Morphometrics, seasonal incidence, behavior and natural parasitization of Aphelinid parasitoid, Encarsia guadeloupae Viggiani (Hymenoptera : Aphelinidae) on Rugose spiralling whitefly

Abstract

Field surveys were conducted on the parasitoids of rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus Martin (Hemiptera: Aleyrodidae) during 2018-20 in coconut growing districts of Tamil Nadu. The parasitoid, Encarsia guadeloupae Viggiani (Hymenoptera: Aphelinidae) was observed on A. rugioperculatus occurring in hosts viz., coconut, banana and custard apple. Among all crops, RSW infesting banana had maximum parasitisation (70.83%). Adults of E. guadeloupae are small (0.6-0.7 mm) brown in colour with body length and width of 0.675±0.014 mm and 0.256±0.010 mm. The natural parasitism by E. guadeloupae was ranging from 31.60 % (August 2018) to 57.60 % (December 2018). Correlation coefficient of E. guadeloupae with A. rugioperculatus population showed that had negative correlation with A. rugioperculatus population E. guadeloupae In the case of coconut trees based on heights the parasitization potential of E. guadeloupae was 5-10 feet height trees with maximum level of parasitisation (61.39 %) followed by 10-15 feet coconut tree with 52.77 %. In banana leaf position impact on E. guadeloupae emergence from parasitized A. rugioperculatus was 47.93 % in 6th leaf (from the top) of banana tree followed by 10th leaf (47.12%). This is because preferred stage of RSW mostly found in top leaves than the old leaves where mostly later instar stages will be available.