Vegetables & Fruit - March/April 2022 by Vegetables & Fruit

SINCE 1988

MAART • APRIL 2022

Macadamia expo brings visitors from far and wide R44,00

(BTW ingesluit) ander lande uitgesluit (Including VAT) other countries excluded

No 206

BROCCOLI & CAULIFLOWER RANGE GONGGA

KAMINO

Domed shaped heads Very good heat tolerance Small-medium sized beads Maturity is 70-80 days in summer

High yielding variety for summer conditions Maturing 64 - 74 days from transplant, depending on area Excellent quality, white colour, very well tucked curds Strong frame size and great curd cover Suitable for loose and prepack heads market

VELOZ

SPACEDREAM

Domed shaped heads Very good cold tolerance Small-medium sized beads Maturity 75 - 100 days in winter

High yielding variety for winter conditions Maturing from transplant, 90-110 days depending on cold and area Excellent quality, smooth texture, very well tucked Strong frame size and great curd cover Suitable for loose and prepack heads market

STAR 2204

STAR 4418

Medium to large frame with good disease resistance Excellent quality head with few sideshoots Very high marketable yield potential Firm, dome-shaped heads with short to medium florets

Excellent quality, smooth texture, very well tucked Early maturing (75 - 85 days in summer) with a medium frame High marketable yield potential Very tightly wrapped heads with intense white colour

11 22 Edition 206

ISSN 1015-85 37

VOORBLAD Purple Cauliflower botanically classified as Brassica oleracea var. botrytis, is a colorful, cool-season hybrid variety belonging to the Brassicaceae family.

NEWS 4

New trade opportunities for South African commodity importers

New market in China for South African pear fruit

Haal die raaiwerk uit gewasoplossings

Wine grape harvesting of to a slow start

Fighting locust plagues

TLU SA welcomes new members

EDITORIAL Willie Louw (Group editor) Carien Daffue (Editor) 018 293 0622 info@mediakom.co.za PO BOX 20250, Noordbrug, 2522

MACADAMIAS 18

Macadamia expo brings visitors from far and wide

SAMAC macadamia crop forecast 2022

Modern day macadamia irrigation and ridging

Macadamia expansion

BRASSICAS

Span brassicas in vir aanvullende plaagbeheer

From grand to super

Loop katvoet vir dikvoetsiekte

Protecting crops takes careful planning

Appels en pere om op trots te wees

South African citrus growers export 161,6 million cartons

DESIGN Mercia Venter studio.chatnoir@gmail.com

Bly ingelig en volg ons op Facebook. Keep up to date and follow us on Facebook. - Groente en Vrugte/ Vegetables and Fruit - www.facebook.com/GroenteenVrugte/

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GROENTE & VRUGTE | MAART • APRIL 2022

New trade opportunities for South African commodity importers DP World Maputo has developed and implemented a new and unique supply chain solution that provides Southern African importers of fertilizer and other similar commodities an effective and reliable option using the Maputo Corridor.

he Port of Maputo is already established as an important export gateway for various bulk mineral commodities, which are currently delivered from South Africa. This presents a unique opportunity for South African fertilizer importers, to take advantage of the high trucking capacity returning empty to South Africa. Together with the Maputo intermodal container depot (MICD), DP World Maputo has implemented a solution where transit import containers are unloaded at DP World Maputo’s container terminal, the cargo de-stuffed and cross docked into waiting tipper trucks at MICD. It is then moved in bond to South Africa, with final clearance done en route at Lebombo/ Komatipoort and moved directly to the customer’s door for final delivery. The successful implementation of this new transit import product highlights DP World's commitment to providing the South African hinterland an efficient and reliable logistics gateway.

New market in China for South African pear fruit

he Department of Agriculture, Land Reform and Rural Development (DALRRD) recently announced that fresh pear fruits from South Africa can now be exported to China. The South African government and the general administration of customs of the People’s Republic of China (GACC) have signed the protocol of phytosanitary requirements for the export of fresh pears from South Africa to China, effective from January 2022. The signed protocol for phytosanitary requirements gives guidance on procedures and processes to be followed for the exportation of the fruit. The initial request for market access of fresh pear started

simultaneously with that of apples in 2008. However, the pest risk analyses (PRAs) for these products were separated and the GACC started with apples. The pears’ PRA started in 2015 after conclusion of the apple protocol in 2014. Since then, there have been bilateral exchanges of technical information between DALRRD and GACC. The draft protocol was finalised in 2020 after DALRRD and GACC agreed on technical issues. The final protocol was signed by ministers of the two countries. All fresh pear fruit to be exported from South Africa to China will have to meet all agreed and applicable phytosanitary requirements, as well as all food safety rules and health standards as defined by GACC. The fruit must also be free of the quarantine pests of concern to China as listed in the protocol. Pear orchards, packhouses and cold storage facilities wishing to export their fruit to China must be registered with the DALRRD and approved by both the GACC and DALRRD. The DALRRD in cooperation with various commodity industries will continue to strive for opening new market opportunities to strengthen the country’s agricultural sector and for South African commodities to compete with that of other countries in international markets.

VEGETABLES & FRUIT | MARCH • APRIL 2022

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Haal die raaiwerk uit gewasoplossings Landbousukses hang toenemend van ingeligte en akkurate besluitneming af - van watter gewas en kultivar op ‘n spesifieke land geplant moet word tot die korrekte plantvoeding en gewasbeskermingsmaatreëls op die regte tyd.

andbounavorsingsinstansies in Suid-Afrika het oor die afgelope aantal jare heelwat kapasiteit verloor. Praktiese navorsing vanuit ’n neutrale oogpunt, ly ongelukkig daaronder. Die uitsondering is ’n instansie soos die Wes-Kaapse Departement van Landbou wat steeds goeie werk op kleingraan en kanola doen. Ook ander instansies lewer kwaliteit navorsing en daarvoor is daar groot waardering. “Ons het ‘n groot gebrek aan onafhanklike, kredietwaardige data oor watter van die vele gewasbeskermings- en plantvoedingsopsies die beste resultate in ‘n spesifieke stel omstandighede gee,” sê Dirk van Eeden, tegniese bemarkingspesialis by InteliGro. InteliGro het toegang tot ’n groot verskeidenheid produkte met hoë kwaliteit wat deur multinasionale en geselekteerdere generiese maatskappye verskaf word. Uit hierdie produkarsenaal word die beste tegniese oplossings vir produsente saamgestel. “Die uitdaging is om die besluit wat rondom ‘n spesifieke oplossing geneem word, met relevante data te rugsteun,” sê Van Eeden. Teen hierdie agtergrond het InteliGro vier jaar gelede die

Intelekt Solutions-projek van stapel gestuur om sy eie kredietwaardige wetenskaplike data te ontwikkel wat kliënte met beter besluitneming kan help. InteliGro se navorsing onder die Intelekt Solutions-vaandel is aanvullend tot die navorsing wat universiteite en die Landbounavorsingsraad (LNR) doen. Die maatskappy maak ook seker dat produsente toegang tot die inligting kry deur demonstrasie- en inligtingsdae aan te bied. “Ons sien onsself as ‘n leier in die ontwikkeling en oordrag van waardevolle, akkurate inligting,” verduidelik Van Eeden. “Ons bestaansreg berus op die doelwit om uit al die beskikbare produkte, die beste tegniese oplossings vir produsente aan te beveel en sodoende waarde op die plaas toe te voeg, waar alles begin.” Hy beklemtoon dat die navorsing ‘n langtermynbehandeling is omdat nuwe produkte voortdurend ontwikkel word, en omdat die natuur dinamies en organismes uiters aanpasbaar is. Een van landbou se grootste uitdagings, naamlik om bestaande chemiese produkte teen die opbou van weerstand te beskerm, kry spesifieke aandag in Intelekt Solutions se navorsing.

Wine grape harvesting of to a slow start

he 2022 wine grape harvesting period has had a slow start as cooler weather conditions in the run-up to this year’s peak season have slowed down ripening. Good cold weather conditions and above-average rainfall in winter replenished water resources and built up sufficient cold units. The cooler weather also meant that the growing stages across all regions, from budding to flowering, flowering and ripening, took place much later than normal. Although heat accelerated ripening in December and January, vineyards were still not able to catch up. “At long last, producers have started harvesting in all ten wine grape growing regions, with some variation between the respective regions in terms of upward and downward trends due to the geographical diversity of our industry,” says Conrad Schutte, manager of Vinpro’s consultation service. According to the third estimate by viticulturists and producer cellars issued by the SA Wine Industry Information and Systems (SAWIS) and Vinpro midFebruary 2022, the 2022 wine grape harvest will still be smaller than in 2021, in line with the previous estimate in January 2022. The decrease is mainly attributed to the uprooting of vineyards, fungal pressure due to unprecedented rainfall and sunburn damage due to heat peaks during January in certain regions.

