Author(s): N. KUMAR AND S K GURU

Abstract: Isoproturon is a substituted urea herbiciderneffectively controlled Phalaris minor which was first recommended in 1977-78rnand widely used since the early 1980s. However continuous use of this singlernherbicide for 10-15 years coupled with monocropping of rice-wheat led tornevolution of resistance in this weed. Earlier first report of resistance wasrnreported in 1993 in Haryana and Punjab. rnA pot culture experiment was conducted to evaluate the mechanism ofrnresistance of P. minor by using piperonyl butoxide, an inhibitor of that enzymernalong with three different doses viz. ISO 0.5 kg ha^-1,rn1.0 kg ha^-1 and 2.0 kg ha^-1 ofrnisoproturon. The bio efficacy of isoproturon could be enhanced by the additionrnof piperonyl butoxide (PBO) and a significant reduction of dry weight wasrnrecorded in different doses of Isoproturon. The mortality rate of P. minor wasrnalso increased by the addition of PBO. These results suggest that enhancedrnherbicide metabolism is the cause of isoproturon resistance in P. minor.

Download Full Article: Click Here