HERBICIDE RESISTANCE AND THEIR MANAGEMENT

Abstract

Farmers have struggled with the presence of weeds in their fields since the beginning of agriculture. Any chemical used in the field to kill weeds and any unwanted plant in the crop field is called herbicide. Herbicides are good tools for effective weed control. The use of these chemicals reduced the labours. The continuous use of same chemical with same mode of action for several years develops the resistance. A weed which is initially controlled by applying herbicide but no longer controlled by same herbicide is called herbicide resistance. First, wild carrot resistance to 2, 4-D in Canada, 1964 and common groundsel resistance to atrazine in Washington, 1970.Herbicide resistant weeds have been reported in 93 crops in 70 countries. In North-West India, Phalaris minor first resistant to isporoturon in 1990. More recently, Phalaris minor is showing resistance to fenoxaprop, clodinafop and sulfosulfuron and pinoxadenin Punjab. In north-west India, Rumexdentatus against metsulfuron-methyl. Resistance management requires both preventive as well as integrated approaches. Prevention will include suitable combinations of weed management methods such as cultivation practices, crop rotations and herbicide rotations. In integrated approaches involving combinations of cultural, mechanical and biological methods.