Synergistic effectsof the entomopathogenic fungus Isaria javanica and low doses ofdinotefuran on the efficient control of the rice pest Sogatella furcifera
2024
Tingting Zhou | Qian Zhao | Chengzhou Li | Lu Ye | Yanfang Li | Nemat O. Keyhani | Zhen Huang
The rice planthopper, Sogatella furcifera, isa piercing-sucking insect pest of rice, Oryza sativa. It is responsible for significant crop yieldlosses, and has developed moderate to high resistance to several commonly usedchemical insecticides. We investigatedthe effects of the insect fungal pathogen Isaria javanica, aloneand in combination with the chemical insecticide dinotefuran, on S. furcifera under both laboratory and field conditions. Our results show that I. javanica displays highinfection efficiency and mortality for different stages of S. furcifera,reducing adult survival, female oviposition and ovary development. Laboratory bioassays showed that the combineduse of I. javanica with a low dose (4–16 mg L–1)of dinotefuran resulted in higher mortality in S. furcifera than the use of I. javanica or dinotefuran alone. The combined treatment also had moresignificant effects on several host enzymes, including superoxide dismutase,catalase, peroxidase, and prophenol oxidase activities. In field trials, I. javanica effectively suppressed populations of rice planthoppers to low levels (22–64%of the level in untreated plots). Additional field experiments showed synergistic effects, i.e., enhancedefficiency, for the control of S. furcifera populationsusing the combination of a low dose of I. javanica (1×104 conidia mL–1) and a low dose of dinotefuran (~4.8–19.2% of normalfield use levels), with control effects of >90% and a population level under50 insects per 100 hills at 3–14 days post-treatment. Our findings indicate that the entomogenousfungus I. javanica offers an attractive biological controladdition as part of the integrated pest management (IPM) practices for thecontrol of rice plant pests.
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