Towards an integrated pest management (IPM) program on okra, Ablemoschus esculents (L.) (Malvaceae)

This study investigated the effect of irrigation intervals and okra varieties, neem squeous extract, synthetic insecticides and ethanolextract of usher against okra insect pests. These pests are, the cotton aphid Aphis gossypii, the white fly, Bemisia tabaci, the jassid Jacobiasca lybica and Egyptian bollworms, Earias insulana and E. vittella. Moreover, 31 okra genotypes were screened in season 1997, 18 in season 1998 and 11 in season 1999 against the natural infestation of Earias spp. The effect of four water intervals (7, 14, 21 and 28 days) and four lkra varieties (Khartoumia, Sennar, Pusa Sawani and Hegiarat) on the above mentioned pests were minor. The use of neem squeous (Aq-extr., at 40 g NSKP/. of water alone or in combination with Benlate (fungicide), compared with Lannate and Folimat as standards on two okra cultivars (Khartoumia and Sennar), showed higher performance compared with untreated control against the above mentioned pests and gave comparable yield to standard insecticides treatments. Moreover, this extract showed fungicidal effect compared with untreated control and insecticides used. The use of different cultivars did not affect the incidence of insect pests and yields. The okra genotypes were screened for the sususceptibility to Earias spp. infestation during three seasons. Khartoumia Red, Wad El-Gamer, OL-11, OL-210 and OL-211 showed high tolerance to Earias damage on shoot stage and gave high number of fruits per plant. Hegierat, OL-1, OL-7 and OL-8 were highly susceptible to the Earias damage and gave less number of fruits per plant. However, other genotypes showed moderate to less tolerant to Earias infestation. Four newly introduced insecticides (Fenkill, Fastac, Cascade and Casfas) were evaluated under field conditons during seasons 1997-1999 for the control of the white fly and Earias spp. infesting shoot and fruit stages. Fenkill at 40 g a.i./F and 60 g a.i./F, Fastac 10% at 6.3 g a.i./F and Casfas at 360 g a.i./F were effective in controlling B. tabaci, E. insulana and E. vittella and performed significantly better than malathion and Sevin (standard treatments). These insecticides increased okra yield compared to standard and untreated control. The potentiality of insecticidal effect of usher ethanolic-extract (EH-Oh) at 5% and 10% alone or mixed with the half dose of Endosulfan 50% were evaluated in two sites against the white fly and Earias spp. for one season (2000). Usher extracts mixed with Endosulfan showed comparable results to Cyrux (cypermethrin), Endosulfan and neem at 40 g NSKP/L. of water and performed significantly better than the other treatments (usher alone and neem at 25 g. a.i./F). According to these results, neem aqueous extract (Aq-extr. at 40 g NSKP/ L. of water) is recommended for the control of cotton sphid, cotton jassid and Earias spp. on okra during the winter- season. Moreover, Fenkill 20% at 40 g a.i./F, Fastac 10% at 6.3 g a.i/F, Casfas (20/40g/L) at 360 g a.i./F and Cyrux. 10% at 17.5g a.i./F are recommended for the control of the white fly B. tabaci and Earias spp. on okra. Furthermore, the botanical extracts require further studies to improve their efficacy particularly during the summer season. An IPM package for okra production in the Sudan is suggested