Environmental Entomology (2021) 50, 160-166

Tao Lian, Hua-long Qiu, Chang-sheng Qin, Eduardo G.P. Fox, Dan-yang Zhao, Tian-song Fang, Hua Yang, Long-yan Tian and Jin-zhu Xu (2021)
Metarhizium entomopathogenic fungi against the beetle Brontispa longissima (Coleoptera: Hispidae): Isolation and species identification
Environmental Entomology 50 (1), 160-166
Abstract: Seven entomopathogenic fungi strains (M1-7) were isolated from field-obtained dead coconut hispine beetles Brontispa longissima (Gestro), identified to species, and bioassayed for their pathogenicity. According to ITS sequences, all isolates belong in the genus Metarhizium, mainly M. flavoviride and M. anisopliae. Measured median lethal times (LT₅₀) of 1×10⁷ conidia/ml of M1-7 against fourth-instar B. longissima larvae within 15 d following exposure were, respectively: 5.43, 10.64, 11.26, 10.93, 6.62, 4.73, and 5.95 d. The isolate M6 yielded the highest mortality to fourth-instar larvae, and was thus selected to be tested against other larval instars and adults of B. longissima, after Time–Dose–Mortality (TDM) models. M6 proved more pathogenic against larvae than adults. The obtained bioassays data produced a good fit to the TDM models, yielding estimated LC₅₀ and LT₅₀ for each of the tested developmental stages of B. longissima. Both the obtained dose (β) and time effect (r_i) parameters from TDM models suggest that first-instar larvae are the most susceptible life stage of the pest insect, while adults are more resistant to M6 infection. Calculated LC₅₀ values were, respectively, 1.23×10³ and 1.15×10⁶ conidia/ml for first-instar larvae and adults, on the 15th day following M6 inoculation. Estimated LT₅₀ were 3.3 and 5.9 d for first-instar larvae and adults, respectively, at 1×10⁸ conidia/ml. Taken together, these results would suggest Metarhizium M6 as an option for the biological control of B. longissima in the field.
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Link to article at publishers website
Database assignments for author(s): Eduardo G.P. Fox

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Brontispa longissima	Coconut (Cocos nucifera)	China (south)
Metarhizium anisopliae (entomopathogen)	Brontispa longissima	Coconut (Cocos nucifera)	China (south)
Metarhizium flavoviride (entomopathogen)	Brontispa longissima	Coconut (Cocos nucifera)	China (south)