Vegetables & Fruit January/February 2022

SINCE 1988

JANUARIE • FEBRUARIE 2022

Trosse tafeldruiwe stroom weer in R44,00

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

No 205

TOMATO RANGE STAR 9037

STAR 9081

A COMPACT INDETERMINATE VARIETY WITH LARGE FRUIT AND SHORT INTERNODES • Ability to keep fruit size to the top of the plant • Strong plants, uniform setting • Highly adaptable with stable performance • Very high yield potential

AN INDETERMINATE SALADETTE, GREENHOUSE OR OPENLAND VARIETY WITH EXCELLENT LARGE SIZE FRUIT OF VERY HIGH QUALITY • Early maturing • Attractive shape and size • Ability to keep its size to the top

HR: Verticillium Wilt (Va, Vd), Fusarium Wilt (Fol 1, 2), Bacterial Wilt (Rs), Tobacco Mosaic Virus (TMV).

IR: Root-knot Nematodes (Ma, Mi,Mj), Powdery Mildew (lt), Tomato Spotted Wilt Virus (TSWV).

HR: Verticillium Wilt (Va, Vd), Fusarium Wilt (Fol 2), Tobacco Mosaic Virus (TMV) IR: Root-knot Nematodes (Ma, Mi,Mj)

RENKA

STAR 9065

AN INDETERMINATE VARIETY WITH A HIGH YIELD POTENTIAL FOR UNDER COVER PRODUCTION • Uniform truss • Keeps size to the top • Good leaf cover

A DETERMINATE SALADETTE TOMATO WITH EXCELLENT FRUIT QUALITY ON A HIGHLY DISEASE RESISTANT PLANT • Compact growth, with a very high yield • Extended bearing period • Very attractive shape and size • Unique disease resistance package

HR: Verticillium Wilt (Va, Vd), Fusarium Wilt (Fol 1, 2, 3), Tobacco Mosaic Virus (TMV).

IR: Root-knot Nematodes (Ma, Mi,Mj), Tomato Spotted Wilt Virus (TSWV), Tomato Yellow Leaf Curl Virus (TYLCV).

HR: Verticillium Wilt (Va,Vd), Fusarium Wilt (Fol 1, 2), Tobacco Mosaic Virus (TMV).

IR: Root-knot Nematodes (Ma, Mi,Mj), Bacterial Wilt (Rs), Powdery Mildew (Lt).

STAR 9011

STAR 9068

A DETERMINATE TOMATO HYBRID WITH AN OUTSTANDING FRUIT QUALITY • High fruit quality • Small attachment, highly refined fruit • Excellent flavour and taste • Excellent disease resistant package

A DETERMINATE BLOCKY TYPE TOMATO WITH AN EXTENDED BEARING PERIOD • Semi- Determinate growth • Extended bearing period • Acceptable shape and size • Idealy for the informal market

HR: Verticillium Wilt (Va, Vd), Fusarium Wilt (Fol 1, 2), Bacterial Wilt (Rs), Tobacco Mosaic Virus (TMV).

IR: Root-knot Nematodes (Ma, Mi,Mj), , Powdery Mildew (lt), Tomato Spotted Wilt Virus (TSWV).

HR: Verticillium Wilt (Va,Vd), Fusarium Wilt (Fol 2), Tobacco Mosaic Virus (TMV).

IR: Root-knot Nematodes (Ma, Mi,Mj), Bacterial Wilt (Rs), Tomato Yellow Leaf Curl Virus (TYLCV), (Ty-2).

30

Edition 205

ISSN 1015-85 37

4 VOORBLAD

NEWS 4

Committed to contribute towards sustainable food production

5

New MD for Netafim

5

Bayer partners with Cerealis

6

Gebruikersvriendelike tegnologie op die plaas

7

Too wet or too dry

8

Golden macadamias acquires sorting technologies

8

Tokara climbs in world’s leading olive oil guide

10

Agri-leaders that are ready to own the future

11

New chair for SABI

As gevolg tamaties se verskeidenheid segmente is bemarkingsgeleenthede legio. Onderskeid word getref tussen ronde, ovaal en spesialiteitstamaties en daar bestaan ‘n aantal kleiner verdelings binne die segmente.

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

TAMATIES

12

Tegnologie bevorder plantgroei op genetiese vlak

15

Uitdagings en geleenthede in die tamatiebedryf

28

ADVERTISING Jana Greenall 011 476 3702 082 780 9914 mediacom@lantic.net DESIGN Mercia Venter studio.chatnoir@gmail.com

POTATOES 18

PSA on the forefront for producers

22

Response documented with the use of potassium nitrate

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/

SUBSCRIPTIONS SPECIAL RATES FOR GROUP SUBSCRIPTIONS AVAILABLE

GENERAL 24

Gebalanseerde voedingsprogramme lewer kwaliteit gewasse

26

Trosse tafeldruiwe stroom weer in

29

Produkte vir meer energie in plante

1 Year @ R222.00

2 Year @ R425.00

(6 issues)

(12 issues)

Complete and send the subscription form to: MEDIACOM, PO BOX 20250, NOORDBRUG 2522.

Tel: 018 293 0622 Email: info@mediakom.co.za

Name: Address:

Postal Code:

30

Potato aphid (Hemiptera: Aphididae) Tel: Email: Banking Details: Mediacom, ABSA, 632005, Acc no.:01-08118-0241 IN CASE OF ADDRESS CHANGE, PLEASE ENCLOSE OLD ADDRESS LABEL.

Slegs op intekening beskikbaar • Available only on subscription

GROENTE & VRUGTE | JANUARIE • FEBRUARIE 2022

3

Committed to contribute towards sustainable food production The increasing demand for safe and sustainably produced food makes it necessary for the agricultural sector to review and broaden its practices and business models.

“C

limate change and the increasing population will test our agricultural systems in the future. This complex scenario requires sustainable measures that will be capable of improving crop yield and quality, but at the same time foster the resilience of the agricultural sector. We need to employ the tools, technologies and opportunities that can address these challenges in a sustainable manner,” says Dr Nicole Hart, Managing Director at Afrikelp.

According to Dr Hart, the use of natural plant biostimulants can play a significant role in improving plants’ resistance to abiotic environmental stresses. Drought, water quality and soil salinity are some of the crucial challenges that farmers need to address. Biostimulants can contribute to enhancing plant growth, improving resource use efficiency and increasing tolerance to unfavourable soil and environmental conditions.

Natural biostimulants are biological or biologically derived products that are used in crop production to supplement and enhance existing agricultural practices and crop inputs.

These products can efficiently improve the performance of the plant's vital processes, contributing towards increased yields and improved product quality.

“At Afrikelp we position ourselves as a leading manufacturer of liquid seaweed biostimulants. Our liquid seaweed products, extracted from the unique South African kelp, Ecklonia maxima, contains various beneficial compounds that are advantageous for crop production. Our extensive quality control and standardisation processes means that every batch meets exceptional standards to ensure that we continue bringing the best the ocean has to offer to our customers.

“The use of biostimulants can assist growers to produce more with less and these products are therefore key inputs on farms. Because biostimulants have the ability to improve various traits, such as root development and the optimal uptake of nutrients, it also addresses commercial quality traits such as homogeneity of fruit size, fruit colour as well as resistance to handling and improvement of shelf life. In short, improved

4

commercial fruit, vegetables and grains quality means less food loss and waste along the food value chain and that is what our ultimate goal is – improved food production.

“I passionately believe that inputs sustainably derived from nature itself, such as those provided by Afrikelp, will be crucial for future food and fibre production.”

According to Dr Hart, collaborative partnerships are fundamental to addressing global challenges.

“We understand the importance of having the right partners in business and in a farmer’s production journey. We see Afrikelp as a trusted global partner to the agricultural industry to provide targeted specialty solutions to improve food security. We value and nurture all of our partnerships to ensure that our farmers receive the best quality products to support their needs,” she says.

The Afrikelp team was part of the recent Biostimulants World Congress held in the USA where they had the opportunity to share and gather the latest scientific and technical knowledge on the use of biostimulants.

“Shared knowledge and experiences will enable us to better position our products and improve our service to our customers. Some of the learnings will be implemented in 2022 and we believe that our industry partners and customers will benefit from these.”

On the local front, the South African authorities have recognised the importance of biostimulants in the agricultural sector through the establishment of the Group III fertilizer registrations. The requirements of the Group III registrations are more stringent, costly and time-consuming than conventional synthetic fertilizers. As a result of these requirements, future products entering the South African market will be adequately backed by science.

Looking at 2022, Dr Hart is positive that Afrikelp will continue to make a major contribution as a highly focused agricultural company to food production, not only in South Africa, but across the globe.

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

New MD for Netafim Adriaan de Lange has been appointed as Managing Director of Netafim South Africa. He takes over the reins from Etienne Erasmus who enters retirement.

B

efore joining Netafim, Adriaan served in different roles at the Omnia Group, including as the CEO of Omnia Holdings, and Managing Director of Omnia's fertilizer business division. He brings more than 20 years of progressive leadership experience in agribusiness combined with vast experience in production and services business models. He has led business growth, transformation, turnaround and innovation in multiple multinational listed companies.

In his new role, Adriaan will drive, supervise and manage all strategic and business aspects of the company. Netafim South Africa is one of 33 business units in the company.

“I want to build on the strong foundation laid by my predecessors and want to enable all Netafim employees to continue doing their jobs with excellence,” said De Lange. “I believe in the value of strategic partnerships among agribusinesses to ensure sustainable agriculture and will place focus on working with other agribusinesses to help farmers grow more with less.

