Effect of Pesticides on Population Dynamics of Trichoderma sp. and Tomato Plant in Pot Culture Study

Abstract

A pot culture study was conducted to see the effect of different agrochemicals on the survival of Trichoderma in the soil in association with tomato plants during March to June 2018. Two fungicides (Copper oxychloride and Mancozeb), two insecticides (Monocrotophos and Chlorpyriphos), two herbicides (Metribuzin and Pendimethalin) were used to assess their effect in pot culture condition with tomato as a test plant. Effect of Trichoderma in presence of the chemicals under study on germination % of tomato seeds was non-significant. The treatments incorporated with chemicals (Trichoderma with chlorpyriphos, metribuzin and pendimethalin) showed an inhibitory effect on growth parameters (height, number of leaves and branches, leaf area and fresh weight) of the tomato plant. Trichoderma in presence of copper oxychloride recorded a plant height of 40.75 cm at 60 DAS at par with control (40.83 cm). Among the treatments applied with chemicals, at 15 DAS the population of Trichoderma was maximum in control i.e. Trichoderma alone (19.58×104 cfu g-1 of soil) which is statistically at par with Trichoderma+mancozeb 75% WP (19.08×104 cfu/g of soil) and Trichoderma+monocrotophos 36% SL (Soluble Liquid) (19.50×104 cfu g-1 of soil), while the lowest population of Trichoderma was observed in soil with the treatment of pendimethalin (10.49×104). The two herbicides metribuzin and pendimethalin and the insecticide chlorpyriphos had overall inhibitory effect on the biocontrol agent Trichoderma and the tomato plant in the present study.