SAFENERS REDUCE CORN (ZEA-MAYS) CHLOROACETANILIDE AND DICAMBA INJURY UNDER DIFFERENT SOIL TEMPERATURES

The results of two experiments involving the effects of safeners on ch loroacetanilide and dicamba injury in corn are reported here. The firs t experiment was conducted to determine whether MON-4660, CGA-154281, dichlormid, and MON-13900 would increase corn tolerance to alachlor, m etolachlor, and acetochlor, respectively, over a range of soil tempera tures (12 to 37 C). All three herbicides, particularly acetochlor, red uced corn shoot lengths at temperatures less than 32 C, The safeners e ffectively increased corn tolerance to their respective chloroacetanil ide herbicide at all soil temperatures. However, acetochlor injury was not completely overcome by dichlormid or MON-13900 when temperatures were less than 27 C. The second experiment was conducted to determine whether these safeners would alleviate injury caused by chloroacetanil ides applied with dicamba in sensitive (Pioneer 3320) and tolerant (Ca rgill 7567) corn hybrids at soil temperatures ranging from 17 to 27 C. Chloroacetanilides (4.5 kg ai/ha) plus dicamba (0.6 kg ae/ha) reduced shoot lengths in both hybrids, with acetochlor/dicamba combinations c ausing the greatest reductions. All four safeners increased corn toler ance to chloroacetanilide/dicamba tank-mixtures equally.