Studies on the Efficacy of Synthetic Jasmonates and Salicylates as Attractants to the Predators of Rice Brown Planthopper, Nilaparvata lugens (Stal.)

Field experiment to evaluate the efficacy of synthetic jasmonates and salicylates as attractants to predators of brown planthopper, Nilaparvata lugens (Stal.) was conducted in rice variety NLR 3449 at Kondayampatti village, Madurai, Tamil Nadu during-2015. Jasmonic acid, Methyl jasmonate, Salicylic acid and Methyl salicylate at three various concentrations (1, 10 and 100 mM) were tested for their effect on rice BPH population and its ability to attract the predators. Significantly greater numbers of predators were attracted to Jasmonates and salicylates treated plants than buffer ad control. As consequences, the population load of BPH on Jasmonates and salicylates treated plants was significantly less as compared to the buffer and control. Even though all the evaluated treatments attracted predators, Jasmonic acid @ 10 mM harboured maximum number of mirids, coccinellids as well as spiders. It recorded 21.90 mirids/5 hills, 14.14 coccinellids/5 hills and 7.25 spiders/5 hills over the study period compared to 15.39 mirids/5 hills, 9.35 coccinellids/5 hills and 4.09 spiders/5 hills in control. Whereas, mean BPH population on Jasmonic acid @ 10 mM treated plants was 69.14 nos./5 hills over the observation period as compared to 106.80 nos./5 hills in control. Thus Jasmonic acid @ 10 mM recorded 1.74, 2.27 and 1.61 fold increase in population of mirids, coccinellids and spiders, respectively as compared to control. The BPH population showed a 1.69 fold decrease when compared with control. In future to the potential of synthetic HIPVs as a tools for attracting predators of BPH into rice fields can be explored.