Behavioral response of Rhyzopertha dominica adults to wheat kernels treated with Beauveria bassiana conidia and mortality rate

This study was conducted to investigate the reaction of Rhyzopertha dominica adults to treated-wheat kernels with Beauveria bassiana spores considering pest movement and mortality. The pest’s reaction to inactivated B. bassiana spores was also tested. Each experimental unit had two equal-sized of compartments without restriction of R. dominica adult movements to both sites. By filling each compartment with wheat kernels treated or untreated, different layouts were created using two compartments. Treatments included either active or inactivated B. bassiana conidia. In setup of two experiments, R. dominica adults were released in either one or both compartments. The distribution of insects and mortalities were recorded at the end of the experiments. R. dominica adults exhibited a marked avoidance behavior towards the presence of B. bassiana spores, reducing the total mortality from 95.00% to 68.75%. R. dominica adults showed the same response to inactivated B. bassiana spores, and could not differentiate between active and inactive spores. The effect of this behavior on the success of B. bassiana treatments depends on the application strategy: while non-homogeneous distribution may lead to reduced efficacy due to insects aggregating in untreated areas, the fungus's inherent repellency offers a strategic advantage for preventing initial infestations.