Overall, the crop looks good with marketable fruit sizes.

Letsitele, the biggest regional exporter of valencias, is expected to be 6% down on last year with 11,4 million cartons of exports anticipated in 2020. Packing will happen from week 21 to week 38.

Recent good rains may push up the volume of late valencias but the dam levels are still low. Fruit size is bigger than last year. Senwes are up 18% to 6,16 million cartons. The Limpopo River valley (5,6 million cartons; up 22%) is back to a 2017 sort of year.

In certain areas, the seedless Valencia is under pressure with poor set, especially Delta, while other areas set a good crop throughout. Hoedspruit (5,7 million cartons; 19% up) have a normal volume with good sizes. Nelspruit expect to be 21% down on 2,3 million cartons but have a good, clean crop with a good size distribution (64, 72, 56).

In the Eastern Cape, Sundays River Valley (6,25 million cartons estimated) anticipates a 3,2% increase on last year, attributed to better sizes of fruit. Patensie also has better sizes, yielding a 12% increase in their export expectation. The Western Cape (4,5 million cartons; 21% up) returns to normal after a poor 2019.

Lemon and soft citrus The soft citrus and lemon categories are expected to show the highest growth in 2020. Soft citrus will see an increase of 28%, with the Boland region contributing 12% more cartons than last year. Regions in the northern parts of the country, including Burgersfort / Ohrigstad, Senwes and Hoedsruit, will also see exponential growth in their soft citrus outputs.

The Sundays River Valley, which exports almost half of the region’s lemons, is expected to export 12 million cartons this year, an 18% increase from 2019. The northern regions of Nelspruit, Letsitele and Burgersfort / Ohrigstad will also show massive growth ranging from 40% to 55% compared to last year.

Table 1. Estimate of Southern African citrus exports or 2020.

8

Valencias

Grapefruit

Navels

Lemons

Soft citrus

Total citrus

2015

52,7m

15,7m

24,5m

15,1m

10,0m

117,9m

2016

42,1m

13,8m

26,2m

15,1m

12,2m

109,4m

2017

54,0m

15,6m

21,1m

19,0m

13,4m

123,0m

2018

54,4m

18,8m

26,7m

19,9m

16,2m

136m

2019

46,8m

15,3m

24,3m

22,1m

18,2m

126,7m

2020 est.

50,4m

16,7m

26,5m

26,4m

23,3m

143,3m

MAY • JUNE 2020 | VEGETABLES & FRUIT

SITRUS

Early soft citrus has been impacted by delays at ports due to port capacity and it will have an impact on fruit quality.

Covid-19 While the Citrus Producers Association (CPA) is confident that the 2020 season will be a success, they are also aware that there are events beyond growers’ control that could impact final export numbers.

Most notably, the Coronavirus (Covid-19) outbreak presents a new challenge to fresh produce exporters across the globe.

When asked how Covid-19 is currently influencing the export of citrus to other countries, Justin said it is very early to tell, as harvesting and packhouses only really gets going now. Early soft citrus has been impacted by delays at ports due to port capacity and it will have an impact on fruit quality.

The World Citrus Organization (WCO) is currently assisting and working on southern hemisphere estimate to see what is expected. The CPA and WCO will work together to ensure consumers around the globe have access to citrus at this time when it is vitally needed to boost immune systems and as a remedy for colds and flu.

Supply chains Agriculture is deemed as an essential service, and food an essential good. As such the government in RSA is making concerted efforts to keep the food supply chains going. Overseas governments are doing the same – for example, in the EU they are introducing green lanes to ensure logistics flows.

However, the outbreak across the European Union (EU), the largest export market for South Africa’s citrus, remains a concern and could still result in a decrease in demand and a shortfall of containers when the export season kicks off in May. It is therefore critical that exporters confirm that there are containers available before they start shipping.

It is also encouraging that China’s logistics services are expected to be fully operational soon, with cargo volumes and ship calls having swiftly rebounded over the past two weeks.

Challenges at South Africa’s ports, including aging and out of service infrastructure as well as unresolved labour issues, remain a threat to export volumes. However, the CPA is proactively engaging with Transnet and welcomes recent steps taken, including those to improve operations at a number of the ports. This includes the procurement of new equipment for both the Port Elizabeth and Durban ports.

With the citrus industry expected to grow by a further 500 000 tons over the next three to five years, the CPA will continue to focus on opening and expanding market access in key markets including China, USA, India, the Philippines, Japan, Vietnam and the EU.

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9

PROMOTION

Fostering confidence in South African produce for over 90 years T

HE PERISHABLE PRODUCTS Export Control Board (PPECB) is South Africa’s official export certification agency for the perishable produce industry. Since its inception 94 years ago, the PPECB has endeavored to support industry and government’s objectives of promoting the export of South African perishable products.

The PPECB has made significant progress on its electronic inspection platform, called TITAN, since the original launch in 2014. A total of 56% of the main product volumes were inspected on TITAN, with 919 activity points completing their service requests on this electronic platform. TITAN was decommissioned on 31 August 2019.

The second iteration of the platform, TITAN 2.0®, was launched on 1 October 2019 with User Registration and Service Request. The enhanced TITAN 2.0® application has been streamlined to be more effective and efficient. During the period 1 October 2019 to 31 March 2020, 11 115 015 cartons were inspected at 192 activity points.

In April 2020, TITAN 2.0® took a significant step forward with the integration of the Tracking Unit Register (TUR).

TUR has been introduced by the Department of Agriculture, Land Reform and Rural Development (DALRRD) as a central database in the official export certification system to store relevant data regarding tracking units. This will allow clients to send their tracking unit data (pallet information) to PPECB for quality inspection after they have added the tracking unit into the TUR. The PPECB was mandated from 2018 by DALRRD to conduct orchard inspections and phytosanitary certification for citrus fruit destined to Europe. The orchard inspections are specifically to determine the presence of Citrus Black Spot on fruit within citrus orchards destined to Europe.

TITAN 2.0® mobile technology.

GROENTE & VRUGTE | MEI • JUNIE 2020

Inspection of citrus by PPECB inspector.

During the 2019 citrus season forty-three Orchard Inspection Technicians were employed to complement existing Orchard Inspectors within PPECB. This initiative supports one of Government’s priorities by creating job opportunities for unemployed graduates. The Orchard Inspection module of TITAN 2.0® went live in April 2019.

On 23 March 2020, the President of South Africa declared a nation wide lockdown. As a National Public Entity, the PPECB delivers an important service to the Perishable Produce Export industry and have continued their services during the lockdown period. Additional precautionary safety measures have been implemented to safeguard the PPECB staff.

Southern Africa is expected to export a record of 143,3 million cartons of citrus fruit this season. This is a 13% increase over 2019 where 126,7 million cartons were exported. The growth is largely a result of new orchards coming into production and good rainfall received across most production regions.

Estimates for this citrus season is that Valencia crop was predicted to increase by 8%, navels 9%, grapefruit 6%, lemons 19% and soft citrus 28% as compared to the previous season.

The efficiencies within South African ports, availability of cold storage space and containers will be some of the challenges that will negatively affect the seamless exports of the record citrus volumes.

The global threat of the COVID-19 pandemic is another major factor that may negatively affect citrus exports. This pandemic has already resulted in decrease in market demand, port closures for some of the Asian destinations and the cancelation of airfreight orders.

The PPECB remain committed to serve the perishable products industries in these unusual circumstances.

11

CITRUS

Satsuma citrus under SpectraNet Code 20 Black/White.

Leaf bleaching from heat stress.

Protect crops with suitable shade nets The demand for shade netting in the agricultural sector is increasing because it can reduce the risk that severe climate poses to the producer.

R

ESEARCH INDICATES THAT shade netting provides the necessary protection for crops from extreme climatic conditions and reduce their adverse effects. The nets have also been found to increase the quality crops.

Water saving is another benefit of using nets, because it reduces the amount of evaporation, this also means less damage to crops by sunburn, insects and birds.

The increased crop quality is largely due to the optimal growth environment created within the shade net structure.

A well-built structure, with the correct density and colour shadenet, creates a protected microclimate which is ideal for growing seedlings, cut flowers and potted plants as well as growing vegetables and fruits.

The choice of the colour and density of the net should be taken into account when erecting the shade net structure. It plays a major role in changing the quality of light transmitted and its different effects on crops.

Red nets allow more red light to pass to the plant and, for example, can help extend the stem length of roses. More blue light transmitted to the plant can enhance colour development or stimulate root development.

The amount of blue and red light as well as the ratio of blue to red light must be determined by the producer to obtain the best quality, size and colour of fruit and vegetables or to improve flower size and stem length of flowers.

When looking at the positive impact of netting on citrus, some factors must be kept in mind. Citrus is native to subtropical and tropical regions in Eastern Asia and has become widely cultivated around the world, which has led to many new challenges for growers because many of these areas are not ideally suited to citrus production.

The trees thrive in a consistent sunny, humid environment with fertile soil and adequate rainfall or irrigation. However, most areas in South Africa where commercial production of citrus takes place are relatively extreme, due to excessive solar radiation and heat, coupled with low humidity. Typically, in the Upington, Citrusdal and Hoedspruit areas, the climate is characterised by hot to very hot summers, with temperatures reaching 42°C, coupled with high solar radiation and low humidity.

Citrus has the ability to adapt and acclimate to and/or compensate for environmental stress for survival, which generally results in less than acceptable quality and yields. However, this does pay the bills and producers do not want their citrus trees to waste valuable energy trying to survive. Instead, they

12

are there to produce good quality fruit and acceptable yields.

Good photosynthetic response is essential and is the net result of many interacting processes which contribute to good growth, development and yield.

