Vegetables & Fruit March/April 2021 by Vegetables & Fruit

SINCE 1988

MARCH • APRIL 2021

Klink 'n glasie op 200 uitgawes R40,00

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

No 200

STAR 3311

SAPPHIRE

Summer to autumn harvest. High resistance to Black Rot. Very uniform growth habit. Early maturing. 75 -85 days in summer.

Summer and autumn harvest. Large upright frame with semi globe head. Very good uniformity and high yield potential. Medium maturing. 85-95 days in summer.

GREEN STAR Spring, summer and autumn harvest. Good heat tolerance. Semi globe shaped heads with excellent internal quality. Early maturing. 75-85 days in summer.

STAR 3301

All year round in moderate climates. Exceptionally uniform, round heads. Good holdability. Medium maturing. 80-85 days in summer. 110-120 days in winter.

MEGASTAR Winter harvest. Large upright frame with excellent head protection. Excellent uniformity and quality. Very high yield potential - produces large to extra-large heads. 120 -140 days in winter.

STAR 3316

Summer to autumn harvest. Large upright frame with excellent head protection. Uniformly Filled heads with Firm internal texture. Medium to late maturing with good holdability. 90-110 days in summer.

EDITION

Nr 200

200

16 20

ISSN 1015-85 37

Cover Brassicas consist of about 400 species centred around the Mediterranean region. There are no species indigenous to South Africa, but 3 species are naturalised here. This includes a number of important vegetables and crop plants, some of which are cultivated in South Africa. NEWS 4 Klink 'n glasie op 200 uitgawes 6 Fruit farmer lights up Ceres valley 6 Experts explain ways to better crops and farmer incomes 7 ZZ2's Clive Garrett is SAAGA's new chairperson 7 South African pome fruit growers expecting a good crop

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

BRASSICAS 8 10

The macro importance of micronutrients Kalsium se sleutelrol in gewaskwaliteit

ADVERTISING Jana Greenall 011 476 3702 082 780 9914 mediacom@lantic.net DESIGN Roelien vd Westhuizen vanderwesthuizenroelien@gmail. com

MACADAMIA 12 14 16 18

Moth borer complex on macadamia Smart macadamia irrigation is the key Why plant diversity is so important for bee diversity Geïnduseerde plantweerstand met voeding PROMOTION

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 2021

NEWS

Klink ‘n glasie op 200 uitgawes Vegetables & Fruit would like our readers and advertisers to celebrate the 200th issue of the magazine with us in March and April, 2021. The magazine has stood the test of time through providing producers with up to date industry information. During the years the magazine has gone from strength to strength through innovation and quality for both the reader and advertiser. Groente & Vrugte wil graag hê ons lesers en adverteerders moet die 200ste uitgawe van die tydskrif in Maart en April 2021 saam met ons vier. Die tydskrif het die toets van die tyd deurstaan deur produsente van inligting oor die bedryf te voorsien. Gedurende die jare het die tydskrif van krag tot krag gegaan deur vindingrykheid en kwaliteit vir beide die leser en die adverteerder.

HE FIRST EDITION of Mediacom's magazine Vegetables & Fruit appeared as SA Groenteboer in March / April 1988. In the foreword of this edition, Vito Rugani, well-known vegetable produ cer and chairman of the then National Vegetable Committee, said that publish- ing such a magazine is a milestone in the development of South Africa's vegetable industry. Three decades ago, vegetables were the only agricultural commodity that was dependent solely on a free-market system. Competition in the vegetable market was fierce and the vegetable producer who wanted to farm successfully had to be a professional entrepreneur. A magazine with valuable technical and agricultural economic information to these producers was therefore appropriate for the time. For suppliers to the vegetable producer, a specialist magazine for the industry was and still is a valuable tool in their annual marketing strategy. farmDecidu In die kommentaarkolom van die eerste uitgawe is geskryf: Cap ers i ous f " Die groentebedryf is vandag een van die min landbouvertakkings ruit e ta n W e ckli in SA wat werklik daarop aanspraak kan maak dat dit kern- ng ster n w cha ater gesond is. Die Suid-Afrikaanse Groenteboer staan in die te- llen ge ken van hierdie lewenskragtigheid. Dit is 'n onafhan- klike publikasie, gemik op die groenteboer en sy be- lange." Ro Die redaksie van SA Groenteboer is ná die eerste er da uitgawe toegegooi onder briewe van produsente en ar die ander belanghebbendes in die bedryf wat baie gunstig ge- ris sie reageer het. Die tydskrif het binne die eerste drie maande met rasse skrede gegroei, van 'n oorspronklike drukoplaag van R3 7, 00 4 500 tot 14 000. F Contributors to the magazine included Chris Bezuidenhout from ro or t ot he the Research Institute for vegetables and ornamental plants at Roode- ve lo plaat Horticulture Association, the then SA Agricultural Union's Horticulg v SIN

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MARCH • APRIL 2021 | VEGETABLES & FRUIT

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NUUS tural Manager, and Philip Theunissen, an agricultural economist. From the very first issue, the latest market trends were regularly provided by the Marco company. After a poll in 1995, readers indicated that there was a huge demand for a column in which the different agricultural markets and trends were analysed. In April 1996, the first of Prof Johan Willemse's regular columns titled Markets and Opinions Unlockin appeared. It was written by himself and Cor Meintjies from g South Africa’s Agrimark Trends. fresh po tential In Februarie 1991, drie jaar na die ontstaan van die tydR40,00 skrif, word die naam verander na Groente & Tuinbou. Hierdie stap is geneem om te verseker dat kwekerye en die huistuinier ook bedien word. Die fokus het egter steeds op die groentebedryf geval. Januarie 1999 ondergaan die tydskrif nog ‘n naamsverandering na die huidige SA Groente & Vrugte. As uitgewer het Mediacom met hierdie stap 'n leemte in die varspro- duktebedryf gevul in 'n tydperk toe deregulasie en 'n skuif na produsente-organisasies veroorsaak het dat daar nie genoeg inligting by die produsente uitgekom het nie. With the inclusion of fruit, information and news about all types of fruit regularly filled a large part of the magazine. In the August / September issue of 2001, the Mango Growers’ Association launches their regular newsletter. Since then, the magazine has served the fruit industry with regular technical information. From the very first edition, producers were kept up to date with the latest developments in the vegetable industry with breaking news and the latest research. An article about plant breeders in the first edition mentions the use of "plant breeding to facilitate or eliminate chemical weed control", which attracted worldwide attention. The June / July issue of 1988 announces the first plans for the development of the Agricultural Research Council. Uit die argiewe van Vegetables & Fruit / Groente & Vrugte word beklemtoon dat daar niks nuuts onder die son is nie, ook in die landboubedryf. In 'n artikel met die opskrif Insetkoste (April/Mei 1988) skryf Philip Theunissen soos volg: "Insetkoste is seker die een onderwerp waaroor boere tans die meeste praat. Die debatte het gewoonlik hulle oorsprong as die boer weer 'n item by die koöperasie gekoop het wat nou twee keer meer kos as ses maande gelede." Met belangrike mylpale van die groentebedryf, soos die eeufeesvieringe van die Johannesburgse Varsproduktemark, was SA Groenteboer teenwoordig. Vegetables & Fruit still strives to serve the vegetable and fruit industry with the latest research, market trends and product information. Adapting to the ‘new normal’ caused by COVID-19, Vegetables & Fruit attended online events such as the PMA Fresh Summit and various industry events. Amidst many negative impacts, the South African agricultural sector is a shining light in the economy and the horticultural sector plays a major role in this regard. Nuwe platforms van kommunikasie en tegnologie in boerdery neem nie die rol weg wat die produsent / boer speel in voedselsekerheid nie. Met aanlyn-toepassings op slimfone, virtuele kommunikasie en die gebruik van hommeltuie in boerderybestuur word plaaslike landbouers steeds beskou as top presteerders in die internasionale arena. (BTW inges (Including luit) ander lande VAT) othe uitge r countries sluit excluded

No 194

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Vegetables & Fruit celebrates 30 years

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No 180

GROENTE & VRUGTE | MAART • APRIL 2021

"From the very first issue, the latest market trends were regularly provided." 5

NEWS

Fruit farmer lights up Ceres valley The solar orchard on Vadersgawe.

In the Ceres valley, known for being the country's fruit bowl, electricity shortage is an on-going struggle. However, one farmer has taken it on himself to install a solar plant, with a much bigger capacity than what he needs, so that he can feed the excess power back into the local grid.

