Shobha Shrivastava

Department of Botany, Govt. M.L.B Girls PG (Auto) college Bhopal-462 008 (India) E-mail:


Trichoderma spp. possesses most of the mechanisms responsible for biological control and plant growth promotion. However, the activity of Trichoderma spp. in soil is highly influenced by several factors. Among all the pesticides used in agriculture, herbicides stand first and are widely applied to soil as pre-emergence to manage a variety of weeds. However, indiscriminate use of herbicides has raised several environmental concerns. Deleterious effects of these herbicides may affect the population and activity of biocontrol agent Trichoderma that is primarily soil inhabitant as well as may also affect the population of Sclerotium rolfsii. Thus, this study was carried out to find out the effect of various herbicides on radial growth of Trichoderma sp. and Sclerotium rolfsii. Nine different pre-emergence i.e. alachlor, butachlor, anilophs, metribuzin, pretilachlor Metolachlor, pendimethalin, oxadiargyl, oxyflurfen and the preplant incorporation (fluchloralin) herbicides were evaluated for their effect on radial growth of Trichoderma sp. and S. rolfsii. In three different concentrations i.e. 0.5 X (half of recommended). Periodic observations were recorded on the radial growth with a view to find out the action of herbicides against Trichoderma sp. and S. rolfsii. Radial growth of S. rolfsii was stimulated by pendimenthalin at X and 2X and Metolachlor at 0.5X concentrations under in vitro conditions. Herbicide oxadiargyl inhibited the radial growth of bio-agent and its higher concentrations were more inhibitory than the lower one. On the basis of visual observations, flluchloralin X and metribuzin 2X slightly reduced the sporulation of bioagent whereas it was slightly stimulated by pendimethalin X. Herbicide alachlor stimulated the total mycelia growth of bioagent and reduced the mycelia growth of pathogen. This differential action of alachlor could be a promising achievement for combined management of weeds and soil borne crop diseases.

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