Population Dynamics of Aphid Pests of Wheat and Their Natural Enemies

Four aphid species (Schizaphis graminum, Sitobion avenae, Rhopalosiphum padi and Diuraphis noxia) were observed when the population dynamics of aphids in four wheat varieties were analysed. Maximum population abundance (104± 1.79 aphids/ plant) was observed during middle of March. Rhopalosiphum padi and D. noxia were predominant throughout (52.86.1± 0.21 and 56.10± 0.24 aphids/ plant, respectively). The variety ANAJ-2017 showed the least incidence (26.28± 0.27 aphids/ plant) being more resistant. Aphid parasitism was also more in ANAJ-2017 with the parasites Aphidius ervi (15.35± 0.13) and Praon volucre (12.45± 0.12). Abundance of predators (ladybird beetle, green lace wing, syrphid fly and spiders) was observed with the highly infested varieties UJALA-2016 and FSD-2008. With incidence of aphids, temperature showed positive correlation while relative humidity (RH) and rainfall did not show any significant effect. The yield varied significantly among the tested varieties and it was found positively correlated with aphid incidence with ANAJ-2017 exhibiting the maximum 1000 grain weight (55 g).