Eight okra varieties were tested in the field during 1999 to 2000 growing seasons to determine important pest (s), effects of such pest(s) on plant growth and yield and to evaluate varieties for resistance against such pest(s). Test plants were left untreated while controls were treated with lumbda cyhalothrin (Karateā) a pyrethroid alternated with an organophosphate fenitrothion. Flea beetle (Podagrica sp.), whitefly (Bemisia tabaci Genn.) and leafhopper (Amrasca biguttula biguttula Ishida) appeared one week after germination. In untreated plants, flea beetles increased rapidly reaching an average of 20 beetles/leaf, at the end of the crop season. A corresponding decline of whiteflies and leafhoppers occurred. Cotton aphid (Aphis gossypii Glover) appeared three weeks after germination in both treated and untreated plants. Aphid numbers increased rapidly in treated plants following insecticide applications. Treated varieties showed significantly higher scores of aphids (mean=2.5236) than untreated varieties (mean 2.0554, P< 0.05). Varieties were also significantly different in aphid scores. Plant heights, yield and wet weight were higher in untreated varieties than treated varieties indicating that these changes were due to aphid infestations. Change in yield and wet weight between treated and untreated plants was significantly different among varieties. Based on aphid scores, change in yield and wet weight, four varieties (two top [Arka Anamika and Kangwani] and two bottom [Pusa Sawani and Clemson Spineless] performers) were selected for further tests.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA