The Department of Agriculture this month again warned South African banana farmers to be on the lookout for banana bunchy top virus, the “silent killer” of banana plantations. New research shows that biological control could offer a realistic solution to halting the spread of the disease.
By Jasper Raats, senior journalist at African Farming and Landbouweekblad
At a recent banana workshop at the Du Roi Laboratory in Letsitele, Natja van Heerden, technical sales adviser at the biological solutions company Koppert, shared the results of a trial in Zambia where banana bunchy top disease (BBTV) was controlled using natural enemies of aphids – the insects that spread the virus.
The trials, conducted at the Riverside Farm Institute near Kikuyu in Zambia, began in May and lasted until October this year. In the commercial control block, 193 banana plants were removed within a week due to BBTV. In the Koppert trial block, where ladybirds (Chrysoperla) and parasitic wasps (Aphidius) were released to target the banana aphid (Pentalonia nigronervosa), the damage was dramatically reduced.
“Over the entire season, only 52 plants were removed in the trial block, compared with 166 in the standard block,” Van Heerden says. “The natural enemies have established themselves well, and the population of virus-carrying aphids has decreased significantly.”
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Viable Alternatives
The trials show that biological solutions offer sustainable alternatives to chemical pest control, especially now that the number of available chemical agents is increasingly limited, Van Heerden says.
Koppert uses a combination of microorganisms, beneficial insects and biostimulants to build an integrated pest management (IPM) system. The company also provides technical support in countries such as Côte d’Ivoire, Kenya and Morocco.
“Our goal is to work with producers to develop technologies that fit their farming practices,” she says. “The Zambian results show that natural enemies such as ladybirds and parasitic wasps can slow or even stop the spread of BBTV.”
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The Benefits of a Few Weeds
An interesting finding from the trial was that a limited number of weeds can actually be beneficial. The researchers found that weeds attracted natural predators that helped keep aphids under control.
“By removing all weeds, you lose certain natural predators,” Van Heerden says. “We’ve seen that ladybirds and some parasitic wasps occur in greater numbers where there is some plant diversity.”
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Department Issues Fresh Warning
The Department of Agriculture’s #StopBBTV campaign encourages local producers to report signs of infected plants and to use virus-free planting material. Farmers in Limpopo and Mpumalanga – where most commercial banana production takes place – are encouraged to integrate BBTV monitoring into their pest management programmes.
Koppert’s success in Zambia suggests that biological pest control is not just a “green alternative” but also a practical safeguard against major economic losses.
“We cannot wait for the virus to break out here again,” Van Heerden warns. “If farmers detect BBTV early and use biological control to suppress the aphids, they can protect their crops without over-reliance on chemicals.”
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