Controlling Strawberry Mites: Comparison of New Bio-Pesticides and Conventional Chemical Pesticides

BACKGROUNDTetranychus cinnabarinus is one of the pest insects most severely influencing strawberry production. It has a high attack rate and causes severe economic losses. Laboratory toxicity tests and greenhouse experiments were carried out using 13 acaricides to determine their efficacy and potential mechanisms of action.\n\nRESULTSAbamectin showed the highest efficacy against T. cinnabarinus female mites; its LC50 value was 0.18mg L-1. Pyridaben, cyhalothrin, veratrine, and carbosulfan showed reasonably high efficacy; their LC50 values were 2.69 mg L-1, 3.94 mg L-1, 5.98 mg L-1, and 6.75 mg L-1, respectively. Less effective were hexythiazox and bifenthrin, their LC50 values were 9.82 mg L-1 and 19.09 mg L-1, respectively. Other acaricides such as spirodiclofen, chlorantraniliprole, chlorfenapyr, spinosad, and bifenazate did not show good efficacy. The status of female mites treated with avermectin, pyridaben, kanghebio and cyhalothrin changed significantly under a fluorescence microscope. There were no significant differences among female mites treated with spirotetramat, chlorantraniliprole, spinosad and bifenazate. Enzyme activity tests showed that Kanghebio and cyhalothrin obviously inhibited Ca2+-adenosine triphosphatase (Ca2+-ATPase), while veratrine and kanghebi obviously inhibited acetylcholinesterase (TChE) and monoamine oxidase (MAO). Cyhalothrinexerted an auxo-action on MAO. Greenhouse experiment indicated that abamectin showed the best efficacy, as well as the longest duration of efficacy, pyridaben, cyhalothrin, veratrine, and kanghebio followed, while carbosulfan, hexythiazox, and bifenthrin performed the worst.\n\nCONCLUSIONSOur study provided a scientific basis for chemical pesticides to be replaced by these and potentially other new bio-pesticides.