Submitted to: Thomas Say Publications in Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 1997
Publication Date: N/A
Technical Abstract: Fungal pathogens are important natural enemies of cereal aphids worldwide. Their role in the regulation of Russian wheat aphid populations has received little attention, in or outside of North America. Pathogenic fungi (Entomophthorales, Beauveria bassiana and Verticillium lecanii) have been identified from Russian wheat aphid in several states of the USA and Canadian provinces. Data on these native natural enemies and the available damage reports indicate that the fungal complex resident in North America is generally not well suited for Russian wheat aphid control. Although native fungi have some impact on D. noxia population levels, they do not prevent economic damage to small grains. While fungi appear to be ineffective in controlling the aphid in N. America, in regions where D. noxia is indigenous (the semi-arid mountain ranges of central Asia) economic damage is rare, suggesting that more effective natural enemies, possibly including fungi, may regulate the aphid populations in these areas. While a number of promising fungal pathogens were collected in N. America and during foreign exploration, to-date, only one exotic isolate (Zoophthora radicans) has been released against the aphid on this continent. Use and success of microbial methods of control of cereal aphids depend upon an accurate assessment of research results conducted over vast and diverse areas. This assessment should consider the limits of efficiency and long-term profit within which a given pathogen might be useful for the protection of the crop.