“I am passionate about agribusiness, and I am excited to

Adriaan de Lange, MD Netafim South Africa.

continue my career in agribusiness. Netafim South Africa plays a crucial role in equipping farmers in Southern Africa with the latest irrigation technology in order to ensure their sustainability. It will be a privilege to be a part of this.”

Gal Yarden, SVP Head of the Netafim EMEA Division, thanked outgoing managing director, Etienne Erasmus, for his tremendous contribution to the company's growth. “He built a strong team that will continue his legacy for years to come.

I wish him much joy and fulfilment on his retirement journey.”

Etienne has led the company since 2006. During this time, the company has shown significant growth. “Netafim South Africa has a strong foundation and has reached great heights.

There is now an opportunity for the next generation to build on this foundation and take the company to even greater heights.

“I hand over the reins to Adriaan with great confidence. I am certain that his experience will benefit the company greatly and that he will lead the Netafim South Africa team to even greater heights,” said Erasmus.

Bayer partners with Cerealis

B

ayer, is constantly working towards staying at the forefront of technology, to ensure that farmers stay ahead of existing and potential threats and challenges.

The digital farming arm, Climate Corporation, has made it their mission to create digital tools that will help the world’s farmers sustainably increase their productivity. To ensure that farmers get expanded support to optimise their FieldView™ experience and access to appropriate equipment technology, Bayer and Climate FieldView South Africa have partnered with Cerealis Precision.

Cerealis Precision is a key player in precision farming technologies and equipment and is therefore a well-suited part-

ner, through providing farmers with excellent innovations that can help them grow sustainably, optimise yields and make informed decisions for future planting and harvesting seasons.

Cerealis Precision was established in 2007 as an importer and distributor of several leading agricultural technologies.

The company has partnered with the foremost companies in the field of precision planting, application, nitrogen management and precision harvesting.

For more information, contact Jaco van Zyl, Climate and SeedGrowth Go-to-Market Lead, Bayer Africa at jaco.vanzyl @bayer.com.

5

Gebruikersvriendelike tegnologie op die plaas I

6

Met dié platform kan boere plaasdata in visuele verslae saamvat.

nteliGro, ‘n verskaffer van geïntegreerde gewasoplossings, en CropWatch Africa, ‘n spesialis op die gebied van tegnologiese hulpmiddels vir gewas- en plaagmonitering, het kragte saamgesnoer om ‘n platform vir landboutegnologie in SuidAfrika bekend te stel.

Met die platform vir landboutegnologie kan boere plaasdata in visuele verslae saamvat wat hulle in staat stel om beter en vinniger besluite te neem. Die InteliGro-CropWatch platform stel boere in staat om moniteringdata, inligting oor grond, blare en opbrengs, spuitprogramme, satellietbeelde en nog meer in ‘n enkele stelsel byeen te bring.

Die resultaat is ‘n bykans intydse blik van die status van hul gewasse en lande, asook insig in historiese patrone. Hierdie inligting help boere om vinnig en presies aandag aan dringende sake soos plaagbesmettings te gee en om plaasbeplanning en -bestuur te vergemaklik.

Roedolf Nieuwenhuis, stigter en besturende direkteur van CropWatch Africa, sê die platform, wat oor die afgelope jare met boere se bydraes ontwikkel is, gee aan boere in SuiderAfrika ‘n hoogs aanpasbare, presisielandbou-oplossing wat vir

stop siektes in hul spore Twee-stap eenvoud: difenokonasool klaar bestaande vroeë roes infeksies op waarna ADEPIDYN™ tegnologie volgehoue beskerming verleen.

Regte plek, regte tyd: ADEPIDYN™ tegnologie se stadige sistemiese beweging deur die blaar se waslaag verleen kragtige blaarbeskerming en beveilig sodoende die biomassa wat vrugte nodig het om te ontwikkel.

Karboksamied tegnologie, herskep: ADEPIDYN™ tegnologie is ’n nuwe klas karboksamied met ’n sterk affiniteit vir die waslaag op blare. Dit verskaf langer nawerking en reënvastheid binne ’n uur. Slim tegnologie, ongeag die weer.

Eenvoudig. Kragtig. MIRAVIS ® Duo.

LEES DIE PRODUKETIKET VIR VOLLEDIGE BESONDERHEDE. MIRAVIS® Duo bevat ADEPIDYN™ tegnologie (Pydiflumetofen) en difenokonasool (Reg. nr. L10750, Wet 36 van 1947) SKADELIK. MIRAVIS®, ADEPIDYN™, die verwantskapraam, die doelwit-ikoon en die woord Syngenta is handelsmerke van ’n Syngenta groepmaatskappy.

Syngenta Suid-Afrika (Edms) Beperk, Privaatsak X60, Halfway House, 1685. Tel. (011) 541 4000. www.syngenta.co.za © Syngenta Ag, 2000. Kopiereg van hierdie dokument is voorbehou. Alle onregmatige kopiëring word verbied.

@SyngentaSA | www.syngenta.co.za

Too wet or too dry South Africa currently finds itself in the midst of an above-average summer-rainfall season. This is a welcome turn of events, especially for parts of the Eastern Cape that had been ravaged by drought for years.

W

hile good rains are usually good news for grain producers, the reality of “too much of a good thing” rears its ugly head when crops end up waterlogged in the fields.

Syngenta, a crop-protection specialist, developed AgriClime several years ago to provide producers with a buffer against the impact of droughts on yield. During the 2020 season, however, abundant rains caused severe and wide-spread damage to dry-bean yields and, in some instances, maize. This prompted Syngenta to also help protect producers against too much rainfall.

Against this background, Syngenta recently adjusted its AgriClime financial solution, offering producers’ much-needed relief so that they are equally supported in seasons that are either dry or marked by heavy rainfall.

It is possible for producers to recover a portion of their Syngenta purchases in cash at the end of a season that had either too much or too little rainfall. AgriClime is not crop insurance, but rather a financial solution that uses a weather derivative which allows Syngenta to support the producer against risk of yield losses caused by either drought or waterlogged conditions.

AgriClime is based on specific coordinates in a producer’s field that the system translates into a 5 km x 5 km quadrant.

The average rainfall in that quadrant over the past 20 years is then determined for a specific period within a season (the risk period). The producer selects the risk period upfront, for example, from 1 February to 15 March – these are more aligned to the dates available to be signed up now.

The producer also chooses to be hedged against either too much or too little rainfall, or both, and the system then calcu-

Syngenta recently adjusted its AgriClime financial solution, offering producers much-needed relief.

lates each producer’s unique pay-out criteria, e.g. R1 400 for every 1 mm above the rainfall pay-out trigger.

The average rainfall is compared to satellite data of the actual rainfall in the quadrant during the risk period. In cases where the actual rainfall was significantly more or less than the producer’s pay-out trigger, a percentage-based pay-out comes into play. Depending on the circumstances, producers can recover up to 27% of their Syngenta crop protection spend, should drought or waterlogged conditions, or both, impact yields negatively.

Producers who are interested in participating in AgriClime can contact their nearest Syngenta agent for all the details. Terms and conditions apply.

Gebruikersvriendelike tegnologie op die plaas VAN BLADSY 6 plaaslike omstandighede ontwikkel is. Dit is ‘n alternatief vir oplossings wat internasionaal beskikbaar is, maar moeilik kan wees om aan te pas. Die alles-in-een, geïntegreerde platform laat ‘n boer toe om ‘n oog op plaasstatus te hou en kragtige rapporteringsfunksies te gebruik om data te ontleed terwyl dit vasgevang word.

“Afgesien van die vele uitdagings wat boere daagliks in die gesig staar, moet hulle meer produseer met minder terwyl hulle hoë kwaliteitstandaarde handhaaf en koste beperk,” sê Niel Kruger, bemarkingsdirekteur by InteliGro. “Tegnologie in landbou is deurslaggewend om hulpbronne optimaal te gebruik en opbrengs te verhoog.

“Ons vennootskap met CropWatch stel boere in staat om

GROENTE & VRUGTE | JANUARIE • FEBRUARIE 2022

verskeie aspekte van hul plaas op een platform te integreer om ‘n meer holistiese siening van hul besigheid te kry. Die ryk data waartoe hulle toegang het, vereenvoudig die monitering en bestuur van gewasse oor groot gebiede. Wanneer insigte wat optrede moontlik maak só geredelik beskikbaar is, kan boere regoor hul plase produktiwiteit verhoog en koste optimaliseer.”

Monitering is volgens hom reeds ‘n gevestigde praktyk in verskeie gewassegmente en dit is besig om veld te wen as die grondslag vir geïntegreerde gewasbestuur.

“Ons platform stel boere in staat om ‘n verskeidenheid inligting, soos satellietbeelde, weerdata en toedieningsinligting, te gebruik om besluitneming en rekordhouding te verbeter.”

7

Golden macadamias acquires sorting technologies A

nticipating the need to produce macadamias in even greater quantities while ensuring perfect quality, South African cooperative business Golden Macadamias has invested in a sorting machine with biometric signature identification technology.

Attaining the highest product quality with large production volumes has been made possible by investing in the best available technologies. The most recent example of this is Golden Macadamias' acquisition of the new Tomra 5C premium optical sorting machine, explicitly developed for nut and dried fruit applications. When this machine is combined with Tomra's biometric signature identification scanning technology, it can detect and eject product defects that no other technology can see.

With the newly developed orchards, the South African macadamia crop volume grew from 9 036 metric ton (Mt) dry-nut-inshell (DNIS) in 2001 to an estimate of 57 834 Mt DNIS in 2021 (SAMAC). This growth of 540% over the past 20 years was necessary for the macadamia industry to stay relevant in the international market. The South African industry contributes roughly 20% to 25% of the world's macadamias, expressed as NIS volume (INC). South Africa is the largest contributor, with other significant contributors like Australia, Kenya and China.

