The incidence of spotted bollworm on desi cotton at few locations, and the attack of American bollworm on non-Bt cotton have been observed, said experts of the Department of Entomology, Punjab Agricultural University (PAU) in a release.
R S Gill, the Head of Entomology, PAU, said spotted bollworm attacks 'desi' cotton at the time of flowering.
"The first spray on desi cotton should be done when 25 per cent plants starts producing squares," he advised growers. Subsequent spray should be done at 10 days interval, he added.
Earlier, whitefly pest had attacked Bt cotton variety in Abohar.