EFFICACY OF SOME NEWER INSECTICIDES AGAINST FRUIT BORER (HELICOVERPA ARMIGERA) IN TOMATO WITH SAFETY TO NATURAL ENEMIES

Abstract

Tomato fruit borer is one of the most harmful insect in our country. This is mostly control by the chemical insecticides, which are available in the market. But the present investigation was undertaken for the evaluation of some management practices against tomato fruit borer. The experiment included 5 treatments T 1 : flubendiamide (Belt 24 WG), T 2 : spinosad (Success 2.5 SC), T 3 : emamectin benzoate (Proclaim 5G), T 4 : Farmer’s practice (Cypermethrin 10 EC); T 5 : Control (no pesticides). Sprayings was done at 7 days interval. The field experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Data on number of healthy and infested fruits/plant, weight of healthy and infested fruits/plant, weight of single fruit/plant, diameter of single fruit/plant, yield per plot and healthy and infested yield per hectare were recorded and at last economic analysis was done. The treatment of flubendiamide (Belt 24WG) was the highest (30.23) number of healthy fruits/plants the control T 5

gives the least (8.93) fruits/plant. Control treatment shows the highest level of infestation which was significantly different from all other treatments. The lowest (1.23) number of infested fruits/plant was found at early stage in Farmer’s practice (Cypermethrin 10 EC) and highest (4.83) for control treatment. T 5 shows the highest level of infestation. At early fruiting stage, the lowest infestation percentage (3.11%) was recorded from flubendiamide (Belt 24 WG) treatment which was significantly different from all other treatments. On the other hand, the highest (26.19%) infestation percentage was recorded from control treatment. The highest (165.11g) fruit weight was observed for flubendiamide (Belt 24 WG) and the lowest (63.9g) for control treatment. The highest (13.8mm) fruit diameter was observed for flubendiamide (Belt 24 WG) and the lowest (5.9mm) for control treatment. The highest (10.86 t/ha.) yield was observed for the treatment flubendiamide (Belt 24 WG) and the lowest (7.79 t/ha.) yield was observed for control treatment. Considering the control of tomato fruit borer, the highest benefit cost ratio was 1.79 recorded from emamectin benzoate (Proclaim 5G). The benefit cost ratio was due to application of the different management practices against tomato fruit borer was T 3 > T 4 > T 2 ii

> T 1 > T 5. Number of recorded natural enemies was relatively low in pesticide treated plots in compare with untreated control.