Adult granary weevils feeding on grain responded selectively to the volatile compounds of different strains of the entomopathogenic fungi Beauveria bassiana and Lecanicillium muscarium. The mycelium of B. bassiana strains had a repellent effect or a neutral effect with a tendency toward repellency. The response to L. muscarium strains varied from weak repellent (G-033) and neutral (Vl 49) to attractive one (Vl 21). Beauveria bassiana strain Bb 17 showed the highest virulence after beetles were sprayed with conidial suspension containing 1.0 × 10⁸ spores / ml: the mortality of the beetles on the 7th day reached 74% with extensive mycelial growth over the dead beetles, LT₅₀ was 5.6 days for this strain and 23 days for strain Bb 13. The L. muscarium strains showed low virulence, with the exception of strain G-033 (LT₅₀ 15.3 days), and they also formed mycelium on the dead insects. The granary weevil response should be considered when assessing the potential of entomopathogenic fungi. Beauveria bassiana strain Bb 17 was selected as a promising pest control agent, since neutral reaction of the granary weevil to its mycelium facilitates the spreading of fungal infection.

In evaluating the effectiveness of entomopathogenic fungi for control of the green peach aphid Myzus persicae (Sulzer, 1776), a dangerous pest and a virus vector, it is necessary to consider the effects of fungal spores and mycelium on the behavior of aphids related to host plant selection. In laboratory experiments, 5 out of 13 strains of different species of the genus Lecanicillium caused the repellency response in aphid females, with the index of aggregation varying from −22.7 to −39.7 and the number of nymphs in the daughter generation decreasing by 1.6–4.2 times. The species of fungi varied significantly in their ability to infect aphid nymphs: Lecanicillium longisporum was the most virulent against the green peach aphid, causing 89% nymphal mortality at a concentration of 1 × 10⁷ spores / mL, while Lecanicillium psalliotae was practically non-pathogenic to aphids. All the strains showing significant repellency also possessed pronounced pathogenicity, while the opposite was not always true.