ABSTRACT

Investigation on survey, biology and management of black flower thrips, Thrips parvispinus (Karny) in chilli was conducted at the Department of Entomology, College of Agriculture, Vijayapur and KVK, Vijayapur, Karnataka during 2023-24. A roving survey in chilli growing areas of Vijayapur and Bagalkote districts in Northern Karnataka revealed that, Thrips parvispinus (Karny) was the dominant species among thrips infesting chilli. Thrips infestation commenced from July, peaking in October and November and persisted until March month. The highest thrips population was recorded in Jamkhandi taluka (Bagalkote) and the lowest in Basawana Bagewadi taluka (Vijayapura). Correlation analysis showed weak and insignificant effects of weather conditions on thrips populations in both districts. Predators such as minute pirate bugs, ladybird beetles, green lacewings, and spiders were observed with populations of 2.39, 1.83, 1.56, 0.67 and 1.78 per plant, respectively.
Life cycle composed of egg, two nymphal instars, prepupa, pupa and adult stages. Developmental duration of egg, first and second instar larva, prepupa and pupa were 4.42±0.43, 1.74±0.28, 3.75±0.44, 1.16±0.26 and 2.09±0.25 days, respectively. Adult female laid on an average of 51.65±7.52 eggs and lived for 8.46±1.06 days. Longevity of adult male was 6.51±0.71 days. The pre-oviposition period, oviposition period and post-oviposition period lasted for 1.67±0.39, 4.19±0.46 and 2.55±0.23 days, respectively. Total life cycle of adult male and female were 19.94±1.67 and 21.89±1.69 days, respectively. Among the different insecticides and biopesticides tested, diafenthiuron 50% WP @ 0.5 g/l was found to be effective in controlling thrips population and recorded highest yield of 9.47 t/ha. It was followed by thiamethoxam 25% WG @ 0.25 g/l with yield of 7.95 t/ha. Among biopesticides, neem-based insecticide (1500 ppm) @ 5 ml/l and Beauvaria bassiana (2×108 CFU/g) @ 4 g/l were found equally effective in controlling thrips population with fruit yield of 4.55 and 4.17 t/ha, respectively.