Effect of Micronutrients on Incidence, Damage Severity of Sucking Insect Pests of Sunflower and its Impact on Yield and other Arthropods

Abstract

An experiment was conducted in a field on 23074/N latitude and 90035/E longitude at the central farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh from November 2021 to April 2022. The experiment of eight treatments as follows: T1 = Urea @ 210 gm/plot + TSP @ 84gm/plot + MoP @ 98gm/plot [recommended doses (RD) of Urea, TSP and MoP] +Boron @ 7.0 gm/ Plot+ ZnSo4 @ 8.4 gm/ Plot ;T2 = RD of Urea, TSP and MoP  +Spraying 0.2% Borax @ 2gm/ L of water; T3= RD of Urea, TSP and MoP +Spraying 0.2% ZnSo4 @ 2gm/ L of water; T4= RD of Urea, TSP and MoP +Spraying 0.5% Borax @ 5gm/ L of water; T5 RD of Urea, TSP and MoP  +Spraying 0.2% Borax + 0.2% ZnSo4 @ 2gm/ L of water; T6 = Urea @ 210 gm/plot+ TSP @ 180 gm/plot+ MoP @ 150gm/plot + Spraying 0.5% ZnSo4 @ 5gm/ L of water; T7 = Urea @ 210 gm/plot+ TSP @ 180gm/plot+ MoP @ 150gm/plot+ MgSo4 @ 12 gm/ Plot and T 8= control. The experiment was laid out in a Randomized Complete Block Design (RCBD) with 8 treatments and 3 replications. The overall result indicates that the combination of different micronutrients decreased the incidence of sucking insect pests of sunflower and increased the abundance of beneficial arthropods compared to T8 treatment. In T1 treatment, the lowest leaf infestation percentage caused by aphid 17.49 and 19.50 %; Jassid 14.19 and 14.89 % and White fly 26.18 and 30.83 % at the vegetative and reproductive stages respectively. The highest number of beneficial arthropods per plot of lady bird beetle both adults and grubs ((3.63 and 5.53 respectively); honey bee (22.36), ant (3.55), spider (1.42) was also recorded in T1 treatment. The highest yield contributing characters of sunflower, the highest of head/ capitulam diameter (9.75cm), height of plant per plot (179.73 cm), leaf width (14.24 cm), leaf length (21.05 cm), area of leaves per plant (62.29 cm) and number of leaf per plant (21.93), number of total head per plot (29.83), number of seed per head (725.56), weight of single seed (1.03 mg), and weight of seed per head (54.96 gm) of sunflower were observed in T1 treatment which was statistically different from among all other treatments. The highest sunflower yield (1.92 kg /plot) and oil content (0.93 liter/2kg and 46.5%) were also observed from T1 treatment. Among the different micronutrient treatment combinations, different micronutrients using in T1 treatment were more effective for the reducing the incidence of sucking insect pests on sunflower. In the term of effect of micronutrients, T1= Recommended doses of Urea, TSP and MoP + Boron @ 7.0 gm/ Plot+ ZnSo4 @ 8.4 gm/ Plot; was an eco-friendly pest management practice for sunflower by which one can significantly reduce pest infestation without use of any chemical insecticides.