Jandricic S E, Filotas M, Sanderson J P, Wraight S P
Department of Entomology, Comstock Hall, Cornell University, Ithaca, NY 14853, USA; Department of Entomology, Gardner Hall, NC State University, Raleigh, NC 27695, USA.
OMAFRA, Simcoe Office, Box 587, Blueline Road & Highway # 3 Simcoe, ON N3Y 4N5, Canada.
J Invertebr Pathol. 2014 May;118:34-46. doi: 10.1016/j.jip.2014.02.003. Epub 2014 Feb 25.
Seeking new isolates of entomopathogenic fungi with greater virulence against greenhouse aphid pests than those currently registered in North America for control of these insects, single-dose screening assays of 44 selected fungal isolates and 4 commercially available strains were conducted against first-instar nymphs of Myzus persicae and Aphis gossypii. The assays identified a number of Beauveria and Metarhizium isolates with virulence equal to or greater than that of the commercial strains against the nymphal aphids, but none exhibited exceptionally high virulence. Virulence of Isaria isolates was unexpectedly low (<31% mortality at doses>1000conidia/mm(2)). In dose-response assays, Beauveria ARSEF 5493 proved most virulent against M. persicae and A. gossypii; however, LC50s of this isolate did not differ significantly from those of B. bassiana commercial strain JW-1. Dose-response assays were also conducted with Aulacorthum solani, the first reported evaluations of Beauveria and Metarhizium against this pest. The novel isolate Metarhizium 5471 showed virulence⩾that of Beauveria 5493 in terms of LC25 and LC50, but 5493 produced a steeper dose response (slope). Additional tests showed that adult aphids are more susceptible than nymphs to fungal infection but confirmed that infection has a limited pre-mortem effect on aphid reproduction. Effects of assay techniques and the potential of fungal pathogens as aphid-control agents are discussed.
为了寻找对温室蚜虫害虫毒力比北美目前登记用于防治这些昆虫的菌株更强的昆虫病原真菌新分离株，针对桃蚜和棉蚜的一龄若虫，对44种选定的真菌分离株和4种市售菌株进行了单剂量筛选试验。试验鉴定出一些球孢白僵菌和绿僵菌分离株，其对若蚜的毒力等于或高于市售菌株，但没有一种表现出极高的毒力。被毛孢分离株的毒力出乎意料地低（剂量>1000分生孢子/mm(2)时死亡率<31%）。在剂量反应试验中，球孢白僵菌ARSEF 5493对桃蚜和棉蚜的毒力最强；然而，该分离株的半数致死浓度与球孢白僵菌商业菌株JW-1的半数致死浓度没有显著差异。还对茄无网蚜进行了剂量反应试验，这是首次报道球孢白僵菌和绿僵菌对这种害虫的评估。新分离株绿僵菌5471在半数致死浓度25和半数致死浓度方面表现出与球孢白僵菌5493相当的毒力，但5493产生的剂量反应曲线更陡（斜率）。进一步的试验表明，成年蚜虫比若虫更容易受到真菌感染，但证实感染对蚜虫繁殖的死前影响有限。讨论了试验技术的影响以及真菌病原体作为蚜虫防治剂的潜力。