VEGETABLES & FRUIT | MARCH • APRIL 2022

Fighting locust plagues Santam, South Africa’s general insurer, donated R100 000 to the Agri SA Disaster Relief Foundation to mobilise aerial assistance in the Northern Cape to control large-scale locust outbreaks.

he ongoing locust invasion of veld and farmland in South Africa, by bands of wingless nymphs, wreaked havoc on a wide area in the vicinity of Vosburg, Van Wyksvlei, Prieska, Marydale, Victoria West and Hopetown. The outbreak is attributed to changes in weather patterns, including warm weather, excellent veld regrowth, and humid conditions. Santam’s donation will help Agri SA to scale up its locust combatting efforts to better mitigate the impact. Daniel Stevens, Head of Santam Agriculture, says that the affected areas are too big and the current equipment too insubstantial to fight the locust plague effectively. Locusts are causing severe damage to the veld, and, without urgent aerial support, the looming crisis will have dire consequences for the livelihoods of farmers, their workers, and rural economies. The contribution will help to prevent further damage to crops and the destruction of livestock pastures. Spraying the locust populations requires covering more than 4 000 hectares of land across the Northern Cape; the farmers’ capacity

to fight the swarms is severely under pressure due to the extent of the outbreaks in the province. “Through this initiative, we can mitigate job losses and protect food security,” says Stevens. “We urgently call on the private sector to contribute financially and assist in putting plans in place to eradicate the locust swarms. This is a publicprivate partnership in practice. “The key to successful eradication is to destroy the locusts before they turn into fledglings. Locusts can cover more than 100 km per day once they develop wings, making them difficult to track and destroy. This is a great concern for organised agriculture and might result in a disaster should locusts fly into irrigation and crop areas in other provinces, such as the Free State, North West, and Eastern Cape.” Santam is working closely with Agri SA to control the hoppers in the affected arrears to reduce the size of the population. Any sightings must be reported as soon as possible to the local district locust officer or the Department of Agriculture.

TLU SA welcomes new members A

fter almost two decades in the service of Transvaalse Agricultural Union (TLU SA), Maj. Gen. Chris van Zyl decided it's time to pass the baton of service to the next generation. “Working at TLU SA initially, was definitely a big challenge and adjustment after my years in the army. However, we all work together for an important cause, and it ensured that all the different personalities found each other for the greater purpose. All residents of our country must be involved and therefore organisations such as TLU SA are of great importance. The current situation means that one farmer's fate, is also the fate of his neighbour.” He urged South Africans to get involved and said that it is necessary for South Africans to speak with one voice about critical issues. TLU SA welcomes Dr Gawie Lötter and Mauritz Lombard to the team. Dr Lötter has years of experience in the South African Army. He left the army with the rank of Colonel and then made his mark in the academic world as a professor of strategic communication. “Each of us is aware of the many challenges that the South African farmer is currently facing. We who still can and have the ability to help and support the farmer, whether by providing timely and accurate information, support, motivation, advice, and good open honest communication, have the duty, if the opportunity arises, to do so with loyalty and pas-

GROENTE & VRUGTE | MAART • APRIL 2022

sion,” said Dr Lötter. “This position specifically caters for that. Representing and promoting the interests of the members of TLU SA is the primary function of this post. For this I have a deep-rooted understanding and passion as I grew up on a farm. To serve in this position creates the opportunity to make a difference in the life of every farmer and his family.” Lombard also gained experience in the Army and finished with the rank of Lt Col. He also practiced as a legal practitioner. “After the years I have practiced as a lawyer, the position at TLU SA presents me with the challenge of making a meaningful contribution to the community by nurturing and promoting the interests of agriculture and in particular the farmer. I look forward to serving the farming community with my knowledge and experience and believe that I can make a meaningful contribution,” said Lombard. “It is with great gratitude that we say goodbye to Chris and wish him all the best. We welcome the exceptional expertise that Gawie and Mauritz will add to TLU SA. We are excited about the contribution they can make to our members, but also the agricultural community at large. In addition to other tasks, Dr Lötter provides administrative support for the safety committee and Lombard to the local government committee,” said Mr. Bennie van Zyl, TLU SA General Manager.

MACADAMIAS

Macadamia expo brings visitors from far and wide The AmberMacs factory is located in White River, Mpumalanga, at the heart one of the largest macadamia growing regions in the world. Recently the factory was the setting for a very successful expo lasting two days, where producers and major players in the macadamia industry came together for two days to focus on macadamia production.

T The AmberMacs team responsible for a successful expo is Andri van den Bergh, Phil Moufarrige and Annatjie Luttig.

Anneri Potgieter, Amorentia Nursery Manager

Jurie Duvenhage and Charles Parsons from Knittex South Africa.

he expo had to be rescheduled from 2021 due to Covid, but according to the organisers this gave them the opportunity to accommodate a lot more people per day. More than 2 800 interested people streamed through the gates to experience some big brand exhibitors and listen to researchers and experts on important issues playing a role in the industry. Industry experts gave presentations on relevant issues in the industry. Michael Esmeraldo, Netafim South Africa’s sales manager for the northern region, talked about modern day macadamia irrigation and ridging. Dr. Schalk Schoeman presented the latest findings regarding nutborer research and dr. Elsje Joubert presented how to control the macadamia nutborer, stink bugs and thrips. On day two there where presentations by Dorran Bungay on the importance of on-farm curing and Ockert Botha explained the importance of soil information in planning and managing macadamia orchards. Mark Penter spoke about nut quality and cultivars. With a total of 165 exhibitors, producers had the opportunity to visit some of the industry leaders and received advice on challenges facing them on a day to day basis. TO PAGE 10

The team from Agriplas: Marius Smit, Pieter Joubert, Sanette Carrick, Nico von Bargen, Jip Better en Eben Ferreira.

VEGETABLES & FRUIT | MARCH • APRIL 2022

PROTECTING YOUR

CROPS FROM THE

wind, sunburn, hail damage, birds & larger insects

MACADAMIAS

Macadamia expo brings visitors from far and wide FROM PAGE 8

One of these exhibitors, Knittex South Africa, was established in 1964 and is known as a leader in the manufacturing and supply of knitted synthetic fabrics / shade net used in the agricultural, domestic, industrial, civil and mining industries. As one of Southern Africa’s longest established suppliers to the macadamia industry, they have built a reputation for reliability and quality. Another exhibitor, Amorentia Nursery, has nearly 50 years of experience in macadamia tree and orchard development. They offered growers advice and a range of value-added services. Amorentia makes every effort to stay ahead by utilising the latest technology in macadamia tree propagation. Agriplas exhibited irrigation equipment. They specialise mainly in the agricultural sector, with additional focus on industrial water filtration. Agriplas is the only manufacturer of both cylindrical and flat dripper line in Southern Africa, thanks to the latest technology and machinery. Looking forward to 2023, Andri van den Bergh, the expo organiser, said that the expo will be an annual event and is sure to become one of the highlights on the macadamia calendar.

Albert van Zyl, plant nutrition consultant for Kynoch, was on hand to help producers with questions.

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MACADAMIAS

SAMAC macadamia crop forecast 2022 The 2021 South African macadamia crop was unfortunately still affected by hot and dry conditions that prevailed for several years. Although most orchards are irrigated, water usage was restricted in certain areas, which together with very high temperatures contributed significantly to physiological stress experienced by many orchards.

t is a well-known fact that trees growing under these conditions have a compromised immune response to many insects and diseases, which further exacerbated the low-yield problem. The final crop of 2021 was 53 585 tonnes of inshell macadamias (measured at 1,5% moisture content). Compared to the 2020 crop, the industry's production increased with 4 660 tonnes in 2021. The feedback from the various provinces looks very positive at the moment and SAMAC hopes that 2022 will be a prosperous macadamia year.

Mpumalanga Prospects for the new season look very optimistic as certain parts of the production region already received ± 750 mm of rain by mid-January 2022. The rain was generally evenly distributed throughout the season, but there was some infrastructure and hail damage in the Mbombela / Nelspruit area. Farms around Mbombela / Nelspruit are generally very wet and farmers struggle with access in their orchards for spraying operations. Despite some initial negative sentiment regarding the effect of cool moist days on flowering and subsequent nutset, quite the opposite is true, and farmers can look forward to a significant improvement over the previous season. Stink bug numbers appear to be on par for this time of the year, but Tortricidae moth damages on susceptible cultivars appeared to increase considerably. Thrip numbers are down, which is consistent with scientific reports indicating low damage levels during wet seasons. While it is too early for an assessment of the macadamia felted coccid, initial reports indicate that some new farms in the White River and Brondal areas are infested. Surprisingly husk rot damage is not as severe as expected for a wet year, but the low disease incidence could possibly be ascribed to diligent spray programmes during critical periods. The very wet conditions may lead to higher incidence of Phytophthora, but the magnitude of this will only be determined in a few months' time.

ing some crop loss. In terms of the 2022 crop, producers are very positive to see a much better set than last year. The Beaumont crop is definitely looking better than in 2021, with better crop across the country. The younger Beaumont trees, which flowered earlier than the mature trees on the South Coast, set a significantly better crop, indicating the possible negative impacts of the extreme hot weather of 45°C late in 2021and early continuous rains (blossom blight). The other hybrids, A4 and Nelmak 2, have also set very well in both young and older orchards. The Integ cultivars are looking very good, especially 344, 814 and 816 with young 5-7-year-old 816's setting particularly well. Nut borer has been an issue on the KwaZulu-Natal coastal areas with spikes in numbers. Stink bug numbers have been fairly typical up to now with no big spikes in scouting numbers being reported.

