Management of Herbicide resistant Phalaris minor: A Review

Abstract

Littleseed canarygrass (Phalaris minor Retz), an annual species of the family Poaceae, is a major weed problem in many wheat-producing countries. The excessive dependence on herbicides for its control led to the evolution of multiple herbicides resistance and yield losses. The first case of resistant P. minor in India was to the Photosystem-II inhibitor isoproturon in the early 1990’s. P. minor has been found resistant to Acetolactate Synthase (ALS) inhibitors, Acetyl-CoA Carboxylase (ACCase) inhibitors, Photosystem II inhibitors. It is highly competitive and in severe cases can cause complete crop failure, forcing farmers to harvest their crop as fodder or ploughing the standing crop along with weeds. For management of these multiple herbicide resistant P. minor, pyroxasulfone, pendimethalin, flumioxazin, trifluralin and flufenacet can be used as alternative herbicides. Moreover, in-depth biological and ecological studies on P. minor should be carried out for devising integrated weed management strategies. The long-term strategies of efficient weed management and sustainability of wheat production should include the use of alternative herbicides, herbicide mixture, crop rotation along with other non-chemical methods like manual removal of weeds, mulching, Summer ploughing etc providing the competitive advantages to the wheat crop over P. minor, at the same time increasing the profitability of the farmer by controlling the weed effectively and reducing the selection pressure on the weeds which will inturn reduce the resistance development in weeds