Laboratory assessment of entomopathogenic fungi Beauveria bassiana, balsamo to control the lesser grain borer Rhyzopertha dominica F. on wheat kernels

Abstract

Effect of Beauveria bassiana on Rhyzopertha dominica parental adult mortality, F1 emerged adults, wheat kernels weight loss and damage were evaluated. Lesser grain borer, R. dominica adults were exposed to B. bassiana (BIOVER ® ) conidia powder admixed with wheat kernels in different six rates w/w (weight of B. bassiana conidial powder to weight of wheat kernels) and compared to untreated (check). Mortality percentage of R. dominica adults increased with increasing rates of B. bassiana after seven days. Significant differences were observed between all tested B. bassiana rates (P=0.0001). The maximum percentage of adult mortality after seven days of exposure was achieved at the highest rate compared to the untreated. Same trend was recorded after 14 days of exposure (P= 0.0001) at the previously mentioned rates compared to the untreated check. Negative relationship between B. bassiana rate and number of emerged R. dominica adults was recorded. Significant difference (P= 0.0001) was recorded between the untreated and the treated mean numbers of adult progeny emerged. The maximum adult progeny emerged was observed in the lowest rate (0.1% w/w) averaged 100.33 adult, while the minimum adult progeny emerged was recorded in the highest rate (1.0% w/w) averaged 16 adult compare to the untreated (225.33 adult). Weight loss means varied significantly among the tested rates of B. bassiana. Increasing B. bassiana rates led to significant decrease in weight loss on wheat treated. The minimum percentage of weight loss was recorded in the highest rate (1.0% w/w) compared to the untreated wheat which showed more feeding activities of the R. dominica beetles. In addition, the untreated wheat grains infested with R. dominica was significantly more damaged by the feeding of beetles than grains treated with B. bassiana. Generally, B. bassiana treated wheat kernels significantly decrease in mean numbers of F1 emerged adult, weight loss and damage compared to untreated wheat kernels. As an alternative control method of stored product insect pests, B. bassiana could be implicated as a part of integrated pest management (IPM) strategies.