EFFECT OF CROPPING SYSTEM ON THE INCIDENCE OF INSECT PESTS OF POTATO AND ASSOCIATED OTHER NATURAL ENEMIES

Abstract

A field experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka to investigate the effect of cropping system on the incidence of insect pests of potato and associated other natural enemies during the period from October-2019 to April 2020 in Rabi season. The experiment consisted of eight treatments and laid out in Randomized complete block design (RCBD) with three replications. Treatments viz. T 1 = Potato+ Groundnut (Ic), T 2 = Potato+ sweet potato (Bc), T = Potato+ Coriander (Ic), T 4 = Potato+ Fenugreek (Bc), T ii

5 = Potato+ Spinach (Bc), T 3 = Potato+ Coriander (Bc), T 7 = Potato+ Radish (Bc) and T 8 6 = Sole potato (Control) where ground nut and coriander were used as Intercrop (Ic) on other hand sweet potato, Fenugreek, spinach, coriander as well as radish were used as Border crop (Bc). Data on different parameters were collected for assessing results for this experiment. The overall result indicate that both border and inter crop in potato field reduced the incidence of major insect pest of potato comparing to sole cropping. The incidence of beneficial arthropods was higher in border crops and intercropping systems. The minimum leaf infestation by aphid, (4.74 %), white fly (2.12 %) and jassid (3.90 %) were recorded in T treatment. The highest number of beneficial arthropods per plant such as pollinators like honey bee (124.33), carpenter bee (3.00), hover fly (5.80) and natural enemies like lady bird beetle (2.84), dragon fly (1.68) and bird (1.56) sat on the stick of bamboo were recorded in T 7 treatment. In term of edible yield and gross return, the highest edible yield of potato (12.30 ton/ha) and gross return (373680 taka/ha) were also recorded in T 7 7 treatment. The overall study of this experiment reveals that border crops and intercropping systems reduced incidence of major insect pest of potato field and border crops perform better than inter crop and significantly reduced pest infestation without use of any chemicals insecticides.