Herbicide resistance in weeds is a global threat to sustaining food security. In India, herbicide-resistant Phalaris minor was the major problem in wheat for more than two decades, but the continuous use of metsulfuron-methyl (an ALS inhibitor) to control broadleaf weeds has resulted in the evolution of ALS inhibitor-resistant Rumex dentatus L. This review summarizes the current scenario of herbicide resistance in R. dentatus, along with its ecology and management perspectives. Studies have provided valuable insights on the emergence pattern of R. dentatus under different environments in relation to tillage, cropping systems, nutrients, and irrigation. Moreover, R. dentatus has exhibited higher emergence under zero tillage, with high infestation levels in rice-wheat compared to other wheat-based cropping systems (sorghum-wheat). Alternative herbicides for the management of resistant R. dentatus include pendimethalin, 2,4-D, carfentrazone, isoproturon, and metribuzin. Although the pre-emergence application of pendimethalin is highly successful in suppressing R. dentatus, but its efficiency is questionable under lower field soil moisture and heavy residue load conditions. Nevertheless, the biological data may be utilized to control R. dentatus. Therefore, herbicide rotation with suitable spray techniques, collecting weed seeds at differential heights from wheat, crop rotation, alternate tillage practices, and straw retention are recommended for addressing the resistance issue in R. dentatus in North India conditions. Overall, we discuss the current state of herbicide resistance in R. dentatus, the agronomic factors affecting its population, its proliferation in specific cropping systems (rice-wheat), and management strategies for containing an infestation of a resistant population.

Morphological response of barley cultivars to different dates of sowing (India) Ankur Chaudhary, Meena Sewhag, V.S. Hooda, Priti Malik and Parveen Kumar Department of Agronomy, CCS Haryana Agricultural University, Hisar, Haryana Abstract A study was conducted during rabi 2013-14 at Barley Research Area of CCS Haryana Agricultural University, Hisar. The experiment was laid out in […]

Drill-seeded rice (DSR) offers several agronomic and environmental advantages over conventional puddled-transplanted rice (PTR), including labor and water savings, reduced cultivation costs, and lower greenhouse gas emissions. Despite these benefits, weed control remains a major bottleneck in the widespread adoption of DSR. Imidazolinone (IMI)-resistant rice, which allows the use of imidazolinone herbicides, has the potential to overcome weed control challenges in DSR and can therefore facilitate the transition from PTR to DSR. However, limited information exists on the effectiveness of IMI herbicide–based weed control programs in drill-seeded IMI-resistant rice in northwestern India. Field experiments were conducted in Karnal, India, from the 2020 through 2023 growing seasons to 1) evaluate the timing and rates of imidazolinone herbicides for effective weed control in IMI-resistant rice under DSR conditions, and 2) assess the potential carryover effects of IMI herbicides on succeeding crops. Results showed that sequential early postemergence applications of imazethapyr followed by (fb) late postemergence applications of either 100 fb 150 g ai ha ⁻¹ or 125 fb 125 g ai ha ⁻¹ ) effectively reduced the biomass of key weed species by 83% to 100%, including barnyardgrass, crowfootgrass, and Chinese sprangletop, and provided yields that were similar to weed-free treatments. These sequential postemergence treatments were consistently more effective than conventional preemergence herbicide applications of oxadiargyl fb a postemergence application of bispyribac-sodium. Sequential preemergence fb postemergence applications of imazethapyr were relatively less effective in controlling weeds and minimizing yield losses compared to sequential postemergence applications. However, in the second and third years, oxadiargyl (90 g ai ha ⁻¹ ) applied preemergence fb imazethapyr (100 g ai ha ⁻¹ ) applied postemergence achieved comparable weed control efficiency to those of sequential postemergence applications of imazethapyr (125 fb 125 g ai ha ⁻¹ ). No phytotoxicity was observed in the succeeding crops of wheat, mustard, chickpea, lentil, and corn from any of the herbicide treatments applied to IMI-resistant rice.