Incidence of Millet Stem Borer, Coniesta ignefusalis Hampson (Lepidoptera: Pyralidae) in Farmers’ Fields in Northern Nigeria
DIKE, M.C., AJAYI O. and AJIBOYE T.O.
ABSTRACT: Farmers’ millet fields in northern Nigeria were surveyed in 1995 and 1996 to determine the current status of stem borers on pearl millet. The surveys confirmed Coniesta ignefusalis Hampson as the predominant stem borer on millet. Sesamia sp. was recorded on millet only once in a sorghum/millet intercrop. C. ignefusalis attacked millet stems in all ecological zones (Guinea and Sudan savannas, and the
Sahelian zone), and in all the northern states surveyed (Adamawa, Bauchi, Benue, Borno, Jigawa, Kaduna, Kano, Kebbi, Katsina, Niger, Plateau, Sokoto, Taraba and
Yobe). Infestation ranged from 0 to 100%, depending on the millet variety, and was lower in the Sahel than in the Sudan, Northern Guinea and Southern Guinea
Savanna ecological zones. Millet intercropped with legumes (cowpea and groundnut)had higher stem borer attack than sole millet or millet intercropped with
cereals (maize’ and sorghum) or cereals plus legumes. Millet near villages where old millet stems were used for fencing and thatching had unusually high stem borer infestation levels, sometimes up to 100% with associated severe damage and yield loss Syzeuctus sp. was the most prevalent stem borer parasitoid. Mean natural infestation of the stem borer by parasitoids was 10.25%. Other insects recorded on millet included various flower and grain feeding beetles, sucking and spittle bugs, grasshoppers, the millet head miner, flies, earwigs, bees and wasps.