The principal environmental parameters that affect the rate of photosynthesis of citrus, are firstly light intensity, quality and duration, then carbon dioxide uptake. Something else to keep in mind is the water supply (quality, quantity and frequency), mineral elements and composition of the soil and the temperature (ambient, leaf, fruit and soil).

Light impacts on growth and development of plants in two ways: Photosynthesis (primarily the conversion of light energy into chemical energy for plant fuel) and photo morphogenesis (the control exerted by light over growth, development and differentiation of plants, e.g. size and shape that is independent of photosynthesis). The subject of photo morphogenesis will not be addressed in this publication.

Photosynthesis is depicted by the following chemical equation: LIGHT + 6H2O + 6CO2 C6H12O2 + 6O2 + H2O (light) (water) (carbon dioxide) (sugars) (oxygen) (water) In other words – give the citrus tree the correct quality and quantity of light, water, minerals and carbon dioxide and it will be equipped to produce adequate sugars and energy to grow and develop into a healthy tree, producing good quality fruit and acceptable yields.

Knittex and Prof Leon van Rensburg of North West University have for the past twenty years been conducting light and temperature management trials on fruit, vegetable and flower production under SpectraNet shade netting, to study and analyse the influence of temperature and visible light energy on plant stress, growth, development, and produce yield and quality.

Creating the ideal light environment is all good and well, but as soon as citrus is subjected to high temperatures, new management practices have to be considered and carefully implemented.

The optimum temperature for citrus photosynthesis ranges from 25°C to 30°C, whilst temperatures above 35°C reduce photosynthetic activity. High temperatures, combined with low humidity, will cause heat stress to the citrus tree, inducing stomatal closure. This reduces leaf transpiration rates and the absorption of CO2, negatively impacting on the photosynthesis efficiency of the tree.

MAY • JUNE 2020 | VEGETABLES & FRUIT

SITRUS

Sunburn of Satuma citrus.

Surface temperature measurements taken on exposed citrus leaves and fruit in an open orchard, compared to that of an orchard covered with SpectraNet Code 20 Active Blue shade netting, differed by between 4°C and 9°C at ambient temperatures of 23°C and 32°C, respectively. The higher the ambient temperature, the bigger the difference. When ambient temperatures reach the 40°C region, exposed leaf and fruit temperatures exceed 50°C, causing bleaching of leaves and the destruction of fruit skin cells.

High solar irradiation and ambient temperatures also increase soil temperatures and water evaporation levels. Citrus trees place high reliance on their water resouces, and therefore can ill afford losses through unnecessary evaporation.

Inadequate water uptake or irregularities of soil moisture will rob the tree of its basic needs, limiting the transportation of food and water to all parts of the tree and increase the possibility of fruit splitting and sunburn.

High temperatures will also promote the abscission of both flowers and fruit, as the tree protects itself against heat stress, resulting in much reduced yields because of reduced energy resources.

SpectraNet shade netting will reduce leaf, fruit, bark and soil temperatures as well as wind and sunburn damage, whilst increasing humidity and transpiration rates. It has been proven to increase citrus yields and quality.

Subject to the growing region, its climatic conditions and soil quality, different grades and colour combinations of SpectraNet shade netting will be required for best performance, because “one size does not fit all”.

Additional benefits of SpectraNet are that the material does not unravel when cut. If the material is damaged, repairs can be done effortlessly. The durable and lightweight material is easy to work with and “breathes” due to its density.

There is no general shade net suitable for all uses, because each crop has its own unique lighting needs which are further influenced by management input and production adjustments. It is therefore advisable to approach a Knittex specialist to obtain the appropriate shade net for specific needs.

For more information, contact one of the Knittex representative for more guidance, as shade netting requirements will depend on plant variant, location, soil type and climatic conditions in a region. Tel: 011 692 1658 or visit www.knittex. co.za. All SpectraNet can be supplied standard or stentered and comes with a 10 year manufacturer’s warranty against UV degradation.

13

Contact us on: +27 (0)11 692 1658 www.knittex.co.za clientliaison@knittex.co.za

PROTECTS YOUR CROP AGAINST SEVERE WEATHER CONDITIONS (I.E. WIND, SUNBURN, HAIL DAMAGE, BIRDS AND LARGER INSECTS)

CITRUS

Focus points for drip on citrus The concept of open hydroponics has been a major driver of the adoption of drip irrigation in citrus production. Open hydroponics in the context of tree crops was first introduced by Professor Rafael Martinez Valero of Spain in the 1990’s. His work and related research carried out in South Africa has greatly changed thinking in citrus irrigation and nutrition.

T

HE OPEN HYDROPONICS concept focuses on increasing productivity through intensified irrigation and nutrition practices. Over time, this concept has been adapted to South African conditions.

“Nutrigation™ has made a massive contribution to the popularity of drip irrigation on citrus and other tree crops,” says Chris Malan, agronomy manager at Netafim South Africa. “Concepts of open hydroponics are used to promote more efficient use of water and fertilizers. Drip irrigation and Nutrigation create benefits for citrus production as it allows the farmer to better control a few major processes, such as water and mineral availability, distribution and uptake, as well as root activity.

He says there has been a steady increase in the number of citrus orchards established in South Africa with drip irrigation over recent years. This is mainly due to improved drip irrigation and Nutrigation technology and products, agronomic support, on-farm managerial skills and increased pressure on water resources.

Further development of drip irrigation on citrus has been driven by the availability of low flow drip irrigation and the concept of a ‘centralised control continuous irrigation system’. “South African citrus producers are world leaders in this regard,” says Malan.

Changed approach Experience with drip irrigation on citrus has shown that the principles traditionally applied for conventional irrigation do not necessarily apply for drip irrigation, or other localised irrigation methods, such as micro-sprinkler irrigation. “We have to change our approach to successfully implement drip irrigation in citrus and other fruit tree orchards,” says Malan.

There are a few prerequisites to successful drip irrigation, the most important of which is a well-established deep root system. This can only be obtained through proper soil preparation.

Malan adds that, in order to succeed with drip irrigation, it is further essential to nutrigate through the system, think in terms of concentrations rather than amounts of fertilizer application; irrigate at frequent intervals according to scheduling principles, adopt the correct type of emitters and spacing to soil type and topography and control the irrigation depth.

Thorough planning and preparation is required for successful drip irrigation. Two of the important parts of this are soil

14

Concepts of open hydroponics are used to promote more efficient use of water and fertilizers.

Experience with drip irrigation on citrus has shown that the principles traditionally applied for conventional irrigation, do not necessarily apply for drip irrigation, or other localised irrigation methods, such as micro-sprinkler irrigation.

MAY • JUNE 2020 | VEGETABLES & FRUIT

SITRUS

preparation and scheduling calculations. Malan shares principles* for preparation and management, to help achieve very efficient use of water, accurate irrigation volumes and finally optimal tree performance.

The four most important activities: • Establish the soil’s water holding capacity and the optimal percentage extraction of the readily plant available water for each phenological stage of the tree. This is to establish the amount of water that needs to be applied per irrigation cycle.

• Calculate the length of the irrigation cycle by using the calculated delivery rate in mm/hour.

• Calculate how long the period between irrigation cycles must be by using the ETo, Kc and amount of water needed per cycle.

• Check the soil water content regularly and make adjustments if necessary, to avoid gradual trends of under- or over-irrigation.

Reported benefits of drip in South African citrus orchards include low maintenance requirements, high fertilizer use efficiency and lower electricity use.

* This is a very basic rendition of principles discussed by Pieter Raath, Chris Malan and Teunis Vahrmeijer in the article, Irrigation of citrus trees: A practical approach, first published in the South African Fruit Journal. Send an e-mail to infoza@ netafim.com for more information.

Benefits of drip Reported benefits of drip in South African citrus orchards include low maintenance requirements, high fertilizer use efficiency and lower electricity use. “We have seen the highest production per unit of water used for citrus as well as the lowest electricity use per unit of fruit produced in drip irrigated citrus orchards. Tree growth is faster, which leads to an improved harvest index.”

For more information, visit www.netafim.co.za or send an e-mail to infoza@netafim.com

Thorough planning and preparation is required for successful drip irrigation.

15

CITRUS

Impact of clogged irrigation systems on citrus Effective irrigation and fertilization are key to achieving optimal yields. The Puricare team conducted research which demonstrated not only how uneven water and fertilizer delivery were, but also how the situation could be remedied within six to twelve weeks.

T

HE CHEMICAL, PHYSICAL and biological quality of irrigation water has deteriorated. Increased minerals, silts and biological matter in irrigation water block and clog pipes, filters, drippers and micros in orchards. Current treatments include flushing of lines, frequent backwashing and cleaning of filters, manually checking emitters and expensive chemical dosing. Despite all these measures, drippers and micros remain somewhat clogged, resulting in uneven delivery.

More than R8 000/ha of fertilizer products are applied via irrigation systems.

If the emitters are dirty and clogged it means that trees in orchards are getting different amounts of both water and fertilizer, which impact various aspects of production.

To illustrate the extent of uneven water delivery, Puricare measured micro-jets (40 orchards) and drippers (28 orchards) in Kirkwood and Addo between 2016 and 2019.

Too little or to much – water and expensive fertilizer Two random sites of 10 drippers each per orchard were selected and water delivery measured. Actual delivery and the specified delivery for each dripper or micro-jet (at the specified pressure) were compared and presented as a percentage of the specified delivery. Note that all the orchards had standard flushing, manual cleaning and chemical dosing treatments in place – and no Puricare treatment.

