فریبا سهرابی

The bean weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae), is a significant pest affecting the storage and production of legumes, particularly beans. This study evaluates the efficacy of diatomaceous earth (DE) formulations, both alone and in combination with imidacloprid and deltamethrin, utilized at a ratio of 0.05 %, on the mortality and progeny production of C. maculatus. The research further assessed the impact of these formulations on oviposition inhibition, egg hatching rates, and prevention of adult emergence in cowpeas. DE formulations were tested at the doses of 500 and 1000 mg/kg, with six replicates for each treatment. The lowest lethal time (LT50) was recorded for the Dryasil DE formulation combined with imidacloprid at 4.695 days. Mortality rates of C. maculatus adults increased with prolonged exposure and higher doses. The control and talcum powder treatments recorded the highest egg-laying numbers, with 21 and 19.16 eggs, respectively. In contrast, at 1000 mg/kg, the lowest egg counts were observed in the Dryasil + imidacloprid (7.33), Dryasil + deltamethrin (8.66), and imidacloprid (9) treatments. The highest oviposition inhibition rates at this dose were noted for Dryasil + imidacloprid (65.08 %), Dryasil + deltamethrin (58.73 %), and imidacloprid (57.14 %). Additionally, the lowest adult emergence percentage (21.67 %) and the most extended developmental period from egg to adult (21.92 days) occurred in the Dryasil + imidacloprid treatment. Weight loss due to C. maculatus was also evaluated in these treatments, with the lowest percentage of weight loss (5.37 %) in the Dryasil + imidacloprid treatment. These findings suggest that DE formulations, particularly when combined with imidacloprid, are effective in managing C. maculatus infestations in cowpeas, offering a potential strategy for pest control in legume storage.