Population dynamics of Aphis gossypii (Glover) and its associated natural enemies in different okra varieties

An experiment to study the population dynamics of aphis gossypii (glover) and its associated natural enemies in different okra varieties was conducted at malakander research farm of kpk agricultural university peshawar during 2009. seven okra varieties including saba pirie,ark anamika,pusa sawani,local multani,hybrid nirali,green star and sarhad green were used in the experiment. data was collected at weekly intervals for eight weeks,from first week of june to the last week of july for mean percent infestation of a. gossypii and its associated natural enemies. the data revealed that lowest mean percent infestation of 2.25% was recorded on hybrid nirali,while sarhad green was mainly attacked by a. gossypii with mean percentage of 3.39%. a. gossypii population increased during 1st to 4th week and ranged from 2.85% to 3.68%. it decreased during 4th to 8th week interval from 3.68% to 2.42%. the population of ladybird beetle was recorded lowest (1.25%) in hybrid nirali,while sarhad green afforded the highest numbers with mean percentage of 2.21%. the population of ladybird beetle increased by 2.76% ranging from 1.05% to 3.81% during 1st to 4th week intervals but gradually decreased (3.34%) ranging from 3.81% to 0.47% during 4th to 8th week intervals. the population of green lacewing was found lower at 0.87% in hybrid nirali,while higher in green star with 1.79%. the population of green lacewing gradually increased (1.95%) ranging from 0.95% to 2.90% during 1st to 4th week intervals but gradually decreased at 2.81% ranging from 2.90% to 0.09%,during 4th to 8th week intervals. lowest population of syrphid fly (0.62%) was recorded in hybrid nirali,while highest percentage (0.96%) was noted in sarhad green. no syrphid fly was found during 1st and 8th week intervals,the population of syrphid fly increased at 2.33% ranging from 0.00% to 2.33% during 1st to 4th week intervals but gradually decreased at 2.33% ranging from 2.33% to 0.00% during 4th to 8 th week intervals. the data showed that hybrid nirali gave higher yield of 8980 kg ha-1 as compared to other okra varieties. it was concluded that hybrid nirali yielded more and also found comparatively more resistant to the attack of a. gossypii as compared to all other varieties. copyright 2013 zoological society of pakistan.