Effectively, only 22% of drippers delivered the correct amount of water and fertilizer while the other 78% delivered either too much or too little. If 7 500 cubic litres of irrigation water were applied

16

per ha/annum for citrus, then some 5 800 cubic litres containing expensive fertilizer was applied inappropriately. The frequency distribution highlighted the actual variation in delivery due to clogged drippers. Flushing, manual cleaning and chemical dosing practices at the test locations appeared inadequate.

A similar picture was evident with micro-jets, with the study showing only 27% delivering the correct amount of water and fertilizer while the remaining 73% delivered either too much or too little. If 7 500 cubic litres of irrigation water were applied per ha/annum, some 5 475 cubic litres with expensive fertilizer was applied inappropriately. The frequency distribution highlighted the actual variation in delivery due to clogged micros. Once again – current irrigation cleaning practices appeared inadequate.

In another test study, two rows of 10 drippers were randomly chosen, marked and tested before and after installation of the Puricare unit on four citrus farms.

The dripper lines were all over 10 years old. The results showed how Puricare

The percentage of micro-jet delivery.

Frequency distribution of micro-jet delivery in 40 orchards.

The percentage of dripper delivery.

Frequency distribution of dripper delivery in 28 orchards.

was able to achieve more uniform coverage with effectively cleaned systems – normally six to twelve weeks after installation. Furthermore, distribution uniformity (DU) increased from an average of 89% before Puricare treatment to 96% afterwards, as did the average coefficient of uniformity (CU) increased from 94 to 98%.

These studies highlighted the current status in citrus orchards and the improvement of uniform water and fertilizer delivery. The study furthermore red-flagged the limited effects of current dripper and micro maintenance practices. In contrast – the installation of a Puricare unit in every pump house would have cleaned the irrigation system and improved uniformity of water and fertilizer delivery within six to twelve weeks.

Furthermore, with every new irrigation system, the damaging effects of normal maintenance practices could have been reduced and the lifespan of the lines, drippers and micros extended.

For more information about Puricare solutions visit the website at www.nexusag.net or contact NexusAG on 021 860 8040.

MAY • JUNE 2020 | VEGETABLES & FRUIT

PURICARE WATER TREATMENT CLEANS THE IRRIGATION SYSTEM AND IMPROVES THE UNIFORMITY OF WATER AND FERTILISER DELIVERY! With 5000 to 7500 cubic litres of irrigation water being applied/ha/annum, water represents the largest input in commercial citrus production. Clogged drippers reduce irrigation efficiency resulting in uneven water and fe ilizer delivery. This has a substantial impact on production costs and the profitability of citrus production.

A recent study conducted by Puricare used standard industry practice to measure the uniformity of water delivery of micro-jets in 40 orchards and drippers in 28 orchards in Kirkwood and Addo between 2016 and 2019. All the test orchards had normal flushing, manual cleaning or chemical cleaning practices in place.

The results indicated alarming inefficiencies with only 22% of drippers delivering the correct amount of water and fe iliser while the other 78% delivered either too much or too li le.

FURTHER RESEARCH MEASURED THE IRRIGATION CLEANING EFFECTS OF PURICARE WATER TREATMENT ON FOUR CITRUS FARMS WHERE ALL TESTED DRIPPER LINES WERE MORE THAN 10 YEARS OLD.

UNIFORMITY OF WATER DELIVERY IMPROVED AFTER 6 - 12 WEEKS BEFORE AFTER

% WATER DELIVERY

125%

115%

110%

105%

65% 75% 85% 95% 105% 115% 125% 135% 145%

95%

0%

50% 40% 30% 20% 10% 0% 70%

10% 5%

23%

Frequency distribution of dripper delivery

100%

20% 15%

60%

Correct delivery (90-100%)

FREQUENCY

FREQUENCY

Frequency distribution of dripper delivery

Over delivery (>100%)

85%

37%

17%

90%

Correct delivery (90-100%)

30%

80%

Over delivery (>100%)

Under delivery (<90%) 33%

75%

Under delivery (<90%)

Puricare treatment - dripper delivery

120%

Puricare treatment - dripper delivery

% WATER DELIVERY

WANT TO KNOW MORE ABOUT THE PURICARE SYSTEM? Our team of ce ified Crop Advisors are ready to assist with effective irrigation planning as well as advice on the latest technology used for the improvement of water quality which form a crucial pa of our customised crop solutions.

WE REMAIN IMPARTIAL AND COMBINE THE BEST PRODUCTS AND SERVICES SUITED FOR UNIQUE ENVIRONMENTAL, FINANCIAL AND RESOURCE VARIABLES. VISIT OUR NEW WEBSITE FOR MORE INFORMATION OR CONTACT US ON 021 860 8040.

021-860 8040

www.nexusag.net

CITRUS

Optimising citrus fertilizer applications with science There can be no general fertilizer recommendations or applications for citrus applicable under all conditions. A general recommendation is there as a guideline and is calculated on plant and crop removal figures. General guidelines are modified to on-farm specific conditions, largely as a result of regular leaf and soil samples. This will optimise yield, fruit quality and fruit size in a cost-effective manner.

T

HE USE OF LEAF and soil analyses will enable the producer to streamline the fertilizer programme in a scientific manner. However, it is imperative that the samples are taken in the correct way.

Leaf samples should be taken from 10 representative trees in a block. These trees should be well marked and used for leaf analysis annually. During the first week of April, 10 healthy leaves should be taken at shoulder height all around the tree, both on the shadow and sun sides of the tree. Leaf number two, three and four on new shoots with a small terminal fruit are the correct leaves to sample. Keep refrigerated and wellsealed in a plastic bag before delivering to your closest lab.

Soil samples should be taken in 10 areas in an orchard. The best way is to dig one-meter deep profile holes and then using a spade to slice off a section in the 0-30 cm and the 0-60cm depth.

The 10 x 0-30 cm and the 10 x 0-60 cm samples should be separately mixed, leaving one 2 kg sample of 0-30 cm and one 2 kg sample of 30-60 cm depth. Soil samples can be taken every three years.

It is also possible to use a soil auger to take these representative samples, once familiar with the soil profiles on the farm.

On studying leaf analyses, one will find that the greatest amounts of nutrients in percentage dry matter are calcium,

The use of leaf and soil analyses will enable producers to streamline a fertilizer programme in a scientific manner.

18

followed by nitrogen and by potassium.

Nutrient removal studies by fruit harvested shows that potassium is removed in the greatest quantity, followed by nitrogen and to a lesser extent calcium. These three elements are thus required in the greatest quantities, either supplied by the soil or by fertilizer applications.

Sufficiency will be indicated annually in the leaf analyses.

It is important to take note that even though a leaf level may be considered optimal, one need to carefully consider the plant and fruit removal on an annual basis. In 2008, during an economic crisis and very expensive fertilizer rates, many growers cut on potassium applications because the leaf analysis showed “normal”.

The following year was heralded by dramatic decreases in leaf potassium levels, with many dipping into low and critical levels, quite possibly lowering yield and quality levels that year. Cutting down on nutrient elements can only be considered if soil and/or leaf analyses show excesses.

Citrus trees are sensitive to high salt concentration in the root zone. This can be induced by high fertilizer applications. Normally soil applications are split to avoid excessive salts being applied. It is equally important not to apply “useless salts”, such as excess chloride or excess sulphates, especially in higher saline conditions.

As described in an earlier article, using Ultrasol K Plus** (Potassium Nitrate) will maximize the uptake of the three most important nutrient elements, namely potassium (K+), nitrogen (NO3-) and calcium (Ca++), in all crops. This is achieved by the anion / cation synergistic uptake.

Ultrasol K Plus also contains no “useless salts” (chlorides or excess sulphates) and will therefore reduce any induced salinity in the root zone, only supplying the essential elements of N and K.

Ultrasol K Plus** (Potassium Nitrate) will maximize the uptake of the three most important nutrient elements, namely potassium (K+), nitrogen (NO3-) and calcium (Ca++), in all crops.

On studying leaf analyses, one will find that the greatest amounts of nutrients in percentage dry matter are calcium, followed by nitrogen and by potassium.

Ultrasol K Plus will enable the citrus producer to optimise yield, fruit size and fruit quality with a greater return on investment. *All claims in this article can be substantiated with references which can be made available on request. **Reg No K5020 Act 36/1947. Registration holder Sociedad Quimica y Minera (Africa)(Pty)Ltd Disclaimer The information herein contained is given to the best of SQM’s knowledge and is believed to be accurate. The conditions of use and application of the suggested recommendations are beyond our control. No warranty is made as to the accuracy of any data or statements contained herein.

SQM specifically disclaims any responsibility or liability relating to the use of the recommendations and shall under no circumstances whatsoever, be liable for any special, incidental or consequential damages arising from such use.

MAY • JUNE 2020 | VEGETABLES & FRUIT

Onion breeder & market leader Enza Zaden is a global market leader in short day onion breeding and in developing new hybrids that revolutionise the industry.

Quality

Innovation

Excellent quality, uniformity and yield are mainly determined by a hybrid’s genetics.

Ask us about what hybrids can work for you.

Actively breeding and developing onions that meet the needs of a changing market.

Continuity

Backed by global expertise in leading markets and the latest breeding and seed production technology, we continue to deliver short day onion hybrids that raise the benchmark.

Our breeding and seed operations infrastructure is developed to ensure continuous introduction of improved hybrids.

Expertise

About Enza Zaden At Enza Zaden we breed and develop new vegetable varieties that are grown, sold and consumed all over the world.

So, it’s very likely that you’ll often find our onion, tomatoes, cucumbers, sweet peppers, lettuce or other vegetables developed by us on your plate. We produce and sell the seeds of those vegetables worldwide.

enzazaden.co.za

WORTELGROENTE

Onion harvest in the Bushveld.

