SUMMARY
In the Northwest of Mexico, Phenacoccus solenopsis has been recognized as an aggressively invasive species on cotton plants. Therefore, the aim of the present study was to evaluate the effectiveness of two fungal commercial bioinsecticides (Verticillium lecanii and Isaria fumosorosea) against P. solenopsis under laboratory and semi-fields conditions. Our results showed a high mortality by V. lecanii (100%) followed by I. fumosorosea (40%) and control (0%) after 96 h of exposure. Thirty days after initiating the experiment, we observed a significant reduction of the disease index in cotton plants exposed to I. fumosorosea and V. lecanii (50% and 48%, respectively) compared with control (76%). The use of V. lecanii and I . fumosorosea did not show significant changes in the physiological parameters of plants (chlorophyll, polyphenol contents, anthocyanins and potential photochemical yield values) compared with the control after 30 days of exposure to entomopathogenic fungi. Currently, the available information about mode of action of commercial formulations using I. fumosorosea and V. lecanii for biocontrol of P. solenopsis is scarce in Mexico compared with other countries. Therefore, studies focused on their effectiveness are necessary.