ITUATED IN THE Ceres valley, El Cuesta Farming is renowned for its apples, pears and nectarines grown on the Vadersgawe farm. The farm was converted from a 180 ha wheat only farm to a 60 ha fruit farming unit supplying supermarkets in Europe and the UK. Later, a large dam was constructed so that the fruit farm division could expand up to 90 ha, a substantial unit in the area producing much sought-after fruit. The owner, Ian Versfeld, realised that the electricity shortages were not going to fix themselves and decided to step in and install a solar plant on his property. Once it had been worked out how much power the Vadersgawe farm needed, he opted to commission a system that would produce more than that amount. In this way, working closely with the Witzenburg municipality, the excess electricity would be fed back into the grid for use elsewhere. Installation of the system that includes 630 (360 W each)

solar panels would produce up to 226 kWp DC power. The system can produce up to 376 882 kWh per year. The ground mount system that was built took up minimal space, therefore, essentially low potential ground was converted into a “solar-orchard” which the farm harvests daily throughout the year. This move has increased the available electricity in the area. The entire community now has more power to draw from and is less vulnerable to load-shedding. "Using the solar plant to produce our electricity, I'm experiencing a much more stable internal network. The Solar Edge technology makes monitoring and fault finding easy," said Versfeld. "Given our sunny climate and open space, I realised that solar was an obvious solution." When asked if this was the end, he quickly added "Certainly not, I'm already considering installing more solar panels on some nearby open land.”

Experts explain ways to better crops and farmer incomes The first One Earth Root and Soil Health Forum were recently held – a new annual event that examines root and soil health’s importance for food security, livelihoods and climate resilience and marks the launch of a community for root and soil health action.

ORE THAN ONE-THIRD of the world’s soils are degraded. Without rapid action, this figure could rise to 90% by 2050. Soil erosion decreases the water, nutrients and root-space available for plants. Healthy roots enable better use of nutrients and water and also help tackle soil erosion. Soil and root health help to mitigate climate change. More carbon already resides in soil than in the atmosphere and all plant life combined. Studies show that there are 2 500 billion tons of carbon in the soil, compared with 800 billion tons in the atmosphere and 560 billion tons in plant and animal life. Healthier soil can store even more. The forum brought together experts from farming, international organisations, NGOs, academia, the public and private sectors. Together they called for collective action in science and technology targeting the early stages of plant growth. The main emphasis was on Africa, which has around 60% of the world’s uncultivated arable land. However, parallel workshops focusing on Turkey, the Middle East, Sub-Saharan Africa and South Africa enabled tailored discussions in regional languages. Plenary keynote speakers were Erik Fyrwald, Syngenta Group CEO and Chairman of the Syngenta Foundation for Sustainable Agriculture, and Dr Ismahane

Elouafi, Chief Scientist at the UN Food and Agriculture Organisation. Erik Fyrwald said that everything starts with the soil. “It is the foundation of productive farming practices. With healthy soil you can have healthy plants, healthy people and a healthy planet. By acting on soil health through regenerative agriculture practices, we are acting on climate change, biodiversity loss and food security, as well as improving farmer livelihoods. This Forum helps an international community shift towards achieving this, together." Dr Ismahane Elouafi added that healthy soils are the foundation for agriculture, as they provide 95% of our food. “Soils also provide fuel, fibre and medical products, and play a key role in the carbon cycle, storing and filtering water, and improving resilience to floods and droughts." Other speakers underlined the link between soil and root health, the long-term economic productivity and the welfare of societies. Other points raised included technologies measuring soil health and their role in enabling informed decision-making by farmers and scientists. The importance of empowering smallholders and enabling access to modern technologies was also underlined, as was the importance of public-private sector collaboration in achieving this.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

NUUS

ZZ2’s Clive Garrett is SAAGA’S new chairperson JAN GREYLING Co-worker

Maximising grower returns for members of the South African Avocado Growers’ Association (SAAGA) through the promotion of production efficiency, increasing demand and improving sustainability will remain the core focus of SAAGA, says Clive Garrett, newly appointed chairperson.

O ACHIEVE THE SAAGA vision and mission, the Association has set several key performance areas. These are market access, market development, technical development and transformation. The focus is mainly on market access. The other key performance areas all support market access as the key to sustainability and growth. Garrett is the Marketing Manager of the ZZ2 farming conglomerate based in Mooketsi. He is also the chairperson of the Perishable Products Export Control Board (PPECB) and since November 2019 he serves as a director of the World Avocado Organisation (WAO). The WAO is a multinational non-profit organisation based in Washington, DC. More than 120 leaders in avocado production, export and import are part of the organisation, which was established in February 2016. The WAO consists of Colombia, Mexico, Peru, USA, South Africa, Tanzania, Zimbabwe, Mozambique and Spain. After being nominated by the SAAGA board of directors to act as chairperson at the board meeting in February, members of SAAGA ratified Garrett’s appointment at the recent online annual general meeting. Goals for SAAGA “I believe SAAGA has a very strong management team that the board can work with to achieve the key performance goals we have set. As the per capita consumption of

Clive Garrett, newly elected chairperson of SAAGA.

avocados in South Africa remains very low compared to Europe and the USA, we will continue developing the local market,” he says. Garrett confirms that SAAGA will continue to support local growers with world class research and technical developments. "At the same time, SAAGA will be assisting in developing emerging farmers. I look forward to the challenges ahead and in taking SAAGA to even greater heights."

South African pome fruit growers expecting a good crop The pome fruit harvest is according to a statement underway and expectations for 2021 are positive. Last year saw a much better winter with enough rain in the majority of the production areas. Cooler weather during spring and the flowering period has resulted in a good crop.

ROWERS IN GENERAL are excited about the season ahead as colour and pack-outs are promising. The season is estimated to be 5 to10 days later; however, the later cultivars could still catch up. Overall, most apple varieties are expected to increase on the previous harvest. Young orchards that will come into production, as well as the favourable weather conditions, have positively impacted the export crop estimates. An increase of 4% is expected on apples and 2% on pears. The increase in pears can be attributed to Peckham's Triumph volumes

GROENTE & VRUGTE | MAART • APRIL 2021

(+6%) and Abate Fetel returning to a normal yield. At this stage, early Bon Chretien pears have been negatively affected by russeting and a decrease of 14% is estimated, compared to the previous season. The Langkloof region experienced a severe hail storm early in 2021. The hail was localised in the Haarlem and and Misgund areas. Fruit size from the orchards that were not affected is looking better and higher pack-outs are anticipated. For more information contact: Jacques du Preez at jacques@ hortgro.co.za or 021 870 2900.

BRASSICAS

The macro importance of micronutrients SAKATA

The recent summer season was extremely hot with very unusual and extreme climatic events. According to some of the most recent publications, the annual temperatures in South Africa have increased by at least 1,5 times the global rate of 0,65°C over the last 50 years. This drastic increase has an enormous effect on many factors like health, infrastructure, water resources, agriculture (food security) and the environment as a whole.

HE DIRECT IMPACT of the temperature on agriculture can not only be seen in factors like the increased demand for irrigation or the effect of higher radiation on crops and livestock, but also the impact that climate change has on pathogens and pests. Studies done on potatoes, for example, indicated that the development rate of various pathogens will increase over the next few years. This could be seen by brassica growers all over the country – controlling diseases like blackrot (caused by Xanthomonas bacteria) and pinrot on broccoli (caused by Alternaria fungi) seemed to be nearly impossible. These pathogens flourish under humid, wet, warm conditions. That is exactly the conditions that so many production areas were faced with. When the amount of inoculum becomes so high, and free moisture is readily available, chemical control of these diseases on its own becomes very difficult to achieve. In times like these, we need to make sure that the plants' immune system is in tip-top condition. This can be achieved by planting the right variety in the right season and making sure the macro, as well as the micronutrients, are applied and available for the plant to take up. The importance of micronutrients is usually better understood when the role of the micronutrients in the plant is explained. There are seven essential plant nutrient elements that are considered micronutrients. They are (in no particular order) boron (B), zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), molybdenum (Mo) and

Cabbage heads with blackrot (Xanthomonas) and Alternaria infection.

chlorine (Cl). The role of each of these elements are explained in table 1. Making sure one plants the right variety in the right slot will also help to harvest a marketable product in these harsh conditions. There are many options to choose from in the Sakata

brassica range. Optima is a cabbage variety that is specifically suited to summer growing conditions, whereas Grandslam and Superslam are excellent choices for the winter harvesting slot. Ares* broccoli has shown to be very well suited to

Table 1: The role of essential plant nutrient elements.

Nutrient/Element Role in the plant Zinc (Zn)

Zinc is important in maintaining a balance in plant hormones and auxin activity. It is also a component of many enzymes.