Golden Macadamias' production facility is located outside Mbombela.

Norman Smith, Area Sales Manager Africa, Tomra Food, said: "Today 98% of the macadamia crop is exported. Approximately 55% of South Africa's macadamias are sold to the ker-

The Tomra 5C premium optical sorting machine.

nel market, mostly for export to the USA, Europe and Asia. The other 45% goes to the in-shell market, some for sale domestically but mostly for export to China, where consumers prefer to crack the shells themselves. It is the kernel market which demands the greatest product quality."

Peter Edmondson, General Manager at Golden Macadamias, commented that their partnership with Tomra has proved strong throughout the years. “It has allowed us to pioneer the ideal processing solution for the macadamia market, where we continuously develop new solutions and technologies.”

Tokara climbs in world’s leading olive oil guide

T

okara, the family owned Stellenbosch wine and olive estate, has been included in the world’s most authoritative international guide for extra virgin olive oil, Flos Olei 2022, with a rating of 96 points.

This comprehensive annual guide, now in its 13th year, ranks the 500 best extra virgin olive oil (EVOO) producers in the world from 55 countries. Available in two versions, Italian and English, and Chinese and English, this international guide is dedicated to producers around the globe.

Tokara enjoys recognition as one of South Africa’s top producers of world-class EVOO. The farm’s olive oil journey began in 2000 with primarily Tuscan olive varieties. Today, four cold pressed EVOOs are produced, two single varietal oils and two more intense multi-varietal blends.

The top tier Tokara Premium EVOO is carefully blended to bring together the best characteristics of Coratina, Leccino, Frantoio and Mission varieties.

Tokara premium extra virgin olive oil.

8

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

PROTECTING YOUR

CROPS FROM THE

wind, sunburn, hail damage, birds & larger insects

Agri-leaders that are ready to own the future The Syngenta Leadership in Agriculture Academy programme, in its ninth year, held their annual graduation event for the 43 candidates.

T

he Syngenta Leadership in Agriculture Academy programme in 2020 completed their programme at the end of 2020, but Covid-19 restrictions prevented the students from receiving their certificates and to graduate at the time. Last year’s combined graduation event was attended by 43 candidates as well as partners of the programme and industry stakeholders.

Now in its ninth year, the Academy is hosted by Syngenta.

The programme is presented by Thinking Fusion Africa in partnership with the Northwest University Business School and with the support of Grain SA. In his address, Anthony Delport, MD Syngenta, asserted that farmers in Africa are in the right place at the right time.

He noted that around 40% of Africans are employed in agriculture and the continent is home to 60% of the world’s arable land. Yet, Africa imports about 60% of its food needs, at a cost

Class of 2021 who completed the Leadership Academy for Agriculture Programme

10

of approximately R607 billion per year. What is more, the average African farmer performs at only around 40% of his or her potential. According to the UN Food and Agriculture Organisation (FAO), the amount of maize and other cereal crops harvested per hectare in Africa is less than half the global average.

“These are not the hallmarks of a sustainable food system,” Delport rightly commented as he urged the Leadership Academy graduates to step up to the challenge of transforming agriculture in South Arica and the continent. “Technology, partnerships and effective leadership are the trio that will advance our industry,” he said.

The impact of Syngenta’s leadership development programme was illustrated in a short address by Jan Teubes, a wine farmer from Vredendal in the Western Cape. In addition to three examples of mutually beneficial contracts he negotiated in the last year by implementing effective communication and systems thinking principles, Teubes emphasised the improved personal and professional relationships that resulted from his newly acquired skills and insights. “Thanks to this programme, the farming business I run with my brother is thriving despite challenging times for the wine industry,” he says.

“Leadership development is a personal journey, and the portfolios of evidence that the candidates submitted show that they have not only internalised the learning, but went back and applied it,” said Professor René Uys from Thinking Fusion Africa. “Judging from their portfolios, we can expect tremendous impact from these young leaders.”

Over the past nine years, 193 commercial and emerging farmers and people in agri-related professions – ranging from economists and analysts to entrepreneurs and academics – have completed the Leadership Academy programme.

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

New chair for SABI Michael Esmeraldo, Netafim South Africa’s sales manager for the northern regions, was elected as president of the South African Irrigation Institute (SABI).

M

ichael has been serving as vice-president of the organisation since 2019 and before that served as chairman of the Mpumalanga branch.

“We are proud of Michael and wish him well in his two years in office as president of SABI,” commented Etienne Erasmus, MD of Netafim South Africa and past president of SABI. Netafim South Africa has been a company member of SABI since it opened its doors in 1992.

At 30, Michael is the youngest ever president of SABI. “What a privilege. I want to encourage younger players in the irrigation industry to be actively involved in organised industry activities. I also want make young people who are still considering their career options aware of the many amazing opportunities in the irrigation industry,” says Michael.

He is proud to be part of the important impact that SABI has in the irrigation industry. “Our greatest challenge and duty in the irrigation industry is to continuously improve the way we use water. The only way to ensure a sustainable future is to use water even more sparingly. Another important challenge the industry faces is to ensure that the next generation of irrigation experts are sufficiently trained and involved in the industry. By taking this on, we will ensure a sustainable future for the irrigation industry in the country and continue to help farmers use water optimally.”

His message for the agricultural industry is that modern farming is not only about using the latest technology, but also about farming more efficiently. He believes in precision irrigation and that it must be adopted across the industry.

“We have to use water, fertiliser and other inputs efficient-

GROENTE & VRUGTE | JANUARIE • FEBRUARIE 2022

Michael Esmeraldo, newly elected president of the South African Irrigation Institute (SABI).

ly to get optimal benefit per unit of input. My message to the irrigation industry is to stay positive. We can and have a responsibility to make a massive impact in the agricultural industry and the country. As author Thomas Friedman said: The pessimists are always right, but it is the optimists that change the world.”

Michael started his career in the irrigation industry when he joined Netafim in 2014. He started as junior agronomist in the Nelspruit region and was promoted to senior agronomist after two years. In February 2019, he was appointed as regional sales manager working from Netafim’s Nelspruit office and joined the managerial team in his current role in April 2020.

Michael holds a B.Sc degree in Agronomy and Agricultural Economics as well as an M.Sc degree in Soil Science.

11

TOMATOES

Tegnologie bevorder plantgroei op genetiese vlak ’n Vinnig groeiende bevolking en langer lewensjare weens mediese tegnologie, beteken dat die wêreld se behoefte aan voedsel en veevoer teen ‘n vinnige tempo toeneem. Na raming sal ’n toename van byna 100% in landbouproduksie nodig wees om die menslike bevolking in 2050 te onderhou (Elferink & Schierhorn, 2016).

Dr Hannes Loubser1, Dr Paul Hills1, Dr Ida Wilson2 en Johan Janse van Rensburg3

derende bakterieë (De Vasconcelos & Chaves, 2019).

1

Hoe C4L-tegnologie gewasproduksie bevorder

Instituut vir Plantbiotegnologie, Departement Genetika, Universiteit Stellenbosch 2 Biorevolution en Departement Agronomie, Universiteit Stellenbosch 3 Oro Agri, Suid-Afrika

L

andbouproduktiwiteit word egter ingeperk deur klimaatsverandering en veral deur gepaardgaande waterskaarste, wat blyk uit grootskaalse wêreldwye droogtes in landbougebiede. Hoër temperature, wisselvallige en onvoorspelbare reënpatrone en uiterste weersomstandighede het verder ook ‘n uitwerking op gewasopbrengste (Challinor et al., 2014). Weens droogtes word gronde brak, wat verdere uitdagings aan gewasproduktiwiteit verleen (Bartels & Sunkar, 2005).

Biostimulante is ‘n deel van die antwoord Biostimulante is produkte wat plante se groei ondersteun en hul help om biotiese en abiotiese stremming te weerstaan.

Biostimulante is voordelig vir die plant se eie natuurlike groeiprosesse, onder meer wortels se groei en die simbiose met grondorganismes. Gesonde wortels en die bevolking van grondmikrobe wat deur die wortels gelok word, beteken dat die plant ‘n verbeterde vermoë het om voedingstowwe uit die grond op te neem. Dit bevorder die plant se algemene gesondheid en gevolglik word beter opbrengste van hoër kwaliteit deur die plante gelewer. Verskeie grondstowwe word gebruik in die vervaardiging van biostimulante, insluitend humiensure, ekstrakte van alge en ander plante en ook plantgroei- bevor-

In navorsing by die Universiteit van Stellenbosch is die uitwerking van die C4L-tegnologie biostimulant (C4L) op die plant Arabidopsis thaliana ontleed. Plante wat met C4L behandel is en plante wat geen C4L ontvang het nie, is met soutwater natgelei. Positiewe groei-effekte is in plante wat met C4L behandel was waargeneem. Die metaboliese reaksie van plante het op geen vlak verander nie en die chlorifil-inhoud en biomassa van die plante het, ten spyte van die soutwater waarmee dit natgelei is, toegeneem. C4L het dus ‘n mate van soutstremmingstoleransie aan die plante verskaf (Figuur 1). Laastens is ook opgemerk dat plante se waterhouvermoë (deur die huidmondjies) ook gereguleer was, tot so ‘n mate dat dit plante se vermoë om te groei bevorder het (Loubser & Hills, 2020).

Hoewel die versagting van soutstremmings baie duidelik sigbaar was in die plante wat ontleed is, is dit ook moontlik dat ander stremmingsversagtiging kan plaasvind. Volgens Zhu (2016) reageer baie van die gene wat deur soutstremming geaktiveer word, ook op koue of droogtestremming. Dit verhoog sodoende die moontlikheid dat C4L ‘n waardevolle hulpmiddel kan wees in die bemiddeling van ander soorte stremming. Dié moontlikheid sal in die toekoms in opvolgnavorsing by die Universiteit van Stellenbosch ondersoek word.

