Insect pests of pearl millet in Sahelian West Africa I. Acigona ignefusalis (Pyralidae, Lepidoptera): Distribution, population dynamics and assessment of crop damage†

Submitted as JA No. 722 by the International Crops Research Institute for the Semi‐Arid Tropics (ICRISAT).

Abstract

Pests were surveyed in farmers’ fields in Burkina Faso, Niger and northern Nigeria from 1980 to 1983, and field trials at research stations in Burkina Faso (1980 and 1981) and at the ICRISAT Sahelian Center in Niger (1984 and 1985). Acigona ignefusalis is widely distributed in West Africa but its predominance as the major stem borer of millet varies with location. There are two generations of the pest annually, with peaks in moth population in July and September. Diapausing larval population declines during the dry season from November to May. A progressive decline in borer infestation was recorded between 1983 and 1985 in Niger. Damage to early‐sown millet was usually low while late sowing resulted in severe stem tunnelling and unproductive tillers. However, under low levels of borer infestation an unprotected crop gave higher grain yield than one which was protected with insecticide.

Keywords:

• pearl millet
• stemborer
• Acigona ignefusalis
• Sahel
• rainfall

Notes

Submitted as JA No. 722 by the International Crops Research Institute for the Semi‐Arid Tropics (ICRISAT).