Limpopo Macadamia growers in the Limpopo province are generally, although carefully, optimistic about this seasons' crop. Unfortunate hail events in the Letaba region have impacted some growers. However, most of the Limpopo production regions are seeing good sets reaching maturity. Producers have received good early season rains with generally good conditions for fruit set. With ± 520 mm rain since last year, the season holds potential for good yields, and the strong summer flush stores energy reserves for coming seasons. An estimated 20% more macadamia tonnes could come out of Limpopo this season, compared to the last year. The harvesting season might hold a lot of rainy days, which highlights the importance of fast turn-around times, and not to leave nuts on the ground for too long. It also makes late stink bug damage control more difficult as equipment often cannot enter the orchards due to too wet soils. Trends of unsound kernel recovery rates have, however, showed proof for better stink bug management in the Province over the past three seasons.

Western Cape/George area KwaZulu-Natal KwaZulu-Natal experienced a very good rainfall season with rains starting early and continuing through into January 2022. The high number of rain days during November and December 2021 did reduce heat units but there was a good increase in heat units in January 2022 as the rains subsided. Some areas on the north coast were hit by hail over December 2021, caus-

GROENTE & VRUGTE | MAART • APRIL 2022

Macadamia growers in the Western Cape are a bit unsure with the weather patterns as it was fairly cold during December 2021and then very hot and dry in January 2022, which made the nuts very slowly to set. The flowering time was not synchronised and flowers bloomed at different times causing some uncertainty regarding the harvest. This is the newest macadamia growing area and the farmers remain positive.

MACADAMIAS

Drip irrigation

Modern day macadamia irrigation and ridging At the recent Ambermacs expo in White River producers came together to hear what experts had to say about research and technology in the industry. Michael Esmeraldo from Netafim South Africa was there to speak about irrigation in the orchards.

he topic of the day was modern day macadamia irrigatechnology and concepts to show for it. Let us never stop tion and ridging. According to Esmeraldo innovating in our pursuit of higher efficiency. modern day farming is not always about new “The agricultural industry has a definite retechnology, high-tech machines and computsponsibility to handle the water it has access ers. The modern approach is also to be more to with care through more efficient irrigation. efficient with the resources that is available to Agriculture is challenged to produce more the producers. with less - to feed the rapidly growing popu“It is important that the entire irrigation lation with limited resources whilst protecting industry, whether at producer, designer and the environment for future generations. supplier level, does its part to ensure that in“Efficient irrigation is not only about usnovation breeds innovation to take the industry ing water responsibly, but also about the vital forward,” he said. “If we do not continue to task of ensuring food security and sustainfind new ways to apply water and develop new ability across the globe. Water use efficiency technology that increases water use efficienmust always be the main focus of any irrigacies, producers will not be able to keep up with tion system. To ensure optimal water use efthe demand for food with the limited resources Michael Esmeraldo, agronomist ficiency, the choice of irrigation system is exat their disposal. Irrigation innovation has come and sales manager for Netafim tremely important with consideration to the a long way and we have incredible irrigation South in the northern region. crop, conditions and circumstances.”

VEGETABLES & FRUIT | MARCH • APRIL 2022

MACADAMIAS

Micro-sprinkler irrigation

Although research and experience suggest that macadamia trees use water quite sparingly when compared to other tree crops, optimal irrigation remains crucial to efficient macadamia nut production. Irrigation of macadamia trees is particularly important during flowering, from the time of nut set, during nut filling and the vegetative growth period in mid-summer. Efficient water use is about preventing water loss on the one hand and ensuring optimal water intake by the roots on the other. Water loss can occur through evaporation, deep percolation, subsurface outflow, run-off and transpiration. The latter is the only positive water loss as water moves through the plant. The aim is, therefore, to maximise tree transpiration while minimising soil evaporation and water use

by vegetation between tree rows. The main concern is evaporation and deep percolation. Limiting these two culprits is key, as they can then ensure highly efficient water use. Various irrigation strategies exist and different methods of irrigation can be implemented. Prevailing climatic conditions in combination with factors such as soil depth and fertility, availability of water for irrigation and more will influence the irrigation strategy. Esmeraldo says that a tree does not know how it receives water. It only has a certain water requirement depending on the season, climate and crop stage. Some of the main questions that needs to be asked is: • For how long should a producer irrigate to ensure that he TO PAGE 14

MACADAMIAS

Irrigation on ridges in the macadamia orchard.

Modern day macadamia irrigation and ridging FROM PAGE 13 starts with a wet soil profile? • How should irrigation take place in the initial crop stages while roots are shallow? • How should irrigation take place in later stages when the root zone is well-established?

Drip irrigation So what is the advantages of drip irrigation? Drip irrigation is the most effective method with up to 30% of water saving. The water and fertilizer can be applied directly into the root zone, it is easy to work with and out of the way. Less labour is involved and less maintenance, which means more savings in the long run. Some of the disadvantages includes the fact that the water cannot be seen while irrigation is on. According to Esmeraldo there are maintenance and management involved and some of the management is not yet well understood by everyone. He continued by saying that most of the new drip developments in the last 5 years have been continuous low flow drip irrigation designs. These systems are designed to have three lines of 0,7 l/h to 1 l/h emitters every one meter apart to get to an application rate of 2,6 to 3,5 m3/ha/h. He suggested that producers start with one line and then add a second one

from about 12 months onward and a third line when the tree is mature and in full production.

Micro-sprinkler irrigation When looking at the advantages of micro-sprinkler irrigation, it has a bigger wetted area, and less technical input is needed when it comes to scheduling and fertilizer. The producer can easily identify problems because irrigation is visible. Organic material decomposes quicker when using micro irrigation. Disadvantages include that it promotes weed growth and the wind has a big impact on the water distribution. It is high on the maintenance side, which in return means that the labour cost involved is also high. Insects is prone to blocking the nozzles. This means that micro irrigation is more expensive in the long run. According to Esmeraldo most of the micro design are between 30 to 50 l/h when there is one micro per tree. Most of the time the sprinkler will be placed between two trees if the spacing is between 8 m to 4 m the sprinkler will then be 2 m from the tree trunk. He suggested that the producer start with deflector/cone or concave spreader on the micro to keep the water close to the tree and not waste any water. When using micro-sprinkler irrigation, the producer should

VEGETABLES & FRUIT | MARCH • APRIL 2022

MACADAMIAS

When asked which type of irrigation he would recommend, Esmeraldo said: “There is no one-size-fits-all solution in irrigation or perfect system. That is why proper planning is so crucial. You have to consider all of the advantages and disadvantages of a system and make a decision based on the circumstances of the farm, given all the variables. The final decision regarding the type of irrigation system will be determined by your experience and knowledge and prioritised irrigation goals. “Various irrigation strategies exist and different methods of irrigation can be implemented. Prevailing climatic conditions in combination with factors such as soil depth and fertility, availability of water for irrigation and more, will influence the irrigation strategy. When we want to manage water optimally in orchards, it is important that we understand water balance in an orchard, soil-water interaction and factors that impact it.” He concluded by saying that there is no silver bullet in any agricultural industry. It is about doing the necessary research and planning to find a solution for specific circumstances and continuously adapting to more efficient farming practices. The producer has to make smart decisions now to benefit later; farming is not a short-term activity. “The industry must shift towards using fewer inputs more efficiently to grow more. If you take on the challenge with the right experts at your side, you can eliminate many inefficiencies and gain better control of your entire production system to finally grow your profit margin.”

have two to three events per week depending on the water holding capacity of the soil and the system design. This system will be designed to apply about 4 mm/day in peak season. The trend with micro irrigation is also to go with lower flow and some of the new developments are 20 to 30 l/h.

Ridges Esmeraldo says it seems that most of the new macadamia developments are ridged regardless of the soils’ physical and chemical properties. Netafim did some research with Dr Phillip Myburgh from ARC to see if ridges really have such a big impact on root growth and tree health in general. The conclusion is that trees on ridges seem as if they are doing better and developing quicker than the trees on flat soil. According to him the advantages of ridges include better drainage and more control of water and fertilizer. It also makes for warmer root zones and no compaction, quicker root development and less sub soil trouble. Looking at some of the disadvantages, there is an initial financial investment and it takes time. In some cases it can be difficult to harvest because of the height and it can cause some management difficulties.

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READ THE LABEL FOR FULL DETAILS. AMISTAR TOP® contains azoxystrobin 200g/L and difenoconazole 125g/L (Reg no. L7897, Act no. 36 of 1947) CAUTION. AMISTAR TOP® is a registered trademark of a Syngenta Group Company. Syngenta South Africa (Pty) Limited, Private Bag X60, Halfway House, 1685. Tel. (011) 541 4000. www.syngenta.co.za © Syngenta Ag, 2000. Copyright of this document is reserved. All unauthorised reproduction is forbidden.