Veranderinge op molekulêre vlak C4L ontlok fisiologiese reaksies in gewasse wat gewasopbrengs en -gehalte verhoog. Die bogenoemde navorsing het ook die NA BLADSY 14 Figuur 1: Bogrondse biomassaproduksie van Arabidopsis thaliana waneer dit met brakwater natgelei is (a) of wanneer dit ‘n C4L-toediening ontvang het en daarna met brakwater natgelei is (Figuur vanuit Loubser, 2020).

12

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

TOMATOES

Tegnologie bevorder plantgroei op genetiese vlak VAN BLADSY 12 Aktivering van tamatieplantgeen

Figuur 2: Die groei van die kontrole tamatieplant wat geen C4L ontvang het nie (links op foto) het visueel verskil van die tamatieplant wat C4L ontvang het (regs op foto) (Loubser, 2020).

In die driejaarlange doktorale navorsing is die reaksie van tamatieplante (Solanum lycopersicum) op die molekulêre vlak ook ontleed. Die reaksie van plante waarop ‘n blaarbespuiting van C4L toegedien is (teen ‘n konsentrasie van 0,05% [v/v]) is bestudeer.

Dit was duidelik dat C4L die plante se biomassaproduksie gestimuleer het. Veral die wortellengtes van behandelde plante was opmerklik langer as plante wat nie die produk ontvang het nie (Figuur 2 en Figuur 3).

Soos vir die Arabidopsis-plante was die gene in behandelde plante anders uitgedruk in vergelyking met dié wat nie C4L ontvang het nie. Vir tamaties was daar ‘n groter reaksie as vir die Arabidopsis-plante. In hierdie geval was dit 18% van die uitgedrukte gene in behandelde plante wat verskil het van die onbehandelde plante. Van hierdie 18% was 9% op-gereguleer en 9% af-gereguleer. Veral gene wat verantwoordelik is vir stremming en proteïenmetabolisme is anders uitgedruk, wat tot ‘n mate die verbeterde groei in die tamatieplante kan verduidelik (Loubser, 2020).

Samevatting

Figuur 3: Die wortels van tamatieplante wat nie C4L ontvang het nie (onderste wortels op foto) was visueel korter as die wortels van plante wat C4L ontvang het (boonste wortels op foto) (Loubser, 2020).

biostimulant se uitwerking op die plante op molekulêre vlak bestudeer. Daar is bevind dat die werking van C4L, toegedien as ‘n grondtoediening teen 0,01% (v/v), se positiewe effekte vanweë die uitdrukking van spesifieke gene in die plant is. ‘n Transkriptoom is ‘n weerspieëling van die onderliggende gene wat vir die sintese van metaboliete (en ander molekules) in ‘n lewende organisme verantwoordelik is. Wanneer ‘n mens kennis insamel met behulp van ‘n transkriptoom, evalueer dit spesifieke geen-uitdrukking en spesifieke metabolietvervaardiging.

Toe die transkriptoomprofiel van C4L-behandelde plante vergelyk is met dié plante wat nie C4L ontvang het nie, is 8% van die gene anders uitgedruk in plante wat die produk ontvang het. Ongeveer 5% van die gene was op-gereguleer.

Op-regulasie beteken dat meer van ‘n spesifieke proteïen deur ‘n geen geproduseer sal word, en ongeveer 3% van die gene is af-gereguleer, wat beteken dat die uitdrukking van ‘n proteïen afgeneem het.

Veral gene wat betrokke is by fotosintese, selwandvorming, koolhidraatmetabolisme en sekondêre metabolisme was deur C4L beinvloed, wat moontlik die verbetering in plantgroei in die plante wat die C4L behandeling ontvang het verduidelik (Loubser, 2020).

14

Toekomstige landbouproduksie staar baie uitdagings in die gesig, en veral dié van die produsering van gewasse onder uitdagende omgewingstoestande. Gelyktydig is daar ‘n groeiende behoefte aan groter opbrengste. Akademiese navorsing het bewys dat C4L, ‘n kommersieel beskikbare biostimulant, die opbrengs en kwaliteit van gewasse verbeter. Ondersoek na die onderliggende meganisme van werking van die produk het aangetoon dat die middel plante se metabolisme beïnvloed deur verandering in die metaboliese weë wat plantgroei en funksionering bepaal.

In die toekoms, namate kennis van die onderliggende meganismes van weerstand en stremmingsverligting in plante uitbrei, sal die potensiaal van C4L ter ondersteuning van gewasverbouing nog duideliker word. Nieteenstaande is C4L reeds ongetwyfeld ‘n hulpmiddel vir toekomstige volhoubare gewasproduksie.

Verwysings Loubser, J. 2020. Analysis of the molecular and physiological effects following treatment with BC204 in Arabidopsis thaliana and Solanum lycopersicum. PhD Dissertation, University of Stellenbosch.

Loubser, J. & Hills, P. 2020. The application of commercially available Citrus-based extracys mitigates moderate NaCl-Stress in Arabidopsis thaliana plants. Plants 9: 1010.

Zhu, J. 2000. Update on stress signalling genetic analysis of plant salt tolerance using Arabidopsis. Plant Physiol. 124, 941–948.

Elferink, M. & Schierhorn, F. 2016. Global Demand for Food Is Rising. Can We Meet It? Harvard Business Review-7 April 2016. Available online: https://hbr.org/2016/04/global-demand-for-food-is-rising-can-wemeet-it (accessed on 22 June 2021) Challinor, A.J., Watson, J., Lobell, D.B., Howden, S.M., Smith, D.R. & Chhetri, N. 2014. A meta-analysis of crop yield under climate change and adaptation. Nature Climate Change, 4(4), pp.287-291.

Bartels, D. & Sunkar, R. 2005. Drought and salt tolerance in plants. Critical reviews in plant sciences, 24(1), pp.23-58.

De Vasconcelos, A.C.F. & Chaves, L.H.G. 2019. Biostimulants and their role in improving plant growth under abiotic stresses. Biostimulants in plant science, pp.1-14.

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

TAMATIES

Uitdagings en geleenthede in die tamatiebedryf

‘n Tamatie-aanplanting waar die blare laatroes ontwikkel het as gevolg van bewolkte, nat toestande.

Met die La Nina- “Little Girl” verskynsel wat nou oor die land aanwesig is, het verbruikers en produsente uitgesien na ‘n goeie reënseisoen Johan Stronkhorst

D

ie reënpatroon het egter reeds vroeg in die seisoen begin met intense storms wat wydverspreid oor die land waargeneem is. Produsente is egter negatief beïnvloed in gebiede waar die weerpatroon gepaard gegaan het met hael en sterk winde, wat gewasse beskadig het. Sommige produsente was genoodsaak om oor te plant, aangesien die skade net té erg was vir enige ekonomiese voordeel. Gewasse is verder aan grondvoorbereidings, uitplantings, oes- en spuitpraktyke blootgestel.

Die meeste verbruikers, veral in die stede, ervaar ongerief met slegs ‘n ligte reënbui – dit beteken die beplande grassny of piekniek word ontwrig. Vir produsente is reën egter ‘n saak van oorlewing. Indien dit te veel of te min reën, kan boere nie

GROENTE & VRUGTE | JANUARIE • FEBRUARIE 2022

grond voorberei, beddings maak of gewasse uitplant nie. Dit beteken ook dat saailinge wat gereed is vir uitplant se aflewering uitgestel moet word, ouer plantjies word gevolglik uitgeplant en daar kan dus reeds oesverliese ter sprake wees.

Wanneer gewasse uitgeplant is, moet bemesting, besproeiing en plaagbeheer gedoen word.

Indien produsente nie in die lande kan kom om te spuit nie, kan sekere siektes groot skade aanrig. Siektes soos laatroes of peste soos Tuta absoluta kan binne enkele dae ‘n algehele verlies aan blaaroppervlak veroorsaak, wat aanleiding kan gee tot lae opbrengste of ‘n oesverlies. Miljoene rand se verliese is in Desember 2021 deur tamatieprodusente gely.

In landboukringe is ‘n welbekende spreuk: “As ‘n tamatieoes jou in die moeilikheid bring, is die volgende tamatie-oes NA BLADSY 16

15

TOMATOES

Uitdagings en geleenthede in die tamatiebedryf VAN BLADSY 15

Vrugte met lae kwaliteit as gevolg van reën.

Verkeerde bemestingspraktyke lei tot tamatieplante met lang internodes en swak vrugset.

16

die enigste oplossing”. Hierdie stelling plaas die produsent egter net onder meer druk om suksesvolle oeste te produseer, veral met die groot styging in insetkoste.

Die beplanning van aanplantings is een van die produsent se belangrikste besluite. Met die huidige situasie in die landboubedryf word produsente genoodsaak om die boerdery te laat groei, maar dit is nóg belangriker om te identifiseer waar die groei vandaan sal kom.

Die maklikste manier om te kwantifiseer is om hektare te vermeerder, maar dit is nie altyd die beste finansiële besluit nie. Boerderye groei horisontaal, nie vertikaal nie. Indien die produsent gevolglik sy opbrengste kan verhoog, is dit meer doeltreffend as om slegs meer hektare by te voeg. Derduisende tonne tamaties is onbemarkbaar omdat die vrugte deur siektes of insekte beskadig word, of omdat die produsent nie op die korrekte tyd kon oes nie. Gewasse soos tamaties en rissies moet deurentyd geoes en bemark word, wat beplanning om op die korrekte tyd te oes krities maak.