From good to great Onions are a staple food globally and constitute around 14% of fresh produce crops traded in South Africa. This makes it the third largest crop, preceded by potatoes with 34% and tomatoes with 16% of total value of fresh produce traded.

T

HE SOUTH AFRICAN onion market is not the largest in terms of hectares, but thanks to breeding companies like Enza Zaden, it is one of the most advanced markets when it comes to genetic quality of hybrids used, specifically the short day onion type.

Since the introduction of the first hybrid onion varieties during the early 1950’s, huge improvements have been made. The first Grano or Granex hybrids, such as Granex 33, led to improvements in quality and yield. In the early 1990’s, varieties such as Primavera from Seminis and Shahar and Hanna from Hazera became household names to commercial growers. Varieties like Savanna Sweet and Gold Rush made their mark soon thereafter.

Open pollinated varieties, like Capricio and hybrids like Dessex, played an important role in the South African market during this same time. They were mainly used for production from sets in key production areas such as Brits.

It was about 25-30 years ago when the first hybrids made a big change. The early hybrids were used during onion

Typical Grano “Spinning top” shape (Left). (Right) Early Grano types were pale with flaking skins. Bulbs were prone to damage during handling.

production in the 90’s and early 2000’s.

They realised yields from 30-50 tons per hectare, to record yields of above 80 tons per hectare. The onion market was growing, consumers became more knowledgeable and disease pressure rose. This led to evolving requirements for onion varieties.

Although the market was not as critical about onion quality as today, new hybrids did stand out from traditional types. At the time, the main weakness of the early Grano hybrids was their shape

and firmness. These varieties were also very daylight sensitive and limited short day onion production to a very narrow planting slot.

During the mid-1990’s, trials started in South Africa with an onion range that would change the face of onion production forever.

“Cavalier from the Yates breeding programme, marketed as STAR5516 through Starke Ayres, was one of the first new generation hybrids and still is a popular variety in many areas of South TO PAGE 22

GROENTE & VRUGTE | MEI • JUNIE 2020

21

ROOT VEGETABLES

From good to great FROM PAGE 21

Copperhead with copper-brown, globe shaped bulbs.

Africa,” says Lewis Lydon, Crop Breeding Manager from Enza Zaden in Narromine, Australia. “Through Cavaliers, globe shape, firmness and above all, improved adaptability, was introduced to the South African market. This was the foundation of the new short day genetics we see today.”

Enza Zaden The acquisition of the Yates breeding programme by Enza Zaden in 2003 combined the good genetics of the breeding programme with larger, more advanced teams of research and product development, seed production, planning and portfolio management. It also developed a range that allows an even wider planting time.

Adaptability, without a doubt, was the biggest improvement. The development

of Enza Zaden’s Late-, Mid- and Early Short Day varieties made it possible for growers in the northern region of South Africa to sow from as early as January all the way through to May. Copperhead is one of Enza Zaden’s first double haploid hybrids with the focus on firmness for machine harvest and uniformity in the Early Short Day type segment. Python is a transitional hybrid from Late Short Day to Early Intermediate and can be used for early sowings in the northern onion growing region of the country.

A distinct change has been in shape. A typical Grano type has a “Spinning-top” shape, with a flattened top to sharply tapered root base. Today, a globe shape is required, offering higher yield that allows uniform grading and easier packing with fewer rejects throughout the supply chain.

Bulb firmness has also been greatly improved. The traditional Grano type had a much softer bulb which was prone to rotting and physical damage through handling. Most Enza Zaden Short Day onions are “rock hard”, suffering less breakdown. This contributes greatly to storability.

Most onions could previously store for four to six weeks at most, compared to the current range of hybrids available, which can store two to three times longer. This gives growers superior flexibility in their marketing options and better feedback from their customers.

This highlights how a seed company with good genetics can add value to the entire crop chain. From the grower to market agent or retailer, to the ultimate judge – the consumer.

The more skins, the better Onion storage is already used in the Northern Cape, but more recently, even Bushveld onion growers are consideringbulb storage to benefit from the premium quality some of the new hybrids offer. The more recent hybrids feature more attractively coloured, copper-brown, better retained and more disease tolerant skins.

An increasingly desired trait is better skin retention, where layers of cured skin don’t flake off so easily. The more

22

‘N OSEAAN VAN VOORDELE AFRIKELP ™ BIOSTIMULANTE

www.afrikelp.com

A26317/SAGV/1

bevorder groei en opbrengs.

WORTELGROENTE

such characteristics, allowing growers in the north to grow “onions from the bushveld with Western Cape qualities”.

(Left) Python and (Right) Zircon after curing exhibit superior bulb quality with beautiful coloured skins.

Onions being sorted and packed in the Northern Bushveld.

skins an onion has, the better the tasty package within is protected. Varieties

like Copperhead and Python are some of the short day onions which exhibit

Looking ahead Change is continuous as markets evolve.

Mechanical harvesting is not a new concept to South African onion growers. For this, not just any onion will do. Onions are required to withstand significantly more handling without compromising quality or pack-out yield, especially as customers such as supermarket chains impose increasingly tough quality criteria on growers. For this, new varieties with more skins and even harder bulbs are in development.

“We are advancing with our pink root tolerant range,” says Johan Bestbier, Onion Portfolio Manager at Enza Zaden South Africa, emphasizing that disease tolerance is and always has been front in mind in their breeding objectives. “We currently have several F1 hybrid varieties with advanced levels of pink root tolerance, like Rebecca and Samurai.”

Backed by world class technology, many years’ experience and a strong footprint in all leading short day onion markets, Enza Zaden is confident it will continue to introduce varieties that not only add value to the entire supply chain, but continue to raise the benchmark for many generations to come.

23

Regalis® Plus Neem die plus en kry meer as wat jy verwag

Regalis® Plus is ’n:

 Groeireguleerder  Opbrengsbestuurder  Plantversterker Het jy jouself die AgCelence® voordeel gegee?

Regalis® Plus en AgCelence® is geregistreerde handelsmerke van BASF.

A26669

BASF Suid Afrika (Edms) Bpk • Sestiendestraat 852, Midrand, 1685 • Posbus 2801, Halfweghuis, 1685 • Tel: +27 11 203 2400 • Faks: +27 11 203 2461 • Webblad: www.agro.basf.co.za Mobielewebblad: m.agro.basf.co.za • Regalis® Plus Reg. Nr. L10535, Wet Nr. 36 van 1947. Aktiewe bestanddeel: Prohexadione-kalsium (acylcyclohexanediones) 100 g/kg.

PROMOTION

Bereik volle potensiaal met BASF se oplossings vir aartappels H

UNTER® 24 SC: ‘n Produsent kan dit nie bekostig dat aartappelmotlarwes die aartappels beskadig nie.

Daarom is ‘n voorkomende blaarinsekdoder nodig. Hunter 24 SC beheer aartappelmotlarwes baie doeltreffend deur inname. Geen kruisweerstand teenoor ander insekdoders is bekend nie, wat die produk ideaal maak vir gebruik in ‘n bestuursprogram teen insekweerstand. Vir gemoedsrus toon die produk ook buitengewone nawerking in die beheer van aartappelmotlarwes. Die uitstekende reënvastheid van een uur na toediening sorg vir vinnige opname in die blaar met translaminêre beweging sodat aartappelmotlarwes wat nie direk aan die bespuiting blootgestel is nie, ook beheer word.

Fastac® SC is nog ‘n betroubare oplossing vir die beheer van aartappelmot en klein komandowurm op aartappels. Die

Kry gemoedsrus met betroubare beskerming teen insekte en siektes op aartappels. BASF: Nou gaan ons boer!

kragtige formulasie word nie deur sonlig of temperatuur benadeel nie. Die produk is bekend vir ‘n goeie uit-klop-aksie wat vinnige beskerming teen vreetskade bied. Vir gerief en kostebesparing kan dit met ander behandelings gemeng word.

Bellis® se kenmerkende dubbele wyse van werking met vinnige opname en verspreiding in die blare, gee doeltreffende beskerming teen vroeë roes vir ‘n oes se goeie opbrengs en kwaliteit. Die kombinasie van boscalid en F500® dra tot betroubare siektebeheer by. Vinnige opname en translaminêre vervoer van die aktiewe bestanddele in die blare gee volledige beskerming aan die blare en dit bevorder die aartappels se opbrengs en kwaliteit. Gerieflike lug- en grondtoediening maak Bellis die ideale keuse in ‘n spuitprogram teen vroeë roes. Die uitstekende formulasie het geen bymiddels nodig nie. Indien die produk teen die hoër dosis reeds by knolinisiasie toegedien word, mag ‘n beduidende opbrengsverhoging gekry word.

Orvego® kombineer die swamdoder Initium®, wat aan ‘n nuwe chemiese klas behoort, met dimethomorf, nog ‘n beproefde swamdoder van BASF, vir uitstekende beheer van laatroes. Die formulasie is gerieflik om te gebruik, deur vinnig in water te meng en dit bly in

GROENTE & VRUGTE | MEI • JUNIE 2020

suspensie sonder om uit te sak. Hierdie eienskappe bring mee dat die produk vinnig aan die waslagie op die blare heg, sodat buitengewone reënvastheid bewerkstellig word. Die aktiewe bestanddele word geleidelik vrygestel en tydens vogtige toestande, soos dou, vergroot die beskermde area vir doeltreffende voorkomende beheer van laatroes op aartapples.

Acrobat® WG word vinnig in die plant opgeneem vir reënvastheid. Dit is onmiddellik in die plant beskikbaar vir voorkomende beskerming tydens toestande wat gunstig is vir laatroes-ontwikkeling en as siektedruk toeneem. Die produk is ‘n gevestigde staatmaker om in ‘n voorkomende laatroesbeheerprogram op aartappels te gebruik.

