Review of research on the insect pests of kenaf and their control in the Sudan.

Kenaf, Hibiscus cannabinus L., is grown in many parts of the Sudan as a fibre plant. During its various stages of growth, 17 different species of insects were detected, out of which only the cotton flea beetle Podagrica puncticollis Weise is of economic importance. The attack by this pest is most serious in the seedling stage; late sowings coupled with early light showers suffer the heaviest damage. In the leaves the beetles eat out round holes ('shot-hole effect'). The entire life cycle takes about 4 to 5 weeks, and about five generations are completed on the plant depending on the weather conditions. Cultural practices incorporating early sowing and eradication of the main host plants, Hibiscus esculentus and Abutilon spp., considerably reduce the size of the initial infestation. Chemicals tested as seed-dressing or sprays for the control of the beetle failed to give good results. However, granular insecticides showed a better performance and longer residual effect. Disyston 5G was effective for six weeks and also improved the general condition of the plants.