Insecticidal effects of modified diatomaceous earth (DE) with different hydroxides (MOH, M=Na,Ca,Al) against Callosobruchus maculatus (F.) beetles (Coleoptera: Bruchidae) on stored cowpea grains.

摘要

The natural diatomaceous earth (DE) was chemically modified by different mono-, di-, tri- valent metal hydroxides (MOH, M=Na, Ca, Al) to increase its efficiency and to evaluate their insecticidal, ovipositional deterrent effects against Callosobruchus maculatus. Examining by IR-spectrum, X-ray diffraction and Transmission electron microscope (TEM) showed that Ca-DE has sharpest edges, hard, increasing crystal numbers and there is no change in the crystallinity and the structure of DEs by X-ray. The application of Ca-DE caused the highest adult mortality, suppression of progeny production and highest repellency of C. maculatus. The highest percentage of DE retention was 96% and 91% for Al-DE and Ca-DE, respectively and a very few particles remained on cowpea grains after agitation. The most effective DE modification was Ca-DE which has insecticidal, repellent and ovicidal effects against C. maculatus and can be used effectively in a stored grain integrated pest management program