Despite huge awareness campaigns, many South African grape farmers are still not taking grapevine leafroll disease, caused by a virus, seriously enough. Vinpro consultant François Viljoen said during a leafroll information session held at Vergelegen wine estate near Somerset West, Western Cape, that he simply could not understand why: "By now it is general knowledge that leafroll virus negatively affects farm income, as it results in lower production volumes and grape quality.
"It also significantly reduces the longevity of the vineyards, meaning vineyards should be replaced over shorter periods. You will be lucky if a leafroll-infected vine lasts longer than 15 years." Prof Gerhard Pietersen, a plant virologist at Patho Solutions, said the virus is severely underestimated in the table grape industry: "We tested 145 vines from 25 vineyards in five major table grape-producing regions between 2017 and 2020. The virus was found in every vineyard we sampled, and over 110 of the samples tested positive."
Despite this, he did not know of any table grape farmer who followed a leafroll management strategy like the one used in the wine grape industry. "Farmers in the table grape industry seem to be less aware of the negative impact of leafroll virus on production. This is probably because the virus takes a few years to manifest symptoms on vigorously growing vines, and table grape vineyards are replaced over a much shorter time than wine grape vineyards, in response to changing market trends and genetic improvements," he said.
Nevertheless, the virus is taking a toll on table grape income. Pietersen pointed out that Patho had identified leafroll virus as the cause of poor colouration on Crimson seedless grapes in a study done between 2019 and 2021. Research on wine grapes had also revealed that leafroll led to uneven ripening and berry sizes.
Denne historien er fra August 09, 2024-utgaven av Farmer's Weekly.
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Denne historien er fra August 09, 2024-utgaven av Farmer's Weekly.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
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More funding needed to flood-proof Olifants River
Western Cape Minister of Agriculture, Economic Development and Tourism Dr Ivan Meyer recently handed over R14,98 million to the Citrusdal Water Users’ Association.
Zambia, Burundi agree to maximise agri potential
In a bid to capitalise on the livestock and arable land in Zambia and Burundi, the two countries have agreed in principle to review the existing bilateral trade agreement in agricultural products under memoranda of understanding (MoUs) and to bolster foreign exchange earnings.
Expanded market brings avocado season success
The South African avocado industry is making headway in India after gaining market access earlier this year. Supported by the World Avocado Organization (WAO), consumers and food businesses in India are being educated about the health benefits of regular avocado consumption and how best to use this fruit in Indian cuisine.
Plan needed to enhance competitiveness of SA's deciduous fruit canning industry
Dr Heinrich Jantjies, group risk, safety and security director at Tiger Brands, says the deciduous fruit canning industry has been on a decline in South Africa since 2016. He suggests implementing a Deciduous Fruit Canning Industry Recovery and Competitive Plan to turn the industry around.
Kruger's memory lingers in his Boekenhoutfontein farmhouses
Lucille Davie visits Kedar Heritage Lodge in North West to see the farmhouses Paul Kruger owned.
From street art to feats of engineering, Bristol has it all
Brian Berkman visits the vibrant UK port city of Bristol and says two days are not enough to explore renowned graffiti artist Banksy's hometown and pop in at all the historical taverns.
Managing broodmares and foals profitably and safely
Broodmares and their foals are at high risk of stress, diseases and injuries if their management is suboptimal, says Dr Mac.
Double cab's leisure features find favour
The GWM P500 2.0T HEV 4x4 Super Luxury AT has launched in South Africa, and the bakkie takes aim at the more premium, leisure-focused offerings from rival brands. Car Magazine's Marius Boonzaier writes.
More fungal diseases that can infect beans
Bill Kerr explains the symptoms of angular leaf spot and anthracnose and how to avoid infection in your fields.
Keeping invasive insects at bay
Featuring an array of delicious fruit from peaches to cherries, stone fruit is attractive to a variety of bugs that can be effectively controlled with integrated pest management, writes Zunel van Eeden.
