Colonization of introduced parasitoid, Encarsia guadeloupae Viggiani, on the exotic spiralling whitefly, Aleurodicus dispersus Russell infesting ornamentals

Abstract

The exotic spiralling whitefly, Aleurodicus dispersus Russell, was observed to infest several ornamentals including rose, hibiscus, poinsettia and acalypha in and around Bangalore. Efforts were made to colonize the aphelinid parasitoid, Encarsia guadeloupae Viggiani, during 2002-2003 on the above ornamentals infested with the spiralling whitefly. A total of five predators, namely, Axinoscymnus puttarudriahi Kapur and Munshi, Cryptolaemus montrouzieri Muls., Anegleis cardoni (Weise), Mallada astur (Banks) and Cybocephalus sp. were observed on the spiralling whitefly on these ornamentals during the study but there impact on the spiralling whitefly was negligible. Inoculative releases of E.guadeloupae were made on rose (156 adults), hibiscus (179 adults), poinsettia (124 adults) and acalypha (247 adults). Encarsia guadeloupae was recovered within a few month after its release with 3.43 – 32.94% parasitism. A steady decline in the population of spiralling whitefly was observed on these ornamentals. Encarsia guadeloupae was found to be the only parasitoid encountered throughout the study and the total parasitism steadily increased up to 96.00% on rose, 86.40% on hibiscus, 90.40% on poinsettia and 39.86% on acalypha at six months from release. Parasitism by E. guadeloupae was significant and negatively correlated with the population of spiralling whitefly on all the four ornamentals.