INSECT SPECIES ASSOCIATED WITH SWEET POTATOES ( Ipomoea batatas (L.) LAMK) IN EASTERN KENYA

Abstract

This study was conducted in Kibwezi, Eastern Ke nya during 20 November 2002 to 04 June 2003 to document the insects associated with sweet potatoes (Ipomoea batatas (L.) Lamk) and delineate the most important pests responsible for the crop damage so that control measures against them can be developed. Sweet potato vines (cv Kemp) were planted in three pl ots of 4m x 4 m, which was a major growing area of the crop in Eastern Kenya. Infestation of the crop by different insect species started immediately after the crop establishment and continued for five months in each year. More than 50 ins ects belonging to several orders and at different stages of development infest ed the crop. About eight insect species caused major damage on the crop leaves, vines and tubers. The most destructive and important economic pest species were sweet potato weevil ( Cylas puncticollis Boh.) and the clearwing moth ( Synanthedon dascyeles ). Some 21 insect species were of minor importance, as their damaging effects were not noticeable on the plant and they had low effects on the yield. Other th an pests, seven insect species were found to be beneficial as predators or parasitoids of the insect pests, implying that any ma nagement practice employed for control of the major pests should consid er conservation of the natural enemies.