Pest Management Science (2022) 78, 1508-1518

Xian Cui Zhang, Meng Jiang, Ya Nan Zang, Hai Zheng Zhao, Cai Xia Liu, Bao Rui Liu, Hua Xue, Coby Schal, Xing Meng Lu, Dong Qin Zhao, Xue Xia Zhang and Fan Zhang (2022)
Metarhizium anisopliae is a valuable grist for biocontrol in beta-cypermethrin-resistant Blattella germanica (L.)
Pest Management Science 78 (4), 1508-1518
Abstract:
BACKGROUND
The widespread use of chemical insecticides has resulted in the development of resistance in German cockroaches worldwide, and biopesticides based on entomopathogenic fungi as active ingredients have become a promising alternative strategy. Resistance can change many of the physiological and biochemical characteristics of insect pests, such as cuticle thickness, detoxification enzyme activity, and even intestinal flora composition. Thus, potential interactions between pathogenic fungi and insecticide resistance may lead to unpredictable changes in pest susceptibility to fungi.
RESULTS
Beta-cypermethrin-resistant German cockroaches were more susceptible to infection with the fungus Metarhizium anisopliae regardless of age and sex. Histopathological results showed that the infection of resistant strains (R) by M. anisopliae was visibly faster than that of susceptible strains (S). The gut microbiota of the S strain indicated a stronger ability to inhibit fungi in vitro. The abundance of Parabacteroides, Lachnoclostridium, and Tyzzerella_3 decreased significantly in the R strain, and most demonstrated the ability to regulate glucose and lipid metabolism, and antifungal infections. The expression levels of Akirin, BgTPS, and BgPo genes in the R strain were significantly lower than those in the S strain, while BgChi and CYP4G19 gene expression were significantly higher. The mortality of cockroaches infected with M. anisopliae decreased to varying degrees after RNA interference, reflecting the role of these genes in antifungal infection.
CONCLUSIONS
Results confirmed that insecticide resistance may enhance cockroach susceptibility to fungi by altering intestinal flora and gene expression. Fungal biopesticides have high utilization value in pest control and insecticide resistance management strategies.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Coby Schal

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
pesticide resistance of pest
Research topic(s) for beneficials or antagonists:
resistance to pesticides

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Blattella germanica
Metarhizium anisopliae (entomopathogen)	Blattella germanica