Field Performance of Three Exotic Parasitoids Against Papaya Mealybug, Paracoccus marginatus (Williams and Granara De Willink) Infesting Cassava in Tamil Nadu

Abstract

The papaya mealybug, Paracoccus marginatus an invasive polyphagous exotic pest assumed alarming status in Tamil Nadu during 2009–2010 because of its sudden outbreak on number of crops. Three encyrtid parasitoids viz., Anagyrus loecki, Acerophagus papayae and Pseudleptomastix mexicana were released in cassava gardens severely infested by papaya mealybug in 3 locations each at Salem, Namakkal and Dharmapuri districts of Tamil Nadu @ 200 individuals per location during November, 2010. An average of 6.08% parasitism and 11.51% reduction in P. marginatus population was noticed a month after release of parasitoids with a corresponding increase in percent parasitism @ 2, 3, 4 & 5th months. The population of P. marginatus from the tapioca garden was eliminated up to 93.15% @ 6th month corresponding to 76.33% parasitism. Among the parasitoids released, highest proliferation and field activity was observed in the case of A. papayae accounting for 80.89 – 94.31% parasitization and P. mexicana registered comparatively lesser performance (5.69 – 19.11%) whereas the field establishment of A. loecki was not noticed during the study period.