Chemical control of onion thrips with insecticides through sequential sprays

Field experiments were conducted at Regional Research Station, NHRDF, Karnal in three consecutive years during rabi 2010-11, 2011-12 and 2012-13 on onion variety Agrifound Light Red for the management of onion thrips through sequential sprays of different insecticides. The chemical insecticides comprising thiamethoxam 25 WG @ 0.2%, fipronil 05 SC @ 0.1%, carbosulfan 25 EC @ 0.2%, profenophos @ 0.1%, lambdacyhalothrin @ 0.05%, acetamiprid 10 EC @ 0.01%, alphamethrin 10 EC @ 0.15% and deltamethrin @ 0.095% were used in a different sequential manner. The application of the treatments was started just after appearance of thrips and total four sprays of different insecticides were given at fifteen days interval. The results showed that significantly lowest mean thrips population (9.71 nymphs/plant) and highest marketable yield (253.53 Q/ha) were recorded in sequential spray of carbosulfan 25 EC @ 0.2%, lambdacyhalothrin @ 0.05%, acetamiprid 10 EC @ 0.01% and alphamethrin 10 EC @ 0.15%. The highest cost benefit ratio (1:4.69) was also recorded in the same treatment. The study revealed that four sequential sprays of different insecticides at 15 days interval could be useful to minimize the thrips population and increase the yield of Rabi onion.