Ecological Studies on Aphid Species Infesting Main cereal Crops

Abstract

The present work was conducted during 2012/2013 and 2013/2014 seasons to survey aphid species infesting maize, wheat and barley at Abo-Hammad district, Sharkia Governorate, Egypt. Effects of some climatic factors on population of the dominant aphid species were also studied. The aphids, Rhopalosiphum maidis (Fitch), Rhopalosiphum padi (L.), Schizaphis graminum (Rond.) and Sitobion avenae (F.) were collected from wheat and barley plants, while R. maidis (Fitch), R. padi (L.) and Aphis gossypii (Glov.) were collected from maize plants. Plant sample proved to be efficient method to collect and survey aphid species during the two successive seasons of investigation. Regarding the seasonal abundance on maize, R. maidis (Fitch) recorded one peak at the 2 nd week of August in both seasons 2012 and 2013 (1640 and 1250 individuals/sample, respectively), also R. padi (L.) and A. gossypii (Glov.) had one peak in the 3 rd week of August in 2012 and 2013 seasons (978 & 95 and 815 & 91 individuals/sample, respectively). On wheat, R. padi (L.) and R. maidis (Fitch) were represented by one peak at the last week of February in 2012/2013 and 2013/2014 seasons (320 & 285 and 450 & 266 individuals/sample, respectively), while S. graminum (Rond.) recorded one peak on the first week of March in 2012/2103 and 2013/2014 seasons (87 and 79 individuals/sample, respectively). S. avenae (F.) recorded one peak on the 2 nd week of April in both studies seasons (199 and 710 individuals/sample, respectively). On barley, R. padi (L.) was represented by one peak at the third week of February in 2012/2013 and 2013/2014 seasons (238 & 271 individuals/sample, respectively) but the only peak of R. maidis (Fitch) was at the third and fourth week of February in 2012/2013 and 2013/2014 seasons (246 & 174 individuals/sample), respectively. S. graminum (Rond.) recorded one peak on the 3 rd and 4 th week of February in 2012/2103 and 2013/2014 seasons (34 and 35 individuals/sample), respectively. The results indicated that the tested meteorological factors play a great role in regulating the population density and seasonal abundance of these aphid species.