BASF Suid-Afrika (Edms) Bpk. Sestiendestraat 852, Midrand 1685, Posbus 2801, Halfway House 1685.

Tel: +27 11 203 2400. Faks: +27 11 203 2461.

E-pos: agcelence-za@basf.com. Bellis® Reg. Nr L7817 Wet No. 36 van 1947. Aktiewe bestanddele: F500® 128 g/kg. Boscalied 252 g/kg Versigtig. F500® - Piraklostrobien. Hunter® 24 SC Reg. Nr L8307 Wet 36 van 1947. Aktiewe bestanddeel: Chloorfenapir 240 g/ℓ. Skadelik. Fastac® SC Reg. Nr L4992 Wet 36 van 1947. Aktiewe bestanddeel: Alfa-sipermetrien 100 g/ℓ. Skadelik. Orvego® Reg. Nr L9185 Wet 36 of 1947. Aktiewe bestanddele: Initium® 300 g/ℓ.

Dimethomorf 225 g/ℓ. Versigtig. Initium® - Ametoktradien. Acrobat® WG Reg. Nr L6526 Wet 36 van 1947. Aktiewe bestanddele: Dimethomorph 90 g/ kg. Mancozeb 600 g/kg. Versigtig.

Lees asseblief produketikette vir volledige gebruiksaanwysings. Acrobat®, Bellis®, F500®, Hunter® 24 SC, Fastac®, Orvego® en Initium® is geregistreerde handelsmerke van BASF.

25

ROOT VEGETABLES

Gesonde uielande.

Swartvrot op uie – neem kennis van Aspergillus niger Aspergillus sp. is die algemeenste swamspesie onder uie en kan groot skade aanrig aan die produsent se oes. Hoewel die swam reeds in die veld, voor oestyd gesien kan word, word die groot skade ná oes aangerig wanneer die uie opgeberg word.

H

OË TEMPERATURE VAN tussen 29 en 35°C en vogtige omstandighede skep die ideale omgewing vir die Aspergillus niger-swam om te floreer en swartvrot in uie te veroorsaak. Aspergillus niger beïnvloed nie net die kwaliteit nie, maar ook die hoeveelheid bemarkbare uie.

Siektesimptome, ontwikkeling en besmetting Aspergillus niger kom algemeen as ‘n saprofiet in die grond en op dooie plantmateriaal voor. ‘n Saprofiet is ‘n swam, plant of mikro-organisme wat op dooie organiese materiaal lewe.

Die swam sal eerste aan die bo-kant of aan die kante van die ui gesien word waar die skutblaar moontlik beskadig is.

Die swam vermeerder tussen die droë, buite skutblare en die eerste laag vlesige skutblare. Wanneer die siek skutblare onder droë omstandighede uitdroog, is die massas swart Aspergillus niger-spore tussen die buitenste skutblare sigbaar.

Die swam-besmetting tot bakteriese sagtevrot veroorsaak wat die ui tot ‘n waterige, sagte, vrot massa laat bederf. Dit is moontlik dat eksterne simptome nie sigbaar is nie, maar wanneer die ui oopgesny word, sal die binnekant swart of grys wees.

Voorkoming en bestuur van Aspergillus niger Geen ui-variëteit is teen swartvrot bestand nie, maar die uie-produsent kan stappe neem om die swam se groei te voorkom of the verminder:

26

Sakata se Duster-ui.

MAY • JUNE 2020 | VEGETABLES & FRUIT

WORTELGROENTE

1. Hoewel daar geen chemikalieë is wat die swam direk kan beheer nie, het navorsing getoon dat ‘n goeie swamdoderprogram vir blaarsiektes die moontlikheid van swart vrot kan verminder.

2. Beskadiging van uieplante moet tot ‘n minimum beperk word, omdat die swam die ui kan binnedring wanneer die skutblaar beskadig is.

3. Uie moet in toestande van lae temperature (≤15°C) en lae humiditeit opgeberg word, dit sal die groei van Aspergillus niger verminder en sodoende die skade verminder.

Vir meer inligting oor die produksie van uie of spesifieke ui-variëteite besoek gerus Sakata se webtuiste by www.sakata.co.za of skakel die naaste Sakata-verkoopsverteenwoordiger.

AFWYSENDE KLOUSULE: Hierdie inligting is op ons waarnemings en/ of inligting van ander bronne gebaseer. Aangesien gewasprestasie van die interaksie tussen die genetiese potensiaal van die saad, die fisiologiese eienskappe daarvan en die omgewing afhang, insluitend bestuurspraktyke, gee Sakata geen uitdruklike waarborg of deur implikasie vir die prestasie van gewasse in verhouding tot die gegewe inligting. Sakata aanvaar geen aanspreeklikheid vir enige verlies, direk of as gevolg daarvan, wat te wyte aan enige oorsaak mag ontstaan nie. Lees eers asseblief Sakata Seed Southern Africa (Pty) Ltd se verkoopsvoorwaardes voordat saad bestel word.

Spore van swart Aspergillus niger op ‘n ui.

27

Sakata Kwaliteit saad

Carvora

Kestrel

Red Ace

Perez Tel: 011 548 2800 www.sakata.co.za e-pos: info.saf@sakata.eu

ROOT VEGETABLES

Bemesting van groente Uittreksel uit die 2016 Bemestingshandleiding

Daar is ongeveer 30 groentesoorte waarvoor min gekontroleerde inligting oor bemestingsnorme bestaan en daar is selfs minder inligting oor die minder bekende groentesoorte.

M

ET DIE SAMESTELLING van ’n bemestingsprogram vir groente moet die uiteindelike doel, benewens opbrengs, ook wees om ’n produk van uitstaande gehalte te produseer. Gehalte word deur ’n aantal faktore, soos klimaat, grond en grondvrugbaarheid, saad, kultivar, plantdatum en spasiëring, asook bemesting, besproeiing, plaagbeheer, hantering en verpakking beïnvloed. Sommige van die faktore kan deur die produsent bestuur word, terwyl daar faktore is waaroor die produsent geen beheer het nie.

waaroor daar nog die meeste onkunde bestaan.

Vanweë die morfologiese eienskappe van die meeste groentesoorte verg die toediening van plantvoedingstowwe en besproeiing veel meer bestuursinsette as by gewone akkerbougewasse. Dit is algemene gebruik om plantvoeding gedurende die groeisiklus toe te dien. Benewens die normale N , P en K voeding, kry die toediening van kalsium, magnesium, spoorelemente, asook groeireguleerders en planthormone, baie meer aandag.

Bemestingsriglyne Bemestingsriglyne, grondontledings en, indien beskikbaar, ook blaarontledings, dien as hulpmiddels by die samestelling van bemestingsaanbevelings. Voorts moet faktore wat plantreaksies en gehalte kan beïnvloed in ag geneem word.

Die toepassing van korrekte bemestingspraktyke vir produksie en gehalte behels veel meer as slegs die toediening van stikstof, fosfaat en kalium. Dit is moontlik een van die produksie-insette wat die meeste verwaarloos word en

Enkele faktore wat plantreaksies kan beïnvloed Die meeste groentegewasse het vlak wortelstelsels. By die meerderheid groentesoorte kom 70% van die wortels in die boonste 200 mm van die grond voor. Hierdie eienskap het tot gevolg dat die gewasse baie sensitiewer vir omgewings- en grondfaktore is. Gevolglik moet gewasbestuur en verbouingspraktyke hierby aangepas word, en daar moet veral op optimale plantvoeding en waterbeskikbaarheid gelet word.

• pH van die wortelmedium: Die ideale pH [H2O] vir meeste groentesoorte is tussen 5.5 en 6.5. Deur die pH by die optimale peil te hou, word die opneembaarheid van plant voedingstowwe verseker.

• Soutinhoud (elektriese geleiding = EG) van die voedingsmedium.

• Grondverdigting en deurlugting: Gekompakteerde grond wat heel dikwels deur besproeiing of bewerking veroorsaak word, benadeel die gewas se groei.

• Plantvoedingstofinteraksies.

• Stikstofbemestingstowwe: Te veel stikstof in ’n bemestingsprogram sal sagte vrugte tot gevolg hê en rypwording van vrugte vertraag.

• Kaliumbemestingstowwe.

• Kalsium: Dit is een van die plantvoedingstowwe wat gewoonlik te min aandag van produsente kry. Kommersiële produkte voorsien, benewens kalsium, ook nitraatstikstow we aan die gewas.

• Besproeiing.

• Klimaat: Temperatuur, lig en humiditeit oefen ’n direkte invloed op die gewasse se groeitempo, lengte van die groeiperiode, blomvorming, stuifmeelstorting en vrugvorming uit.

• Oesbeskerming.

• Onkruidbeheer is van kardinale belang omdat die swakker wortelstelsel van groente baie gevoelig vir mededinging van vog en voedingstowwe is.

• Wisselbou.

• Spasiëring en saaidigtheid.

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www.fertasa.co.za ONS STAAN VIR DIE BESKERMING VAN DIE VOLHOUBARE GEBRUIK VAN KUNSMIS. Fertasa is verbind tot die bevordering van volhoubare grondvrugbaarheid en verbeterde plantvoeding.

Fertasa-lede is verbind tot: Ÿ

'n Gedragskode.

Standaarde deur 'n onafhanklike nakomingsbestuursliggaam geouditeer.

Ÿ

Gehalte produkte.

Ÿ

Toepaslike wetenskaplik-gebaseerde aanbevelings.

Ÿ

Voortgesette onderrig en verbetering.