Boron (B)

Boron is important in the production of amino acids and also plays a role in sugar transport and cell division.

Chlorine (Cl)

Chlorine is not only of the utmost importance in resisting diseases, but also in turgor regulation and photosynthesis reactions.

Copper (Cu)

Copper is also involved with photosynthesis and makes up an important component of enzymes.

Molybdenum (Mo)

This element is involved in nitrogen metabolism - making it essential in nitrogen fixation by legumes.

Iron (Fe)

Iron is also a component in enzymes and it is essential for chlorophyl synthesis and thus photosynthesis.

Manganese (Mn)

Involved in the activation of enzymes and chloroplast production. Manganese is also a cofactor in many plant reactions.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

BRASSICA

Pinrot on broccoli heads and leaves caused by Alternaria.

hot summers, where Parthenon deals much better with colder growing conditions. Twister* cauliflower is a faster-maturing variety, better suited to warmer conditions, whereas Incline is better adapted to the winter slot. Be sure to contact the closest Sakata representative when selecting varieties to plant. They will not only be able to provide producers with the right cultivar for the right sowing slot, but they will also be able to assist with technical advice on how to produce the

best crop possible. References J. E. van der Waals & K. Krüger & A. C. Franke & A. J. Haverkort & J. M. Steyn, 2013. Climate Change and Potato Production in Contrasting South African Agro-Ecosystems 3. Effects on Relative Development Rates of Selected Pathogens and Pests. D. Mengel, 1990. Role of micronutrients in efficient crop production. Purdue U. Extension pub AY-239.

*Experimental: This variety does not appear on the current South African Variety list, but has been submitted for registration. 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 warranty express or implied, for the performance of crops relative to the information given, nor do they 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.

Sakata Quality Seed

Parthenon

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

BRASSICAS

Kalsium se sleutelrol in gewaskwaliteit Kalsium (Ca) bevorder koolgewasse (brassicas) se groei en stoorkwaliteit en gee ‘n langer raklewe.

IE BELANGRIKHEID VAN kalsium in die verbouing van koolgewasse word dikwels onderskat. Kalsium is een van die hoofelemente in plante se selwande. Dié element speel ’n belangrike rol tydens seldeling, goeie wortelontwikkeling, beskerming van gewasse teen swam-infeksies deurdat dit ’n fisiese blokkasie teen die swam vorm dra tot grondvrugbaarheid en plantvoeding by, verhoog die plant se weerstand teen biotiese en abiotiese stremming en verleng groente en vrugte se stoorkwaliteit en raklewe. Kalsium is een van die elemente in ’n bemestingsprogram wat baie belangrik is vir groentekwaliteit. Dit werk ook besonder goed saam met boor om plantsterkte te verbeter en sodoende die plant teen afwykings te beskerm, soos groeipuntbrand, hol stamme of interne verbruining. Groente-bemestingsprogramme is deel van NexusAG se leuse van “Customised Crop Solutions”. Die doel van die programme is om groente se opbrengs te verbeter. Kalsiumtekorte kan nekrotiese letsels veroorsaak en blaarvorming belemmer, wat tot groot verliese kan lei weens vrugte van swakker kwaliteit. Gewasse in die brassica-familie, waaronder kool, blomkool en brokkoli, vind veral baat by die tydige toediening van kalsium. Ongelukkig word kalsium-toediening tydens die groeiseisoen dikwels agterweë gelaat. Die effek van kalsiumtekorte word eers sigbaar as die misvormde of oormatige donkergroen blare en swak stamme sigbaar is, of as plante vroeg bloeisels en botsels afgooi. Ander aanduidings van kalsiumtekorte sluit gebrande blaarpunte, verbruining, klouagtige blaarvervorming en glasigheid, veral by blomkool, in. Dit is die direkte resultaat van te min kalsium in die selwande. Die hoofrede waarom kalsium nie tydig toegedien word as deel van die bemestingsprogram nie, is die algemene wanindruk dat die plant se totale kalsiumbehoefte in die groeiseisoen met die toedienings van kalk en gips verkry word. Kalsium is egter nie só mobiel in plante soos stikstof en kalium nie. Kalsium beweeg net in die xileem, en daarvolgens slegs opwaarts in die plant, en word dus nie ge-hermobiliseer na ontwikkelende weefsel nie. Wanneer ‘n plant vinnig groei of stremmingstoestande beleef, kan vrugte en jong blare nie voldoende kalsium kry nie. Gewoonlik bevat die meeste grondtipes genoeg kalsium,

maar wanneer die plant, om watter rede ookal, te min kalsium opneem begin dit tekortsimptome toon. Stremmingstoestande wat tot kalsiumtekorte lei sluit in warm, droë weer, sterk wind of hoë humiditeit. Braktoestande en hoë toedienings van stikstof en kalium kan ook die opname van kalsium beperk. Ander faktore wat kalsium-opname kan verlaag, is sanderige grond, aluminium- of natriumryke grond en groot vrugladings wat hoë hoeveelhede stikstof of kalium bevat. In brokkoli is die kalsiumtekort dikwels op die jong blaarpunte sigbaar. Nekrotiese letsels versprei van die blaarpunte af na die stam en vrug. In blomkool en kool vertoon die tekort op soortgelyke wyse as by brokkoli, maar wanneer die kalsiumtekort in die vroeë ontwikkelingstadium voorkom, sal geen vrugte of koppe ontwikkel nie. Kalsiumtekort in blomkool laat die selweefsel van die blare kwyn en die simptoom staan bekend as glasigheid. Kalsium moet gevolglik deur die seisoen beskikbaar wees om vrugkwaliteit te verseker. NexNUTRI beskik oor ’n verskeidenheid bemestingsprodukte om te verseker dat die tegniese span pasmaat-bemestingsprogramme kan opstel om aan die spesifieke gewas se voedingsbehoeftes te voldoen. Die tegnici benut onder meer organiese, half-organiese, water-oplosbare en korrelprodukte. Meer onlangs word die korrelprodukte ook geformuleer saam met mikrofyn kalk- en gipskorrels. Die vloeibare kalk- en gipsprodukte word aangewend om vinnige grondregstellings in seisoen te kan doen en kalsium-blaarvoedings word gerig op die jong blare en vrugte se tydelike kalsiumtekorte. NexusAG beskik oor ’n volledige reeks kalk- en gipsprodukte vir gebruik tydens grondregstellings, asook produkte vir gewasse se kalsium-behoeftes gedurende die produksieseisoen, waaronder: • mikrofyn kalk- en gipskorrels, • vloeibare kalk- en gipsbronne, • wateroplosbare kalsium-enkelprodukte en -mengsels, en • kalsiumblaarvoedings in verskeie formulerings. Kontak 'n NexusAG Croplife-geakkrediteerde gewasadviseur vir meer inligting. Skakel 021 860 8040 of besoek www.nexusag.net.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

BESKERM EN VERSEKER OPTIMALE OESTE MET PASGEMAAKTE GEWASBESTUURSPROGRAMME WAT VOEDING EN GEWASBESKERMING KOMBINEER, VIR VOLHOUBARE VOEDSELPRODUKSIE. Die belangrikheid van kalsium in gewas-verbouing word dikwels onderskat. Dié element verrig ‘n belangrike rol om gewaskwaliteit te verseker, en vorm dus deel van NexusAG se omva ende gewasbestuursprogramme. Kalsiumteko e kan nekrotiese letsels veroorsaak en blaarvorming belemmer, wat tot groot verliese kan lei. Stresfaktore soos warm, droë weer, sterk wind of hoë humiditeit en braktoestande, beperk die opname van kalsium deur die plant. NexusAG beskik oor ‘n volledige reeks kalk- en gipsprodukte vir gebruik tydens grondregstellings, asook produkte om gewasse se kalsium-behoe es gedurende die produksieseisoen aan te spreek. Hierdie reeks bestaan uit:

mikrofyn kalk- en gipskorrels, vloeibare kalk- en gipsbronne, water-oplosbare kalsium-enkelprodukte en -mengsels kalsium-blaarvoedings in verskeie formulasies.

KONTAK GERUS U NAASTE CROPLIFE GEAKKREDITEERDE GEWASADVISEUR VIR PASGEMAAKTE ADVIES.

021-860 8040 www.nexusag.net

MACADAMIA

Moth borer complex on macadamia Schalk Schoeman SAMAC

Various mating disruption products are available, but these products are expensive as well as species specific.

The economic importance of the moth complex is often vastly underestimated as growers often tend to only take notice of the direct kernel damage reported by various kernel processing facilities. Typically, this type of damage seldom exceeds 5%, which is accepted as a general action threshold in lieu of a more scientifically based value.

