Wheat is a premier winter cereal crop in India. Among the various insect pests, aphids appear as a complex of species including Sitobion avenae (F.), S. miscanthi (Takahashi), Rhopalosiphum maidis (Fitch) and R. padi (L.). Coccinella septempunctata L. is a dominant predator of aphids. Various spray patterns were tested to check their effectiveness against aphids. All the treatments more effectively controlled the aphids compared to control. However, the insecticides adversely affected the predator population. The predator populations was reduced by 87.5, 85.4 and 78.9%, respectively, one day after spray in completely sprayed, sprayed strip and unsprayed strip plots, whereas the reduction was only 22.8% in peripherally sprayed plot. The predator recovery started after 3 days in all the treated plots but it was very slow in the completely sprayed plot. Among all the treatments, the peripherally treated plot conserved maximum predator population and controlled the multiplication of the pest.
Keywords
Wheat Aphids, Coccinellid, Coccinella septempunctata, Spray Pattern, Recovery, Weather Factors.
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