Survey of lepidopterous stem borer pests of sorghum, maize and pearl millet in Eritrea

Abstract

A survey of lepidopterous stem borers attacking sorghum, maize and pearl millet was done in Eritrea during the cropping seasons of 1996 and 1997. The survey area covered the highlands, western and eastern lowlands and the coastal region of the Red Sea, where sorghum, maize and millet are the major crops. Four lepidopterous stem borers species, namely Busseola fusca Fuller, Chilo partellus Swinhoe, Sesamia calamistis Hampson and Chilo orichalcociliellus Strand were found attacking these crops. B. fusca in the highlands and C. partellus in the lowlands were the major pests of these crops in Eritrea. Two predators and four parasitoids were recorded as natural enemies of the stem borers. The population of the natural enemies was low with 9–20% parasitism. Nineteen cultivated and wild plants were identified as host plants of the stem borers of which sudan grass, elephant grass and hyparrhenia were found with high numbers of stem borer larvae. The pests were able to survive from one season to another and during the dry periods as diapausing larvae on crop residues, maize grown under irrigation and on wild host plants mainly grown in forest enclosure areas.