Produsente moet terselfdertyd probeer om op hoogte te bly van omstandighede in die verskeie streke, pryse en tendense op verskeie markte en by die informele sektor, asook ander moontlike kanale waar die produk bemark kan word. Markte kan baie spesifieke voorskrifte hê indien ‘n produk in oorvloed is, maar sodra daar ‘n tekort is, is die spesifikasies en pryse meer vloeibaar.

As gevolg tamaties se verskeidenheid segmente is bemarkingsgeleenthede legio. Onderskeid word getref tussen ronde, ovaal en spesialiteitstamaties en daar bestaan ‘n aantal kleiner verdelings binne die segmente. Vruggrootte is ‘n subjektiewe maatstaf en dit wat vandag in die mark gewild is, is môre weer minder aanvaarbaar. Op sy beurt bepaal dit weer die verskeidenheid tamatieverpakkings.

Die een faktor wat vir die produsent baie moeilik kan wees is die keuse van ‘n variëteit. Daar bestaan ‘n groot verskeidenheid opsies en dit wat vir een produsent sukses verskaf, werk nie noodwendig vir ‘n ander nie. Oor die algemeen is die keuse van ‘n variëteit nie ‘n vinnige besluit nie. Dit is die moeite werd om eers proefnemings te doen om te sien of die spesifieke variëteit aangepas is vir die gebied en die produsent se bestuurspraktyke. Dit is baie seldsaam dat een variëteit onder alle omstandighede die beste sal wees. Variëteite wat die afgelope tyd goed presteer het, het as gevolg van die hoër reënval in ‘n gebied ook nie optimaal geproduseer nie.

Die ander faktor wat belangrik is met variëteitskeuse, is bemesting. Hoe moet ‘n produsent die spesifieke variëteit bestuur om sodoende die beste

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

TAMATIES

Simptome van Phytophthora-laatroes op vrugte.

resultaat te verkry? Variëteite verskil baie van mekaar ten opsigte van die hoeveelheid en stadiums wanneer dit bemesting benodig. Baie groeikragtige plante, wat aan die begin oorbemes word, kan uit balans groei en slegs vegetatief groei. Die gevolg is baie lang internodes en laer vrugset. In die meeste gevalle moet plante bestuur word vir vroeë vrugset en kort internodes - dit kan vir die produsent baie besparing in arbeid meebring en die effektiwiteit van bespuitings vir siektes en peste verbeter.

Die huidige tamatieseisoen gaan nog baie uitdaging vir talle produsente meebring. Deur insetkoste te bestuur en praktyke te skep om opbrengste vir die huidige toestande te optimaliseer, kan hierdie seisoen ‘n suksesvolle een vir die tamatieprodusent maak.

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

17

POTATOES

PSA on the forefront for producers “The year under review will go down in history as the year all historic reference points was challenged. Since the beginning of 2020, producers in the potato industry had to adapt several times during their production seasons to Covid-19 regulations.”

T

his is according to Willie Jacobs, Chief Executive Officer Potatoes South Africa (PSA). In the PSA annual report, Jacobs say that in order to adhere to social distancing, many producers have been implementing work shifts by extending operating hours in their pack houses, a step which necessitates greater pressure on all resources, including electricity usage.

“The agricultural sector was but one of a few that managed to hold its own during and after the major Covid-19 lockdown periods. The minimum wage increase earlier in the year, along with electricity price hikes, had a significant effect on the potato industry. Yet, having faced various challenges in 2020, the potato industry still contributed positively to South Africa’s farm economy, employment and food security.

“This is evident in the per capita potato consumption in South Africa, which has increased markedly in the last ten

18

years, proving the powerful impact that the staple food has in the country. Potatoes helped ensure food security throughout the pandemic in South Africa last year,” said Jacobs.

Continued involvement from all role-players will be required to optimise the potato industry’s impact. Potatoes, like all other fresh produce, are sold through multiple channels, with national fresh produce markets being the main driver of fresh produce sales. However, during Alert Levels 5 and 4 of lockdown, the restrictive regulations limited trade, thereby inspiring traders and producers to find direct ways of connecting. Volumes recorded by PSA (under the levy requirements) revealed a migration from national fresh produce markets to direct transacting.

He emphasised that the consumer still sees potatoes as a good value proposition, compared to substitute products, TO PAGE 20

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

Tindrum 21/045

Aartappelprodukte wat werk Die beproefde sukses van die Philagro produkreeks verseker dat ons produkte kop en skouers uitstaan in ‘n koste-doeltreffende aartappelprogram!

• Verbeter die uitloop van moere met ProGibb® 4% en ProGibb® 40 WG. Beheer: • Laatroes met Leimay® 200 SC – NUWE EN UNIEKE CHEMIE IN S.A. • Swartskurf en Stamkanker met Rizolex® WP • Aartappelmot en Tuta absoluta met SumiPleo® • Aartappelmot, Snywurm en Afrika (Amerikaanse) bolwurm (in die Wes Kaap) met Sumi-Alpha® 200 EC en Sumi-Alpha® 200 EW • Plusia landmeters met DiPel® DF en Florbac® WG • Vroeëroes met Sumisclex® SC Praat gerus met jou naaste Philagro-agent oor betroubare aartappelprodukte wat werk.

RAADPLEEG DIE ONDERSKEIE PRODUKETIKETTE VIR VOLLEDIGE GEBRUIKSAANWYSINGS & -BEPERKINGS. DiPel® DF (Reg. nr. L6441, Wet nr. 36 van 1947) bevat Bacillus thuringiensis var kurstaki, versigtig. Florbac® WG (Reg. nr. L5531, Wet nr. 36 van 1947) bevat Bacillus thuringiensis var aizawai, versigtig.

Leimay® 200 SC (Reg. nr. L10884, Wet nr. 36 van 1947) bevat Amisulbrom (sulfoamied), versigtig. ProGibb® 4% (Reg. nr. L5118, Wet nr. 36 van 1947) bevat gibberelliene. ProGibb® 40WG (Reg. nr. L6777, Wet nr. 36 van 1947) bevat gibberelliene. Rizolex® WP (Reg. nr. L6376, Wet nr. 36 van 1947) bevat tolklofosmetiel, versigtig. Sumi-Alpha® 200 EC (Reg. nr. L6452, Wet nr. 36 van 1947) bevat esfenvaleraat, giftig. Sumi-Alpha® 200 EW (Reg. nr. L8821, Wet nr. 36 van 1947) bevat esfenvaleraat, skadelik. Sumisclex® SC (Reg. nr. L6377, Wet nr. 36 van 1947) bevat prosimidoon. SumiPleo® (Reg. nr. L8377, Wet nr. 36 van 1947) bevat piradaliel dichloropropeen derivaat, versigtig. SumiPleo®, Rizolex®, Sumi-Alpha® en Sumisclex® is geregistreerde handelsmerke van Sumitomo Chemical Company, Tokyo, Japan.

ProGibb®, DiPel® en Florbac® is geregistreerde handelsmerke van Valent BioSciences, VSA. Leimay® 200 SC is die geregistreerde handelsmerk van Nissan Chemical Industries LTD, Tokyo, Japan.

Philagro Suid-Afrika (Edms) Bpk l Reg. nr.: 98/10658/07 PostNet Suite #378, Privaatsak X025, Lynnwoodrif 0040 Pretoria: 012 348 8808 l Somerset Wes: 021 851 4163 www.philagro.co.za

P R O D U K T E W AT W E R K V A N M E N S E W AT O M G E E

POTATOES

PSA on the forefront for producers FROM PAGE 18

20

which offer good support for the price of potatoes. Another important point to get across to the consumer, is that potato producers are completely invested in providing food for South Africa. Not only do they work to feed the nation, but they are also heavily invested into keeping the rural communities going.

“Towards our existing potato producers, we hence express our sincere appreciation. At PSA we see and understand the difficult circumstances under which they sometimes have to keep producing and we assure them – it does not go unnoticed. South Africa needs them and from PSA’s side we will continue to assist and facilitate, as and where necessary. We can indeed assist the producers with the economy of their business and can help facilitate the demand for a good product. Hold on tight, persevere – the market is ready for the producer.

“For those who want to venture into potato production, there is still secure space for new entrants into the potato market. PSA is there to actively support those entrants with advice. Potato production is a complex business, because it is a complicated crop. I want to be as bold as to say that potato production is perhaps more of an emotional challenge than facing a climate challenge.

“Potato production requires huge capital input and if one wants to produce table potatoes, a farm is not all that you need. A lot of capital and inputs are required to establish pack houses and other important facilities. At PSA we have all the technical knowledge required to support a novice producer,” said Jacobs.

In his report, Jacobs emphasises that PSA focuses pertinently on one of the largest factors affecting the market price of potatoes, namely the line of communication between what happens in the production environment, as opposed to what the markets need. Jacobs says that interaction is required and there should be a better understanding of the seasonal nature of the industry and how it works.

“It is important that we know when shortages are expected and that we find ways to bring about price stability for both the consumer and the producer. Not only will it improve the economy of the industry – it will also positively affect the

consumer’s pocket.

“Producers, as marketers and business owners, must also understand all the factors that have an impact on their businesses by making informed decisions for themselves. PSA knows that communication with the producers is thus very important. For this reason, communication tools, such as WhatsApp, are used to exchange information, for instance marketing periods of different production regions.

“Where lack of reliable information could be both the biggest threat and the most promising opportunity, optimising data technology can unlock huge potential for one of the country’s favourite foods. In this, PSA embraces technology to fulfil its role as industry body,” said Jacobs.