Ÿ

Die nakoming van wetlike vereistes.

Fertasa - Fertilizer Association of Southern Africa Tel: +27 (0) 12 349 1450 | Faks: +27 (0) 12 349 1463 | E-pos: general@fertasa.co.za Reg. Nr. 1971/000012/08 | VAT Reg. Nr. 4830104164

MES CONSULTANTS - 082 563 4427

Ÿ

Kontak Fertasa by tel: +27 (0)12 349 1450 of e-pos: general@fertasa.co.za.

MAY • JUNE 2020 | VEGETABLES & FRUIT

VERPAKKING

How to close bags: some basic system options It was not until the early 1950’s that the bag closing industry changed. Before then, textile bags filled with agricultural and industrial products were typically closed by tying, wiring or being hand sewn.

I

T WAS WITH THE introduction of the Fischbein bag-closing sewing machine that a packaging revolution began. Sewing now sped up the packaging closing process and allowed paper bags to be used. However, these early sewing systems often required delicate adjustment.

Now in 2020, Buckle Packaging’s sewing systems can stitch different bag materials interchangeably without critical adjustment. Customers have the ability to select from a host of different bag types, such as paper, plastic, woven polypropylene, laminated woven polypropylene, biaxially oriented polypropylene (BOPP) material as well as netting. Closing options can be selected according to the bag material being used. In addition to stitching, other options are also available, such as heat sealing and gluing. Each type of bag-closing system offers its own combination of advantages and limitations; selecting the optimum system depends on a number of factors.

When tasked with closing bags of a product like powdered milk, there are a number of factors that need to be considered. A company must look at the production volume, the cost of the system, the bag material and the number of people available to operate that system. When bagging a powder product, one also needs to take the dust factor into consideration.

Some options Stitching is not limited to bag type, thus has the widest number of applications in closing bags of powder. Buckle Packaging offers a range of options with regard to bag stitchers. A customer can opt for anything from the entry level hand-held portable Fischbein ‘F’ stitcher to the more industrialised

in-line heavy duty systems that can run continuously.

Other machines in the Fischbein equipment range are the double needle stitcher that sews two lines; the unit with an automatic driven infeed device that folds the bag top over prior to stitching; and the unit that applies crepe paper tape over the bag top. All these options will be considered when offering the correct solution.

The company also provides non-sewing options such as the Pinch Bottom Closers (PBC6000), to close bags with pre-applied glue strips. These machines are designed for continuous production of large bags of powdered products. The machine has a high output capacity and reactivates the pre-applied glue, then creases, folds and compresses the bag top neatly and securely.

The third option is the heat sealer for powdered products that are bagged in polyethelene plastic bags. The cost of plastic bags is generally less than that of either paper or woven polypropylene bags. Recently a local manufacturer of powdered milk, looking to seal the inner poly liner and then stitch the outer paper kraft bag, took delivery of a Fischbein-Saxon Radiant 1000 continuous heat sealer. This innovative machine is ideal for sealing the plastic inner liner of multi-wall paper kraft bags as it allows for the product to be free of contamination and sealed within the inner poly liner.

This therefore is a perfect solution to seal bags of whey powder, soya and milk powder. This type of sealer is fitted with a variable speed drive and can seal many bags per minute. It joins the plastic surface at the mouth of the bag with the heated bars, while transferring heat to the bag as it is fed through the sealer.

Contact Buckle Packaging for a wide range of solutions.

29

GENERAL

Navorsing belig stamsiektes by olyfbome Daar is heelwat maniere waarop olyfboere kan keer dat stamsiektes hul boorde infekteer. Dit help onder meer om bome te snoei tydens min vog in die lug, om snoeiwond-beskermingsmiddels binne ‘n week ná ‘n snoeisessie aan te wend en om snoeirommel uit boorde te verwyder. Hierdie raad kom uit die doktorale navorsing van dr Meagan van Dyk van die Strand, wat haar doktorsgraad in plantpatologie onlangs aan die Universiteit van Stellenbosch (US) verwerf het.

“D

IE SUID-AFRIKAANSE olyfbedryf produseer olyfolie van ‘n besonderse hoë gehalte. Die onlangse Olyfsektor-ontwikkelingsplan van die Departement van Handel en Nywerheid het egter lae produksie en ‘n gebrek aan plaaslike navorsing uitgelig as leemtes waarmee die bedryf sukkel. Die doeltreffende bestuur van peste en siektes, insluitend stamsiektes, vorm dus ‘n integrale deel van ‘n poging om die lewensduur en opbrengs van bestaande olyfbome te verbeter, en om sodoende olyfproduksie in veral die Wes-Kaap te verhoog,” sê prof Francois Halleen van LNR Infruitec-Nietvoorbij, wat benewens sy werk by die LNR ook ‘n buitengewone assosiaat-professor in die US se Departement Plantpatologie is.

Volgens prof Halleen het stamsiektes gewoonlik ‘n lang, uitgerekte uitwerking op bome. Dit begin by die afsterwing van lote en versprei mettertyd na die res van ‘n boom. Hy reken egter dat boere wat ‘n goeie oog op hul bome hou en dit goed bestuur, steeds goeie oeste kan kry.

Dr Van Dyk het gedurende haar navorsing 33 funguss pesies in gevestigde boorde en kwekerye geïdentifiseer wat moontlik stamsiektes veroorsaak. Sy het ook ‘n nuwe Pseudophaeomoniella-spesie geïdentifiseer. Dié kom wydverspreid in boorde en in ‘n mindere mate in kwekerye voor en word beskou as die een enkele patogeen wat die meeste skade ten opsigte van stamsiektes sou kon aanrig.

Snoei Snoeiwerk speel ‘n belangrike rol in die instandhouding van boorde en verbeter uiteindelike olyfproduksie. Dit word ook gedoen om siektes te beheer. Sodoende word die hoeveelheid sonlig in ‘n boord verhoog, asook die lug wat daardeur kan beweeg. Dit help ook dat plaagbeheermiddels eenvormig oor bome aangewend kan word.

Snoeityd is egter ook die tyd op ‘n olyfplaas wanneer bome veral vatbaar is vir besmetting. Volgens dr Van Dyk se navorsing is bome die vatbaarste binne die eerste week nadat hulle gesnoei is. In sommige gevalle het besmettings deur die Pseudophaeomoniella-spesie egter tot 42 dae later steeds voorgekom.

Nie een enkele seisoen (winter of lente) het uitgestaan waarin dit noodwendig beter is om snoeiwerk te doen in ‘n poging om besmetting deur stamsiektepatogene te vermy nie. Hoe meer vog in die lug was, hoe groter was die kans egter dat besmetting sou plaasvind.

30

Dr Meagan van Dyk het in 2018 die kans gekry om bevindinge rondom haar navorsing oor olyfboomstamsiektes voor te dra by die internasionale kongres oor plantpatologie in Boston in die VSA. Foto: Francois Halleen.

Die bruin V-vormige patroon is tipies van die skade (bekend as ‘n kanker) van ‘n stamsiektepatogeen aan ‘n besmette olyfboom in ‘n boord. Foto: Francois Halleen.

MAY • JUNE 2020 | VEGETABLES & FRUIT

ALGEMEEN

Dr Van Dyk het die volgende raad oor die snoeiproses: • Snoei wanneer daar min vog in die lug is, ongeag van watter seisoen dit is.

• Wend snoeiwondbeskerming aan binne die eerste week nadat ‘n tak gesnoei is.

• Dit help nie net om groter takke wat van besmette bome afgesny is uit boorde te verwyder en te verbrand nie.

Kleiner takke wat gewoonlik opgekerf word moet ook verwyder word, want hulle kan steeds ‘n skuiling bied vir mikrobes en verdere besmettings veroorsaak.

Snoeiwondbeskerming Met die gebruik van snoeiwondbeskerming het dr Van Dyk die volgende bevind: • Onder hoë vlakke van besmetting het Tree Seal en Coprox Super/Bendazid die beste beskerming gebied teen die Pseudophaeomoniella-spesie.

• Tree Seal verskaf ook goeie beskerming aan snoeiwonde indien besmettingsvlakke laag is.

• Wanneer besmettings min is, help MT1, ‘n Trichoderma-gebaseerde produk wat deur die US Departement Plantpatologie ontwikkel word, om die voorkoms van die Pseudophaeomoniella-spesie binne die eerste week nadat bome gesnoei is te verminder.

Dr Meagan van Dyk (middel), saam met sommige van haar studieleiers, dr Chris Spies van die Landbounavorsingsraad en prof Lizel Mostert van die Universiteit van Stellenbosch, tydens ‘n opname by ‘n kwekery. Foto: Francois Halleen.

Dr Van Dyk se proewe met MT1 is op Frantoio-olyfbome gedoen.

“Volgens die bevindinge lyk dit asof MT1 doeltreffend gebruik kan word om stamsiektes te beheer wat sou kon ontwikkel op snoeiwonde in goed-bestuurde ‘Frantoio’-boorde wat nie hoogs besmet is nie,” sê sy.

Sy sal graag verdere navorsing wou sien oor die gebruik van snoeiwondbeskermers op ander olyfkultivars in verskillende klimaats- en geografiese sones, en hoe doeltreffend hulle ook ander olyfstampatogene soos Botryosphaeriaceae- en Phaeoacremonium-spesies kan beveg.

Kwekerye Gedurende haar studies het dr Van Dyk ook opnames by twee kwekerye gedoen. Sy het gevind dat sommige jong olyfbome in potgrond geplant is wat met Phaeoacremonium parasiticum en Pleurostoma richardsiae besmet was.

