Chemical control of wild-oat (Avena sterilis L.) and other weeds in wheat (Triticum durum Desf.) in Jordan

Field experiments were conducted for 2 years to evaluate the effectiveness of certain herbicides on wild-oat (Avena sterilis L.) in wheat (Triticum durum L.). Results showed that tralkoxydim (0.3 l a.i. ha−1), imazamethabenz-methyl (0.5 and 0.63 l a.i. ha−1) and the mixture of imazmethabenz-methyl (0.38 l a.i. ha−1) and isoproturon (0.5 l a.i. ha−1) increased wheat grain yield up to the level of the weed-free control. In contrast, when used alone both isoproturon (1 and 1.5 l a.i. ha−1) and dimethenamid (1.8 l a.i. ha−1) reduced grain yield below that of the weed-infested control. The highest average straw yield was with imazamethabenz-methyl (0.38 l a.i. ha−1). Considering total wheat yield (grain and straw), imazamethabenz-methyl (0.38 l a.i. ha−1), imazamethabenz-methyl/isoproturon mixture, fenoxaprop-ethyl (0.09 l a.i. ha−1) and tralkoxydim (0.3 l a.i. ha−1) gave similar yield to that of the weed-free control. Imazamethabenz-methyl (0.5 and 0.63 l a.i. ha−1), imazamethabenz-methyl/isoproturon mixtures (0.38+0.5 or 0.38+0.75 l a.i. ha−1), diclofop-methyl (0.9 l a.i. ha−1) and fenoxaprop-ethyl (0.09 l a.i. ha−1) were most effective against A. sterilis. Imazamethabenz-methyl (0.5 and 0.63 l a.i. ha−1) severely reduced A. sterilis population, tiller number and dry weight compared with the weed-infested control. Poor A. sterilis control was obtained using dimethenamid, difenzoquat and isoproturon. However, while most herbicides increased growth of broadleaved weeds, isoproturon alone and its mixtures with imazamethabenz-methyl were most effective against these weeds. Based on grain and straw yields obtained, dimethanamid, isoproturon, diclofo-methyl, and difenzoquat appeared somehow phytotoxic to crop plants and lowered wheat yield beyond the weed-infested control.