author(s)
V Manimaran, M Suganthy, A Balasubramanian and P Pretheep Kumar

abstract
Ailanthus excelsa is a multipurpose, fast growing tree species belongs to the family Simaroubaceae. Severe infestation of Helopeltis antonii Signoret causing drying and death of terminal shoots and forking was documented in two years old plantations of A. excelsa at Forest College and Research Institute (FC&RI), Mettupalayam from November, 2018 to February, 2019.Results of field experiment conducted to test the efficacy of chemical pesticides against tea mosquito bug (TMB) revealed that at 14 days after treatment (DAT), the reduction in TMB population over untreated control was recorded to be 96.30 per cent in thiacloprid treatment, as against 62.96 per cent in dichlorvos treatment. Mean number of TMB per tree after 14 DAT was observed to be 0.05 per tree in thiacloprid treatment as against 7.40 bugs per tree in untreated control. All the treatments have recorded more than 90 per cent reduction in TMB population except chlorpyriphos which has registered 88.12 per cent reduction over a period of 14 days of treatment. Results of field experiment conducted to test the efficacy of bio-pesticides against TMB revealed that mean number of tea mosquito bugs recorded per tree over a period of 14 days of treatment was minimum (1.53 per tree) in azadirachtin 10,000 ppm treated trees followed by NSKE 5 per cent (1.93 per tree) treatment. Among the three microbials tested, Beauveria bassiana recorded the minimum bug population of 3.47 per tree, as against 3.93 bugs per tree in Metarhizium anisopliae treatment. The mean per cent reduction over control was observed to be 77.66 and 72.13 per cent in azadirachtin and NSKE 5 per cent treatments, respectively, while, the standard chemical check profenophos registered 93.40 per cent reduction over untreated control.