Efficacy of imazethapyr applied alone and its mixture with other herbicides in green gram and their residual effect on mustard

An experiment on evaluation of herbicides in greengram and their residual effect on succeeding mustard crop was conducted at Research farm of Department of Agronomy, CCSHAU, Hisar during Kharif 2013 and Rabi 2013–14. Weed flora of the experimental field was dominated by Echinocloa colona (78%), Cyperus rotundus (18%) and other weeds (4%) at 30 DAS. Pre-emergence application of ready mix (RM) imazethapyr + pendimethalin at 1000 g/ha provided good control (80%) of Echinocloa colona up to 30 DAS. At 60 DAS, imazethapyr + imazamox (RM) at 80 g/ha applied at 3–4 leaf stage provided maximum control of weeds, which was at par with two hoeings employed at 20 and 40 DAS. Post-emergence use of imazethapyr + imazamox (RM) at 60–80 g/ha exhibited 70–80% control of weeds with slight crop suppression which mitigated within 10–15 days after spray resulting maximum crop growth and seed yield. Early post-emergence application of imazethapyr at 50, 60 and 70 g/ha although caused mild injury to greengram in terms of yellowing of leaves and stunted crop growth up to 30, but it diminished within two weeks. Maximum seed yield (1078 kg/ha) of green gram was obtained with two hoeings at 20 and 40 DAS followed by imazethapyr + imazamox (RM) at 80 g/ha and imazethapyr at 70 g/ha applied at 3–4 leaf stage. All herbicides, irrespective of their dose and time of application, did not cause any injury to succeeding mustard crop due to high rainfall (594 mm) during crop growing season that resulted in to enhanced microbial degradation of herbicides.