5 December 2023
Producers of summer crops should be on the lookout for African bollworm (Helicoverpa armigera) infestations in their crops.
Prof Johnnie van den Berg, head of the integrated pest management programme at North-West University, says he is receiving inquiries and reports of “extremely high pressure” from African bollworm on crops, including lucerne and forage crops, from various regions.
“It could possibly lead to bollworm infestation occurring soon on soybeans, sunflowers and maize that are starting to bloom,” he says.
Van den Berg explains that it is not common practice to apply treatment against bollworms on crops, so producers should monitor plants for the destructive pests.
Farmers are advised to monitor sunflowers during head formation, soybeans when they begin to bloom and maize when it starts tasselling.
The African bollworm attacks more than 180 plant species. In South Africa, it causes the most damage to cotton and maize but there are also sporadic outbreaks in vineyards, soft fruits and citrus.
The pest is part of the typical noctuid moth family and is nocturnally active. Moths feed on sugary substances and lay their eggs near or on flowering plants. The larvae are the most harmful phase as they feed on plants’ reproductive structures, creating inconspicuous holes that make fruits unmarketable or reduce the vitality and yield of affected plants.
Click here for more information on the African bollworm compiled by Stellenbosch University.