HE SHELLS OF MOST macadamia cultivars begin to harden after mid-January and any nut borer/false codling moth larvae already present in the husks of infected nuts find it impossible to penetrate this seemingly impenetrable barrier. These larvae then feed on the husk tissue and in so doing they sever the vascular bundles connecting the nuts to the plant. Because the embryo is compromised, these nuts drop prematurely and are often reflected in processors reports as immature. Damage induced by these insects may also cause nut drop during the early part of the season. Estimates of average crop losses of up to 15% are probably realistic. Of course, there are big differences between various cultivars with 816 788 as well as most of the hybrid cultivars being preferred. It is important to note that only the egg or recently hatched larvae can be controlled with conventional pesticides. Fortunately, the egg-laying peak at the end of the premature nut drop phase (during late Nov/early Dec) is well synchronised, which would be the time to apply a pesticide with an ovicidal or larvicidal activity. Once the larvae have burrowed into the nut, they are effectively out of reach of any insecticide. Spray coverage is of the utmost importance as these insects prefer to oviposit in the darker and denser areas of the tree. Chemicals must be applied so that both areas of the nuts facing away from the spray rig as well as areas facing

The shells of most macadamia cultivars begin to harden after mid-January and any nut borer/false codling moth larvae already present in the husks find it impossible to penetrate.

Larvae feed on the husk tissue and in so doing they sever the vascular bundles connecting the nuts to the plant.

towards the spray rig are equally covered in fine droplets. High spray volumes do not necessarily equate to good coverage, in fact, quite the opposite could be true. Over spraying will in most cases result in a run-off with most of the pesticide ending up off-target on the orchard floor. Fortunately, there are a considerable amount of alternative environmentally sensitive methods that can be used to control this pest complex, such as: • A range of products containing entomopathogenic viruses, nematodes, bacteria and fungi. Except for the nematodes, all products have to be sprayed and are therefore subject to problems highlighted above. • Various mating disruption products are also available, but these products are expensive as well as species specific. Growers have to make sure that they are targeting the correct specie before selecting this as an option. • Inundative releases of the parasitoid Trichogrammatoidea cryptophlebiae is a very target specific method of control, but its efficacy depends on the number of broad-spectrum products used in the orchard at the time. • Any spray against this complex from January onwards (when larvae are most visible in the nuts) are largely ineffective, as generations overlap to such a degree that only a small portion of the new eggs and/or larvae are affected. Please be very critical when a spray is advised during this period.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

‘N OSEAAN VAN VOORDELE AFRIKELP™ BIOSTIMULANTE

bevorder groei, kwaliteit en opbrengs.

Waar land en water ontmoet … daar lê ’n oseaan van voordele. Afrikelp het met die natuur kragte saamgespan om vir jou ’n natuurlike oplossing vir verbeterde landbouprestasie te bring. Ons vloeibare seewierekstrak is wetenskaplik ontwikkel om noodsaaklike komponente te behou wat opbrengs en gewaskwaliteit verbeter en weerstand bied teen omgewingstresfaktore. Bou ’n vennootskap met ’n maatskappy wat die voordele van die oseaan benut tot die voordeel van jou boerdery.

Bou ’n vennootskap met Afrikelp.

Mengbaarheid: Afrikelp is mengbaar met ’n wye verskeidenheid ander landbouprodukte. Grond: Verbeter die groeikragtigheid van saailinge deur middel van direkte toediening in die wortelsone. Volhoubaarheid: Ons vloeibare seewierekstrakte word geproduseer van seegras wat op ‘n volhoubare wyse geoes word. Groei: Afrikelp se unieke samestelling van natuurlike biostimulante, hoofsaaklik ouksien, stimuleer die groei van wortels, spruite en vrugte. Plant: Kan direk op plante toegedien word deur middel van blaarsproei. Dinamies: Verbeter die dinamiese biochemiese prosesse in die plant vir optimale plantselontwikkeling. Kelp: Die unieke Suid-Afrikaanse kelp, Ecklonia maxima, verbeter groei-eenvormigheid en bevorder gewasproduksie.

Het jy al die krag van die natuur aangewend? Gesels met ons vir meer inligting.

+27 21 551 3556

uppe marketing A28450/G&V

www.afrikelp.com

Elim is ’n eksklusiewe verspreider van Afrikelp-produkte. Kontak jou naaste verkoopsverteenwoordiger by 012 252 4455

MACADAMIA

Smart macadamia irrigation is the key NETAFIM

“Experience in macadamia production indicates the importance of proper soil preparation,” says Chris Malan, manager of agronomy at Netafim South Africa. These actions will result in a larger and healthier root zone that will ensure consistently high production.

LTHOUGH 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. Chris explains that 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. "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." Both drip irrigation and micro-sprinkler systems are used in macadamia tree irrigation across Southern Africa. These systems cater for different conditions, preferences and approaches to production. “Macadamia tree irrigation approaches are still being refined as the industry learns more about tree water requirements and how climatic conditions affects it. Approaches range from highly intensive daily irrigation and fertigation to an extensive approach where irrigation events are adapted to the most important phenological growth stages, the climatic conditions and available resources.” Chris emphasises that there is a shift towards increased implementation of drip irrigation as increased focus is placed on water-use efficiency. Efficient water use “We know that there is no one-size-fits-all answer to improved irrigation scheduling on macadamias or any other

Sources of water loss.

crop. As we aspire toward increased efficiency, various aspects must be kept in mind. 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," explains Chris. "Efficient water use is about preventing water loss on the one hand and ensuring optimal water intake by the roots on the other hand. 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. Our aim is, therefore, to maximise tree transpiration while we minimise soil evaporation and water use by vegetation between tree rows."

MARCH • APRIL 2021 | VEGETABLES & FRUIT

MAKADAMIA

The main concern is evaporation and deep percolation. Chris explains that limiting these two culprits is key, as they can then ensure highly efficient water use. “Evaporation is limited by wetting a smaller soil area and deep percolation is limited with proper irrigation scheduling through which we can ensure we do not irrigate beyond the active root zone.”

tree in every orchard and that a holistic approach to macadamia irrigations scheduling is necessary, taking into account everything from soil type to tree variety. For more information, visit www.netafim.co.za or send an email to infoza@netafim.com.

Balanced irrigation Comparisons of daily transpiration rates with evapotranspiration demand have indicated that transpiration initially increases in line with evapotranspiration demand. It however plateaus at a certain point. A study headed by SAMAC draws from this that climatic conditions are not the soil driver of transpiration rates in macadamia trees. The assumption is that the tree exerts some control over water loss through stomata. "What we can take from this is a warning of the risk of over-irrigation. The study shows that trees will not necessarily use more water in hotter and dryer weather. If we therefore apply more, and eventually too much water, we can do more harm than good with over-irrigation,” says Chris. Soil knowledge Scheduling decisions greatly depend on not only the knowledge of tree water requirements and climatic conditions as mentioned above, but also the knowledge of soil composition and attributes, how water moves through the soil and the size of the root zone is critical to proper irrigation scheduling. The three most important questions to answer are: • For how long should a producer irrigate to ensure that he 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? The aim is to not irrigate past the active root zone, while ensuring sufficient water availability. The question of how much water macadamia trees truly need however remains and the industry is working hard to determine this. It is clear that many factors will determine the true water requirements of every

The question of how much water macadamia trees truly need however remains and the industry is working hard to determine this.

MAKADAMIA

Why plant diversity is so important for bee diversity UNIVERSITY OF SUSSEX

As abundant and widespread, it is common to see both bumblebees and honey bees foraging on the same flower species during the summer, whether in Britain or any other country.

