author(s)
Sunitha Devi R, Raji Reddy D, Srinivas G and Mahadevappa G

abstract
The field experiment on cotton was conducted during two cropping seasons of kharif, 2013 and kharif, 2014 sown at two different dates namely July second fort night and august first fortnight. Data was collected on weather parameters and population of leafhoppers in cotton under no pesticide spray condition. Results revealed that population of leafhoppers were significantly affected by sowing dates and weather parameters. The pooled data of both years revealed that maximum leafhoppers population (6.03 leafhopper s/plant) was recorded in late sown crop while minimum (5.60 leafhoppers/plant) population was recorded in early sown cotton. In both the years i.e., Kharif, 2013 and Kharif, 2014 peak leafhopper infestation was recorded at 38^th standard week with 13.73 leafhoppers/plant in early sown crop and 20.40 leafhoppers/plant in late sown crop; 11.50 leafhoppers/plant in early sown crop and 16.10 leafhoppers/plant in late sown crop, respectively. Population of leafhopper showed significantly positive correlation with temperature, relative humidity, rainfall and negatively correlated with sunshine hours in early sown crop. While, in late sown crop minimum temperature and wind speed showed significant positive correlation.