Emerging insect pests in Indian agriculture.
One of the major challenges to humankind is threat to food security due to emerging and invasive pests. Increased global trade in agriculture has increased the chances of the introduction of exotic pests. Papaya mealybug (Paracoccus marginatus Williams and Granara de Willink), cotton mealybug Phenacoccus solenopsis (Tinsley), coconut mite (Aceria guerreronis Keifer), serpentine leaf miner (Liriomyza trifolii Burgess) and tomato leaf miner [Tuta absoluta (Meyrick)] are some examples. Insect pests on an average are estimated to cause 15-20% yield losses in principal major food and cash crops. Pest whose status has been changing from minor to major or secondary to primary pest is termed as an emerging pest. Bemisia tabaci (Gennadius) on cotton, Helicoverpa armigera (Hubner) on vegetables and pulses, Spodoptera litura (F.) on vegetables, cotton and oilseeds, Pieris brassicae L. on crucifers, L. trifolii on vegetables and Atherigonia spp. on spring maize, have become increasingly severe during last decade. Increasing incidence of aphid complex, comprising of Sitobion avenae (F.), Rhopalosiphum maidis (Fitch) and Schizaphis graminum (Rondani) is now observed on wheat, barley and oat. Mites of the Eriophyiidae and Tetranychidae family have emerged as major pests of bean, brinjal, cotton, cucurbits, okra, apple, ber, citrus and mango in Northern India. Maruca vitrata Geyer has emerged as a predominant pest in recent years in all pigeonpea and cowpea growing areas of India causing up to 42% damage in cowpea in Andhra Pradesh. The invasive pest, coconut eriopyhid mite, Aceria gurrreronis Keiffer caused 64.16-89.42% nut infestation in at Thane, Maharashtra in 2014. During 2015-16 an epidemic of whitefly was noticed during August in the cotton growing areas of Haryana and Punjab (Kranthi, 2015). In this review the situation of emerging insect pests of crops is discussed along with the probable reasons for their changing pest status.