“Die feit dat sommige 1- tot 2- jaaroue boompies en grond uit kwekerye met belangrike stamsiekte-patogene besmet was, wys net hoe belangrik dit is om baie streng siektebeheermaatreëls te hê. Dit is nodig sodat kwekerye siektevrye plantmateriaal aan boere vir aanplanting kan verskaf,” sê dr Van Dyk. “Dit sal nodig wees om verdere ondersoek in te stel om te kan uitvind of dit slegs geïsoleerde gevalle was, en of chroniese besmettings in kwekerye voorkom.”

Dr Van Dyk het die meeste van die stamsiekte-patogene wat sy in kwekerye opgespoor het gevind op die dele van jong plante wat in potgrond begrawe was.

“Dit lyk asof die meeste besmettings ontwikkel in die onderste (basale) dele van die steggies wat direkte kontak het met perliet, grond en water,” voeg sy by. “Ek sou graag verdere navorsing wou doen om uit te vind watter van hierdie komponente besmet is en hoe mens dit kan verhoed of ontsmet.

GROENTE & VRUGTE | MEI • JUNIE 2020

Snoeiwerk speel ‘n belangrike rol in die instandhouding van boorde en verbeter uiteindelike olyproduksie.

“Hierdie studie het heelwat nuwe kennis tot gevolg gehad oor olyfboomstamsiektes, die patogene wat dit veroorsaak, asook die verspreiding en beheer daarvan. Dit kan gebruik word om beter bestuurstrategieë te ontwikkel om stamsiektes in olyfbome in Suid-Afrika te beperk,” sê prof Lizel Mostert van die US se Departement Plantpatologie.

31

WETCIT A single product with multiple uses

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More than 600 trials over 15 years, who else can claim this?

Recommendations backed by local R&D team

Unique next-generation patented technology Value to agent & grower

Safe, highly compatible with other chemistry.

Leaves no residue.

www.oroagri.co.za Tel: 021 850 0667 info_sa@oroagri.com

GROW SUSTAINABLY

Registration (ActNo. 36 of 1947) L10448 CAUTION: WETCIT DUO contains 50 g/L Orange oil and 68 g/L Non-ionic surfactant. CAUTION Copyright © JANUARY 2020 • All rights reserved. WETCIT DUO, ORO AGRI and OROWET are registered trademarks of Oro Agri SA (Pty) Ltd, P.O. Box 475, Somerset Mall 7173.

ALGEMEEN

Winter sprays essential for better pest control Tertia van Wyk ORO AGRI SUB SAHARA AFRICA

Spraying during the dormant period is an essential step to achieve low pest pressure in the orchard.

Effective spray coverage of the entire architecture of the tree is possible and the impact on beneficial organisms is at its minimum.

P

ERNICIOUS SCALE IS A cosmopolitan pest and is distributed widely in Southern Africa. It is highly polyphagous and has been found on about 200 different host plants with apple, pear, plum and peach trees being highly susceptible.

Scales are sucking insects that extract plant sap and inject toxin into the plant during feeding. The toxin breaks down plant cells, causing discolouration around the feeding site.

Pernicious scale occurs on the branches, shoots, leaves and fruit of infested plants. They overwinter as immobile immature scales on trees, predominantly in the black cap stage.

Development resumes in spring when winged males emerge to mate with wingless females. With three to four overlapping generations per year, all life stages of the insect are present on trees throughout the year. In warmer climates, gravid females may also survive the winter.

To prevent problematic outbreaks of scale in the growing season, it is vitally important to reduce the overwintering population to a minimum. Since coverage of the trunk and main scaffold branches of trees are critical for effective control of scale insects, spray applications during the dormant phase of the crop is recommended.

Wetcit Duo At low rates, Wetcit Duo is a multi-purpose surfactant effective in improving wetting and spray coverage. The product can be used as a surfactant with pesticides, herbicides and foliar nutrients.

At higher rates it is a registered bio-pesticide providing broad spectrum control of insects, mites and diseases. Wetcit Duo can be used in Integrated Pest Management systems, as it has no chemical residue with minimal impact on beneficial insect populations.

Since it is a contact pesticide with no residual activity, good contact with the target organism as well as correct application timing is required. It is advised to monitor pest development and aim for the immature stages of the target organism.

The efficacy of Wetcit Duo in controlling Pernicious scale was demonstrated in a trial done on pioneer plums in the 2017 season in the Western Cape, where dormant and early season sprays of Wetcit Duo at 250 ml/hl were primarily targeted at immobile immature stages. Two late dormant sprays (early bud swell and green bud) resulted in a 60% reduction in scale infested fruit at harvest (28 November). Following these dormant sprays up with a further two early in-season sprays (90% petal fall and 40 days later) resulted in 81% reduction in infested fruit at harvest.

GROENTE & VRUGTE | MEI â&#x20AC;˘ JUNIE 2020

Wetcit Duo can be used in Integrated Pest Management systems as it has no chemical residue with minimal impact on beneficial insect populations.

Percentage Pernicious scale infestation on fruit @ harvest 28 November 2017 16 14 12

10 8 6 4 2 0 Untreated Control

WETCIT DUO @ 250mL/hl 4 Sprays

WETCIT Duo @ 250mL/hl 2 Sprays

Pioneer plums - Western Cape Application dates: 3 & 9 Aug, 15 Sep, 24 Oct. 2017.

Percentage Pernicious scale infestation on fruit at harvest 28 November 2017.

Summary Pesticide applications during the winter and early season are essential measures to ensure low pest pressure in the coming season. When a Pernicious scale infestation occurred on fruit during the previous season, it is recommended that control measures be put into place during the dormant phase in preparation for the coming season.

Wetcit Duo is a versatile surfactant and biopesticide that has little negative impact on beneficial organisms and is an excellent mixing partner for broad spectrum insect and disease control whilst optimising spray application efficacy.

References Prinsloo, G.L. & Uys, V.M. (2015). Insects of Cultivated Plants and Natural Pastures in Southern Africa, The Entomological Society of Southern Africa.

Mague, D. (1980). Fruits IPM Fact Sheet: San Jose Scale, Tree Fruit IPM, Insect Identification Sheet No. 12, New York State IPM Program.

For more information or any technical questions, contact ORO AGRI on 021 850 0667 or e-mail: info_sa@oroagri.com or visit www.oroagri.co.za ORO AGRI, OROWET and WETCIT-DUO are registered trademarks of ORO AGRI SA (Pty) Ltd.

33

GENERAL

Impressive increases in productivity Katopé Kiepersol in Mpumalanga.

“The productivity of our drivers has improved by at least 30% since FarmTrack has been installed on our tractors,” says André Bam of Katopé Kiepersol in Mpumalanga.

K

34

ATOPÉ KIEPERSOL HAS 235 hectares of avocados and 23 hectares of macadamias and is part of the Fruit Farm Group with fruit farms throughout South Africa, as well as abroad. FarmTrack is a GPS tracking device fitted to tractors and farm vehicles to track their movements. They have been installed on ten tractors at Katopé Kiepersol over the past three years and the resulting increased efficiency and productivity are impressive.

According to André, FarmTrack is not used as a policing system to watch their tractor drivers all the time, but rather as a management tool that adds value.

“The productivity of each driver has increased by approximately one hour per day since installing the devices on the tractors, as they are now aware that there is a record of where they were and for how long,” explains Bam.

He adds that FarmTrack has given him peace of mind, knowing that he is now in control of his tractors by monitoring the activities of a tractor at any given time and being able to gain access to the information in real time via the internet.

“Our avocados are exported to Europe while our macadamias are destined for the Chinese, European and USA markets. To enter and to continue doing business in these markets requires complying with strict standards pertaining to chemical applications. FarmTrack allows us to monitor and manage spray accuracy of the fruit as well as measure the speed of spraying and prevent any rows in the orchards being missed,” says Bam. Contact FarmTrack for information: tel: 021 880 1163 or visit www.farmtrack.co.za.

ALGEMEEN

Swamsiektes kán sonder chemikalieë beheer word

Strenger vereistes deur die Europese Unie oor die gebruik van chemiese middels om swamme te beheer het gelei tot navorsers se bevinding dat warm water en gis dieselfde resultate as ‘n chemiese swammiddel gee.

P

ROF MARK LAING van die Universiteit van KwaZulu-Natal het by die Suid-Afrikaanse Avokadokwekersvereniging (SAAKV) se navorsingsimposium gesê hulle metode om siektes op geoeste avokado’s is dié nuwe pasteuriseringsproses vir alle vars produkte.

Die metode behels kortliks dat avokado’s vir ‘n kort tydperk aan ‘n baie warm oplossing met gis daarin gedompel word. Volgens prof Laing het die Grieke hierdie metode met warmwaterbehandeling reeds ongeveer 2 000 jaar gelede toegepas en die Israeli’s het dit onlangs aangepas.

Die warm water aktiveer ‘n plant se weerstand en die gis beskerm die vrug se skil, maar gaan nie in die vrugvleis in nie. Prof Laing sê hulle metode is by verskillende produksiegebiede en op die algemeenste avokadokultivars getoets.

Tot dusver is prochloras gebruik om swamme wat antraknose en stingelendvrot veroorsaak, te beheer. Die

plaaslike avokadobedryf ly volgens prof Laing verliese van sowat 50% weens dié twee swamprobleme. Dieselfde probleem en verliese word in ander wêrelddele ervaar.

Die Europese Unie het die neerslagvlak van prochloras op avokado’s sodanig aangepas dat dit van 2020 af nie meer gebruik kan word nie. Navorsing was gevolglik daarop gemik om alternatiewe beheer vir die belangrikste naoessiektes op avokado’s te vind.

