Productivity and resistance of okra (Abelmoschus spp.) to the cotton aphid Aphis gossypii glover (Hemiptera: Aphididae) under tropical conditions.

Aphis gossypii Glover (Hemiptera: Aphididae) is among major arthropods causing significant damage to okra in the tropics. Resistant varieties could reduce aphid infestation and increase productivity. This study was carried out to identify aphid-resistant and high yielding okra accessions for management of the pest. Eleven farmers' varieties and four aphid-resistant accessions from AVRDC were evaluated at its Nkolbisson station in Yaounde, Cameroon. Field screening was done to determine resistance to aphids, days to 50% anthesis and days to 50% commercial maturity. Aphid data was expressed as the area under infestation pressure curve and subjected to statistical analysis based on mean (m) and standard deviation (S.D.). Crop cycle and yield data were subjected to analysis of variance. Accession 'VI033824' was the most resistant to aphids (474 ± 41.9 per leaf) with yield 0.76 ± 0.26 t/ ha whereas the yield of the highly susceptible Babungo (1519.8 ± 0.0 aphids) was 1.33 ± 0.07 t/ha, 75.5% higher that the yield of the only resistant variety. Abelmoschus esculatus was less attacked (601.4 ± 60.0 aphids) by aphids than Abelmoschus caillei (826.0 ± 71.6 aphids; df = 1, 41; Pr {>Chi} = 0.037). The yield of A. caillei species were higher (1.26 ± 0.14 t/ha) than A. esculentus species (0.43 ± 0.08 t/ha; df = 1, 41; Pr {>Chi} = 0.0002). Hence, varieties with resistance, tolerance to aphids and earliness could be incorporated into integrated pest management of aphids and enhance productivity of okra. [ABSTRACT FROM AUTHOR]