Insect pests of pearl millet in Sahelian West Africa—II.Raghuva albipunctellaDe Joannis (Noctuidae, Lepidoptera): Distribution, population dynamics and assessment of crop damage

Abstract

Pest surveys in farmers’ fields were conducted for Raghuva albipunctella infestations on pearl millet in Burkina Faso, Niger and northern Nigeria in 1980–1983. Field studies on the seasonal fluctuations of moths and diapausing pupae, assessment of crop damage and grain yield loss were conducted in Niger. The results indicated that R. albipunctella occurred between latitudes 11° N and 15 ° N, within the Southern Sahel and Sudan bioclimatic zones. R. albipunctella is a univoltine species, and off‐season carryover is through diapausing pupae in the soil. The majority of diapausing pupae (51%) were found at 10–20 cm of soil depth. The onset and continuity of rains, favourable soil moisture and temperature conditions were key factors in diapause termination, duration of post‐diapause development and adult emergence. Crop damage and grain yield loss were a function of sowing date, time of panicle exsertion and the occurrence of critical numbers of adult moths. Percentage crop lost varied from 1% to 41% with a mean of 20%.