EFFECT OF SOWING DATES AND MICRONUTRIENTS ON INCIDENCE OF MAJOR INSECT PESTS OF MUNGBEAN

Abstract

The experiment was conducted at the farm of Sher -e- Bangla Agricultural University, Sher-e Bangla Nagar, Dhaka, Bangladesh to evaluate the effect of sowing dates and different micronutrients on incidence of insect pests of mungbean (Vigna radiata (L.) Wilezek) during kharif-II season (August to December) of 2013. The experiment comprised two factors, viz., factor A: Sowing date (two levels) – S1: Sowing on 24 August, 2013; S2: Sowing on 23 September , 2013 and factor B: Micronutrient treatments (five levels) – F0: {Recommended doses (R) Urea (45 kg/ha), TSP (100 kg/ha), MP (58 kg/ha)}; F1: {R + Boron (1.0 kg/ha)}; F2: {R + Boron (2.0 kg/ha)}; F3: { R + Zinc (8.5 kg/ha)} and F4: { R + Zinc (17.0 kg/ha)}. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Incidence of insect pests was recorded during the entire cropping season. Whitefly, jassid, thrips and pod borer were observed as important pests. Considering the sowing times, the lowest number of whitefly (1.13), jassid (1.40) and pod infestation (24.10%) of pod borer was observed in S2 and the highest population of those was found in S1. The lowest (3.93) and highest (5.36) number of thrips was observed in S1 and S2. In case of micronutrient treatments, the lowest number of whitefly (0.83), jassid (1.33), thrips (3.83) and pod infestation (19.98%) of pod borer was found in F0, F3, F0 and F4 respectively. On the other hand, the highest number of whitefly (1.48), jassid (2.33), thrips (5.30) and pod infestation (26.44%) of pod borer was found F1, F2 , F3 and F3 respectively. Considering the combined effect, the lowest number of whitefly (0.57) was found in S1F0, S2F1 and S2F3 while jassid (1.00), thrips (0.20) and pod infestation (19.10%) of pod borer was found in S2F3, S1F4 and S1F4 respectively. Contrary, the highest number of whitefly (2.40), jassid (3.00), thrips (10.20) and pod infestation (28.59%) of pod borer was found in S1F1, S1F2, S1F3 and S1F3 respectively. In case of yield effect, there was strong negative correlation between yield with insect infestation. But there was a negative relationship between yield and jassid infestation.