MESOSULFURON-METHYL + IODOSULFURON-METHYL-SODIUM: NEW POST-EMERGENCE HERBICIDE REGISTERED FOR BROADLEAF AND GRASS WEED CONTROL IN WHEAT IN MOROCCO .

Two field experiments were conducted at Doukkala (Zemamra) and Gharb (Souk Tlat) regions to evaluate the efficacy of Mesosulfuron-methyl + iodosulfuron-methyl-sodium for broadleaf and grass weeds control in wheat under Moroccan conditions during 2000-2003. Five other trials were carried out in the greenhouse to determine grass weed response to three herbicide ratios (5:1; 3:1, and 1:1) used with or without genapol. Effects of genapol on the herbicide efficacy and that of soil residues on subsequent rotational crops were also studied. About 30 weed species were recorded at each site. More than 50 % of the weed species belonged to pea, sunflower, mustard, parsley, and backwheat families. Mesosulfuron-methyl + iodosulfuron-methyl-sodium used at 1:1 ratio + genapol controlled broadleaf weeds as good as or relatively better than when used without the adjuvant. The herbicide used at 3:1 and 1:1 ratios with genapol gave excellent control of the main grass weeds compared to treatments without the adjuvant. Based on fresh weight reduction, rye-grass was the most susceptible weed to the herbicide treatments followed by canary-grass and wild oat. Ripgut grass was moderately susceptible to these treatments. Wheat grain yield significantly increased with all herbicide treatments compared to non-treated check. Under our climatic conditions and farming practices, mesosulfuron-methyl + iodosulfuron-methyl-sodium treatments did not cause any damage to rotational crops planted nine months after the herbicide application. Thus, sowing rotational crops such as chickpea, corn, faba bean, lentil, sugar beet, sunflower and vetch four month after wheat harvest is safe, assuming conditions are similar to ours.