ET RESEARCHERS AT THE Laboratory of Apiculture and Social Insects (LASI) at the University of Sussex show that these two different bees dominate on different flower species and through research can now determine why. By studying 22 flower species in southern England and analysing the behaviour of more than 1 000 bees, they found that “energy efficiency” is a key factor when it comes to mediating competition. Bee bodyweight and the rate at which a bee visits flowers determine how energy efficient they are when foraging. Bodyweight determines the energy used while flying and walking between flowers, with a bee that is twice as heavy using twice as much energy. The rate at which a bee visits flowers, the number of flowers per minute, determines how much nectar, and therefore energy, it collects. Together, the ratio of these factors determines bee foraging energy efficiency. Professor of Apiculture, Francis Ratnieks, said: "While they forage on the same flowers, frequently we find that bumblebees will outnumber honey bees on a particular flower species, while the reverse will be true on other species growing nearby. "What was remarkable was that differences in foraging energy efficiency explained almost fully why bumblebees predominated on some flower species and honey bees on others. "In essence, bumblebees have an advantage over honey bees in being faster at visiting flowers, so can gather more nectar (energy), but a disadvantage in being larger, and so using more of the nectar energy to power their foraging. On some flower species, this gave an overall advantage to bumblebees, but on others to honey bees." In the study, published in the journal Ecology, the researchers used stopwatches to determine how many flowers a bee visited in one minute. Using a portable electronic balance to weigh each bee, researchers found that, on average, bumblebees are almost twice as heavy as honey bees. This means that they use almost twice as much energy as honey bees. The stopwatch results showed that they visit flowers at twice the rate of honey bees, which compensate in terms of energy efficiency. On some flower species such as lavender, bumblebees dominated and were visiting flowers at almost three times the rate of honeybees. The differences in the morphology of flowers likely affect how energy efficient the two bee types were. Ling heather, with its mass of small flowers, was better suited to the nimbler honey bee who was able to visit more flowers per

A bumblebee foraging on lavender. Photo by Prof Francis Ratnieks.

minute than the bumblebees. By contrast, Erica heather, which was growing beside the ling heather in the same nature reserve, has large bell-shaped flowers and was better suited to bumblebees. Author Dr Nick Balfour said: “The energy efficiency of foraging is particularly important to bees. The research showed that the bees were walking (and flying) a challenging energy tightrope; half the energy they obtained from the nectar was expended in its collection.” Energy (provided by nectar for bees) is a fundamental need, but the fact that honey bees and bumblebees do not compete head-on for nectar is reassuring in terms of conservation and co-existence. Prof Ratnieks explained: "Bumblebees have a foraging advantage on some plants, and predominate on them, while honey bees have an advantage on others and predominate on these. "Bee conservation, therefore, benefits from flower diversity, so that should certainly be a focus on bee conservation efforts. But fortunately, flowering plants are diverse." The research team, which included Sussex PhD student Kyle Shackleton, Life Sciences undergraduates Natalie A. Arscott, Kimberley Roll-Baldwin and Anthony Bracuti, and Italian student volunteer, Gioelle Toselli, studied flower species in a variety of local locations. This included a nature reserve, the wider countryside, Brighton parks, Prof Ratnieks's garden and a flower bed outside Sussex House on the University campus. Dr Balfour said: "Whether you have a window box, allotment or a garden, planting a variety of summer-blooming flowers or cutting your grass less often can help pollinators during late summer."

MARCH • APRIL 2021 | VEGETABLES & FRUIT

This is the slogan of Villa Crop Protection. For the last 25 years, Villa has been a leading agrochemical supplier. With the rapid expansions in the nut industry, tree nuts have been priority crops and we have allocated vast numbers of resources to the development of crop protection products that will not only benefit producers, but the industry as a whole. In South-Africa, all crop protection products must be registered under Act 36 of 1947. This is an intensive, costly and time-consuming process. Statistical trials must be completed successfully in different climate zones over a period of two- to three seasons. Thereafter the data can be submitted to the registrar for approval. From the first trials to registration of a single product can take up to five years.

Insights: As part of our data-driven decision- and precision-ag strategies nationally, Villa is erecting more than 100 state-of-the-art weather stations imported from Switzerland. This will enable us to improve our pest- and disease predictive models, weather risk management, irrigation planning and numerous other valuable data resources.

It is therefore an intricate planning process, taking in consideration current needs in the industry, predicting future needs, keeping up with international legislation, managing constant limitations in maximum residue levels (MRL’s) and changing consumer & market demands. With more than 750 registrations over all major commodities, Villa’s strategy is to develop and secure sustainable, effective and affordable crop protection products as part of a larger integrated pest management system. Effective control of pests and diseases without compromising operator health, food safety or the environment, became all too important over the past couple of decades. Hard chemicals are being banned annually from international markets, and the maximum residue levels of allowed chemicals are being regulated and monitored with an eagle’s eye. Products: Villa’s portfolio covers all areas; herbicides, fungicides, insecticides, plant growth regulators, and a patented range of new technology micronutrients. Winfield United, our American partners are the world leaders in the field of adjuvants and some ground-breaking innovative new products will soon be available locally as well. INSECTICIDES:

HERBICIDES:

FUNGICIDES: PGR: ADJUVANTS:

ALPA-THRIN 100 SC CYPERMETHRIN 200 EC NEMACUR 100 GR LAMBDA 50 EC APEX 500 WDG KLAXON 240 EW THIATOX 240 WDG TRIVIA 500 WDG IMIDOR 350 SC SEVIN XLR PLUS WALKER 240 SC GRAINWATCH 400 WDG SCAT 360 SL GLYGRAN 710 SG SKOFFEL 200 SUPER BOUND 200 SL COPPER OXYCHLORIDE WP PROPICONAZOLE 250 EC ETHAPHON 480 SL AVOCET CHARGE E AQUABUFF SUMMIT SUPER AMS SUPER

“Orchard Blitz” is a concept through which principles and practices are visibly demonstrated in the orchards. Presentations are done on several relevant topics and technical levels accommodating everyone from farm workers to producers and technical advisors.

Expertise: The Villa team consists of a treasury of knowledge, experience and expertise ranging from product development, technical assistance, training, on-farm support, to accredited online agricultural courses and webinars.

For more information contact : Charla Meyer -cmeyer@villacrop.co.za

MACADAMIA

Geïnduseerde plantweerstand met voeding JACQUES SWANEPOEL AECI Plant Health

Met die uitdaging van onvoorspelbare klimaatstoestande kan gewasse in ‘n oogwink verwoes word en die finansiële implikasies kan noodlottig wees. AECI Plant Health het ‘n oplossing na vore gebring om plante se immuunstelsel te versterk, om verliese te beperk en plantstremming vir optimale opbrengste te bestuur.

LEXIN® IS 'N ORGANIESE voedingskompleks wat salisielsuur bevat. Salisielsuur is ‘n planthormoon wat die natuurlike weerstand van die plant verhoog deur die plant se eie verdedegingstelstel, die “sistemic acquired resistance” (SAR), te aktiveer. SAR is ‘n proses waartydens fitoaleksiene geaktiveer word. Alexin bevat koolhidrate wat energie aan plant voorsien vir beskerming teen biotiese faktore, soos peste en siektes, asook abiotiese faktore, soos droogte, ryp en hael. Hoewel die weerstand geaktiveer is, word siektes nie noodwendig heeltemal beheer nie. Alexin word met sekere swamdoders gekombineer vir goeie beheer. Wanneer ‘n gewas fitotoksisiteit ervaar sal Alexin help om die gewas vinniger te laat herstel. Alexin bevat ook kalsium (Ca), boor (B), magnesium (Mg) en kalium (K). Die kalsium is baie belangrik vir seldeling en beheer plantmetabolisme- en ontwikkeling. Kalsium versterk die selwandstruktuur en boor help dat kalsium in die selwande vaskleef. Boor bevorder ook die opname en die beweging van K, Mg en Ca in die plant, asook die beweging van suiker. Die magnesium vorm die kern van die chlorofilmolekule en bevorder gesonde groen groei en fotosintese. Kalium aktiveer ensieme in die plant en verhoog die suikervlakke. Hoër suiker vehoog plantenergie (Brix), wat beter weerstand tot gevolg sal hê. Kalium reguleer ook die stomata-opening en -sluiting en beïnvloed die transpirasie-aktiwiteit.