The continuous input cost-squeeze demands high marketable yield as counter-measure. PSA’s research core business is focused on the identification of improved cultivars to increase yield potential. Research on water and nutrient use aims to reduce the limiting factors whereas research on pests and diseases aim to address the reducing effect on yield.

When addressing the research that was done by PSA, Jacobs said that 14 on-farm trials were carried out successfully.

Product trials were conducted by the Eastern Free State Work Group under controlled conditions (fertilizer, spraying, etc).

PSA remains responsible for trail lay-out, planting, harvest, data analysis and reporting.

This is important for farmers, because the trials are objective through a scientific evaluation of fertiliser and plant protection products, giving farmers peace of mind that products perform as claimed. Cultivar exhibitions after results have been analysed make it possible for farmers in the region to evaluate the quality of the tubers of the cultivars put to trial under commercial conditions in the climate prevailing in the region.

Research on the sustainability of irrigation in the Sandveld region involves co-operation in funding from various industry bodies, research partnerships with different institutions and co-workers in the Sandveld. The research addresses national and international concerns and is the only study of this nature on potatoes in the world. The research required sophisticated instruments and large amounts of data. Results showed that

AARTAPPELS

21

SCAN ME

in most of the nine case studies, water and nutrients are used efficiently. This research also highlighted the risk of over-irrigation in the rainy season.

Research on diseases such as leaf blights (early blight and brown spot) brought to light that there are four Alternaria species causing blights in South Africa – not two as previously thought. Fungicides are used to control early blight and brown spot. However, a loss of sensitivity of Alternaria to fungicides has been reported in countries in the northern hemisphere.

He notes that the question then arouse whether the fungi in SA were still sensitive to fungicides to afford good control.

After one year’s research, signs of loss of sensitivity to two fungicides were shown. The results were communicated to not only farmers, but also to plant protection companies to enable them to position their products so that the development of tolerance of Alternaria to these fungicides can be availed. Research on diseases such as these is important and

confirms that dependency of fungicides means that we cannot afford to lose valuable chemistry.

Jacobs emphasises that market intelligence forms the backbone of decision-making. Subsequently PSA (NPC) constantly seeks to better align the sources and range of information with the needs of the industry.

The objective of the information core business is to make information – and more importantly intelligence – available to producers. This empowers them to make strategic and tactical decisions to optimise the sustainability of their potato farming.

Although with 570 producers across 16 regions of production, the potato industry provides employment for between 50 000 and 60 000 people, the industry remains largely untransformed, considering that only 1% of the country’s production comes from black owned farms. Despite having proved resilience last year by producing 2,6 million tonnes, the South African potato industry appeals to stakeholders to form more partnerships to drive growth and transformation.

During the last financial year under review, the transformation core business assisted in the development of black potato farmers to commercial farmer level through its Enterprise Development Programme. Furthermore, industry related training on DVD’s were released in eight languages and distributed at various agricultural related events. Business mentorship for farmers on the programme was introduced and accounting services in support for farming enterprises were provided.

FERTASA, FERTASA , CERTIFIED CERTIFIED CREDIBILITY. CREDIBILITY.

ITS MEMBERS ARE COMMITTED TO THE PROMOTION OF FFERTASA ERTAND ASOIL S AFERTILITY , CEAND RTENHANCED IFIED CNUTRITION. REDIBILITY. SUSTAINABLE PLANT

© MES CON SA

Fertasa strives to provide information on fertilizer and crop related topics. Apart from assistance with fertilizer applications, queries relating to fertilizer usage, plant nutrition and soil fertility usage, plant nutrition and soil fertility are referred to our Technical Advisers or Subject Matter Specialists for their expert opinions and advice.

Member companies and others are encouraged to share their experiences in proven techniques and novel approaches in ensuring social, environmental and economic sustainability for all.

Tel: +27 (0) 12 349 1450 | Fax : +27 (0) 12 349 1463 Email: general@fertasa.co.za

FERTASA MEMBERS ARE COMMITTED TO: Ÿ

A code of conduct.

Ÿ

A set of standards audited by an independent compliance management body.

Ÿ

Quality products.

Ÿ

Relevant scientifically-based recommendations.

Ÿ

Continual learning and improvement.

Ÿ

Complying with all legal requirements.

FERTASA Fertilizer Association of Southern Africa

www.fertasa.co.za

POTATOES

Beneficial nutritional responses documented with potassium nitrate* Horticultural crops are high feeders of both nitrogen and potassium, with potassium being taken up in the largest quantities.

W

hat growers strive to achieve are yield increases from more and larger marketable product per unit area, quality improvement – whether it be increased brix, specific gravity, total suspended solids (TSS), acidity, vitamin C, less peel defects as well as improved colour – and by reducing crop losses by increasing disease resistance. Potassium nitrate has been shown to improve all the above-mentioned parameters.

Fertigation programmes including potassium nitrate It has been well documented in many crops and many soil conditions that the combination of a positive potassium cation (K+) with the negative anion of nitrate (NO3)- act synergistically in the uptake of each other. Since both the elements of nitrogen (N) and potassium (K) are used by horticultural crops in the greatest quantities, this combination is highly beneficial in fertigation programmes.

Excessive ammonium nutrition can induce calcium deficiencies in many crops, even though calcium (Ca) is supplied in adequate quantities. Examples of this are tip-burn in lettuce, blossom end-rot in tomatoes and peppers, bitter-pit in apples and internal browning in pineapples.

Nitrate-N in a nutrient solution also directly proportionately limits the uptake of excess chlorides. Small amounts of chloride are essential but in many horticultural crops, excess chlorides have been shown to be detrimental to quality and yield.

Chloride sensitivity is dependent on crop type.

Maximising nitrate-N (NO3)- maintains an optimal pH close to the roots (rhizosphere pH). If the plant is fed ammonium (NH4)+, along with all the other cations, then there is an excess of H+ given off by the plant that causes the rhizosphere pH to drop by as much as 1,5 units (between 10 and 100 times more acidic). This acidity can be toxic to the roots per se and induce pH-dependent nutrient deficiencies.

Using potassium nitrate to maximize the supply of negatively charged nitrates, is thus the ideal way of optimizing K+ uptake, N uptake and the uptake of the other cations, Ca2+ and Mg2+, into horticultural crops, while at the same time, limiting the uptake of chlorides. Greater plant dry weight, reflected in yield and quality, is always the result.

Foliar applications with potassium nitrate alone or in combination** Foliar applications are required in times of peak demand, poor rooting conditions, salinity, cold, waterlogging, drought, incorrect fertilizer applications and root diseases.

Periods of rapid fruit/crop filling are periods of peak nutrient demand. Potassium nitrate foliar applications at these times can result in greater yield and quality. In deciduous trees, post-harvest foliar sprays will boost the stored N and K reserves for the following years’ budbreak and fruit set improving both fruit uniformity and yield.

Potassium nitrate foliar applications have been shown to increase the resistance of plants towards diseases (systemic acquired resistance – SAR). This occurs on both the metabolic level (phenols, auxins, phytoalexins and short chain carbohydrates), as well as on a physical level (firmer cell walls and faster recovery). According to the International Potassium Institute, Perrenoud (1990) extensively reviewed the effect of potassium applications on disease severity in crops. With bacterial infections, potassium application decreased severity in 99 out of 144 cases with 14 unchanged. For fungal infections, potassium application decreased disease severity in 1 080 of 1 549 cases with 112 cases unchanged.

Potassium nitrate is the preferred N and K source in horticultural crop nutrition often resulting in: • optimum K and N uptake, • stronger healthier plants, • better set and fruit yields, • increased fruit/crop size, • better colour intensity, • increased disease resistance and • enhanced stress tolerance such as drought, frost and salinity.

For both fertigation and foliar applications, consult an agronomist regarding rates and timing of applications. *Reg No K5020 Act 36/1947. Registration holder Sociedad Quimica y Minera (Africa)(Pty)Ltd **All claims in this article can be substantiated with references which can be made available on request.

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.

22

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

GENERAL

PROMOSIE

Gebalanseerde VOEDINGSPROGRAMME lewer kwaliteit gewasse Gebalanseerde voedingsprogramme verhoog plantweerstand teen siektes en bevorder kwaliteit gewasse. Dit is ook kostedoeltreffend en bevorder volhoubare landboupraktyke. Enige groenteof vrugtegewas het ’n spesifieke groeikurwe van plant- tot oestyd en verskeie voedingstowwe word volgens die groeikurwe opgeneem.

D

ie plant gebruik elke voedingselement in verskillende hoeveelhede en verhoudings op spesifieke tye deur die groeiseisoen. NexusAG spesialiseer in omvattende gewasbestuurprogramme en bied drie strategiese fokusgebiede, naamlik NexSOLUTIONS, NexSERVE en NexTECH. NexSOLUTIONS behels doelgemaakte wetenskaplik gebaseerde gewasprogramme. Omdat die maatskappy plantvoeding- en grondgesondheid as só ’n belangrike aspek van volhoubare boerdery beskou, is ’n sub-fokusarea, NexNUTRI, tot stand gebring.

NexNUTRI bevorder gesonde groente- en vrugtegewasse deur aanwending van grondgesondheid en gewasspesifieke voedingsprodukte. ’n Proaktiewe program jeens grondgesondheid verg ’n balans tussen die grond se chemiese, fisiese en biologiese eienskappe. Tegnies-korrekte en mededingende plantvoedingsprogramme vereis kennis van die fisiologiese en chemiese prosesse in die gewas en gewasadviseurs span hul kundigheid hiervoor in.

NexNUTRI het ’n reeks produkte soos koolstof, humien en fulviensure waarmee grondgesondheid bevorder kan word.

