Study of 2,4-DB (Butress) Efficacy in Weed Control in Established Alfalfa (Medicago sativa)

In this study the efficacy of 2,4-DB (Butress 42.3%EC) on weed control of alfalfa was compared with commonly used herbicides in Alfalfa. This experiment was conducted in Hamedan and Yazd during 1386-1387 in a randomized complete block design with 3 replications and 11 treatments in established Alfalfa. Treatments were included of bentazone (Bazagran) (SL 48%) at doses of 2, 3, and 4 L/ha, 2;4-DB (Buterss) (EC 42.3%) at doses of 2.5, 2.8, 3.1, and 3.5 L/ha, imazethapyr (Pursuit) (SL 10%) at doses of 0.4, 0.7, and 1 L/ha and weedy check as treatment.The effect of herbicides on alfalfa biomass and the biomass and weeds biomass and density were studied during 3 harvestings. In Hamedan, all herbicides treatments had no phytotoxocity on alfalfa.Only bentazone caused chlorosis in alfalfa that recovered after 1 to 2 weeks. Butress not only was suitable to control the weeds, especially in field bindweed (Convolvulus arvensis) control. In Yazd, 2,4-DB specially in its higher doses had partial phytotoxicity on alfalfa, but controlled well Malva, Lactuca and field bindweed. Butress reduced the density and biomass of field bindweed by 100% and 84%, respectively. As a conclusion, 2,4-DB specially in its higher doses was the best herbicide to control field bindweed