MANAGEMENT OF OKRA YELLOW MOSAIC VIRUS (OYMV) THROUGH CONTROLLING INSECT VECTOR WITH IMIDACLOPRID AND LIGHT REFLECTING MULCH

Abstract

A field experiment was conducted at the central farm of Sher-e- Bangla Agricultural University, Dhaka-1207, during March to July, 2017. The aim of the study was to investigate the varietal performance of two popular okra varieties namely BARI Dherosh-1 and Green finger against Okra yellow mosaic virus (OYMV) by controlling the insect vectors with Imidacloprid and light reflecting silver color mulch. Two experiments were carried out in two blocks layouted with RCBD and four treatments viz. T 0 (control/no spray), T 1 (only mulching), T 2 (1 spray+ mulching) and T (3 times spray) with three replications. The mulch was used at 15 DAS and insecticide was sprayed at 30 DAS and continued with 15 days interval. At 95 DAS, the lowest disease incidence (%) was estimated in T (one spray+ mulching) that were 34.72 % and 19.65 % in BARI Dherosh-1 and Green finger respectively. The highest disease incidence (%) was estimated in T 0 2 (untreated/control) that was 73.71 % in BARI Dherosh-1 and 51.11 % in Green finger. In case of morphological parameters; the highest number of leaves, flowers and fruits per plant was recorded in T (one spray+ mulching) and that was 46.33, 9.33, 7.00 in BARI Dherosh-1 and 48.00, 12.33, 10.67 in Green finger respectively up to last harvesting. Yield and yield contributing characters were significantly varied among the treatments. The highest yield per plant and plot was obtained in T (one spray+ mulching) treatment in case of both varieties (0.15 kg/plant, 2.86 kg/plot in BARI Dherosh-1 and 0.24 kg/plant, 4.37 kg/plot in Green finger). The highest plant height was also found in T 2 (one spray+ mulching) in both varieties (128.62 cm and 130.33 cm respectively). It was also observed that when percent disease incidence increased, the yield of okra was also decreased. However, considering the economic conditions/cost-benefit ratio T 2 2 (one spray+ mulching) gave the best results in terms of controlling the insect vector whitefly.