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Both active ingredients are transported upward in the xylem to also protect new growth

MACADAMIAS

PROMOTION

Macadamia expansion

The macadamia industry Many areas in South Africa are already established to develop macadamias commercially. With further growth in the industry, macadamia nut production continues to be an attractive alternative to existing crops, achieving a high return per hectare.

ccording to Lauren Strever from Amorentia Nursery, something that is noteworthy is the expansion of macadamias into Africa; with Zambia, Zimbabwe, Mozambique, Tanzania, Kenya, Angola and the Congo featuring on the list of just some of countries in a phase of growth. This bodes well for the global macadamia industry, creating stability for the future supply. Some of the trees which Amorentia has supplied into Southern Africa over the past 12 months is varients 816, 849, 842, A4, A16, A4, Daddow, N2, Beaumont, 791 and 814. Amorentia Macadamia Nursery remains the most established nursery in the industry, having propagated macadamia trees for 50 years. Under the leadership of their new senior nursery manager, Anneri Potgieter, Amorentia is happy to have trees available on demand for the 2022/23 planting season. Many areas which are suitable to growing macadamias are also suitable to growing avocados and dragon fruit. Amorentia Nursery offers all modern avocado selections, grafted on Guatemalan / West Indian rootstocks for the 2022/23 planting season. Data extracted from a national benchmark study performed by Sourcebi Agriculture Data Analytics, shows the role that rootstocks play in the yield and quality in avocado production. Over a seven-year period, seedling rootstocks yielded the same average tonnage per hectare as clonal rootstocks. The Nursery also offers an exciting opportunity to grow Amorentia Sweet Dragon Fruit. It is an exciting market which is exploding in South Africa. All the Amorentia Sweet Dragon Fruit selections are deliciously sweet and have been trademarked to adequately differentiate this amazing fruit from, old, bland and boring tasting Dragon Fruit selections. People who have never tasted one of Amorentia’s Sweet Dragon Fruit selections, are missing out. Farmers who have available land to develop, may consider this new and exciting crop as a real possibility for great returns per hectare. For more information, contact the Amorentia team or visit www.amorentia.co.za.

Seedling.

VEGETABLES & FRUIT | MARCH • APRIL 2022

BRASSICAS

Span brassicas in vir aanvullende plaagbeheer Brassica- en mosterd-dekgewasse is bekend vir hul vinnige groei, wonderlike biomassa-produksie en vermoë om voedingstowwe uit die grond te onttrek, maar deesdae is dit ook toenemend gewild vir hul eienskappe oor plaagbeheer.

ie meeste brassica-spesies stel chemiese bestanddele vry, wat giftig is vir gronddraende patogene en plae, soos nematodes, swamme en sommige onkruide. Die mosterdspesies het gewoonlik hoër konsentrasies van hierdie chemikalieë. Brassicas word toenemend gebruik as winter- of wisselgewasse in groente en spesialiteitsgewas-produksie soos aartappels en boomvrugte. Sommige brassicas het ’n groot penwortel wat beter deur ploegwalle kan breek as graandekgewasse of mosterd-spesies se veselagtige wortels. Die brassicas wat in die winter doodgaan, breek baie gou af en laat ’n saadbed agter wat maklik is om te beplant. Verskeie spesies is beskikbaar en dit is gevolglik maklik om ’n geskikte spesie vir ‘n boerdery te vind. Brassicas gaan egter nie plaagprobleme heeltemal uitskakel nie. Hulle is ’n goeie hulpmiddel en uitstekende wisselbougewas, maar plaagbeheerresultate is teenstrydig en onvolledig. Baie meer navorsing word benodig om die veranderlikes wat die vrystelling en giftigheid van die betrokke chemiese bestanddele te verduidelik. Dié gewas het egter baie voordele wat erosiebeheer, voedingopname, plaagbeheer, nematodebestuur, onkruidbeheer en bestuur van die grondstruktuur insluit.

Erosiebeheer en voedingstof-opname Brassicas kan tot meer as 80% grondbedekking verskaf as dit as ’n winterdekgewas geplant word. Afhangende van die ligging, plantdatum en grondvrugbaarheid, kan brassicas tot 3 600 kg biomassa per 0,405 ha. produseer. Omdat dit vinnig groei, is brassicas ideaal om grondstikstof (N) wat ná die oes agterbly, vas te vang. Brassicas immobiliseer minder stikstof as sommige graandekgewasse en heelwat stikstof kan in die vroeë lente deur die hoofgewasse opgeneem word. Brassicas se wortels kan tot 182 cm diep groei en voedingstowwe veel dieper as die meeste gewasse uit die grond onttrek.

Plaagbeheer Alle brassicas stel biogiftige bestanddele of metaboliese byprodukte vry, wat wye aktiwiteite jeens bakterieë, swamme, insekte, nematodes en onkruide toon. Brassica-dekgewasse word dikwels gesny en in die grond ingewerk om van hul natuurlike berokingspotensiaal gebruik te maak. Die berokingschemikalieë word net vrygestel wanneer individuele plantselle breek of bars. Brassica- en mosterd-gedekgewasse se biogiftige aktiwiteite is laag in vergelyking met kommersiële berokingsmid-

dels. Dit verskil ook van spesies, plantdatum, groeistadium toe dit doodgemaak is en van grondbewerkingstelsel.

Nematode-bestuur Verskeie brassicas lok plantparasitiese nematodes en kan as lokgewasse gebruik word, wat met ’n sintetiese aalwurmdoder opgevolg kan word.

Onkruidbeheer Brassica-dekgewasse onderdruk onkruid in die herfs met hul vinnige groeivermoë en blaarbedekking. In die lente kan brassica-reste klein gesaaide jaarlikse onkruid onderdruk, hoewel sommige onkruidweerstandigheid getoon het.

Grondstruktuur Sekere brassicas se lang penwortel kan help om grondverdigting teen te werk. Hierdie sogenaamde "bio-boring” is die doeltreffendste wanneer die plant in ’n tyd van die jaar groei waartydens die grond vogtiger en makliker is om te penetreer. Hierdie lang wortels laat gewasse toe om voedingstowwe uit die dieper grond op te neem. Soos hierdie wortels ontbind, laat dit kanale na die oppervlak oop, wat beter wateropname verseker en die groei en grondpenetrasie van gewaswortels bevoordeel.

Voorsorg Dit is nog nie algemene gebruik om brassicas vir plaagbeheer in te span nie. Die sukses verskil in verskillende geografiese gebiede en die resultate is onvolledig en van jaar tot jaar teenstrydig. Gesels eers met ‘n gewasadviseur en begin met klein toetsblokke op die plaas. Biogiftige aktiwiteite kan kontantgewasse se groei belemmer en geen aanplantings moet dus in groen residu wat pas doodgemaak is, gedoen word nie. Brassica-dekgewasse moenie in rotasie met ander brassicas soos kool, brokkoli en radyse geplant word nie, want hulle is ontvanklik vir soortgelyke siektes. NexusAG se gewasadviseurs spesialiseer in verskeie dekgewasse as deel van volhoubare gewasbestuursprogramme. Hulle vorm deel van die omvattende span interne gewasspesialiste wat bygestaan word deur spesialiste van bedryfsliggame en internasionale en plaaslike verskaffers, wat op die voorpunt van nuwe tegnologiese ontwikkeling bly. Die maatskappy dien reeds die afgelope 21 jaar die landboubedryf. Kontak NexusAG by 021 860 8040 of besoek www.nexusag. net vir meer inligting.

VEGETABLES & FRUIT | MARCH • APRIL 2022

BOER JY VIR ’N BETER TOEKOMS? HET U GEWEET DAT BRASSICAS ’N UITSTEKENDE DEKGEWAS IS EN DAT DIT HELP MET PESBEHEER? Brassicadekgewasse groei vinnig, beskik oor wonderlike biomassa produksie en on rek voedingstowwe uit die grond, maar trek deesdae aandag oor hul pesbeheer-karaktereienskappe. Die meeste Brassica-spesies stel chemiese bestanddele, wat gi ig is vir gronddraende patogene en peste, vry.

BOONOP ONDERSTEUN DIE DEKGEWAS GRONDGESONDHEID DEUR: Erosiebeheer Voedingstofopname Grondstruktuur bestuur

NexusAG se gewasadviseurs spesialiseer in verskeie dekgewasse as deel van volhoubare gewasbestuursprogramme.

KONTAK ONS VIR MEER INLIGTING: www.nexusag.net 021-860 8040

BRASSICAS

From grand to super Sakata Southern Africa is well-known in the agricultural industry for its high quality cabbage varieties. Over the past decade, Grandslam has become a market leader as an excellent performing F1 hybrid cabbage variety.

abbage producers throughout South Africa immediately took a liking to the sweet taste, large yield potential and its very good field holding ability. This, together with excellent cold tolerance, has permitted harvesting over a prolonged period which is also to the producer’s advantage. Sakata’s cabbage breeders have done a lot of research into refining Grandslam and improving the variety even further. The breeders specifically focused on seed availability

Superslam produces large round cabbage heads with a big frame and good head weight.

