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Natural control of <i>Diuraphis noxia</i> and <i>Rhopalosiphum maidis</i> (Aphidoidea) by parasitic entomophthorales (Zygomycota) in Slovakia

Barta, M., Cagáň, L.
Cereal research communications 2007 v.35 no.1 pp. 89-97
Conidiobolus obscurus, Diuraphis noxia, Entomophthora, Erynia neoaphidis, Metopolophium dirhodum, Neozygites fresenii, Rhopalosiphum maidis, Rhopalosiphum padi, Sitobion avenae, Zygomycota, barley, crops, fungi, seasonal development, summer, Slovakia
Seasonal development of entomophthoralean unfection in colonies of <i>Diuraphis noxia</i> and <i>Rhopalosiphum maidis</i> was evalauted on summer barley under conditions of south-western Slovakia in 2001 and 2002. <i>D. noxia</i> was infesting summer barley during both years, while <i>R. maidis</i> was only recorded in 2002. Further three cereal aphids, <i>Rhopalosiphum padi</i> , <i>Metopolophium dirhodum</i> and <i>Sitobion avenae</i> , were also observed on summer barley. Complex of entomophthoralean fungi identified in cereal aphid colonies included four species, <i>Pandora neoaphidis</i> , <i>Entomophthora planchoniana</i> , <i>Conidiobolus obscurus</i> and <i>Neozygites fresenii</i> , with <i>P. neoaphidis</i> as the most prevalent fungus during both years. Two parasitic fungi, <i>P. neoaphidis</i> and <i>E. planchoniana</i> , were identified from <i>D. noxia</i> , but <i>P. neoaphidis</i> was predominant. Infection rate in <i>D. noxia</i> colonies was low, not exceeding 15% and 10% in 2001 and 2002, respectively. Only nine <i>R. maidis</i> individuals were killed with entomophthoralean fungi. The fungi were identified as <i>P. neoaphidis</i> and <i>C. obscurus</i> . No epizootics were observed in the aphid colonies. The fungi could not control development of the aphid populations since they did not appear until high host densities had been established in the crops.