Abstract

A field experiment was conducted during 1972-74 at Udumal net to study the cumu letive effect of repeated application of 2,4-D on the control of white horsenettle. The treatments comprised of five levels of 2,4-D viz., 0.5 1.0, 1.5, 2.0 and 2.5 kg a.i./ha each under three intervals (monthly, bimonthly and trimonthly) of application and one un- treated control. The herbicide was applied as per the treatments upto one and half years. After the final applications, the population of white horsenettle was estimated at different stages. Results indicated that the population in 2:4-D applied plots were always less when compared to untreated control. Among the five levels of 2,4-D the differences in the population were not significant. Application at monthly intervals had significantly less population than bimonthly and trimonthly intervals of application.

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