Winter Annual Weed Control with Fall-Applied Corn (Zea mays) Herbicides1

Field studies were conducted during the 2000 to 2001 growing seasons to evaluate winter annual weed control and crop tolerance with fall-applied herbicides in corn at Belleville, IL. Atrazine, simazine, and rimsulfuron plus thifensulfuron applied in the fall controlled mouseear chickweed, henbit, and Carolina foxtail 93% or greater at planting the following spring. Flumetsulam controlled mouseear chickweed and henbit 98 and 93%, respectively, at planting. Metribuzin controlled mouseear chickweed and henbit 100 and 97%, respectively. CGA-152005 controlled mouseear chickweed, henbit, and wild garlic 93 to 100%. CGA-152005 provided the greatest control of wild garlic, with control ranging from 94 to 100% at planting. CGA-152005 plus simazine controlled 99 to 100% of all winter annual weeds evaluated. Reducing winter annual weed vegetation did not increase soil temperatures at 5-cm depth in May. CGA-152005 caused discoloration and height reduction of corn. CGA-152005 at the highest rate (60 g ai/ha) reduced corn plant height by 7% and grain yield by 8%.Nomenclature: Atrazine; CGA-152005, 1-(4-methoxy-6-methyl-triazin-2-yl)-3-[[2-(3,3,3-trifluoropropyl)-phenylsulfonyl]]-urea; flumetsulam; metribuzin; rimsulfuron; simazine; thifensulfuron; Carolina foxtail, Alopercurus carolinianus Walt. #3 ALOCA; henbit, Lamium amplexicaule L. # LAMAM; mouseear chickweed, Cerastium vulgatum L. # CERVU; wild garlic, Allium vineale L. # ALLVI; corn, Zea mays (L.) ‘Pioneer 33G28 LL’.Additional index words: Discoloration, height reduction, preemergence.Abbreviations: DAP, days after planting; DAT, days after treatment; POST, postemergence.