Interaction of glyphosate with chlorimuron, fomesafen, imazethapyr, and sulfentrazone

Abstract

Field experiments were conducted on eight weed species to determine if chlorimuron, fomesafen, imazethapyr, or sulfentrazone at two rates (labeled and one-half the labeled rate) were complementary tank mixtures with glyphosate at 210 and 420 g ai ha−1. Laboratory experiments were conducted on barnyardgrass, pitted morningglory, Palmer amaranth, and velvetleaf using radiolabeled glyphosate, chlorimuron, and imazethapyr to determine the absorption and translocation pattern of these herbicides applied alone and in combination. In the field, glyphosate plus chlorimuron tank mixtures were generally additive. Adding chlorimuron did not decrease absorption or translocation of14C-glyphosate by barnyardgrass, pitted morningglory, or velvetleaf. Adding glyphosate increased absorption of14C-chlorimuron by Palmer amaranth and velvetleaf. All four fomesafen plus glyphosate rate combinations were antagonistic to goosegrass, sicklepod, Palmer amaranth, and velvetleaf, and three of the four were antagonistic to barnyardgrass and entireleaf morningglory. Fomesafen decreased absorption and translocation of14C-glyphosate in barnyardgrass, pitted morningglory, and velvetleaf. Ninety percent of glyphosate plus imazethapyr combinations were additive or synergistic, with all rate combinations synergistic for pitted morningglory. Adding glyphosate to imazethapyr increased absorption of14C-imazethapyr by Palmer amaranth and velvetleaf. Glyphosate plus sulfentrazone tank mixtures were antagonistic at all rate combinations for barnyardgrass and Palmer amaranth and at three of the four combinations for goosegrass and entireleaf morningglory, indicating that these herbicides are not complementary in tank mixtures.

Halosulfuron and 2,4-D Mixtures' Effects on Common Lambsquarters (Chenopodium album)

“…Herbicide interactions have been extensively investigated and reported with respect to synergism, antagonism, and additivity (Colby 1967;Hatzios and Penner 1985). Previous research has demonstrated the benefit of utilizing reduced rates of selected soybean herbicides in mixtures to enhance weed control and diminish the development of resistant weed biotypes (Defelice et al 1989;Gressel 1990;Starke and Oliver 1998). However, little information has been published examining reduced rates of corn herbicides in mixtures for common lambsquarters control.…”

Absorption, localisation, translocation and activity of glyphosate in barnyardgrass (Echinochloa crus-galli (L) Beauv): influence of herbicide and surfactant concentration

“…Studies of absorption and translocation of [ 14 C]glyphosate indicate that uptake occurs rapidly following application. In Echinochloa crus‐galli (L) Beauv, an annual weed which is susceptible to glyphosate, studies with [ 14 C]glyphosate have shown 50% of the radiolabel to be absorbed within 72 h of treatment, with 50% of the radiolabel distributed in the treated leaf, 19% in the roots and 31% translocated 4. Absorption and translocation of [ 14 C]glyphosate has been found to be less in plants at more advanced growth stages or under water stress 5.…”

Compatibility of herbicides with boron fertilizers for weed desiccation and mineral nutrition of sunflower

“…However, antagonistic effects may occur in controlling some weed species due to the combination of these two active ingredients. Starke and Oliver (1998) reported that a mixture of glyphosate+ sulfentrazone was ineffective for barnyardgrass (Echinochloa crusgalli), palmer amaranth (Amaranthus palmeri), goosegrass (Eleusine indica) and ivy leafed morningglory (Ipomoea hederaceae) control. Here, when this mixture of herbicides was combined with both B sources, the percentage of control was lower in relation to the herbicide application without B, indicating no additive effect of these two herbicides with the two boron sources in controlling Euphorbia heterophylla and Bidens subalternans.…”