Die tegniese span, met kundiges wat spesialiseer in ‘n reeks gewasse, stel maatpas bemestingsprogramme saam om regdeur die goeiseisoen aan die betrokke gewas se voedingsbehoeftes te voldoen. As voorbeeld kan die verhouding van stikstof tot kalium genoem word. In die vegetatiewe fase word ’n verhouding van 3 tot 1 (N:K) toegedien en in die reproduktiewe stadium draai die verhouding om na 1 tot 3 (N:K).

Die tegniese span kan die beste produkte van die top internasionale en plaaslike verskaffers kombineer en het toegang tot organiese, half-organiese, wateroplosbare en korrelprodukte.

NexusAG het ook die afgelope paar jaar hul eie produkte geformuleer, omdat unieke behoeftes ontstaan het waaraan huidige produkte nie voldoen nie. Die maatskappy besit 10 wateroplosbare, 2 korrel- en 1 half-organiese registrasies.

Die bemestingsprogramme sluit kunsmis soos makro- en mikrovoedingstowwe in, asook groei-aktiveerders soos bioflavonoides, kelpprodukte, Fulvien en Humiensure, Rhizobium en Trichoderma en vishidrolisate. Produsente word onder-

24

steun deur kundige advies deur gewasadviseurs met betrekking tot grond, bewerking, reste, voginhoud en besproeiingskedulering, ideale gewasse vir die betrokke kombinasie van grondfaktore, asook wisselboupraktyke.

As deel van NexusAG se waardetoevoegende dienste onder die NexSERVE strategiese fokusgebied, sorg NexANALYSE dat grond-, water- en plant-ontledings, in samewerking met erkende laboratoriums, die basis vorm van die maatpas voedingsprogramme.

Kundige gewasadviseurs kan gevolglik vir produsente unieke mengsels meng om optimaal aan hul spesifieke behoeftes te voldoen.

Die twee ander afdelings wat onder NexSOLUTIONS val, is NexPROTECT en NexBIO. Om doeltreffende gewasbeskerming te bevorder en plae en algemene siektes te beheer, kombineer gewasadviseurs NexPROTECT-produkte in onpartydige produkaanbevelings van top landbouchemiese verskaffers. Dit word gedoen sodat wetenskaplik-korrekte chemiese aanbevelings gemaak kan word, wat aan nasionale en internasionale standaarde voldoen. Die produkte sluit swamdoders, onkruiddoders, insekdoders en groeireguleerders in.

NexBIO spesialiseer in bioprodukte met ’n baie lae invloed op voordelige organismes, vir doeltreffende siektebeheer. Dit sorg dat daar voldoende dreinering, goeie grondstruktuur, hoë mikrobiese aktiwiteit en hoë organiese materiaal in die grond teenwoordig is. Diverse mikrobiese aktiwiteit bevorder die algemene onderdrukking van patogene en siektes en dit kan help om meer voordelige organismes te stimuleer, wat antagonisties teenoor patogene is. Daar is verskeie ekovriendelike aanbiedinge wat die stygende gewildheid in NexBIO verklaar.

NexusAG se gewasadviseurs spesialiseer in verskeie groentegewasse. 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 die landboubedryf reeds die afgelope 22 jaar.

Kontak NexusAG by 021 860 8040 of besoek www.nexusag. net vir meer inligting.

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

BOER JY VIR ’N BETER TOEKOMS? NEXUSAG BIED PASGEMAAKTE GEWASBESTUUR-OPLOSSINGS om winsgewende boerderybedrywighede, wat bydra tot die volhoubaarheid van landbou-ondernemings, te bevorder.

NexSOLUTIONS

NexSERVE

NexTECH

Verskaf ’n kombinasie van gewasbeskerming- asook plantvoeding- en grondgesondheidprodukte.

Deel ons gespesialiseerde kundigheid deur tegniese dienste en oplossings wat waarde toevoeg.

Pas die jongste tegnologie en sagteware-oplossings toe om presisie-landbou te bevorder.

NexusAG Croplife-geakkrediteerde gewasadviseurs bied maatpas gewasbestuursprogramme, wat elke produsent se unieke omgewing en spesifieke omstandighede in ag neem, om volhoubare oplossings te bied.

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

GENERAL

Trosse tafeldruiwe stroom weer in Die huidige Suid-Afrikaanse tafeldruifseisoen kan tussen 70,6 miljoen en 77,77 miljoen 4,5 kg ekwivalente kartonne se wêreldklas-vrugte lewer.

Jan Greyling MEDEWERKER

D

ie eerste oeskatting vir die 2021/22-seisoen van die SuidAfrikaanse Tafeldruifbedryfvereniging (SATI) bevestig dat die skattings vir hierdie oesjaar grens aan die totale lewerings wat tydens die 2020/21-oes behaal is.

Willem Bestbier, uitvoerende hoof van SATI, het in Stellenbosch aan lede van die Landbouskrywersvereniging van SuidAfrika gesê die gemiddeld van die geskatte opbrengs uit al vyf produksiestreke is 74,2 miljoen kartonne – baie na aan die volle lewering van die vorige seisoen.

“Hoewel nuwe aanplantings van die hoëropbrengskultivars

na verwagting vanjaar hul volle opbrengs sal lewer, dui 2021 se wingerdsensus op ‘n afname van 536 hektaar tafeldruiwe, met ‘n daling vanaf 21 100 ha tot 20 564 ha.”

Die sensus vorm die grondslag van die eerste seisoenale oesskattings vir 2021/22 in die bedryf. Meer skattings sal met die oesseisoen se verloop volg.

Die eerste oesskatting is onder leiding van Jacques Ferreira, inligtings- en stelselsbestuurder by SATI, bereken. Die skatting berus op die beste moontlike beskibare inligting, ondervinding, waarnemings, die jongste wingerdsensus en historiese inligting.

Oeskattings word in noue samewerking met produsente en besdryfspesialiste gedoen, verteenwoordigend van al die produksiestreke. SATI gebruik hierdie forum om so spoedig as NA BLADSY 28

Tabel 1: Die eerste oesskatting vir 2021/22-tafeldruifseisoen (miljoen 4,5 kg ekwivalente kartonne).

Skatting 2021/22-seisoen

Werklik gepakte hoeveelhede

Lae beraming

Hoë beraming

2020/21

2019/20

2018/19

Noordelike provinsies

7,70

8,30

7,88

6,10

7,12

Oranjerivier

18,50

21,20

18,51

19,86

19,21

Olifantsrivier

4,30

4,50

4,44

3,32

2,37

Streek

Bergrivier

17,80

19,50

20,06

16,27

13,79

Hexrivier

22,30

24,20

24,00

20,60

18,65

Totaal

70,60

77,70

74,89

66,15

61,13

26

Willem Bestbier, uitvoerende hoof van SATI.

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

GENERAL

Trosse tafeldruiwe stroom weer in VANAF BLADSY 26

28

moontlik op seisoenale afwykings en verwikkelinge te reageer.

Bestbier sê wanneer die jongste sensus met die 2019 opname vergelyk word is daar nou 1 234 hektaar minder tafeldruifwingerde in die land. “Dit beaam die konsolidasie van die plaaslike bedryf.”

Anton Viljoen, voorsitter van SATI sê, te midde van internasionale handelstoestande en die impak van die Covid-19 pandemie sal Suid-Afrikaanse produsente daarop fokus om “na basiese dinge” terug te keer. “Produsente sal op die bestuur van optimale groei, trosvoorbereiding, verpakking en die behoeftes van verbruikers let.”

Aangesien die twee vroeë streke, die Noordelike Provinsies en die Oranjerivier, vroeg in November begin oes het, maar die mid- tot laterstreke - Olifantsrivier, Bergrivier en die Hexrivier – eers teen middel Desember ten volle op dreef kom, is daar baie faktore wat die oeskatting en finale lewering kan raak. “Ons boer onder die uitspansel en daar kan baie gebeur.”

Volgens Clayton Swart, kommunikasiebestuurder van SATI kan veral wind en onvoorsiene hael soms sake deurmekaar krap. “Produsente het oor die afgelope meer as 125 jaar egter hierdie uitdagings ten beste leer bestuur.”

Swart is trots op nuwe kultivars wat na 15 tot 20 jaar en miljoene rande se ontwikkelingskoste, deur die Nietvoorbij In-

fruitec Instituut van die Landbounavorsingsraad en plaaslike en internasionale kommersiële teelprogramme die lig sien vir produksie-uitdagings en verbuikervoorkeure - soos vir pitlose tafeldruiwe. ”Elke moontlike nuwe kultivar word oor baie seisoene lank ontleed. So word daar onder meer gekyk hoe dit kleur, smaak, ryp word, stoor, siekteweestandig is, verskeep en so meer, voordat dit moontlik geregistreer en geplant kan word.”

Swart benadruk die bedryf se verbintenis tot die vestiging van nuwe toetreders. “Ons help hulle om as bestuurders, spanleiers en voormanne en -vroue te groei. Ons verleen bystand met besigheidsplanne en voorleggings vir finansiering vir nuwe grond of verbeteringe soos moderne koelkamers, pakstore of tegnologie, waar dit lewensvatbaar is,” sê hy.

Viljoen sê plaaslike produsente bestuur die werklikheid ten beste “om te verseker dat ons gesogte gehalte gehandhaaf word”.

“Ons boere se omvangryke beleggings in plantmateriaal soos die nuutste produsent- en verbruikervriendelike kultivars, moderne pakgeriewe, tegnologie, koelkamers, toerusting en mense spreek van hul strewe om die strawwe internasionale etiese, omgewings- en sosiale standaarde te handhaaf en die verskaffers van die lekkerste tafeldruiwe ter wêreld te bly,” sê Viljoen.

