Seasonal Dynamics of Aphis Gossypii and Relative Abundance of its Coccinellid Predators on Cucumber

Studies on the seasonal dynamics of Aphis gossypii Glover and relative abundance of its important coccinellid predators were done for two consecutive years 2008 and 2009 on cucumber, Cucumis sativus L. var. local (Kalen thabi). The infestation of A. gossypii commenced from January and attained its peak during May. Four important coccinellid species viz., Harmonia octomaculata (F.), Coccinella transversalis (F.), Cheilomenes sexmaculata (F.) and Coccinella septempunctata (L.) were present. They were observed throughout the incidence period, however, maximum density of H. octomaculata was observed when the aphid density was appreciably high during May. The relative abundance revealed that H. octomaculata was the most abundant (52.38%) in 2008 and (52.51%) in 2009.