Entomophthorales fungi (Zygomycetes) pathogens of aphids (Hemiptera: Aphididae) associated with cereal crops in Argentina.

MANFRINO ROMINA GUADALUPE; LÓPEZ LASTRA CLAUDIA CRISTINA; SALTO CÉSAR EDUARDO

Congreso; International Congress on Invertebrate Pathology and Microbial Control.; 2012

The aphids represent for cereal production in Argentina a of the main cause of economic loss. Control of aphids has been done predominantly by using chemical insecticides. However this practice has caused problems for the environment, human health, and some species of aphids have developed resistance to insecticides. As natural enemies of aphids, Entomophthoralean fungi have been found to be important mortality factors in the field. The overall objective of this study was to do a survey and identification of entomophthoralean fungi species pathogenic to aphids of cereal crops. The studies were conducted in crops of Triticum aestivum L. (wheat), Avena sativa L. (oats) y Sorghum bicolor L. Moench (sorghum) during two consecutive years with weekly frequence in West region of Santa Fe, Argentina. Six aphid species were recorded as hosts of Entomophthorales fungi: Rhopalosiphum maidis (Fitch), Rhopalosiphum padi (Linnaeus), Rhopalosiphum rufiabdominalis (Sasaki), Shizaphis graminum (Rondani), Sitobion avenae (Fabricius) y Sipha maydis Passerini. Three species of Entomophthoralean fungi were found infecting these species of aphids. Pandora neoaphidis (Remaudière & Hennebert) Humber y Zoophthora radicans (Brefeld) Batko (Entomophthorales: Entomophthoraceae) were the dominant pathogens of aphids during 2010 y 2011 respectively. However Neozygytes fresenii (Nowakowski) Remaudière & Keller (Entomophthorales: Neozygitaceae) was only recorded during the second year of the survey. Entomophthoralean fungal infections occurred mostly in autumn-winter season, coinciding with periods of high relative humidity and relatively low temperatures. This study is the first report of Entomophthoralean fungi infecting aphid pest in cereal crops in Argentina.