Objective Compatibility of Metarhizium pingshaense with some commonly used pesticides was evaluated for safe application of the biological agent in pest control.

Method Effects of 13 pesticides commonly used at tea plantations on the spore germination, mycelia growth, and sporulation of M. pingshaense 1530 were determined in an indoor in vitro experiment.

Result Among the pesticides tested, veratrine, afidopyropen, and bifenthrin were found most compatible with the fungus. The pesticides were applied in the conventionally used dosage, 5x or 10x dilutions on the fungal mycelia. The 10x dilutions of the pesticides exerted rates of sporulation inhibition ranging from 14.27% to 25.68%, and those of spore germination retardation from 13.93% to 27.88%. Green glume mineral oil and beta-cypermethrin slightly promoted the mycelial growth but strongly inhibited the sporulation and conidial germination of the fungi. As tea saponin and azadirachtin in 3 concentrations completely inhibited the fungal sporulation as well as 36.18-66.71% and 56.37%-80.74% on conidial germination, respectively, they were deemed not suitable to be used along with M. pingshaense.

Conclusion Among the 13 pesticides, veratrine, afidopyropen, and bifenthrin appeared most compatible, while tea saponin and azadirachtin incompatible, with M. pingshaense. Consequently, M. pingshaensis could be safely applied for pest control in the presence of veratrine, afidopyropen or bifenthrin at tea plantations.