International Journal of Tropical Insect Science (2020) 40, 403-411

Julius Mugonza, Michael H. Otim and James P. Egonyu (2020)
The comparative virulence of an atoxigenic strain of Aspergillus flavus (Eurotiales: Trichocomaceae) and the commercial ICIPE 69 Metarhizium anisopliae (Hypocreales: Clavicipitaceae) to the bean leaf beetle Ootheca mutabilis (Coleoptera: Chrysomelidae)
International Journal of Tropical Insect Science 40 (2), 403-411
Abstract: The recent isolation of an atoxigenic strain of Aspergillus flavus (Link) (Eurotiales: Trichocomaceae), which was virulent to all stages of Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae) has generated interest to investigate virulence of the entomopathogenic fungus against other crop pests, and how it compares with established commercial biopesticides. In this study, we tested the pathogenicity and virulence of the atoxigenic A. flavus strain to Ootheca mutabilis (Sahlberg) (Coleoptera: Chrysomelidae) in the laboratory compared to the commercial Metarhizium anisopliae (Metschnikoff Sorokin) (Hypocreales: Clavicipitaceae; OD®, ICIPE 69). Serial dilutions of both entomopathogenic fungi (1 × 10⁶–1 × 10⁹ conidia/ml) were evaluated against adult O. mutabilis. Distilled water and cypermethrin 5% EC were included as controls. The treatments were replicated four times and the bioassay was repeated once. Both fungi at 1 × 10⁹ conidia/ml killed 100% of tested O. mutabilis within seven days in the 1st and 2nd trials. The concentration of both fungi that killed 50% of O. mutabilis was the same in both trials (5.3 × 10⁶ conidia/ml). The time taken by A. flavus and ICIPE 69 to kill 50% of O. mutabilis was not significantly different in the 1st trial (3.4 ± 0.1 days and 2.9 ± 0.4 days, respectively). However, ICIPE 69 took a significantly shorter time (2.1 ± 0.4 days) than A. flavus (3.6 ± 0.2 days) to kill 50% of O. mutabilis in the 2nd trial. We concluded that A. flavus is comparably as pathogenic and virulent (in terms of cumulative mortality and LC₅₀) against O. mutabilis as ICIPE 69, and therefore both fungi may be viable biopesticides for commercialization against this pest.
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Link to article at publishers website
Database assignments for author(s): Michael Otim

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ootheca mutabilis
Metarhizium anisopliae (entomopathogen)	Ootheca mutabilis
Aspergillus flavus (entomopathogen)	Ootheca mutabilis