Alexin kan voor of ná ‘n stremmingstydperk op enige gewas toegedien word. Wanneer dit voorkomend in ‘n gewasprogram toegedien word, sal dit die kommunikasie tussen die plant en die wortels verbeter en die plant se energie en weerstand verbeter. Op brassica-gewasse word ‘n maksimum van 3 l/ha Alexin as ’n blaarbespuiting voor kopvorming aanbeveel en word elke 28 dae herhaal. By makadamias word ook met ‘n blaarbespuiting van 2-3 l/ha Alexin na-oes begin, om reserwes en weerstand na die vorige seisoen verhoog. Makadamias blom tussen Augustus en September en ‘n wortel- en blaarstuwing vind plaas. Die boom gebruik dan baie reserwes, daarom is ’n opvolgbespuiting nodig. Energie moet deurentyd bestuur word en gevolglik is ’n herhaling in Oktober nodig om neutval te probeer beperk. Met hoë temperature in November en Desember is Alexin noodsaaklik om die boom se reserwes te optimaliseer en die stremming te verlig. Kaliumpolifosfaat (Rappid® K) kan ook saam met Alexin toegedien word vir hoë energievlakke, verbeterde sapvloei en vrugvergroting. Met Alexin word baie minder neutval ervaar en beter opbrengste behaal as gevolg van meer koolhidrate wat energie verskaf. Elemente is meer opneembaar en weerstand en reserwes is hoër. Die produk verhoog die plant se imuunstelsel sodat herstel ná stremmingstoestande vinniger kan plaasvind. Die verhoogde gewaskwaliteit maak dit meer winsgewend vir die boer.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

Twee-in-een insekdoder Cyperfos is ‘n enkelproduk met ‘n unieke formulasie in Suid-Afrika, wat insekweerstand verminder deur op twee maniere te werk. Die kombinasie van die twee aktiewe bestanddele gee ‘n vinnige uitklopaksie, sowel as ‘n residuele maagaksie vir langtermyn beheer. Cyperfos is geskik teen ‘n wye reeks insekte. CYPERFOS 500 EC Reg. Nr. L7606, Wet Nr. 36 van 1947 Bevat Chloorpirifos (Organofosfaat), Sipermetrien (Piretroïed) (Skadelik) Registrasiehouer: Nulandis® (‘n Afdeling van AECI Beperk)

AECI Chem Park, 200 Bergrivier Drive, Chloorkop Ext. 24 Kempton Park, South Africa, 1619 T +27 11 823 8000 aeciph.com planthealth@aeciworld.com aeciworld.com

PROMOTION

The potential for the export market is now notable with a growing interest for ASDF selections in Europe.

It is Amorentia Sweet Dragon Fruit season LAUREN STREVER

The reddish-pink fruit exterior with green scales looks exotic and perhaps this is the reason why it has its mystical name. The fruit encloses white, pink, red or purple pulp which, more recently, is deliciously sweet and enormously refreshing. When looking in store for fruit, ask for the fruit bearing the little red Amorentia tree sticker - because that is the mark of taste excellence.

RAGON FRUIT PLANTING material (only cultivars that produce sweet tasting fruit) is available from Amorentia Sweet Dragon Fruit (ASDF) Nursery for the commercial grower. The fully rooted plants cost 20% less than the price of macadamia trees and 70% less than avocado trees. ASDF’s crop modelling shows the potential for a positive cash flow in year 3 or 4, rather than year 7 to 8 as is the case for macadamia and avocado production. The initial capital cost to develop per hectare of dragon fruit is higher than these crops, but the return on investment makes it an attractive option to commercial growers in subtropical and temperate areas which are frost free. The development of ASDF hectares is growing steadily and the ASDF marketing company is encouraged by the leap in the demand for the exotic superfood. Last year, COVID-19 certainly put a spanner in the works for the Dragon Fruit industry at large. Trials with certain retailers were abandoned, while tastings and events had to be canceled. Consumers are starting to pay attention to dragon fruit and more importantly, there is a growing confidence due to the availability of sweet-tasting selections in a variety of local outlets – from SA's top supermarkets, mini markets, municipal markets to online health food markets. The local

price thus far has remained solid. The reason why previous attempts to market Dragon Fruit have not succeeded is due to the old selections of poor tasting fruit. In the case of these exciting, sweet cultivars, the marketing is focused, showcasing the superior taste of the trademarked ASDF selections. Previously there was little effort to differentiate any exciting, dynamic and sweet-tasting fruit from older, bland tasting cultivars. The potential for the export market is now notable with interest for ASDF selections in Europe. With an already flourishing market in Vietnam producing a million tons of Dragon Fruit annually, the evidence is clear that as our production increases, there is an opportunity for South African producers to supply into the Northern Hemisphere. It is too early to tell, but it appears that, despite the increase in hectarage, supply is down, with many growers in the northern regions of South Africa having experienced incredible summer rains. The Dragon Fruit flower opens overnight and closes the next morning, leaving a very small window for pollination to occur. The plants produce a series of flowers throughout a season, therefore with seemingly drier months ahead, there is hope for an opportunity of an increase in production for the remainder of the season.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

PROMOSIE

Also known as Pitaya, dragon fruit contains certain beneficial vitamins and minerals.

In-field Because Dragon Fruit is a member of the cactus family, the water requirements are considerably lower than for macadamias, avocados and citrus. They require a third of the water, if not less. ASDF growers have recorded their irrigation requirements as low as 700 cubic meters per ha per year, depending on the rainfall in the area. Nutrition requirements are being tweaked all the time as certain methods produce different results in different regions, highlighting the impact of microclimates, like with most commercial crops. Sweet Dragon Fruit is a super food, packed with health benefits and is easy to eat in a variety of exciting ways. Health benefits • Lowers blood sugar levels and blood pressure. • Strengthens bones and teeth. • Promotes healthy blood and tissue. • Strengthens the immune system. • It slows down the aging process. • Reduces inflammation. • Prevents cancer. Also known as Pitaya, dragon fruit contains certain beneficial vitamins and minerals. The fruit is rich in antioxidants, vitamins B1, B2, B3 and C, polyunsaturated fatty acids, carotene, protein, calcium, iron and phosphorus. How to prepare your Sweet Dragon Fruit: • Slice in half and scoop the flesh out with a spoon. • Peel and dice into blocks. • Enjoy alone, in a fruit salad or a garden salad. • Blend into a smoothie or a juice. • Make ice lollies or ice cream. • Deserts.

GROENTE & VRUGTE | MAART • APRIL 2021

Dragon Fruit planting material (only cultivars that produce sweet tasting fruit) is available from Amorentia Sweet Dragon Fruit (ASDF) Nursery for the commercial producer.

GENERAL

Maak ekstra wins met sitrus deur optimale bemesting Optimale bemesting deur die besproeiingstelsel verbeter opbrengste by sitrus en ander permanente gewasse drasties.

EUR 'N OPTIMALE bemestingsprogram te volg wat N, P, K, Ca, S en mikro-elemente gebruik kan sitrus en ander gewasse se opbrengste drasties verhoog word. Tans behaal sitrus wat uitgevoer word uitstekende pryse in die buiteland. Indien produsente die huidige situasie tot hul voordeel wil gebruik is dit krities om ‘n optimale en gebalanseerde bemestingsprogram te gebruik. Die koste vir die pes- en plaagbeheer is dieselfde vir ‘n swak of goeie oes. Produsente moet seker maak dat ‘n bekwame persoon met die regte kwalifikasie en ondervinding as adviseur of konsultant gebruik word. Die tydstip in ‘n sitrusboom se fisiologiese ontwikkeling waarop die bemestingstowwe toegedien word kan die doeltreffendheid daarvan en dus ook die opbrengs beïnvloed. Die toedieningstye van verskillende bemestingstowwe is krities en stikstof en kalium moet byvoorbeeld op verskillende stadiums toegedien word. Produsente moet mengsels vermy wat al die makro- en mikro-elemente gelyktydig toedien. Stikstoftoedienings moet volgens ‘n sekere tydsbepalende fisiologiese proses van die boom geskied. Bemesting deur die besproeiingstelsel: • Produsente kan self bemesting meng deur gebruik te maak van ‘n A, B en C tenkstelsel vir verskillende bemestingstowwe. Produsente gebruik enkelvoudige bemestingstowwe wat ook aansienlik goedkoper is as mengsels wat vooraf gemeng word. • Bemesting deur die besproeiingstelsel of sproeibemesting

Nadorcotts met 'n gemiddelde opbrengs van 90 ton per hektaar.

Voorbeeld van sproeibemestingstelsel waar produsent bemesting self meng.

word meer doeltreffend en akkuraat toegedien indien die besproeiingstelsel korrek ontwerp is. • Deur sproeibemesting toe te pas word die bemesting dus in die wortelkonsentrasiegebied toegedien. • Die grootste voordeel is dat al die verskillende voedingselemente optimaal en in korrekte klein hoeveelhede toegedien word. Kalsium en oes-resultate Kalsium speel ‘n belangrike rol by selmetabolisme, selstruktuur en selsterkte. Dit is baie belangrik by selgroei en selverdeling en is aktief in selmembrane. Optimale kalsiumvlakke verbeter ook vrugte se rakleeftyd en interne kwaliteit. Bemestingaanbevelings moet gebaseer wees op grond- en blaaranalises wat jaarliks geneem word vanaf Februarie tot Junie. Nutrichem het reeds ‘n unieke databasis saamgestel vir blaarmonsters wat elke 6 weke geneem word deur die hele jaar by hoë potensiaal sagte sitruskultivars soos byvoorbeeld Novas en Nadorcotts. Kontak: Adriaan Badenhorst - 082 850 2166, Dr Hennie Swart - 082 579 1892 of Yolande Claassen - 082 928 8588 vir navrae. Nutrichem voorsien tans bemestingsprogramme aan verskeie produsente wat saam ongeveer 25 miljoen kartonne sitrus per jaar uitvoer na die buiteland.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

GENERAL

Illegal imports could destroy local avo industry JAN GREYLING

SAAGA and the local avocado industry support the legal importation of avocado fruit from Tanzania.

