Effects of Additives on Efficacy, Uptake, and Translocation of Chlorimuron Ethyl Ester

Abstract

Effects of a 28% N solution containing urea and ammonium nitrate (28% UAN) and a nonionic surfactant on efficacy, uptake, and translocation of chlorimuron ethyl ester in soybean and broadleaf weeds were investigated. Chlorimuron applied postemergence at 8.8 and 13 g ai/ha with either nonionic surfactant at 0.25% (v/v), 28% UAN at 9.4 L/ha, or nonionic surfactant plus 28% UAN controlled weeds better than without additives. Chlorimuron with nonionic surfactant and with 28% UAN controlled weeds similarly but with 28% UAN injured soybeans least. Chlorimuron with nonionic surfactant plus 28% UAN controlled velvetleaf best but injured soybeans most. Less than 2% of applied14C-chlorimuron was absorbed in velvetleaf 84 h after treatment (HAT) when no additive was present, but adding nonionic surfactant, 28% UAN, and nonionic surfactant plus 28% UAN resulted in 21, 9, and 32% uptake, respectively, 84 HAT. Nonionic surfactant plus 28% UAN also increased translocation (primarily acropetal) of the14C. Adding 28% UAN increased14C-chlorimuron uptake in velvetleaf grown at low fertility but had no effect under high fertility.

Maximizing Herbicide Efficiency with Mixtures and Expert Systems

“…More than 500 different mixtures are used in Europe each year (4). A person no longer can consider all mixture possibilities and complete the complex analyses needed to use herbicide mixtures efficiently (3,4,9).…”

Herbicides and Adjuvants

“…Several researchers have observed that adjuvant efficacy is dependent on the herbicide being applied and the characteristics of the target weed species [61][62][63]. For example, MSO increase foliar absorption and efficacy of many herbicides, including primisulfuron, rimsulfuron, imazethapyr, quinclorac, and several graminicides for grass weed control [21,[64][65][66].…”

“…The addition of AMS or UAN to the spray solution can enhance herbicide effectiveness by further increasing herbicide absorption [26,72] which gives better result up to 12%--13.5% than use of herbicide alone [73]. For instance, thifensulfuron absorption into velvetleaf (Abutilon theophrasti Medicus) was increased from 4% to 45% when 28% UAN was added to the spray solution [61,74,75]. Addition of AMS and potassium phosphate to the spray solutions of MSMA and dalapon enhanced control of Sorghum halepense (L.) Pers.…”

Influence of Water Hardness and Co-applied Herbicides on Saflufenacil Efficacy

“…However, saflufenacil treatments with DAS did not show any differences in control of common lambsquarters compared to saflufenacil in deionized water without DAS. Several studies have suggested that DAS increases the foliar absorption of herbicides, which consequently increases efficacy (6,7,9). Moreover, according to the label of saflufenacil, this product must be applied with DAS and methylated seed oil (2).…”