Effect of Pyrethroids on the Colony Growth and Metabolic Activity of Entomopathogenic Fungi of the Beauveria Genus

Pyrethroids are chemical insecticides used on a large scale in agriculture, horticulture, and forest protection. In order to reduce their use in IPM, alternative methods of controlling insect pests are introduced, such as the use of biopesticides based on entomopathogenic fungi (EPF). Species of the <i>Beauveria</i> genus are characterized by a very broad spectrum of action, which is why they are often used to produce preparations based on EPF. The aim of the study was to determine the effect of different doses of tested pyrethroids on the colony growth and metabolic activity of EPF from the <i>Beauveria</i> genus. In vitro, the effect of three pyrethroids (deltamethrin, λ-cyhalothrin, and α-cypermethrin) added to SDA medium at a dose 10 times lower than the recommended field dose (A), the recommended field dose (B), and 10 times higher than the recommended field dose (C) on colony growth and metabolic activity of <i>B. bassiana</i> and <i>B. brongniartii</i> was tested. The research carried out showed that pyrethroid insecticides used in the experiment showed various toxic effects towards the tested EPF of the genus <i>Beauveria.</i> The studies conducted showed that on the 20th day of the observation, λ-cyhalothrin used in the recommended field dose limited the growth of <i>B. bassiana</i> to the least extent in relation to the other tested pyrethroids. However, with respect to the fungus <i>B. brongniartii</i>, no toxic effect of this pyrethroid was found. Based on the results obtained, it was found that λ-cyhalothrin used in the recommended field dose and 10 times lower than recommended significantly increased the metabolic activity of <i>B. bassiana</i>. In relation to the <i>B. brongniartii</i> strain, detlamethrin used in each of the tested concentrations significantly affected its viability.