At a recent banana workshop at the Du Roi Laboratory in Letsitele, Natja van Heerden, technical sales adviser at Koppert, presented results from a trial in Zambia showing the use of natural enemies to manage banana bunchy top disease (BBTV). The virus is transmitted by the banana aphid (Pentalonia nigronervosa).
The trial, conducted at the Riverside Farm Institute near Kikuyu, ran from May to October this year. In the commercial control block, 193 banana plants were removed within a week due to BBTV infection. In the Koppert trial block, where ladybirds (Chrysoperla) and parasitic wasps (Aphidius) were released to target the vector, damage levels were considerably lower.
"Over the entire season, only 52 plants were removed in the trial block, compared with 166 in the standard block," Van Heerden said. "The natural enemies have established themselves well, and the population of virus-carrying aphids has decreased significantly."
Biological alternatives to chemical control
The results demonstrate that biological solutions can serve as alternatives to conventional pest control methods, especially as the number of chemical agents available to growers continues to decline. Koppert applies microorganisms, beneficial insects, and biostimulants as part of an integrated pest management (IPM) system. The company also supports producers in Côte d'Ivoire, Kenya, and Morocco.
"Our goal is to work with producers to develop technologies that fit their farming practices," Van Heerden said. "The Zambian results show that natural enemies such as ladybirds and parasitic wasps can slow or even stop the spread of BBTV."
Role of plant diversity
The trial also found that limited weed growth supported populations of beneficial insects. "By removing all weeds, you lose certain natural predators," Van Heerden said. "We've seen that ladybirds and some parasitic wasps occur in greater numbers where there is some plant diversity."
Monitoring and prevention in South Africa
The Department of Agriculture's #StopBBTV campaign urges local growers to report infected plants and use virus-free planting material. Farmers in Limpopo and Mpumalanga, South Africa's main banana production regions, are encouraged to include BBTV monitoring in their pest management programs.
Koppert's work in Zambia suggests biological control can form part of a preventive approach against BBTV outbreaks. "We cannot wait for the virus to break out here again," Van Heerden warned. "If farmers detect BBTV early and use biological control to suppress the aphids, they can protect their crops without over-reliance on chemicals."
Source: AfricanFarming
