Biological control potential of some selected endophytic bacteria against the Colorado potato beetle, Leptinotarsa decemlineata (Say, 1824) (Coleoptera: Chrysomelidae), and their effects on potato plant growth

Abstract

This study evaluated the efficacy of six selected endophytic bacteria both against the Colorado potato beetle, Leptinotarsa decemlineata (Say, 1824) (Coleoptera: Chrysomelidae), and potential impact on potato plant growth. The bacterial isolates, selected based on prior activities, were tested in in vivo pot trials against L. decemlineata larvae. Their influence on plant growth was also measured under both pest-infested and pest-free conditions. The experiments were conducted between 2022 and 2024 under controlled growth chamber conditions at the Plant Protection Department of Ege University's Faculty of Agriculture. Bacterial applications caused corrected larval mortality rates of 21.87-56.25% compared to the untreated control. The most effective isolate, Chryseobacterium gleum (Holmes et al.) Vandamme et al. (Flavobacteriales: Weeksellaceae) (6), caused 56.25% mortality and exhibited significantly high proteolytic activity. These results demonstrate that the selected endophytic bacteria can significantly reduce L. decemlineata populations and enhance plant growth, showcasing their potential as dual-action biocontrol agents in potato cultivation.