Are you doing business with a REGISTERED AGENT? FRESH PRODUCE

LIVESTOCK

EXPORTS

It is a criminal offence for a person to act as an agent without registering with the Agricultural Produce Agents Council (APAC).

Do not support illegal traders and only use the service of a registered agent as reflected on our website.

Tel: (011) 894-3680, 087 095 1335, Fax: 086 669 9178

www.apacweb.org.za

PROMOSIE

ALGEMEEN

Produkte vir meer energie in plante CCM, Complex CalSus, Complex Calsul en Complex SuperCa is drie nuwe produkte wat boere met plantvoeding en energie in plante help.

C

CM is ’n alkaliese bron wat die kalsium- en magnesium-konsentrasies in die behandelde grondsone verhoog, terwyl Complex CalSus ’n alkaliese bron van kalsium vir verhoogde kalsium-konsentrasies in die behandelde grondsone is. Complex Calsul suiwer KalsiumKarbonaat en Complex SuperCa is ’n bron van kalsium-chelaat met ‘n kombinasie van organiese sure, wat as blaarvoeding en of sproeibemesting gebruik kan word.

Beide CCM en Complex CalSus bevat bestanddele soos kalsium, magnesium en organiese komponente. Albei produkte is ’n gemikroniseerde ultrafyn kalsium/magnesium(Ca/Mg) bron in ’n karbonaatvorm. Die gemiddelde grootte is tussen 5 en 15 µm. Die klein partikelgrootte lewer ’n verhoogte reaktiewe oppervlakte in die grond. Een kilogram konvensionele kalk behoort ’n reaktiewe oppervlakte van ongeveer 365 m² te lewer, terwyl een kilogram ultrafyn kalk (5-15 µm) ’n reaktiewe oppervlakte van ongeveer 60 000 m² het.

Voordele is dat die verhoogde reaktiewe oppervlakte ’n versnelde reaksietyd gee en dit skep ’n hoër elektrostatiese lading vir element/energie-oordrag. Daar is positiewe verandering van die Ca:Mg en suurversadiging en katioon-uitruilkoëfesient (KUK). Die plantvoedingstof Ca++ raak beskikbaar vanweë die chemiese en biologiese reduksie-reaksies van Ca/Mg-karbonaat.

Complex SuperCa bevat kalsium, stikstof (NH2) en ‘n verskeidenheid organiese sure. Die produk is ’n unieke bron van Ca met ’n hoë opnamekoers. Dit is gecheleer deur van sekondêre metaboliete gebruik te maak. Dit bestaan uit organiese sure, aminosure en suikeragtige organiese sure.

Proefresultate wys dat die meeste gewasse ’n Ca++ tekort deurlopend in die groeisiklus het wat optimale metaboliese prosesse kortwiek (opbrengs en kwaliteit). Die regstelling van hierdie tekorte is krities om die plant se optimale groeisiklus te lewer. Die produk is dadelik plantopneembaar en kan as deel van ’n spesifieke plantvoedingsprogram of as ’n losstaande produk aangewend word.

Aanwending is deur sproeibemesting of blaarbespuiting.

Dit is versoenbaar met alle plantvoedingstowwe, behalwe water-oplosbare fosfate. Dit bevat geen nitraat (NO3- ), chloor (CL2- ) of sulfaat (SO4-- ) nie.

Aangesien Ca so ’n belangrike rol in plantgesondheid speel, sal voldoende Ca-vlakke die volgende funksies in foto-

GROENTE & VRUGTE

JAN • FEB 2022

29

sintese ondersteun: adenosien tri-fosfaat (ATP) en adenosien difosfaat (ADP). Dit is ‘n belangrike element vir endofitiese-mikrobes in die grond en die versterking van selwande. Dit bied fisiese beskerming teen meganiese skade.

Saam met calmodulin (Ca-afhanklike ensieme) het dit polariteit vir diffusie en die opname van voedingstowwe, wat noodsaaklike funksies in die sel is. Dit bied die afskeiding van ensieme en hormone, groeikragtigheid, seldeling, genetiese-uitdrukking (RNA) vir voortplanting en vrugvorming en Ca-ensieme vir beskerming teen swam- en ander patogeen-aanvalle.

Skakel At van Schalkwyk vir meer inligting by 082 452 8983 of besoek die webtuiste www.worldfocusagri.co.za .

Energy management using Innovative Technology

UNLEASH THE GREEN REVOLUTION! World Focus Agri products act as an organic growth stimulant throughout the plants life cycle.

ORGANIC GROWTH STIMULANT

ORGANIC LEAF NUTRITION

MICRONIZED LIME GYPSUM

LAND CORRECTORS

World Focus Agri concentrates on developing and producing organic as well as biologic growth stimulants and enhancers via root and leaf applicants.

Our ambitions, change the conventional view of plant protection to plant health via its biology.

Contact us www.worldfocusagri.co.za

082 452 8983 l 083 417 4369 at@worldfocusagri.co.za Address: 9 Silver Crescent, Delmas, 2210

INSECT COLUMN

Potato aphid (Hemiptera: Aphididae) Potato aphid is native to North America. It has spread throughout the world to Central and South America, Europe, Asia and Africa. It is a highly polyphagous pests, feeding on over 200 species from 20 plant families. Host plants include eggplant, sweet potato, roses, lettuce, maize, sugar beet and many other cultivated plants.

However, it prefers plants from Solanaceae family, especially potato and tomato.

Figure 1: Winged potato aphid.

Source: https://www.cabi.org/isc/datasheet/32154#toPictures

Nozibusiso Maphumulo IPM-PROGRAMME, NORTH-WEST UNIVERSITY, POTCHEFSTROOM

Potato aphid classification: Class: Insecta (insects) Order: Hemiptera (true bugs) Family: Aphididae Genus: Macrosiphum Species: euphorbiae

T

he adult potato aphid is a relatively large, slender aphid with an elongated pear-shaped body. Its body colour varies depending on the food source, it is either a shade of yellowish-green or pinkish-red. It is often shiny with distinctly reddish eyes.

The aphid comprises of both winged and wingless forms.

The wingless forms are 3 to 4 mm long with a dark longitudinal stripe running along the dorsal surface. In green individuals, this stripe is dark green, while in pink individuals it is dark red. This longitudinal stripe is a specific characteristic of the potato aphid and is also visible in the nymphs. Nymphs are paler than adults with a light dusting of whitish-grey wax.

Aphids have a complex life cycle. The life cycle of the potato aphid is similar to that of the peach potato aphid. They reproduce both sexually and asexually. However, sexual reproduction occurs in North America where it originates. When reproduction is sexual, aphids lay eggs that overwinter. Young aphids are born as developed nymphs when reproduction is asexual. They immediately start feeding on plant sap and grow quickly. They moult four times before becoming adults (four nymphal stages).

Infestations on potatoes occur from mid-June through July.

Plants belonging to the rose family become alternate hosts to the potato aphid during autumn and spring. A wide variety of weeds are hosts in summer, including field crops and vegetable crops. In potatoes, potato aphid first feed on young, growing tips and spread downwards into older leaves.

Both nymphs and adults cause damage by sucking sap from the foliage. Damage symptoms include leaf deformity and dieback. Potato aphid can reduce foliage when populations are high. They also spread viruses such as potato virus Y (PVY) and potato leafroll virus (PLRV) to seed and table stock

30

Figure 2: The wingless stage of potato aphid on tomato.

Source: https://www.cabi.org/isc/datasheet/32154#toPictures

Figure 3: Infestation on lettuce buds of different life stages of potato Source: https://www.cabi.org/isc/datasheet/32154#toPictures aphid.

potatoes which can result in the reduction of both yields and quality.

Potato aphid can be managed by scouting the fields in late June. Fully grown compound leaves should be examined from top, middle and bottom of the canopy. Insecticide should be applied when there is an average of 5 aphids per leaf. The economic threshold is when 50% of the plants are infested or when one winged aphid is present in the field.

Enquiries: mashimanenozi03@gmail.com

VEGETABLES & FRUIT | JANUARY • FEBRUARY 2022

Ontgin die landboumark ten volle...

Maak gebruik van die spesialiste UITGEWERS VAN: Koringfokus / Wheat Focus: Die spesialistydskrif vir kleingraan in Suid-Afrika Vegetables & Fruit / Groente & Vrugte: Ontgin alternatiewe moontlikhede in nismarkte

Navorsingsjoernaal: SA Avokadokwekersvereniging (SAAGA) SA Lietsjiekwekersvereniging (SALGA)

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

NORTH WEST: POTCHEFSTROOM  018 293 0622 info@mediakom.co.za GAUTENG: NORTHCLIFF

GAUTENG: PRETORIA

 011 476 3702 mediacom@lantic.net

 082 927 8294 vegandfruit@mediakom.co.za

www.mediacomcc.co.za

Clarkstraat 17, Potchefstroom, 2531

Using modern technology to simplify and enhance the fruit exportation process First Technology is bridging the gap between one of the oldest industries in the world and the endless wonders of modern and emerging technology.

Through infrastructure transformation and a seamless digital ecosystem of traditional and cloud-based offerings, our holistic range of industry-leading solutions offers tremendous flexibility and can be scaled to address the needs of both SMMEs and Large Enterprises.

Evolve your business and become a global competitor.

From warehouse modernisation and streamlining the exportation process, to automating governance and compliance procedures, our solutions will liberate your workforce from menial responsibilities, significantly cut down operational costs and provide your business with the ability to quickly adapt to market demands and needs.

Get in touch with Marizelle Saayman at marizelles@firsttechnology.co.za or call us directly on 021 525 7000.

www.firsttech.co.za /company/first-technology

Blog

www.firsttechwc.co.za/blog