Evaluvation of new insecticides against major pests of okra, Abelmoschus esculentus

Abstract

An experiment was conducted on ‘Evaluation of new insecticides against major pests of okra, Abelmoschus esculentus L.’ at College of Agriculture, Padannakkad and RARS Pilicode sub centre, Karuvachery in two seasons viz., rabi season (September to December 2018) and summer season (January to April 2019).The objective of the study was ‘to study the efficacy of different new insecticides against major pests of okra, viz., shoot and fruit borer, gram pod borer, leaf roller and leafhopper’. The variety selected for the study was Varsha Uphar released by Haryana Agricultural University, Hisar. The experiment was laid out in Randomized Block Design with 8 treatments and 3 replications. The different treatments were; T1: Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC (Voliam flexi®) @ 0.7ml/l; T2: Lambda cyhalothrin 4.6 per cent + Chlorantraniliprole 9.3 per cent ZC (Ampligo®) @ 0.4 ml/l; T3: Thiamethoxam 12.6 per cent + Lambda cyhalothrin 9.5 per cent ZC (Alika®) @ 0.5 ml/l; T4: Flubendiamide 19.92 per cent w/w + Thiacloprid 19.92 per cent w/w (Belt-expert®) @ 0.4ml/l; T5: Novaluron 10 EC @ 2ml/l; T6: Chlorantraniliprole 18.5 SC @ 0.3 ml/l (check); T7: Thiamethoxam 25 WG @ 0.3g/l (check); T8: Absolute control. Treatments were applied one at vegetative and one at reproductive stage after the incidence of pest. The observations like damage symptoms were recorded at seven and fourteen days after treatment and population of jassids were recorded at one, three, five, seven and fourteen days after treatment. Biometric observations and yield parameters were recorded during each harvest. The data recorded from field experiment was tabulated and statistical analysis was performed using analysis of variance (ANOVA). Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC (T1 -Voliam flexi) @ 0.7 ml/l of water significantly reduced the percentage of shoot and fruit damage during both rabi and summer season. No infestation was recorded at seven and fourteen days after treatment. It was on par with the standard check Chlorantraniliprole 18.5 SC. The damage caused by leaf roller was significantly reduced by Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC @ 0.7 ml/l of water. There was no incidence of leaf roller after seven and fourteen days after first spray until the end of the crop period during both rabi and summer season. Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC @ 0.7 ml/l of water was very effective against the population of leafhopper. The population of adults and nymphs of leafhopper was drastically reduced by Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC and three days after spray no hoppers were found on plots treated with Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC. It showed non-significant difference with standard check Thiamethoxam 25 WG @ 0.3 g/l of water. Alika (Thiamethoxam 12.6 per cent + Lamda cyhalothrin 9.5 per cent ZC) @ 0.5ml/l of water significantly reduced the population of leaf hopper after Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC. Hopper population was negligible at fifth and seventh day after treatment while it was increased by fourteenth day. Length of the fruit was inversely proportional to the percentage of damage caused by Earias vitella. Maximum fruit length of 14.85 cm and 15.99 cm was recorded from Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC treated plots during both rabi and summer season respectively. This indicates higher efficacy of Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC against E. vitella. The highest total yield was recorded from Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC treated plots during rabi and summer season with yield of 469.86 and 594.31 g/plant respectively. Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC also showed high benefit-cost ratio of 2.42 and 3.12during rabi and summer season respectively.