Role of abiotic factors on the incidence of major insect pests of pigeonpea, Cajanus cajan (L.) Millsp

Abstract

During present studies incidence of pod fly; Melanagromyza obtusa Malloch (Diptera: Agromyzidae), thrips; Megalurothrips usitatus Bagnall (Thysanoptera: Thripidae), pod bug; Clavigralla gibbosa (Spinola) (Hemiptera: Coreidae), Kudzu bug; Megacopta cribraria Fabricius (Hemiptera: Plataspidae) and cow bug; Otinotus oneratus (Walker) (Hemiptera: Membracidae) was found negatively correlated with temperature (both maximum and minimum) and rainfall whereas positively correlated with morning relative humidity except thrips. It was also found that Leaf webber; Grapholita critica (Meyr.) (Lepidoptera: Tortricidae) incidence was positively correlated with temperature and morning relative humidity. Regression analysis showed that minimum temperature significantly contributed more than 49% variation to the high population buildup of the C. gibbosa, M. cribraria and O. oneratus insects. The present study also report first time the effects of different abiotic factors on the incidence of Kudzu bug; M. cribraria.