Ná proefnemings met verskillende temperature en tye op die kultivars Hass, Fuerte en Pinkerton, het die navorsers bevind die kombinasie van 56ºC en 10 sekondes het die doeltreffendste resultate gegee. Dié behandeling het nie die vrugte benadeel of beskadig nie.

Prof Laing se span het meer as 100 soorte gis beproef en daaruit drie gekies. Een van die suksesvolste soorte gis was van sitrus afkomstig.

Nuwe wortelstokke gaan kwekers se vriende word Twee nuwe wortelstokke vir avokadobome wat ná jare se navorsing ontwikkel is, gaan die volgende 25 jaar “kwekers se vriende” wees.

W

ESTFALIA SE TEGNOLOGIESE dienste gaan die wortelstokke met die kodename Merensky 5 en Merensky 6 kommersieel beskikbaar stel. Produsente wat dit koop sal planttelersregte daarop moet betaal, sê Theo Bekker van Westfalia.

Hy het by die Suid-Afrikaanse Avokadokwekersvereniging (SAAKV) se navorsingsimposium gesê navorsing duur normaalweg 20 tot 25 jaar om finale aanbevelings oor ‘n nuwe wortelstok te kan maak.

Die vroeëre gebruik om wortelstokke uit sade te ontwikkel, het bykans heeltemal in onbruik geraak. Volgens Bekker bied gekloonde wortelstokke die voordeel van eenvormige produksie en verdraagsaamheid teen wortelsiektes.

Saam met die avokadobedryf se uitbreiding word nie net produsente se uitdagings meer nie, maar ook die verskeidenheid daarvan. Tot ‘n mate kan die regte wortelstok die uitwerking van hierdie uitdagings op die produsent se uitgawes en inkomste verlig.

GROENTE & VRUGTE | MEI • JUNIE 2020

Westfalia se tegnologiese dienste doen reeds die afgelope sowat veertig jaar navorsing oor wortelstokke. ‘n Deel van die evaluering is om die wortelstokke met bedryfstandaarde te vergelyk en dit onder alle groeitoestande in Suid-Afrika te beproef. Dit word ook op produsente se plase getoets.

Die SAAKV het die ontwikkeling van nuwe wortelstokke gedeeltelik befonds. Die twee nuwelinge is volgens Bekker nog nie die kitsoplossing van wortelstokke nie, maar dit presteer in alle verbouingsgebiede van avokado’s. Proefnemings duur voort, ook met ander wortelstokke wat nog nie uitgekies is nie.

Kwekerye wat daarin belangstel kan met Westfalia in verbinding tree. Bekker raai produsente ook aan om die nuwe wortelstokke by kwekerye te bestel en dit onder hulle eie plaastoestande te beproef. Hulle kan ook studiegroepe bywoon waar proefpersele met die nuwe bome besoek word en vergelykings met ander wortelstokke getref word.

35

GENERAL

Blueberry boom continues Justin Mudge

South Africa’s blueberry exports for 2019/20 grew by more than 50% on the previous year, setting a new industry record and continuing the industry’s remarkable growth story.

South Africa’s blueberry exports for 2019/20 grew by more than 50%.

I

N THE LAST FINANCIAL year, South Africa exported 12 282 tons of blueberries. This represents a 53,5% increase on the previous year’s 8 000 tons.

Almost 70% of South Africa’s blueberries are destined for export markets. Since 2013 this has led to a growth in export revenues from R133 million to well over R1 billion.

This growth has led to an equally significant growth in employment opportunities. Employment in the industry more than quadrupled from about 1 000 jobs in 2014 to more than 5 700 in 2018. This number has since risen to more than 8 000 jobs in the past two years.

This increase in export numbers is a rare piece of good news in the midst of the national Covid-19 lockdown, which is expected to exact a heavy toll on economic growth and jobs.

The agricultural sector remains relatively resilient during this pandemic, as international trade continues with few limitations on the transportation of goods, especially food.

In addition, global demand for blueberries remains strong due to the fruit’s well-known nutritional and immune boosting properties – an increasing priority for healthfulness of conscious consumers around the world.

However, for the berry industry to improve on its export figures in the year ahead, and to create more South African jobs in the post Covid-19 environment, certain conditions will need to be met.

Firstly, expanding market access into demand markets is a priority.

The United Kingdom imported about 46% of South Africa’s blueberries in this last year, with the rest of Europe accounting for another 46%. Less than 5% of the fruit went to markets in the Far East.

Expanding access to the Eastern markets could create an additional 12 000 jobs in South Africa, which would more or less double projected employment in the industry by 2023.

Secondly, there need to be an increase in air freight out of the country, particularly for commodities with a short shelf life.

Currently, raspberry exporters are experiencing extreme difficulty with exporting their berries as a result of limited air freight. The resulting delays diminish the quality of the product reaching their destinations, compromising South Africa’s stellar international reputation.

The peak season for blueberry exports (which account for almost 90% of all berry exports) will be between October and November. A failure to resolve these impediments will negatively impact the berry industry.

36

The United Kingdom imported about 46% of South Africa’s blueberries in the last year.

Expanding access to the Eastern markets could create an additional 12 000 jobs in South Africa.

The peak season for blueberry exports (which account for almost 90% of all berry exports) will be between October and November.

The South African Berry Producers Association is proud of the industry’s growth, and its contribution to the South African economy in terms of jobs and export revenue.

“We are working harder than ever to make sure that the industry surpasses its projections from season to season; creating more jobs, exporting more fruit and bringing desperately needed export revenue into the country,” said Justin.

MAY • JUNE 2020 | VEGETABLES & FRUIT

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ INSECT COLUMN

False codling moth (Lepidoptera: Tortricidae)

False codling moth (FCM), Thaumatotibia leucotreta, is a very important pest of fruit and vegetable species in South Africa. Since this pest is also a quarantine pest in Europe and the Americas, its presence in export produce is not allowed. FCM was previously known as Cryptophlebia leucotreta and can easily be confused with codling moth, Cydia pomonella.

Nozibusiso Maphumulo IPM-PROGRAM, NORTH-WEST UNIVERSITY POTCHEFSTROOM

e-mail:mashimanenozi03@gmail.com

False codling moth classification:

Class: Insecta (Insects) Order: Lepidoptera (moths and butterfIies) Family: Tortricidae Genus: Thaumatotibia Species: Leucotreta

Figure 1: Eggs (left) and larvae (right) of false codling moth (www. sun.ac.za).

F

MC IS A POLYPHAGOUS insect pest with more than 70 host plants from 40 families. It attacks numerous important export crops in South Africa. Citrus, stone fruit, avocados, pomegranates, persimmons, macadamias and hot peppers are some of the cultivated host plants of the FCM. It also infests grapes, litchis, cotton and maize, but it is of secondary importance on these crops.

Eggs of the FCM are flattish and oval in shape with a translucent white colour. They are very minute in size with a length of 0,9 mm. There are five instars (larval stages) of the FCM. The early instar larva is spotted and pale in colour with a brownish-black head, while the late instars are light pink with a light maroon-coloured head. The length of the final instar is 15 mm.

Pupae are formed in a tough cocoon in the soil. It is initially soft and cream in colour and turns yellow to dark brown as it hardens. The length of the pupa is 11 mm. Adults are greyish-brown to dark brown or black in colour, with a length of 6-9 mm. They are distinguishable by a triangular marking on the forewings, with a C-shaped black mark on top of it. Hindwings are lighter grayish-brown and darker on the outer edges. Males have a wingspan of 15-16 mm, and that of females is 19-20 mm.

Eggs are laid either singly or in batches on the surface of

Figure 3: Adult female of false codling moth (www.sun.ac.za).

38

Figure 2: Pupal case of false codling moth, covered in soil particles (www.sun.ac.za).

fruit. Females lay 100-400 eggs. Eggs hatch within 9-12 days in winter, and 6-8 days in summer. After hatching, the larvae bore into the fruit. All larval instars develop inside the fruit.

The duration of larval stages takes 35-67 days in winter and 25-35 days in summer. Final-instar larva drops to the ground, spins a cocoon and pupates in the soil.

Moths emerge within 29-40 days in winter and 21-24 days in summer, but the average duration of the pupal period is usually two weeks. FCM has 2-10 overlapping generations per season, without a winter diapause. The duration of the FCM life cycle ranges from 30-174 days depending on environmental conditions.

The damaging stage of the FCM is the larval stage as it burrows into the fruit. The initial penetration holes of the larvae are usually difficult to notice as they are minute. When larvae emerge from the fruit to go into the pupal stage in the soil, it leaves a larger noticeable hole. This damage and these holes can result in premature ripening and fruit drop. Damage may differ depending on the type of crop.

Orchard sanitation and biological control using egg parasitoids are preventative measures used against FCM in citrus.

CrleGV virus, mating disruption, sterile insect technique and attract-and-kill techniques are control measures employed against the FCM. Chemical control should be the last resort for controlling the FCM.

MAY â&#x20AC;˘ JUNE 2020 | VEGETABLES & FRUIT

O n t gi n

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Maak gebruik van die spesialiste UITGEWERS VAN: Koringfokus / Wheat Focus: UITGEWERS VAN: Die spesialistydskrif vir kleingraan in Suid-Afrika Koringfokus / Wheat Focus:

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Subtrop Journal: Subtrop Journal: mango- en lietsjiekwekers Joernaal vir avokado-,

Joernaal vir avokado-, mango- en lietsjiekwekers

Navorsingsjoernale: Navorsingsjoernale: SA Avokadokwekersvereniging, SA Avokadokwekersvereniging, SA Mangokwekersvereniging, SA Mangokwekersvereniging, SA Makadamiakwekersvereniging enen SA Makadamiakwekersvereniging SA Lietsjiekwekersvereniging.

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