فهرست نشریات علمی دسترسی آزاد ایران

The oak defoliator moth, Leucoma wiltshirei Collenette, 1938 (Lepidoptera: Erebidae), is one of the most important pests of the Persian oak (Quercus brantii Lindl.) in the Zagros forests, causing significant damage to these trees. Developing integrated pest management (IPM) programs using biological control agents, especially entomopathogenic fungi (EPF), can be an effective and environmentally sustainable strategy to reduce the use of chemical insecticides in forest pest management. In the present study, eleven indigenous isolates of Beauveria bassiana were obtained from larvae of L. wiltshirei collected from the Zagros forests in southwestern Iran. Under laboratory conditions, isolate BG4 at a concentration of 10⁸ conidia mL⁻¹ caused the highest larval mortality (33.3%) after 48 hours of exposure. The pathogenicity of this isolate, along with three other fungal isolates, B. bassiana B2, Metarhizium anisopliae M1, and Lecanicillium lecanii (Vertalec®), was evaluated against second-instar larvae of L. wiltshirei. The median lethal concentrations (LC₅₀) of isolates B2, BG4, M1, and Vertalec® were calculated as 2.1×10⁵, 1.2×10⁷, 5×10⁹, and 1.9×10¹³ conidia mL⁻¹, respectively, 96 hours after treatment. In two consecutive field trials, trunk spraying of oak trees with formulations of isolates B2 and BG4 containing nonionic surfactant and paraffin resulted in 73–75% and 61–62% larval mortality, respectively, 30 days post-treatment in Rostam, Fars Province. The high mortality rates observed following treatments with native B. bassiana isolates indicate the strong potential of this fungus and the effectiveness of trunk spraying for biological control of L. wiltshirei. Future studies should focus on the stability of fungal formulations under variable climatic conditions and their potential effects on non-target organisms.