OUTH AFRICA AND Tanzania are both members of the World Trade Organisation (WTO) and the International Plant Protection Convention (IPPC) and therefore officially engage on phytosanitary issues / risks with trade partners according to the rights and obligations of the WTO SPS Agreement and the IPPC, says Subtrop CEO, Derek Donkin. Over the past months, SAAGA has participated in a process to finalise a South African phytosanitary import protocol for fresh avocado fruit from Tanzania. However, the new protocol for the importation of avocados from Tanzania has not yet been finalised, says Clive Garrett, Chairperson of SAAGA. He confirms that the South African Department of Agriculture, Land Reform and Rural Development (DALRRD) and the Tanzanian governments are working hard to do things correctly. This confirms that rejection of the Tanzanian consignment at the Beit Bridge border post on 19 February 2021was not based on claims that South Africa is protecting the local industry without concern about the Tanzanian growers. "If you take shortcuts, which have been taken here, by bringing in fruit that has the possibility of bringing in pests, you are illegal. We know exactly why this consignment has been intercepted and destroyed," says Garrett. "These avocados have been brought into the country without the necessary phytosanitary certificates. Ignorance of the law is no excuse. In this case, I think the supplier knew what is expected of them, but they took a chance and did not get away with it." Let’s do it legally Subtrop, who manages the affairs of SAAGA, recorded the process leading up to the interception and confiscation of between 40 and 56 tons of avocados from a Tanzanian grower: 20 July 2020: DALRRD forwarded Subtrop a draft phytosanitary work plan for the import of fresh avocado fruit from Tanzania for inputs and comments. 29 July 2020: Comments and inputs from Subtrop were submitted to DALRRD. August 2020: A SAAGA member who processes avocados contacted Subtrop regarding the possibility of importing avocados from Tanzania for processing. Donkin contacted the Acting Director of Plant Health at DALRRD, who said that it should be possible to arrange a special import permit for the fruit to be processed. Such a permit would include a specific procedure for disposing of waste. Similar permits for the import of mangoes from other African countries for processing had been issued in the past.

Over the past months, SAAGA has participated in a process to finalise a South African phytosanitary import protocol for fresh avocado fruit from Tanzania.

Donkin referred the SAAGA member who contacted him to the Fresh Produce Importers’ Association (FPIA) to assist with import matters. The member joined the FPIA to facilitate the process to obtain an import permit for processing. 23 November 2020: The FPIA approached Subtrop to find support for the finalisation of the import protocols for fresh avocado fruit, without the customary physical verification visit by DALRRD to the exporting country, due to the COVID-19 travel restrictions. “A virtual verification inspection would therefore expedite the finalisation of the import protocols,” says Donkin. Subtrop supported this proposal since hard, green avocado fruit, without false codling moth (FCM) or other damage, constitute a low phytosanitary risk regarding Bactrocera dorsalis which is the main phytosanitary pest of concern. Phytosanitary measures are necessary to mitigate the risk of importing avocado fruit which is not hard, green, and free of FCM or other damage. It is important to note that Bactrocera dorsalis is not present in all regions of South Africa. Consequently, phytosanitary measures for this pest are necessary to protect fruit production in areas free of this pest and safeguard exports of fruit from these areas to certain markets – the same reason why South African growers are required to have removal permits when moving avocados out of an area where Bactrocera dorsalis occurs. 15 December 2020: After discussions with relevant DALRRD officials, the FPIA emailed DALRRD recommending that DALRRD finalise the protocol for the import of Tanzanian avocados without a physical verification visit to Tanzania due to the COVID-19 travel restrictions. This email clearly stated that there was an out-of-season shortage of avocados in South Africa and that the import of avocados from Tanzania would be beneficial. TO PAGE 26

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GENERAL

Illegal imports could destroy local avo industry FROM PAGE 24

Since December DALRRD has requested the Tanzanian Department of Agriculture to propose dates for a virtual meeting to finalise the protocol. “In addition, this specific Tanzanian exporter has been advised by FPIA to contact the Tanzanian Department of Agriculture to request them to expedite replying to the request from DALRRD,” says Donkin.

are suffering due to Covid-19. That is not the issue. The issue is about following the correct rules of the game and they did not follow the rules.” Currently, in South Africa early new season avocados have been entering stores nationwide, implying that legal Tanzanian imports during the local off-season may perhaps only be on South African shelves from their next harvest.

Do not waste food Garrett states that, "nobody wants to see food destroyed and SAAGA does not support food being destroyed for any reason. If, however, it needs to be done to protect our avocado industry then so be it. Unfortunately, that was what happened in this situation." He is clear that the priority of South African authorities should be to protect local growers and they did do so. “If you are going to play a game of rugby you need to know the rules of the game before you run onto the field. The Tanzanians know the rules of the game. Once you have been caught with your pants of you are going to say that prices in South African are high – which is due to imports during the local off-season – and that food cannot be destroyed while the small farmers in Tanzania who have grown these avocados

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Produsente besef belangrikheid van bekalking al hoe meer Dr Pieter Haumann FERTASA

‘n Doeltreffende bekalkingsprogram met landboukalk van goeie kwaliteit, saam met tegnologie wat presisieboerdery moontlik maak, is deurslaggewend vir volhoubare gewasproduksie.

OLHOUBARE EKONOMIESE gewasproduksie is slegs moontlik indien minstens die volgende twee toestande bereik word: onderhoud van die grond se fisiese en chemiese eienskappe op aanvaarbare vlakke en die produsering van optimale oesopbrengste. Baie veranderlikes het ‘n direkte invloed op gewasproduksie. Indien hierdie faktore nie optimaal bestuur word nie, kan sub-optimale oesopbrengste verwag word. Enige aksie wat nie korrek uitgevoer word nie kan die oesopbrengs verlaag. Grondsuurheid ‘n Aantal faktore moet in ag geneem word by die definisie van suur grond. In die breë beskou is daar basies twee definisies vir suur grond: • pH (H2O) is laer as 7,0; en • ‘n relatiewe oormaat suurvormende katione (H+ en Al3+) teenoor basis-vormende katione (Ca2+, Mg2+, K+, Na+). Die graad van grondsuurheid of alkaliniteit, uitgedruk as grond pH, is ‘n belangrike veranderlike wat ‘n wye reeks grondchemiese en biologiese prosesse beïnvloed. Die chemiese veranderlikheid beïnvloed grootliks die opneembaarheid van voedingstofelemente, asook toksiese stowwe deur die plant se wortels. Die aktiwiteit van grondmikro-organismes word ook deur die grond se pH beïnvloed. Verskeie faktore het ‘n invloed op grond pH. Twee basiese faktore is die balans tussen suur en nie-suurkatione op die grondkolloïedeoppervlak, asook die balans tussen H+ en OH- ione in die grondoplossing. Hierdie balans word grootliks bepaal deur die aard van die grondkolloïede. Onlosmaakbaar verbind aan grondsuurheid is die toksisiteit van die nie-voedingselement, aluminium (Brady & Weil, 2008). Regstelling van grondsuurheid Grond se kalkbehoefte kan gedefinieer word as die hoeveelheid kalk wat toegedien moet word sodat grondsuurheid nie ‘n beperkende faktor in gewasproduksie is nie. Die beperkings hou verband met laer basisversadiging, toksiese vlakke van aluminium en mangaan, verminderde beskikbaarheid van die meeste plantvoedingselemente en ‘n laer aktiwiteitsvlak van mikro-organismes. Verder word ‘n gunstiger grondomgewing geskep waar plante kan groei (MVSA, 2016). Bepaling van kalkbehoefte Die eerste stap in die bepaling van kalkbehoefte is die

Verskeie faktore het ‘n invloed op grond pH. Twee basiese faktore is die balans tussen suur en nie-suurkatione op die grondkolloïedeoppervlak, asook die balans tussen H+ en OH- ione in die grondoplossing.