BRASSICAS

The Superslam F1 hybrid shows good uniformity in the field to ensure uniform harvesting. The field holding ability of this variety is also excellent.

Johan Stronkhorst, product specialist at Sakata Seed, holding a large Superslam head.

and uniformity of growth. When the trials on the improved varieties started in 2016, high expectations and cautious optimism were part of every evaluation. Because it was so well positioned in the market, the replacement variety had to be better than Grandslam in every aspect. Superslam F1 hybrid exceeded all expectations as a very vigorous grower with exceptional uniformity both in the field and the nursery. The seedlings are very uniform, which usually results in an excellent pull rate. It produces large, white, round to semi-round cabbage heads with a big frame. It has a unique sweet taste that is similar to Grandslam’s eating quality. The variety has an upright growth habit with the ability to tolerate cold temperatures. The planting slot of Superslam is also very similar to Grandslam. For more information on Superslam or any other product in the Sakata vegetable range, please contact your local sales representative or visit the website at www.sakata.co.za. DISCLAIMER: This information is based on Sakata’s observations and/or information from other sources. As crop performance depends on the interaction between the genetic potential of the seed, its physiological characteristics and the environment, including management, Sakata gives no expressed or implied warranty for the performance of crops relative to the information given, nor do Sakata accept any liability for any loss, direct or consequential, that may arise from whatsoever cause. Please read the Sakata Seed Southern Africa (Pty) Ltd Conditions of Sale before ordering seed.

GROENTE & VRUGTE

MAART • APRIL 2022

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BRASSICAS

Loop katvoet vir dikvoetsiekte ‘n Verhoging in die pH van grond is die enigste doeltreffende oplossing om koolgewasse volhoubaar in grond te verbou waarin Plasmodiophora brassicae nie sal ontkiem nie. Jan Greyling MEDEWERKER

ir ongunstige dikvoetsiekte-toestande waarin koolplante steeds sal floreer moet die water-pH-toets van die grondmonster minstens 7,2 tot 7,3 wees – dit is hoër as wat vir die meeste gewasse aanbeveel word, maar sal nie die kool se eie potensiaal demp nie. Slegs gereelde grondmonsters sal die teenwoordigheid van veilige pH-vlakke, wat reuse verliese kan voorkom, verskaf. Grond-pH neig om van nature oor tyd geleidelik af te neem. Slegs wanneer die toetsuitslag ‘n veilige water-pH wys, sal koolgewasse weer veilig gevestig kan word. Hoewel beide ‘n water-pH en ‘n KCl-pH neutraal is by 7,0, is die water-pHmeting altyd minder suur as die KCl-pH-lesing, wat misleidend kan wees vir veilige brassica-verbouing. Sou ‘n produsent enige van die kruisblomgewasse (Brassicaceae) in grond wil produseer waar dikvoetsiekte reeds voorkom, is die enigste oplossing om die grond se pH doelgerig te verstel. Dit is hoofsaaklik van toepassing vir kool, blomkool, brokkoli, brusselse spruitjies en radys- en mosterd-

soorte, wat kanola insluit. Hoe suurder die grond, hoe meer onstuitbaar sal die teenwoordigheid van dikvoetsiekte wees. Die patogeen wat dikvoetsiekte veroorsaak kom regoor die wêreld voor. Dit kom egter net in sekere dele van Suid-Afrika voor, aangesien hoë temperature en lae reënvalstreke nie gunstig is daarvoor nie. Die identifisering van dikvoetsiekte en die benaming daarvan as P. brassicae is reeds in 1875 deur ‘n Russiese wetenskaplike, Mikhail Woronin, gedoen. “Dit is in wese ‘n oerswam,” vertel Francois Barnard, koolgewas-spesialis. “Woronin se werk is gedoen ten tye van die verlies van ‘n reuse koolaanplanting buite St Petersburg in Rusland. Bykans ses eeue voor dit is daar reeds in Europa na dikvoetsiekte verwys. Dr. Mariette Truter, senior navorser: gewasbeskerming by die LNR-kampus vir Groente, Industriële en Medisinale Plante, sê hulle weet nie wat die omvang van ekonomiese skade weens dikvoetsiekte is nie. Internasionaal, soos saadmaatskappye bevestig, is oesverliese gemiddeld 10% tot 15%, maar in toestande wat die siekte bevorder kan dit tot 50% en meer wees. NA BLADSY 24

VEGETABLES & FRUIT | MARCH • APRIL 2022

BRASSICAS

Loop katvoet vir dikvoetsiekte VAN BLADSY 22

Kan vernietigend wees Barnard sê dikvoetsiekte wat reeds in 176 lande voorkom is nie die boer se vennoot nie. “Die siekte is in wese ‘n verskrikking wat die ekonomie van enige koolgewasboerdery kan verwoes.” Hy is reeds langer as ses jaar ‘n saadspesialis by InteliSeed op George en praat ernstig wanneer hy kwekers teen hierdie oesvernietiger waarsku. “Die keuse van die heel beste weerstandige kultivars en nougesette bestuur sal bydra om volhoubaar te kan produseer. Die antwoord is egter nie om onbesmette saailinge in besmette grond te plant of besmette steggies in onbesmette grond nie. ‘n pH-verhoging kan sekerlik ‘n groot bydrae tot volhoubare produksie lewer, maar hoewel dikvoetsiekte volgens die aard van die seisoene minder kan word, sal dit nie verdwyn nie.” Dr. Truter sê onder die kruisblomtipes is kool een van die mees vatbare gewasse vir dikvoetsiekte. “Verskeie ander plante in die roos-, poppie- en grasfamilies word ook hierdeur geraak. Plante buite die kruisblomgewas-familie kry egter nie maklik die tipiese simptome nie.” P. brassicae produseer veelkernige massa protoplasma (lewende deel van ‘n sel). Dit word plasmodium genoem, waaruit bewegende soöspore en langrustende spore ontstaan – hulle oorleef en reproduseer in grond en plantreste. Die rustende spore ontkiem wanneer gunstige wortelgroei (van gasheerplante) teenwoordig is. “Dit is die plasmodia in die wortels wat deurlopend vermeerder en die verdikte wortelstelsel – dikvoetsiekte – tot gevolg het. Dié verdikkings vorm weer massas rustende spore,

Brokkoli-plante se dikvoet besmette wortelstelsels.

wat in die grond vrygestel word nadat verdikkings deur sekondêre organismes binnegedring word.” Dr. Truter sê die dikvoetsiekte-patogeen se langrustende spore kan langer as 15 jaar in die grond bly voortleef. “Die siekte is nie saadgedraagd nie, maar versprei wel in plantmateriaal, meestal saailinge. Saailinge wys eers na 3 weke simptome van infeksie en dit word dikwels gemis.“ Volgens Barnard kan die oorlewingstyd tot 20 jaar wees. “Dikvoetsiekte kan deur enige beweging van grond – meganies, natuurlik, met skoene of voetsole of deur aangetaste saailinge – oor relatiewe lang afstande versprei. Verspreiding in ‘n spesifieke blok grond vind deur bewegende soöspore plaas, wat oor kort afstande swem en deur nat toestande bevoordeel word.” Dit is dan wanneer die massas amebe-tipe selle ‘n plasmodium word – ‘n klomp protoplasma met baie selkerns, maar met geen selwande nie. Sy stem saam dat koel, nat grond (70% tot 80% waterhouvermoë) met ‘n lae pH (suuragtig) die patogeen bevoordeel en tot verdere verspreiding van dikvoetsiekte sal lei.

Ligloop om skade te verhoed Dr. Truter sê die voorkoms van gunstige plantwortels en die teenwoordigheid van rustende spore en soöspore sal onder gunstige klimaatstoestande tot verspreiding lei. Barnard voeg by: “Dit is werklik baie moeilik beheerbaar. Die organisme word deur grondbeweging van blok tot blok, plaas tot plaas en streek tot streek versprei, sonder dat jy dit sien gebeur. Die soöspore swem letterlik in nat grond. Die gasheer-

VEGETABLES & FRUIT | MARCH • APRIL 2022

BRASSICAS

Francois Barnard is 'n saadspesialis by InteliSeed en 'n bedryfskundige van koolgewasse.

Dikvoet-simptome op blomkool se wortels.

plante se wortels word deur die wortelhare of wonde aan die stelsel binnegegaan.” Vermenigvuldiging gebeur waneer die spore dieselfde gasheer herindring, óf ‘n ander gasheerplant kies om aan te val. Sommige van die bekendste spesies wat ideale gashere vir die soöspore is, sluit in rooiklawer, herderstassie (Capsella bursapastoris), doringpapawer, kweekgras, watergras, peperwortel, mosterd, boerenkool, koolrabi, brokkoli, blomkool, rape, kanola, roketslaai, radyse en wasabi.

