Several species of bugs feed on beans. The most common in East Africa are the spiny brown bug (Clavigralla tomentosicolis), Riptortus bugs (Riptortus dentipes), the green stink bug(Nezara viridula) and the tip wilter (Anoplocnemis curvipes).
Bugs suck on pods causing tiny lesions, and may cause shrivelling and rotting of the seeds, which lose viability. The whole pod may also shrivel. French bean pods showing signs of bug attack (pimples) are not marketable. Tip wilters sometimes suck the sap on shoots, causing them to wilt and turn necrotic and rot. The green stinkbug transmits a fungus to developing seeds, causing yeast spot, which is a widespread but a minor disease of beans in Africa.
Bugs are difficult to control since they usually feed on a wide range of crops and are very mobile.
- Bugs can be collected by hand regularly and killed, especially during flowering and pod formation.
- Natural enemies such as assassin bugs, spiders, praying mantises and ants are important natural enemies of bugs. They kill or deter bugs. Conserve and attract predatory natural enemies to your crop by planting flowering plants. For more information on Natural enemies click here
- Neem products are reported to repel bugs. If necessary spraying should be done in the morning when the immature stages are exposed