13 Insect Environment, Vol 19(1), April-June 2013 Preliminary survey and surveillance of major pests of agriculture crops in Dharwad district
K. P. Gundannavar, P. S. Tippannavar and J. S. Hilli
KVK, Saidapur Farm,
University of Agricultural Sciences
Rowing surveys were carried out during 2012 in both kharif and rabi seasons in Dharwad district. Karnataka, India During kharif -2012 , the population of Spodoptera litura was noticed to the tune of 2.5 to 3.25 larvae/mt row on groundnut and 2.0 to 3.0 larvae /mt row on soybean in different taluks of Dharwad district. Maximum population (3.25 larvae /mt row) of S. litura was recorded in a groundnut ecosystem and infection of Nomuraea rileyi (10 %) was noticed in soybean in the Kalaghatagi taluk. Incidence of Apion weevil was noticed in green gram ecosystem in different taluks viz., Hubli, Dharwad and Kundgol. The green gram pod damage due to Apion weevil ranged from 13.0 to 15.5 percent.
In different taluks like Hubli, Dharwad, Kalaghatagi and Navalgund, incidence of stem borer in maize causing dead heart symptoms appeared to the tune of 4.5 to 9.3 percent. A maximum of 9.3% damage was recorded in Kalagatagi taluk.
In Bt cotton, incidence of different pests like aphids leaf hoppers, whitefly and shoot weevil was recorded except in Navalgund taluk. In Hubli, Dharwad, Kalaghatagi and Kundagol, incidence of aphid, leaf hoppers and white fly was to the tune of 3.8 to 4.5, 4.0 to 5.5 and 2.0 to 3.0 individuals per leaf respectively. Similarly incidence of cotton shoot weevil was noticed in the district except in Navalgund taluk and shoot damage was to the tune of 18.5 to 25.5 per cent. Very meager population of natural enemies like Chrysoperla and Coccinellids was noticed in cotton ecosystem. During rabi, the Bengal gram pod borer Helicoverpa armigera could cause the pod damage to the tune of 11- 12 percent in the district. However, the incidence of stem borer in rabi sorghum was noticed to the tune of 15.5 per cent in only Kalagatagi taluk. In Dharwad and Kundgol the incidence of safflower aphid was noticed to the tune of 3.75 to 4.5 individuals per leaf. The surveillance was done to alert farmers as well as to detect invasive insects, if any.