Simptome is duidelik “Hoewel die siekte homself baie soos swamme gedra, is dit nie

‘n swam, ‘n virus of ‘n bakterie nie,” sê Barnard. “Wat jy sien is meestal opgeswelde wortels, wat gepaard gaan met blare wat verwelk voorkom tydens warm dae. Namate die plant agteruitgaan sal die verwelking permanent word.” Die duidelikste simptoom van dikvoetsiekte is die abnormale groot wortels, wat verdikte sywortels en haarwortels, asook die penwortel en selfs die ondergrondse deel van die stam insluit, sê dr Truter. “Geïnfekteerde wortels vergroot om knoppe (‘clubs’) van verskillende groottes en vorme te word, afhangend van die gasheerplant. Gewoonlik is die grootste knoppe net onder die NA BLADSY 26

BRASSICAS

Loop katvoet vir dikvoetsiekte VAN BLADSY 25

Wortels van die twee jong blomkool-plante.

grondoppervlak op die groter wortels. Op gewasse met vleesagtige wortels, soos radyse en rape, vorm knoetse op die penwortel en sywortels. Op veselagtige wortels soos by kool en brokkoli se knopagtige wortelswellings, vorm spiraalvormige verdikkings op afsonderlike wortels. Wortelknoetse word dikwels deur bykomende bakterie of swamme binnegedring, wat wortelverrotting veroorsaak, wat tot plantvrektes kan lei.” Een van die eerste simptome van ‘n land wat die siekte het, is dat dele wat nie versuipte kolle is nie, teen omtrent 3-4 ure na sonop verwelk, wanneer die plant se transpirasievlakke sy water-opname oortref. As sulke plante uitgetrek word, is daar abnormale swelling van die wortels en die knoetse belemmer die opname van voedingstowwe en water.

Ander simptome sluit die volgende in: • • • •

Vergeling, verdwerging en verwelking van plante; verlaagde produksie en kwaliteit (houvermoë); plante gaan voortydig dood; en jong, wit knoetse op die wortels wat ferm is (die Britte het dit vingers-en-tone-siekte genoem).

Wat staan produsente te doen? Dr. Truter bevestig daar is geen doeltreffende oplossing vir die uitwissing van die siekte nie. Dikvoetsiekte se beheer is moei-

lik en produsente moet volgens haar probeer om nie gesonde landerye met die patogeen te besmet nie. Dikvoetsiekte kan deur ‘n omvattende, geïntegreerde beheerprogram bestuur word, wat uit ‘n kombinasie van verskillende verbouings, chemiese en biologiese beheermaatreëls soos die volgende bestaan: • By ‘n lae klei-inhoud met ‘n pH < 7.2 kan bekalking van grond help. Te veel kalk kan egter tot voedingstekorte lei. Byvoeging van kalsiumnitraat en boor in die grond het al gehelp om die siekte se voorkoms te verminder. • Wees baie versigtig om nie besmette grond deur implemente, werkers of afloopwater na gesonde lande toe te versprei nie. • Dit is baie belangrik om skoon, siektevrye plantjies te plant. Saadbeddings moet goed gedreineer wees en minstens agt jaar vry wees van kruisblomgewasse. • Afloopwater van aangrensende grond af moet weggehou word van die saadbeddings. • Gebruik weerstandige kultivars, waar dit beskikbaar is. • Doen vir sewe jaar gewasrotasie met meerjarige voergewasse. • Verbeter landboupraktyke, soos deuropende dreinering. • Roei kruisblomgewas-onkruid uit, soos wilderadys, wildemosterd en voëlgras, binne en rondom produksielande.

VEGETABLES & FRUIT | MARCH • APRIL 2022

ALGEMEEN

PROTECTING CROPS takes careful planning “A weapon you held and didn’t know how to use belonged to your enemy.” This saying by Sir Terry Pratchett also rings true when it comes to protecting crops against pests, ensuring maximum yields and minimal loss.

esearchers conduct continuous and extensive research and trials on stink bugs and stink bug complexes. At the same time, numerous chemical actives have been registered and used successfully over decades. Why do we still see the devastating effect of these bugs on our pack-out percentages? Several factors could cause pests to effect crops. However, by understanding the situation and by using the best weapons and tools, effective control strategies can be implemented.

Scouting It is impossible to change what you cannot measure, so scouting remains the foundation for protecting crops effectively against pests and disease. Simply taking the standard approach and following a general spray programme every season can be expensive and unexpected pests and diseases can go unnoticed and untreated. In addition, the repeated use of pesticides with similar modes of action can result in serious resistance challenges.

Pyrethroids are a very economical option. Unfortunately, this active ingredient does not affect two-spotted stink bugs in most of the northern and eastern regions of South Africa due to resistance. Identifying the species is therefore very important during scouting to select the correct product..

Integrated pest management (IPM) A good IPM approach helps prevent resistance build-up and includes a combination of biological, mechanical and chemical control measures to reduce stink bug populations.

Biological Beauveria bassiana is a fungal contact insecticide and an excellent biological option as part of the IPM programme.

Mechanical Bugweed and castor-oil plants are good hosts for stink bugs. TO PAGE 28

The table includes the most used active ingredients, the groups they belong to and their mode of action.

Examples of active ingredients

Group

Mode of action

3A Pyrethrins & pyrethroids

Axon sodium channel inhibitors. (nerve & muscle targets) Pyrethroids interact with open sodium channels on the axons of the insect’s nervous system to hold them in an open conformation. Pyrethroid treated neurons exhibit uncontrolled firing and neurotransmitter release resulting in twitching and convulsions in the insect. The overstimulation causes total loss of electrical activity and therefore paralysis and kills the insect.

4A Neonicotinoids

Acetylcholine mimics. thiamethoxam (Nerve target) imidacloprid Acetylcholine is the main neurotransmitter in the insect brain. acetamiprid AI molecules fit into the binding sites of acetylcholine receptors on the synaptic sodium channel to imitate real acetylcholine. This keeps the sodium channels open, so nerve impulses fire constantly and erratically. All bodily systems controlled by the nervous system become overstimulated and eventually, the insect is exhausted, collapses and dies.

1B Organophosphates

Acetylcholinesterase inhibitors. acephate (Nerve and muscle targets) Acetylcholinesterase is the enzyme that catalyses the breakdown of acetylcholine. Organophosphates fit into the active sites of acetylcholinesterase. The enzyme is deactivated and cannot break down acetylcholine. The accumulation of acetylcholine results in overstimulation of the nervous system. The insect is exhausted, collapses and dies.

cypermethrin lambda-cyhalothrin tau-fluvalinate beta-cyfluthrin

9B Chordotonal organ TRPV channel modulators. pymetrozine Pyridine azomethine (Selective feeding blockers) derivatives Prevents insects from feeding by interfering with neural regulation of plant fluid intake in the mouthparts. It modifies behaviour by inhibiting or disrupting stylet penetration into plant vascular fluids, which prevents insects from obtaining nutrients, resulting in starvation. 28 Diamides

Ryanodine receptor modulators. chlorantraniliprole (Nerve and muscle target) It activates the unregulated release of internal calcium stores, which leads to Ca2+ depletion, feeding cessation, lethargy, muscle paralysis, and insect death.

GROENTE & VRUGTE | MAART • APRIL 2022

GENERAL

Protecting crops takes careful planning FROM PAGE 27 Keep host weeds and grasses under control by slashing and physically removing larger plants.

Chemical

It is important to ensure good coverage by using quality spray nozzles at the recommended pressures.

Time of application Adult stinkbugs migrate out of the orchards during the day when it is hot. Spraying very early in the morning or during the night proved to be more effective.

Several factors can influence the efficacy of insecticides.

Water quality and adjuvants Modes of action Alternating insecticides containing active ingredients from different chemical groups will reduce the risk of resistance against certain active ingredients.

Coverage and penetration Spray volumes must be sufficient to ensure that enough product reaches the intended target – stink bugs throughout the canopy of the trees. When spraying for stink bugs, a mediumto full cover spray is recommended depending on the product used. Always make sure to read the product labels carefully for instructions.

Water quality is one of the most important factors in any spray mix. Organic matter in spray water can bind with active ingredient molecules, rendering them inactive. It can result in unsatisfactory insect control. Use non-ionic adjuvants with spreading and penetrating properties with insecticides. Most insecticides work optimally at a lower pH (around 5). At this pH, the products are stable and take longer to break down due to climatic factors. The active ingredients are thus available for longer to do their job. When the pH is high (>7), use a buffer to reduce the pH to levels around 5. Consult your chemical advisor and read the product label carefully for preferred pH levels.

Climatic conditions Dosage Under- or over dosage can seriously compromise the optimal performance of the product, resulting in ineffective control or resistance build-up.

Spray equipment Ensure that spray equipment is well maintained and calibrated.

Weather conditions have an immense influence on stink bug population numbers. Late season rains can result in out-ofseason hatching of eggs. Weekly scouting is very important to detect untimely outbreaks. In combination with the tools and measures, an arsenal of well tested, trusted chemical products, and common sense, stink bugs can effectively be controlled.

