Effect of Inorganic Fertilizers on the Cotton Leaf Hopper Amrasca Biguttula Biguttula Ishida in Relation to Plant Protection*

Field experiments were conducted to study the effect of varying rates of NPK fertilizer spplications on leafhopper, Amrasca biguttula biguttula Ishida incidence on the three cotton genotypes under protected and unprotected conditions, during 1987–88 and 1988–89 at M.A.U., Parbhani. The leafhopper population was significantly higher on hybrid 4 (Gossypium hirsutum x G. hirsutum) as compared to Pumima (G. hirsutum) and Eknath (G. arboreum). It was greatly influenced by the luxuriant plant growth due to higher NPK fertilization even in the insecticide sprayed plots. There was a considerable response to protecting fertilized cotton, but when popula-qion was very low as on unfertilize" cotton. there was no response to protection.