Population Dynamics of Thrips (Thrips tabaci L.) Infesting Tomato (Lycopersicon esculentum L.) and their Sustainable Management

Population dynamics of thrips (Thrips tabaci L.) in relation to abiotic factors and its botanical management in tomato was assessed by Randomized Block Design for two consecutive seasons (2011-2013) at Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal, India. Minimum number of thrips (0.42−53 leaf⁻¹) population was recorded during 38^th to 44^th standard week and maximum level of population was observed during 45^th to 2^nd (1.05−1.89 leaf⁻¹) ^{and again during 6th to 20th (1.00−2.22 leaf−1) standard week. Correlation co-efficient indicates that activity of thrips population decrease with high temperature, high relative humidity and heavy weekly total rainfall but population increase with the rise of temperature difference. Management result shows that acetamiprid was most efficacious against thrips providing 84.15% suppression. However, neem+Spilanthes gave satisfactory result providing 72.27% suppression. The individual mean percent suppression of neem pesticides, extracts of Spilanthes, Polygonum, tobacco, garlic were 60.73%, 53.21%, 50.70%, 42.10% and 41.52% respectively. Highest yield 30.15 t ha−1 followed by 27.55 t ha−1 was recorded in acetamiprid and neem+Spilanthes. Treated plots respectively. Lowest 18.32 t ha−1 followed by 23.11 t ha−1 was recorded in control and garlic plots respectively. The yield obtained in remaining were 26.67 t ha−1 (Spilanthes), 26.32 t ha−1 (Polygonum), 24.02 t ha−1 (tobacco extract), 25.56 t ha−1 (neem pesticides).}