VARIETAL PREFERENCE AND CHEMICAL CONTROL STRATEGIES FOR MANAGEMENT OF HELOPELTIS THET VORA WATERHOUSE

Among various biotic stresses that tea plants face, insect attack especially the Tea Mosquito Bug, Helopeltis their ora, has been a major challenge leading to severe losses in crop yields to the tune of 15-25 %. On account of complex pest situations, total avoidance of pesticides in tea is not possible all nough due to the sensitive nature of the crop pesticide use must be minimal. The main objective of this programme is to find out the effective utilization of chemical pesticides, minimize the pesticide load and development of a specific management package for conventional commercial tea gardens in North East India. Different new generation molecules have been tested under field conditions and Thiomethoxam, Imidacloprid and Cartaphydrochloride were found effective. Highest ovicidal activity was observed in Dimethoate. Neonate killing of nymphs was recorded in Deltamethrin, Endosulfan and Etofemprox. Field persistency of different classes of pesticides was evaluated under field conditions and ranged between 10 and 23 days. Imidacloprid, Thiomethoxam and -cy fluthrin persisted for longer period. Rate of feeding was high in female (56-339 feeding spots) than males (9- 182 feeding spots). Feeding site preference in both male and female was second leaf followed by third leaf, first leaf and least by bud. Lesser feeding spots were observed in TV, and TS, when exposed with males. All the chosen 15 tea cultivars are susceptible to female population.