Effects of Safener CGA-154281 on Metolachlor/Atrazine Injury to Corn (Zea mays)

Abstract

Three seed lots each of two varieties of field corn were compared in greenhouse and field studies. Cold test germination percentages of the seed lots were as follows: 79, 85, and 93% for ‘DK656’; 77, 84, and 91% for ‘T1100’. Tank mixes of metolachlor or metolachlor with safener CGA-154281 plus atrazine or formulated metolachlor/atrazine with and without the safener were applied preemergence. Crop stand of either variety or among seed lots within a variety was not affected by herbicide treatments. In the greenhouse, fewer corn plants were injured and growth of plants was greater with herbicides with safener than herbicides without safener. Plant heights and weights at harvest from the most vigorous seed lot of DK656 were higher than those of the other two seed lots. Herbicide treatments with the safener did not cause significant injury to corn in the field. Yields of both varieties increased with herbicide treatments in one conventional planting. No significant differences in injury or yields occurred among seed lots within varieties.

Influence of Wheat (Triticum aestivum) Straw Mulch and Metolachlor on Corn (Zea mays) Growth and Yield

“…611 may be tolerant to metolachlor or the GDD were sufficient to over come delay in maturity. Others have shown that metolachlor at X -and 2X-rate did not significantly reduce com yields on soils where seedbeds were prepared with tillage even though there was visual herbicide injury earlier (14,21). The shortage of sufficient GDD at North Platte and Sidney hindered grain development but not stover development (Figure 1).…”

“…Com during early July did not exhibit typical chloroacetamide injury symptoms such as twisting and curling of leaves and shoot height reductions (9,14). This might have been due to metolachlor being intercepted by the crop residue and less be ing available to cause early com injury symptoms (Table 1).…”

“…Higher soil temperatures also cause more evaporation and roots developed deeper in the soil. Seed safeners may have prevented this injury but were not used (8,14,28). This points to the need of a seed safener to be used with metolachlor on com since rates, application timings, straw levels, soil types, and hybrids can vary greatly.…”

Sodium Safens Saflufenacil Applied Postemergence to Corn (Zea mays)

“…Herbicide safeners have been used to reduce crop injury and expand the window of application for several herbicides. For example, metolachlor applied preplant or PRE in corn can cause crop injury under cool, wet soil conditions (Foy and Witt 1991). The addition of the safener benoxacor [4-(dichloroacetyl)-3,4-dihydro-3-methyl-2H-1,4-benzoxazine] to metolachlor reduced corn injury caused by metolachlor under unfavorable soil conditions (Foy and Witt 1991;Viger et al 1991).…”

“…For example, metolachlor applied preplant or PRE in corn can cause crop injury under cool, wet soil conditions (Foy and Witt 1991). The addition of the safener benoxacor [4-(dichloroacetyl)-3,4-dihydro-3-methyl-2H-1,4-benzoxazine] to metolachlor reduced corn injury caused by metolachlor under unfavorable soil conditions (Foy and Witt 1991;Viger et al 1991). The addition of the safener cyprosulfamide {N-[[4-[(cyclopropylamino)carbonyl]phenyl]sulfonyl]-2-methoxybenzamide} to isoxaflutole extended the use pattern of this herbicide in corn from PRE to POST use up to the two-leaf collar stage of corn growth (Nelson and Penner 2006;Philbrook and Santel 2008).…”