Vol. 10, Special Issue 11 (2021)

Author(s):
S Suriya, G Preetha, N Balakrishnan and J Sheela

Abstract:
Field surveys were conducted at fortnightly intervals in the southern districts of Tamil Nadu viz., Thoothukudi, Tenkasi, Tirunelveli and Kanyakumari districts from December 2020 to August 2021. The prevalence of rugose spiralling whitefly Aleurodicus rugioperculatus in coconut gardens that are grown as a single crop has been observed for the parasitization and establishment of nymphal parasitoid, Encarsia guadeloupae. The affected coconut leaflets were assessed by destructive sampling for the parasitic potential of E. guadeloupae under Leica stereo zoom microscope with image analyser. Based on the obtained results, the natural parasitization of E. guadeloupae was found to be highest in Kanyakumari district (33.86%) throughout the period of study. The order of per cent nymphal parasitization by E. guadeloupae is as follows: Kanyakumari (33.86%) > Tirunelveli (17.66%) > Thoothukudi (12.45%) > Tenkasi (11.20%). The per cent adult emergence of E. guadeloupae was found to be maximum (21.41%) in the coconut gardens of Kanyakumari district, where as it was least in Tenkasi district (5.37%). The mean population of A. rugioperculatus observed in the districts were 49.46, 44.01, 39.68, 32.76 nymphs/leaflet in Kanyakumari, Tirunelveli, Thoothukudi, Tenkasi districts respectively.