Effect of plant extracts on yield and mortality of plants due to root rot of okra (Abelmoschus esculentus L.) caused by Macrophomina phaseolina (Tassi) Goid

The leaf extracts of Azadirachta indica (Neem tree), Acacia arabica (Acacia), Proposis glandulosa (Australian acacia), Calotropis gigantean (Giant milk weed) and Solvadora persica (Tooth brush tree) were used to study their effect on yield and mortality of plants due to root rot of okra caused by Macrophomina phaseolina (Tassi) Goid. The extracts were applied through drenching followed by artificial field inoculation of the causal fungus. All the treatments showed significant differences. The maximum number of pickings per plant (13.0) was recorded in case of A. indica leaf extract, followed by A. arabica (12.5), P. glandulosa (12.3), C. gigantean and S. persica (12.0). Even the uninoculated plants significantly produced more pickings (11.8) as compared to inoculated plants (9.0), kept as control. Similarly, highest yield per plant (130.1, 126.6 and 126.4 g) was also recorded in case of A. indica and A. arabica leaf extract and the plants not inoculated neither treated with extract, respectively, followed by the plants treated with P. glandulosa (116.7 g) and C. gigantean (105.8 g). Significantly lowest yield per plant (70.3 g) was recorded in the inoculated plants-kept as control, followed by 86.0 g yield per plant, when the plants were inoculated and treated with S. persica leaf extract. The extracts also showed statistically highly significant effect on mortality (%) due to root rot. Significantly less mortality (1.5) was observed in the uninoculated non-treated plants and inoculated plants treated with A. indica (2.0). The inoculated plants treated with A. arabica (2.5), P. glandulosa (2.5), C. gigantean (3.0) and S. persica (3.3) also showed positive response for significant reduction in mortality (%) as compare to control. Significantly more mortality (5.3%) was recorded in inoculated un-treated plants, kept as control. Overall, the okra plants inoculated with root rot causing fungus (M. phaseolina) and treated with leaf extract of A. indica performed better for yield parameters and significantly decreased mortality of plants, followed by A. arabica, P. glandulosa, C. gigantean and S. persica, respectively.