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GENERAL

Appels en pere om op trots te wees

Ondanks die uitwerking van die ergste droogte oor meer as honderd jaar tussen 2015 en 2018 in die Wes-Kaap, verwag die Suid-Afrikaanse appel- en peerbedryf om te midde van gunstige reëntoestande in 2020/21 weer gesond te wees. Jan Greyling MEDEWERKER

ie spreekwoord lui dat ‘n vergelyking van appels met pere onwenslik is, want sake wat nie regtig vergelykbaar is nie, kan nie vergelyk word nie. Tog is veerkragtigheid ‘n gemene deler tussen Suid-Afrika se appels en pere. Die huidige geslag produsente het, soos baie van hul ouers en grootouers, vasgebyt en die steil bult van die groot droogte oorkom deur te fokus en met die genadewater van Bo. Appels en pere is deel van die groente- en vrugtebedryf wat met ‘n reële groei van 9% in reële bruto inkomste op ‘n jaargrondslag in die derde kwartaal van 2021 ‘n pronkerige landboubedryf is. Veral die Britte, Europeërs, die Midde-Ooste en die VerreOoste se vrugteliefhebbers geniet die room van die Suid-Afrikaanse kernvrugte-oes. Volgens Hortgro, Suid-Afrika se sagtevrugtebedryfsorganisasie, lei terugslae vir Italiaanse peerboere tans tot heelwat navrae vir die lewering van Suid-Afrikaanse pere aan Europa en Brittanje. Terwyl Suid-Afrikaanse appels sedert 2015 na China uitgevoer word, gaan pere ook vanjaar vir die eerste keer die Chinese se monde laat water. Die peer-protokol is teen die einde van 2021 tussen die twee lande onderteken. Volgens die Wes-Kaapse minister van landbou, dr Ivan Meyer, word

pakhuisregistrasies en verifikasies nou gefinaliseer, voordat uitvoer begin.

Uitvoeruitdagings Die minister sê koördineringvergaderings word weekliks met vrugte-uitvoerders, Transnet se beplanningshoofkanoor vir haweterminale, terminaalbestuurders en verskepers gehou. “Sodoende bestuur ons skerp toenames in die oes van vrugte en verpakking. Die plan sluit beter gebruik van nagskofpersoneel en doeltreffender kommunikasie en sinchronisasie tussen agentskappe en die hawe se logistieke ketting in. Die sukses hiermee blyk uit die rekord getal vraghouers van 19 268 wat in die week wat op 13 Februarie geëindig het hanteer is.” Later in Februarie het hoë windspoed oponthoude by vraghouerterminale veroorsaak. Indien die weer verbeter sou die aantal vraghouers na verwagting verhoog het, het dr Meyer aan Groente & Vrugte gesê. Die Suid-Afrikaanse appel- en peerbedryf voorsien tans 42 756 werksgeleenthede – seisoenale arbeid word omgeskakel na ‘n ekwivalent van 12 maande. “Gegrond op ekonomiese ontleding het appel-aanplantings oor die afgelope jaar met 2,8% toegeneem tot sowat 26 000 ha. Dit sal bydra tot ‘n verwagte groei van sowat 16,3% in ton per hektaar oor die volgende tien jaar, hoofsaaklik weens hoër plantdighteid, skadunetverbouing en die verbruikersvraag na tweekleur-appels.”

VEGETABLES & FRUIT | MARCH • APRIL 2022

ALGEMEEN

Tabel 1. BFAP appel-uitvoer.

Karton ekwivelent (kg)

2019

2020

2021

3 jaar gemiddeld

2022skatting

Appels

12,5

33.87

36,71

38.44

47.47

+2.73

+6%

Pere

12,5

17.09

16.82

17.42

19.83

+1.47

+8%

50.96

53.53

63.1

55,86

67.30

+ 4.2

+7%

KERN-VRUGTE

Totaal

Skatting vs 2021

Bron: https://www.freshplaza.com/article/9391053/south-africa-industry-set-for-a-promising-pome-fruit-2022-harvest/

Gunstige klimaat Hortgro sê welkome reën saam met genoeg koue-eenhede het meegebring dat produsente gedurende die winter van 2021 deurlopend kon besproei. Die gunstige klimaat vir kernvrugteverbouing het tot einde Augustus 2021 voortgeduur en saam met goeie vrugset die verwagting vir goeie oeste en vruggehalte versterk. “Koeler temperature in die lentemaande en hoë temperature in die vroegsomer het egter die vruggrootte negatief geraak, maar nie gunstige verwagtinge vir vruggehalte en goeie opbrengste gedemp nie.”

Geskatte opbrengs Samevattend vergelyk die Buro vir Voedsel- en Landboubeleid (BFAP) se senior analis: tuinbou, Kandas Cloete, die uitvoervolumes van 12,5 kg kartonne appels en pere van die afgelope drie seisoene én 2022 se verwagtinge in Tabel 1.

Pere Volgens Hortgro het die verskillende peerboom-variëteite in

GROENTE & VRUGTE | MAART • APRIL 2022

die land in die afgelope jaar 12 913 ha beslaan. Dit is ‘n toename van 5% van die 2016-seisoen af – die eerste jaar van die knellende doogte. Weens goeie vruggehalte én uitpakpersentasies is die verwagte toename in peervolumes sowat 8% meer as in die vorige seisoen. Die bedryf verwag dat peerproduksie na verwagting stadiger as appels sal bly toeneem, met ‘n verwagte groei van 12,6% meer pere teen 2030, relatief tot die tydperk van 2018-2020. Hier moet in ag geneem word dat die droogte volumes in dié tydperk negatief beïnvloed het. Vanjaar het die oes van pere reeds voor einde Januarie 2022 begin en was in Februarie volstoom. Sekere variëteite word tot April geoes. In die Wes-Kaap was die gemiddelde bydrae wat pere sedert 2013 tot uitvoer uit Suid-Afrika gemaak het, meer as 88% van die totale uitvoerwaarde. Sedert 2017 was die jaarlikse gemiddelde uitvoer-peeroes uit die Wes-Kaap se waarde 9% hoër, ondanks die uitmergelende droogte. In 2020 het die waarde van uitgevoerde pere tot NA BLADSY 32

GENERAL

Appels en pere om op trots te wees VAN BLADSY 31 sowat R3,1 miljard toegeneem. Ondanks ‘n volume-afname van 14% in die 2020 Bon Chretien-oes, weens stingel-entverruwing en haelskade in dele van die Langkloof, het die peerobrengs destyds steeds met sowat 2% toegeneem. In 2019 het die land 17,09 miljoen kartonne pere van 12,5 kg uitgevoer. Dié syfer het in 2020 tot 16,36 gedaal en in 2021 weer tot 17,42 miljoen kartonne toegeneem, met 19,83 miljoen uitvoerkartonne wat in 2022 verwag word.

Appels Dr Meyer sê appels uit die Wes-Kaap is jaarliks gemiddeld sowat 85% van die land se appeluitvoer. Die waarde van SuidAfrika se jaarlikse appeluitvoer het, ondanks die droogte, sedert 2012 met sowat 13% toegeneem. Oor die afgelope vyf jaar was die groei 7%, ondersteun deur die swakker rand. Na afloop van die uitermatig droë jare het die nasionale waarde van appeluitvoer in 2020 met 24% tot R6,6 miljard toegeneem teenoor 2019 se uitvoer. In 2019 is 33,87 miljoen kartonne appels van 12,5 kg uitgevoer, vergeleke met 36,71 miljoen kartonne in 2020 en 44,73 miljoen in 2021.

Kernvrugte ekonomie “Volgens die bedryf word Suid-Afrika se appeluitvoer se waarde

op R7,3 miljard beraam, met ‘n gemiddelde jaarlikse toename van 18%. Die waarde van peeruitvoer was in 2020 R3,6 miljard, met ‘n toename van sowat 13% per jaar,” sê dr Meyer. Cloete sê voorrade in die noordelike halfrond speel ‘n rol in die potensiaal van prysverdienste. “Ons kyk gewoonlik na Februarie se syfers omdat dit ‘n aanduiding is van die volumes wat in voorraad is in die EU en in die VSA teen die tyd wat SA begin uitvoer. Teen druktyd was net die eerste elf maande se syfers beskikbaar en die historiese verhouding tussen Januarie en Februarie se syfers is vir ‘n skatting op 2022 se verwagtinge gebruik.” Sy beaam dat wanneer volumes hoog is, laer pryse gewoonlik in dollar-terme realiseer. Verder bepaal die wisselkoers hoe die verdienste teenoor die vorige jaar sal wees. “In hierdie stadium kan ons moontlik staatmaak op ‘n 5-7% jaar-op-jaar verswakking van die rand teenoor die dollar,” sê Cloete. Internasionale appelvoorrade is met +2,9% effens hoër, op ‘n jaargrondslag. “Gegewe die volume wat in die EU en VSA geproduseer word, beteken daardie 2,9% bykans 170 000 ton meer, wat meer as ‘n kwart van SA se totale uitvoer in ‘n jaar is,” sê sy. Uitvoerverdienste op appels kan dus heel moontlik tot ‘n mate onder druk kom.

