Integrated weed management is the key to delay the evolution of herbicide resistance in weeds under conservation tillage – insights

Zero tillage is a no-till technique for raising crops in conservation agriculture. It has been proven that zero tillage causes a shift in weed flora from annuals to perennials and remnant emerged weeds are controlled by chemical tactics. Many developed nations such as the United States of America, Southern Brazil, Australia, Argentina, Paraguay, and Uruguay practice zero tillage (with or without surface cover) over a large area. In India, zero tillage is being adopted over an area of 7.6 mha with increasing herbicidal market trends at a rate of 15%. Over-reliance on a single group of herbicides results in the evolution of resistance. Presently, the reported number of unique resistance cases is 532 in 273 weed species (156 dicots and 117 monocots). The Indo-Gangetic plains, being at the forefront of the agricultural revolution in India, are witnessing a surge in zero tillage adoption. However, this trend raises concerns regarding the emergence of herbicide resistance, especially in regions where certain modes of action are already under threat. In India, 7 unique herbicide resistant cases have been reported in rice and wheat crops. The problem of herbicide resistance in weeds is feared and imminent and different weeds in India may evolve the same resistance mechanisms. The integrated and diversified weed management approach is the need of the hour to realize higher yields, and also to delay the evolution of resistance in weeds.