Mortality effect of wettable powder formulations containing entomopathogenic fungal spores against some stored-product pests

In this study, the effectiveness of wettable powder formulations containing entomopathogenic fungal spores of Beauveria bassiana Vuillemin (Hypocreales: Cordycipitaceae) and Metarhizium robertsii Sorokin (Hypocreales: Clavicipitaceae) was examined against major stored-product pests in 2021 in Bioinsecticide Mass Production Laboratory of Plant Protection Department, Faculty of Agriculture, Kahramanmaraş Sütçü İmam University. Twelve formulations were developed: six of which were based on B. bassiana isolate 5-4 and the other six on M. robertsii isolate S3. The formulations were applied on both wheat and concrete surfaces at predetermined dosages. Bioassays were conducted using Plodia interpunctella (Hübner, 1813) (Lepidoptera: Pyralidae) third-instar larvae, Rhyzopertha dominica (F.,1792) (Coleoptera: Bostrichidae) and Sitophilus oryzae L.,1763 (Coleoptera: Curculionidae) adults, under controlled conditions at 30±2°C, 65±5% relative humidity, and in darkness. When applied to wheat, all formulations exhibited high mortality rates against R. dominica and P. interpunctella, while showing limited efficacy against S. oryzae. Conversely, applications on concrete surfaces demonstrated higher efficacy to all pests, particularly against S. oryzae. Amongst the formulations, those containing B. bassiana outperformed M. robertsii-based formulations in terms of efficacy, both on concrete surfaces and wheat. The findings suggest that the developed formulations have significant potential as an effective alternative for pest management in empty storage facilities. Notably, surface applications provided superior results compared to applications directly on stored products.