Invasive Insect Pests and their Management on Tapioca ( Manihot esculenta Crantz ) in India

Abstract

Several insect pests have got introduced into India, and some of them were known to cause extensive damage to economically important crops in India. The present paper deals with the existing invasive insect pests and future pest threats of tapioca (cassava - Manihot esculenta)). Invasives include the spiralling whitefly Aleurodicus dispersus Russell, papaya mealybug Paracoccus marginatus Williams & Granara de Willink, Madeira mealybug Phenacoccus madeirensisGreen, cassava mealybugs Phenacoccus manihotiMatile-Ferrero and Phenacoccus herreni Cox & Williams.Aleurodicus dispersus,native to Caribbean islands and Central America, was first reported to occur in 1993 in Kerala, andlater in Tamil Nadu. Heavy incidence of spiralling whitefly caused yield reduction up to 54% in tapioca in India. The accidentally introduced parasitoids Encarsia quadeloupaeViggiani and Encarsia(?) haitiensisDozier were able to suppress spiralling whitefly infesting tapioca in Tamil Nadu and Kerala.Papaya mealybug Paracoccus marginatus, native to Mexico, Central and North America was reportedfirst on many agricultural and horticultural crops including cassava in July 2008 in Tamil Nadu.Tapioca yield was reduced considerably by the infestation of P. marginatus in Kerala and Tamil Nadu.The encyrtid parasitoid Acerophagus papayaeNoyes and Schauff imported from Puerto Rico has givenexcellent control ofP. marginatusinfesting tapioca in peninsular India.Phenacoccus manihoti, theNeotropical species (South America), was accidentally introduced into Africa in the early 1970s, andit has spread fast to many Asian countries,viz., Thailand, Vietnam, Lao PDR, Cambodia and Myanmar.It is an immediate threat to cassava industry in India. The encyrtid parasitoidApoanagyrus (=Epidinocarsis) lopezi(DeSantis) had given excellent control ofP. manihotiin several African countries.Phenacoccus herreniis known to cause yield losses in cassava in its native South America. It is afuture threat to cassava in India. Three encyrtid parasitoidsApoanagyrus diversicornis(Howard),AenasiuvexansKerrich andAcerophagus coccoisSmith, are used to control the cassava mealybugP. herreniin South America. If the mealy bug gets introduced into Asian countries, the above parasitoids can beimported to suppressP. herreni.