Compatibility of Isaria fumosorosea with Selected Botanical Insecticides for Integrated Management of Tetranychus urticae

Abstract

Compatibility of Isaria fumosorosea with selected botanical insecticides was evaluated for integrated management of Tetranychus urticae to determine the potential of combining biological and botanical control strategies. Laboratory assays were conducted to assess the effects of botanical formulations on fungal growth, sporulation, and conidial germination, along with their combined efficacy against spider mite populations. Results indicated variable compatibility among treatments, with certain botanical insecticides showing minimal adverse effects on fungal viability, while others significantly inhibited mycelial growth and sporulation. The combined application of compatible botanical insecticides with I. fumosorosea resulted in enhanced mite mortality compared to individual treatments, suggesting synergistic or additive effects in pest suppression. Sub-lethal effects on T. urticae included reduced feeding activity, impaired reproduction, and delayed development, contributing to overall population decline. The entomopathogenic fungus maintained infectivity under compatible treatment conditions, indicating its suitability for integration into botanical-based pest management programs. However, incompatibility observed with certain extracts highlights the need for careful selection of tank-mix partners to avoid reducing fungal efficacy. The study emphasizes the importance of evaluating microbial–botanical interactions prior to field application to ensure effective integrated pest management strategies. These findings support the combined use of I. fumosorosea and compatible botanical insecticides as a sustainable approach for controlling T. urticae in agricultural systems.