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• APRIL 2022 VEGETABLES & FRUIT | MARCH WWW.FERTASA.CO.ZA

ALGEMEEN

South African citrus growers export 161,6 million cartons Southern African citrus growers delivered 161,6 million cartons of local citrus across the world during 2021, an increase of 18,6 million cartons when compared to the previous year, despite an extremely difficult and complex season that put the entire industry under severe strain.

statement by the Citrus Growers’ Association (CGA) says the citrus sector faced a number of serious challenges during 2021, including the global shipping crisis, stringent additional phytosanitary measures by the European Union (EU) that are costing the industry more than R4 billion annually, as well as serious operational challenges at South African ports. The on-going issues at the ports were intensified by the violence and looting that hit parts of KwaZulu-Natal and Gauteng, which resulted in Durban port being closed for days on end. This was followed by Transnet declaring a force majeure across all ports as a result of a cyber-attack, which coincided with the height of the citrus export season. These challenges had a major impact on the timeous arrival of fruit programmes in overseas markets, which negatively affected grower revenue. Growth was seen across a number of citrus varietals with 29,5 million cartons of soft citrus exported, which was an increase of 5,9 million cartons from 2020. Grapefruit volumes increased by almost 16%, with 17,2 million cartons shipped this season. A record 27,2 million cartons of navel oranges were packed, up from the previous record of 26,7 million cartons shipped in 2018. Export volumes of lemons increased by nearly 5%, with 29,7 million cartons shipped in 2021. Despite this impressive growth, the global shipping crisis saw logistics prices soaring, while the slow turnover of ships caused major uncertainty in shipping schedules and backlogs at ports across the world. As a result, there was a dramatic increase in logistics prices and a global shortage of containers, which meant cargo had to be stored at ports, and across the supply chain for longer and at a greater cost. On average freight costs increased by approximately 30% to 40% when compared to the previous year. On top of this, vessel schedules also became erratic as a result of shipping lines responding to a strong demand on the East-West trade routes. These changing schedules meant that growers were also unable to optimise between markets, in particular the fast growing Far East market. Shipping to the Middle East from southern ports in the country became near impossible at times, which meant growers had no choice but to ship from the Durban port infrequently. Compounding these global challenges was the unprecedented domestic events in July that resulted in South African

GROENTE & VRUGTE | MAART • APRIL 2022

ports being shut down at the peak of the season, causing major backlogs across the citrus value chain. In order to ease congestion, growers were requested to stop packing fruit in August 2021. The Citrus Growers’ Association (CGA) convened daily disaster management meetings throughout the crisis to understand the current state of events, communicate with growers about the implications and engage with partners to reduce the impact of these exceptional problems. While the remarkable efforts of stakeholders across the value chain meant that fruit continued to be exported throughout the season, this still came at a major personal and financial expense to everyone involved. Fruit arrived way too late in some markets – in some cases by over a month – while there was an under-supply in other regions. Finally, the global and domestic challenges also resulted in an over-supply in other key markets, which drove down prices, particularly for lemons and soft citrus. As a result, the increased volumes of citrus exports in 2021 did not translate into higher returns for local growers. The ongoing challenge faced by South African growers is the European Union’s import measures on citrus black spot (CBS), which is a major threat to future growth in this market. It is currently costing the local industry in excess of R4 billion annually (with FCM measures) in order to comply with these market access conditions. This is despite the fact that there is scientific evidence that citrus fruit without leaves is not a pathway for the spread of the CBS pest. With these challenges in mind, the fact that the local industry achieved another record breaking export season in 2021, is truly remarkable. This was only possible due to the close collaborations and partnerships within the industry and with government and the extraordinary efforts of growers. With the local industry expected to export 200 million cartons of fruit within the next five years, it is critical that challenges experienced during this season are resolved ahead of 2022. The CGA remains committed to working with all stakeholders and partners in government to ensure the local industry continues expanding, optimising and retaining key markets across the globe so the sector creates even more jobs and brings in increased revenue for the country’s economy in the future. It currently sustains 120 000 jobs.

INSECT COLUMN

Large cabbage white butterfly

Figure 1: Egg mass of the large cabbage white butterfly. Source: https://candide.com/ZA/insects/ eaabf98455d9bdfef9c454fdb2e744bb

(Lepidoptera: Pieridae) Large cabbage white butterfly is native in Europe, where it is widely distributed. It is also found in Asia, North Africa, Europe and South Africa. The first recognition of the large cabbage white butterfly in South Africa was reported in 1994 in the Western Cape. They are migratory insects, which is the reason why they are widely distributed. They are found in open habitats that include agricultural land, parks and gardens, especially where there are brassicas. Brassicaceae (cabbage family) is the primary host of the large cabbage white butterfly. Other host plants include mustard and as well as wild hosts.

Figure 3: Final larval instar of the large cabbage white butterfly. https://commons.wikimedia.org/wiki/ File:Pieris_brassicae_(caterpillar).jpg

Figure 2: The wingless stage of potato aphid on tomato. https://candide.com/ZA/insects/ eaabf98455d9bdfef9c454fdb2e744bb

Figure 4: Pupa of the large cabbage white butterfly.

Nozibusiso Maphumulo

https://www.cabi.org/isc/ datasheet/41157#toPictures

IPM-PROGRAM, NORTH-WEST UNIVERSITY https://www.cabi.org/isc/ datasheet/41157#toPictures

Large cabbage white butterfly classification: Class: Insecta (insects) Order: Lepidoptera (moths and butterflies) Family: Pieridae Genus: Pieris Species: brassicae

ggs of the large cabbage white butterfly are bright yellow in colour and have a bottle-like shape. They are 1,4 mm high and ribbed vertically. Their colour changes to bright orange prior to hatching. Neonate larvae are yellow with shiny black heads. The colour changes to yellowish-green with yellow lines that runs through the length of the body after their first moulting. The back and sides of the larvae have numerous hair-topped tubercles (nodules), which makes the larva to have a rugose texture. Mature larvae are 45 mm long, with an olive-green colour. Their dorsal view is more greyish and have a noticeable yellow dorsal line, with dorsolateral black spots and squares on either sides. Fine, hair-bearing tubercles, most of which are black in colour, covers the entire body of the mature larvae. They have a bluish-grey head with black spots. Pupae have a length of 20 mm. Non-diapausing pupae are pale green, while the diapausing ones are greyish-white in colour and are marked with black and yellow dots. Their ventral surface is flattened. They have a lateral ridge on either sides. Their head is pointed forward with a similar ridge that extends from head up over the head, thorax and abdomen. It has numerous blunt spikes on the abdomen. Pupae can be found on walls, fencing, tree-trunks and stones, or under roofs and branches where it is attached to the substrate by a silken belt and pad. The final colour is similar to the substrate. Adult butterflies are 55 - 70 mm, females are larger than the males. The wings of both sexes are shiny white on the upper sides,

Figure 5: Adult male (left), and adult female (right) of the large cabbage white butterfly.

with a noticeable black tip on the forewing. The female has a larger black tip with a pair of black spots. The undersides of both sets of wings are pale yellow dusted with grey. In females, the black spots of the forewings also appear on the undersides. The head, thorax and abdomen are black with grey hair-like scales. Adult female lays eggs uprightly (Fig. 1) in clusters of 40 - 100 on the underside of the leaves of brassicas. Neonate larvae emerge within 7 - 14 days. There are five larval instars. Larval stage takes 26 - 29 days before they pupate. Fully grown larvae leave their host plants to find a place for pupation. Pupation takes 10-15 days, then adult butterflies emerge. There are 2 to 3 generations per year. Neonate larvae starts feeding immediately after they emerge. They feed in groups whereas the mature larvae feed individually. Feeding damage leaves holes on the foliage of brassicas. Cabbage white butterfly can be controlled biologically using various parasitic wasps and flies that predate on it. Garden wildlife such as reptiles, mammals and birds also prey on the large cabbage white butterfly. Cabbages can be covered using butterfly-proof netting to prevent egg-laying on the plants. Crushing egg-shells is also another method of control against the large cabbage white butterfly. Other control methods include diatomaceous earth and wood shavings. Attracting natural predators using refuge spots such as native grasses and wildflowers can also help in controlling the large cabbage white butterfly. It can also be controlled through chemical control. Enquiries: mashimanenozi03@gmail.com

VEGETABLES & FRUIT | MARCH • APRIL 2022

Tindrum 21/204

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Blog

Vegetables & Fruit - March/April 2022

Articles inside

Large cabbage white butterfly (Lepidoptera: Pieridae

Protecting crops takes careful planning

Modern day macadamia irrigation and ridging

Appels en pere om op trots te wees

South African citrus growers export 161,6 million cartons

Macadamia expansion

SAMAC macadamia crop forecast 2022

From grand to super

Loop katvoet vir dikvoetsiekte