Weed Management in Glufosinate- and Glyphosate-Resistant Soybean (Glycine max)¹

Abstract

An experiment was conducted at six locations in North Carolina to compare weed-management treatments using glufosinate postemergence (POST) in glufosinate-resistant soybean, glyphosate POST in glyphosate-resistant soybean, and imazaquin plus SAN 582 preemergence (PRE) followed by chlorimuron POST in nontransgenic soybean. Prickly sida and sicklepod were controlled similarly and 84 to 100% by glufosinate and glyphosate. Glyphosate controlled broadleaf signalgrass, fall panicum, goosegrass, rhizomatous johnsongrass, common lambsquarters, and smooth pigweed at least 90%. Control of these weeds by glyphosate often was greater than control by glufosinate. Mixing fomesafen with glufosinate increased control of these species except johnsongrass. Glufosinate often was more effective than glyphosate on entireleaf and tall morningglories. Fomesafen mixed with glyphosate increased morningglory control but reduced smooth pigweed control. Glufosinate or glyphosate applied sequentially or early postemergence (EPOST) following imazaquin plus SAN 582 PRE often were more effective than glufosinate or glyphosate applied only EPOST. Only rhizomatous johnsongrass was controlled more effectively by glufosinate or glyphosate treatments than by imazaquin plus SAN 582 PRE followed by chlorimuron POST. Yields and net returns with soil-applied herbicides only were often lower than total POST herbicide treatments. Sequential POST herbicide applications or soil-applied herbicides followed by POST herbicides were usually more effective economically than single POST herbicide applications.

Chemical Control of Glyphosate-Resistant Goosegrass

“…None of the ammoniumglufosinate treatments were efficient controlling goosegrass. The low efficacy of ammonium glufosinate on goosegrass, especially for plants at advanced development stages, is also reported in other studies (Culpepper and York, 1999;Culpepper et al, 2000). In these works, the maximum control provided by ammonium-glufosinate (490 g ha -1 ) is 60% over plants with 4-8 leaves.…”

Weed Control and Corn (Zea mays) Response to Planting Pattern and Herbicide Program with High Seeding Rates in North Carolina

“…Other research [17][18][19][20] has demonstrated that atrazine, dicamba, glufosinate, and glyphosate control common ragweed. Differences in Texas panicum density between fields were associated with fewer differences observed between treatments in field 1 compared with more differences among treatments in field 2 ( Table 2).…”

“…Dicamba alone or in combination with other herbicides can be effective in controlling common ragweed and other broadleaf weeds [16,17]. Dicamba and glufosinate applied to small common ragweed can control this weed effectively and can serve as alternatives to atrazine and glyphosate in corn [8,[17][18][19][20].…”

Weed Control and the Use of Herbicides in Sesame Production

“…A weakness of glyphosate is poor morningglory control (Corbett et al, 2004;Jordan et al, 1997). Another development from the use of glyphosate-tolerant (Roundup Ready ® ) crops has been, in some instances, reduced weed pressure or increased weed species shifts when a Roundup Ready ® crop has been grown for a number of years (Culpepper et al, 2000;Hilgenfeld et al, 2004;Marshall et al, 2000). In these areas, glyphosate has been so effective at controlling weeds that farmers are not concerned with a build-up of weed seed in the soil.…”