Efficacy of diatomaceous earth and wood ash for the control of Sitophilus zeamais in stored maize

Abstract

The effectiveness of diatomaceous earth (FossilShield) and wood ash from Acacia polyacantha and Hymenocardia acida were assessed on Sitophilus zeamais, regarding adult mortality, progeny production, persistence, population increase, grain damage and seed viability. Maize grains were admixed with the dusts at the rates 0, 0.5, 1, 1.5 and 2 g/kg for FossilShield and 0, 5, 10, 20 and 40 g/kg for ash. FossilShield at 0.5 g/kg achieved 100% mortality of S. zeamais within 7 days of exposure and was more efficacious than the wood ash from H. acida (87.11% mortality) and A. polyacantha (4.82% mortality) at the rate of 40 g/kg for the same time-point. The three dusts caused significant reduction of progeny emergence, damaged grains and weight loss, but showed no adverse effect on the viability of the protected seeds. FossilShield and wood ash from A. polyacantha and H. acida could be of value as green stored grain protectants against S. zeamais.