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椰心叶甲[Brontispa longissima(Gestro)]是椰子的重要害虫,近年来,该虫在海南岛发生普遍,椰子受害严重。由于椰心叶甲受到自然界中某些致病微生物的侵袭,在受害的椰子树心叶上常可发现椰心叶甲僵虫,并发现大部分僵虫表面长出了霉菌,本研究的目的在于从椰心叶甲僵虫表面的霉菌中分离出绿僵菌,并对分离菌株进行鉴定和致病性测定。从僵虫表面刮下孢子或菌丝体,置于绿僵菌选择性培养基(DOA)上培养,挑出真菌菌落,经纯化后,进行生物学特性、菌落生长速率及产孢量的测定,并从PPDA、OMA、V8A和PDA中筛选菌落生长及产孢最适培养基,同时对所分离的菌株进行对椰心叶甲的致病性测定。结果表明,所有分离菌株均鉴定为金龟子绿僵菌[Metarhizium anisopliae (Metschnikoff)],PPDA是菌落生长及产孢的最适培养基,大多数菌株对椰心叶甲有较强的致病力。选取强毒菌株MA4在田间进行防治效果的初步测定,结果表明,该菌株能显著降低椰心叶甲成虫的虫口密度。这些金龟子绿僵菌菌株是首次从海南的椰心叶甲僵虫中分离到的昆虫病原真菌,该菌对海南的椰心叶甲具有很好的生防潜能。
Brontispa longissima (Gestro) is an important pest of coconuts. In recent years, it has become common in Hainan Island and its coconuts have been seriously affected. Since Coconut palm leaf is affected by some pathogenic microorganisms in nature, caterpillar fungus can often be found on the damaged coconut palm heart, and most of the surface of the caterpillar is found to grow mold. The purpose of this study is to find the caterpillar fungus Metarhizium anisopliae isolated from the mold, and isolates were identified and pathogenicity determination. The spores or mycelium were scraped from the surface of the sclerotia, placed on Metarhizium anisopliae selective medium (DOA), and the fungal colonies were picked out and purified to determine the biological characteristics, colony growth rate and sporulation , And the colony growth and sporulation optimum medium were screened from PPDA, OMA, V8A and PDA. The pathogenicity of the isolated strains was also tested. The results showed that all isolates were identified as Metarhizium anisopliae (Metschnikoff). PPDA was the most suitable culture medium for colony growth and sporulation. Most of the isolates had strong virulence to C. catechu. The virulent strain MA4 was selected in the field for the preliminary determination of the control effect. The results showed that the strain could significantly reduce the population density of Coccinella septempunctata. These strains of Metarhizium anisopliae are the first entomopathogenic fungi isolated from the brown caterpillar of Hainan coconut palustris, which has good biocontrol potential on Hainan coconut leaf palm.