Bioefficacy of Newer Molecules Insecticides against Tea Mosquito Bug, Helopeltis theivora Waterhouse under Laboratory Condition

Aims: Bio-efficacy of newer insecticides against the Tea mosquito bug (TMB) in Tea.

Study Design: CRD

Place and Duration of Study: R&D center, Parry Agro Industries Limited, Murugali Tea Estate, Valparai, Coimbatore, Tamil Nadu between September 2019 and September 2021.

Methodology: Field populations of H. theivora were collected and Bouquet bioassay method was used to assess the efficacy. Eleven insecticides with three replications (15 shoots/ replication) and Completely Randomized Design (CRD) was followed. The treatments includes viz.,T1- Chlorantraniliprole 18.5 SC @ 0.3ml/lit., T2- Spirotetramate +Imidacoprid 11.01 SC @ 2ml/litre., T3 - Thiacloprid 21.7 SC @ 1ml/lit., T4 - Thiamethoxam 25 WG @ 0.5gm/lit., T5- Spinosad 45 SC @ 0.5ml/lit., T6- Dinotefuran 20 SG @ 0.5g/lit., T7- Emamectin benzoate 5 SG @ 0.5g/lit., T8- Buprofezin 25 SC @ 3ml/lit., T9- Sulfaxaflor 21.8 SC @ 1.8ml/lit., T10- Tolfenpyrad 15% EC @ 2ml/lit., and T11- Control (Water). The shoots were sprayed with hand atomizer and observations on the % adult mortality and Feeding puncture/ shoots were recorded at 24, 48 and 72 hours after treatment (HAT). Moribund insects were consider as dead and taken for the count and data were analyzed statistically.

Results: Among all the treatments tested, tolfenpyrad 15% EC after 72 HAT treated tea shoots having less no of feeding punctures (85.33 Nos) and maximum 100 percent adult mortality followed by dinotefuran 20 SG (100.00%), sulfaxaflor 21.8 SC (93.33%), emamectin benzoate 5 SG (90.00%), thiacloprid 21.7 SC (88.33%), spirotetramate + imidacoprid 11.01 SC (81.67%), buprofezin 25 SC (75.00%), thiamethoxam 25 WG (71.67%), chlorantraniliprole 18.5 SC(68.33%), spinosad 45 SC (61.67 %). The feeding punctures were maximum in untreated control (167.22 Nos).

Conclusion: The present study revealed the application of Tolfenpyrad 15% EC @ 2ml/lit. is the optimum dose for the effective control of Helopeltis theivora under laboratory conditions.