author(s)
A Manivannan, R Philip Sridhar, S Karthikeyan and A Kuzhandhaivel Pillai

abstract
The study was conducted for preliminary screening trial of 350 cotton genotypes for relative susceptibility/resistance against leafhopper, Amrasca biguttula biguttula (Ishida) laid out in Department of Cotton, TNAU, Coimbatore during 2014-2015. Among the 350 genotypes screened, no genotypes were found to be resistant, 50 genotypes were categorized as tolerant, 158 genotypes moderately tolerant, 91 genotypes susceptible and 51 genotypes highly susceptible against leafhopper with a population ranged from 0.10 to 0.78, 0.79 to 1.57, 1.58 to 2.36 and 2.37 to 6.25 leafhopper/3 leaves/plant respectively based on the standard deviation value. The trichomes were compared against leafhoppers, incidence of leafhopper was less in high hairy varieties whereas high in less hairy varieties.