|Hatting, Justin - S AFRICAN AGR RES COUNCIL|
|Miller, Ray - UNIVERSITY OF NATAL|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 16, 1999
Publication Date: N/A
Interpretive Summary: A survey of the fungal pathogens of aphids pests of cereal grains in South Africa was undertaken as a fundamental aid towards establishing useful programs for the biological control of these insect pests. Cereal aphid, including Russian wheat aphid (Diuraphis noxia), cause losses of up to 90% of cereal crops in some environments in South Africa where the use of chemical pesticides has become prohibitively expensive, so their control i a major agricultural issue. This survey found the presence of 8 fungal pathogens from aphids on grain crops. Six of the eight fungi have been cultured and are now available from the ARS Collection of Entomopathogenic Fungal Cultures (Ithaca, NY); at least five of these cultured species might be good candidates for use in applied biocontrol. All eight fungi are illustrated and described, and their distributions, incidences, and effectiveness against natural aphid populations is discussed. In addition to the more applied aspects of this study, this represents one of the firs targeted surveys for the biodiversity of fungal pathogens of insects in South Africa and one of very few surveys ever done on the African continent; it is notable that the fungi found all have global distributions (a fact that underscores the potential utility of these fungi for practical use in biological control).
Technical Abstract: Surveys of entomopathogenic fungi of aphids in South Africa were conducted from 1995 through 1998. A total of eight species of fungi known to infect and kill aphid hosts were collected, including six Entomophthorales and two Hyphomycetes. The Entomophthorales included PANDORA NEOPHIDIS, CONIDIOBOLUS THROMBOIDES, C. OBSCURUS, C. CORONATUS, ENTOMOPHTHORA PLANCHONIANA, and NEOZYGITES FRESENII. The two Hyphomycetes collected wer BEAUVERIA BASSIANA and VERTICILLIUM LECANII. P. NEOAPHIDIS, C. THROMBOIDES, C. OBSCURUS and E. PLANCHONIANA were first reports from South Africa, and V. LECANII was isolated for the first time from a South African insect. Most findings of entomopathogenic fungi were from cereal aphids including six species from the Russian wheat aphid, DIURAPHIS NOXIA. In both the summer and winter rainfall regions of S. Africa, fungi recorded from the cereal aphid complex were found from early spring through early summer. Findings from non-agricultural aphid hosts were usually made during late summer through late fall with two find during the winter (June and July). The number of species of fungi collected reflect a great diversity in the aphid-pathogenic flora from South Africa.