Control of Italian Ryegrass (Lolium multiflorum) in Wheat (Triticum aestivum) with Several Postemergence Herbicides

Field experiments were conducted in Virginia in 2000 and 2001 to investigate responses of wheat and diclofop-methyl-sensitive and –resistant Italian ryegrass to POST applications of several experimental and registered herbicides. The experimental herbicide combination AE F130060 03 was as effective as diclofop-methyl and more effective than chlorsulfuron plus metsulfuron, chlorsulfuron plus metribuzin, MON 37560, ICIA 0604, and CGA 184927 for control of diclofop-methyl-sensitive Italian ryegrass. AE F130060 03 also controlled diclofop-methyl-resistant Italian ryegrass better than all other herbicides applied. AE F130060 03 also reduced late-season inflorescence emergence of diclofop-methyl-sensitive and –resistant Italian ryegrass by 91 to 100%. Although 10 to 24% wheat injury from AE F130060 03 was greater than from the other herbicides, wheat recovered and injury did not influence grain yield. Grain yield from wheat treated with AE F130060 03 was similar to or greater than yield from wheat treated with the other herbicides. Italian ryegrass control, inflorescence emergence, and grain yield was not influenced by AE F130060 03 rate or the addition of methylated seed oil. In these experiments, AE F130060 03 was comparable to diclofop-methyl for control of diclofop-methyl-sensitive Italian ryegrass and more effective than all other herbicides for control of diclofop-resistant Italian ryegrass. Nomenclature: AE F130060 03 {8.3:1.7 mixture of AE F130060 00, proposed common name mesosulfuron-methyl, 2-[(4,6-dimethoxypyrimidin-2-yl carbamoyl)sulfamoyl]4-methanesulfonamido)-p-toluic acid, plus AE F115008 00, proposed common name iodosulfuron-methyl-sodium, 4-iodo-2-[3-(4-methoxy-6-methyl-1,3,5-triazin-2yl)ureidosulfonyl]benzoic acid}; AE F107892, proposed common name mefenpyr