Efficacy of wood ash and diatomaceous earth against Sitophilus granarius : influence of dose, environmental conditions, and geomorphological composition

This study evaluates the insecticidal efficacy of wood ash derived from various coniferous sources and a commercial diatomaceous earth product SilicoSec against adults of granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae). Morphological analyses revealed significant differences in particle sizes among treatments, with SilicoSec averaging 14.70 ± 1.85 μm, and wood ashes ranging from 160.51 ± 58.25 to 500.10 ± 183.58 μm. Geochemical analyses indicated that SilicoSec comprised 79.5% SiO2, whereas wood ashes contained 12.8% to 17.5% SiO2 and 31.0% to 37.6% CaO. Insecticidal assays demonstrated that all treatments achieved over 90% mortality