Population dynamics of Aphis gossypii Glover infesting okra at Manipur

The population dynamics of Aphis gossypii Glover in relation to abiotic and biotic factors was studied on okra, Abelmoschus esculentus (L.), var. ‘Pusa Sawani’ during 2005 and 2006. Incidence of aphid in field started in the first week of May and continued till the first week of September. The peak population was recorded during last week of July with the maximum abundance of 450.40 and 393.65 aphids/plant during 2005 and 2006, respectively. Eight species of aphidophagus predators viz. five of coccinellids, two of syrphids and one of hemerobiid were found associated with Aphis gossypii. Correlation studies revealed that average sunshine and windspeed were significantly positive whereas average relative humidity and total rainfall showed significant negative correlation. The biotic factors exhibited high significant positive correlation with aphid density on the host plant.