vasstelling van die grond se suurheidstatus deur ontleding van ‘n verteenwoordigende grondmonster. Om vas te stel of dolomitiese of kalsitiese kalk toegedien moet word, is die Mg- en Ca-ontleding van die grond nodig. Die kalkbehoefte kan met verskeie metodes gekwantifiseer word. Dit wissel van laboratoriummetodes, waar grond geïnkubeer of getitreer word met CaCO3, of Ca(OH)2 of waar pH-metings in bufferoplossings gedoen word, tot die berekeninge met uitruilbare Ca, Mg, K en suurheid. Verder word bekalkingsnorme wat uit regressievergelykings ontwikkel is gebruik ten einde ‘n werkbare kalkaanbeveling te kan maak. Praktiese oorwegings en aanbevelings Grondversuring op veral sandgronde is ‘n voortdurende proses en moet gereeld gemonitor en reggestel word om te sorg dat grondsuurheid so ver as moontlik optimaal vir gewasproduksie bly. Die meeste suksesvolle graanprodusente bekalk hul lande NA BLADSY 28

GROENTE & VRUGTE | MAART • APRIL 2021

GENERAL

Produsente besef belangrikheid van bekalking al hoe meer VAN BLADSY 27

Praktiese oorwegings en aanbevelings Grondversuring op veral sandgronde is ‘n voortdurende proses en moet gereeld gemonitor en reggestel word om te sorg dat grondsuurheid so ver as moontlik optimaal vir gewasproduksie bly. Die meeste suksesvolle graanprodusente bekalk hul lande elke derde jaar in ‘n rotasie van een derde per jaar. Meerjarige gewasse, soos lusern, weiding en bome, word minder dikwels bekalk. Indien die aanvanklike bekalking te min was en dit nie gemonitor word nie, vind oesverliese dikwels plaas. Die kwaliteit van die oes word ook dikwels benadeel. Bekalking vereis beplanning en monitering. Oes- en kwaliteitsverliese is dikwels baie meer as die koste om betyds en voldoende te bekalk. Deeglike grondontledings en landinspeksie is al manier om laasgenoemde vas te stel. Sodoende kan die grond se reaksie en die kalk se gedrag vasgestel word. Bekalking kan sodoende in die toekoms doeltreffender gedoen word (MVSA, 2007). Verwysings BRADY, N.C. & WEIL, R.R. 2008. The nature and properties of soils. 14th edition. Upper Saddle River: Pearson Prentice Hall. MVSA 2016 Bemestingshandleiding. Sewende hersiene uitgawe. Lynnwoodrif.

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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.

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ALGEMEEN

South Africa ranked the highest in food security South Africa has ranked the highest in food security out of 28 countries in Sub Saharan Africa (SSA), according to the new global food security index (GFSI) report.

HE GLOBAL FOOD SECURITY Index, sponsored by Corteva and produced by the economist intelligence unit (EIU), the research and analysis division of The Economist Group, measures the drivers of food security in developing and developed countries, based on the core factors of food affordability, availability, quality and safety, alongside natural resources and resilience, across 113 countries. This year, the GFSI formally includes Natural Resources and Resilience as a fourth main category. This addition marks a significant shift in methodology, revealing food systems’ resiliency against climate change. Using a new methodology, South Africa’s global ranking, however, fell from 67th to 69th out of 113 countries. The lack of effective food safety net programmes has been a main driver of this decrease, as well as the increasing costs of food. South Africa received strong scores in seven indicators, achieving 94,3 points for the country’s food safety – which includes national nutrition plans, dietary diversity and guidelines, nutritional monitoring and access to drinking water – and the presence of food ‘safety net’ programmes (public initiatives that protect the poor from food-related shocks). When it comes to quality and safety of food, which remains a challenge in SSA, South Africa ranked number one, while in affordability and availability it came in second and ninth positions respectively. “The demand, not just for more food but more nutritious food, is growing by the day. And yet, farmers who feed all of us are asked to grow significantly more with fewer resources,” said Tony Esmeraldo, business director for Corteva Agriscience in South Africa. “Food security is declining and everyone must recommit to building resiliency in agriculture through innovation and collaboration.” Although South Africa fared better than other countries in

Kontrole - boomopbrengs

18.6 kg

Kelpak - 3 x 0.3%

SSA, food inadequacy and hunger is still a challenge. The COVID-19 lockdown restrictions have ravaged many industries with those living below the poverty line desperate for food. Farmers, mainly smallholders, also suffered a significant loss of income as lockdowns prevented market access and interrupted the planting season, according to the report. “Despite the challenges posed, in particular by the pandemic, South Africa’s regional ranking comes as no surprise. The country’s agricultural sector is globally competitive and tremendously resilient. The political leadership was also keenly aware of the need to protect livelihoods and pulled out the stops to cushion the economic blow brought on by COVID-19, for example by providing direct cash payments to citizens that contributed to food security,” says Herman Warren, Africa Director at The Economist Corporate Network. On a global level, the 2020 Global Food Security Index report shows an overall decline in food security. This comes after seven years of consistent improvement. The global pandemic has starkly exposed the strengths and vulnerabilities of the food supply system, revealing the role of persistent inequality in driving food insecurity. SSA countries recorded the weakest average performance across all regions examined in the latest GFSI report. Rising food prices were the main factor driving deterioration in the overall food security environment. Along with persistently high levels of poverty, the region has experienced significant food price volatility in the past decade. However, food availability has improved. “Food security will require significant investment in research and development to increase the production potential of South African farmers, new technologies and adoption of more sustainable farming practices and the development and adoption of digital platforms to manage and use data to make better decisions across the food chain,” says Esmeraldo.

20.1 kg

Kelpak - 5 x 0.2%

21.4 kg

Een aan die boom is beter as twee op die grond Beter set en neutretensie beteken meer neute asook ‘n hoër kerngewig per boom. Kelpak, die natuurlike seewier ekstrak is wêreldwyd deur wetenskaplike proewe bewys om neutboere se opbrengs en wins aansienlik te verbeter.

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

African jumping spider (Araneae: Salticidae)

South Africa is the world's third-largest producer of macadamias. However, macadamias are prone to infestation by pests just like most commercial crops in the country. In South Africa, pentatomid and coreid stinkbugs are serious pests in macadamia orchards. Macadamia orchards are, however, also populated by various spider species. Based on the reviews of the role that spiders have in the agroecosystems, it is recognized that spiders serve as biological control agents of insects and mites in these systems. All species of spiders form part of a complex community of predators and may have a significant role in the control of pests and suppressing their numbers. Nozibusiso Maphumulo IPM-PROGRAM, NORTH-WEST UNIVERSITY POTCHEFSTROOM

e-mail:mashimanenozi03@gmail.com

Salticid spiders’ classification:

Class: Arachnida (spiders and scorpions) Order: Araneae (Spiders) Family: Salticidae Genus: Thyene Species: Coccineovittata

ALTICID SPIDERS ARE THE most dominant spiders in the macadamia orchards in many areas of South Africa. They have been also reported on orchards of citrus and pistachio as well as in cotton crops. The Salticidae family is known to prey on numerous pests that attack crops, for example, stinkbugs, spider mites and bollworms. Salticid spiders are not limited to adult prey only, but predation also includes the eggs and larval or nymphal stages of insects. Therefore, they may provide an important ecosystem service as biological control agents of pests. Thyene coccineovittata (previously known as Thyene pulchra), commonly known as the African jumping spider, is one of the most dominant species of Salticidae in macadamia orchards. It is also reported to be abundant on avocados. The African jumping spider is native to Africa. In South Africa, it is widely distributed in KwaZulu-Natal, Mpumalanga and the Limpopo Province.

Figure 2: Adult female of the African jumping spider http://jumpingspiders.co.za/spiderviewer.php?g=Thyene&s=coccineovittata&x=f&u=205.jpg

Figure 3: Immature male of the African jumping spider. https:// peckhamia.com/peckhamia/PECKHAMIA_173.2.pdf

Figure 1: African jumping spider feeding on the eggs of a stinkbug. https://peckhamia.com/peckhamia/PECKHAMIA_216.1.pdf

The African jumping spider is a medium-sized spider; with a body length of 8-11 mm. Females are smaller than males. The male is dark brown to black while the female is yellowish cream with distinct black spots on the carapace (epidermis) and abdomen. The immature stages of both males and females closely resemble adult females.

MARCH • APRIL 2021 | VEGETABLES & FRUIT

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Vegetables & Fruit March/April 2021

Articles inside

SA ranked the highest in food security

Produsente besef belangrikheid van bekalking al hoe meer

African jumping spider

Illegal imports could destroy local avo industry

Moth borer complex on macadamia

Maak ekstra wins met sitrus deur optimale bemesting

Klink 'n glasie op 200 uitgawes

PROMOTION

Kalsium se sleutelrol in gewaskwaliteit

Smart macadamia irrigation is the key

Geïnduseerde plantweerstand met voeding

Why plant diversity is so important for bee diversity