EFFICACY OF IMIDACLOPRID AND THIAMETHOXAN AGAINST LEAFHOPPER , AMRASCA BIGUTTULA BIGUTTULA ( ISHIDA ) ON

Okra, Abelmoschus esculentus L. Moench (Malvaceae) also known as lady’s finger (or) bhendi and is an important vegetable crop which grown throughout the country. It is key vegetable of the tropical countries and also it is most popular in India. It is grown over an area of 4.52 lakh ha with a production of 48.03 lakh tons in India, whereas in Karnataka it is cultivated over an area of 8,600 ha with a production of 75.1 thousand tons. Bihar ranks first in production (819.00 metric tons) followed by Orissa (654.7 metric tons) (Anonymous, 2011). One of the major bottlenecks in successful production of okra is the damage caused by early season sucking pests and fruit borers. About 72 species of insects have been recorded on okra (Srinivasa Rao and Rajendran, 2003) of which, most destructive insect pests reported are Leafhopper (A. biguttula biguttula Ishida), Aphid (Aphis gossypii Glover), Whiteflies (Bemisia tabaci Gennadius), Fruit borer (Helicoverpa armigera Hubn.) and Spotted bollworm (Earias vittella Fabricius). The pest problem in okra is more or less similar to the cotton crop. Among the sucking pests, A. biguttula biguttula is the major constraints in achieving the potential yield (Atwal and Singh, 1990; Shah and Jhala, 2001). Leaf hoppers are important pests in the early stage of the crop which desap the plants, make them weak and reduce the yield to 54.04 per cent (Chaudhary and Dadeech, 1989). Krishnaiah (1980) reported about 4056 per cent losses in okra due to leafhopper. The leafhopper attack, at times, is so serious that the entire crop is lost (Jotwani and Sarup, 1996). Therefore, for the sound management, it is essential to know the weak links in the bioecology, life history and development of the insect viz., feeding habits, behavior and duration of different developmental stages as we studied in detail in our earlier studies (Jayarao et al., 2015). Further to tackle this menacing sucking pests a number of insecticidal sprays are given, which led to several problems like toxic residues, elimination of natural enemies, environmental disharmony and development of resistance. In order to overcome these problems and keeping in view, the importance of okra crop, the present studies were undertaken to evaluate the bio-efficacy of different doses of imidacloprid and thiamethoxam against okra leafhopper.