Influence of Water Quality, Formulation, Adjuvant, Rainfastness, and Nozzle Type on Efficacy of Fomesafen on Palmer Amaranth (<i>Amaranthus palmeri</i>) Control

• 作者: Jason A. Bond Vijay K. Nandula William T. Molin
• 来源期刊: 美国植物学期刊(英文)
• 学科: 医学
• 关键词: ADJUVANT FOMESAFEN FORMULATION Nozzle Palmer AMARANTH Rainfastness Soybean Water QUALITY
• 年，卷（期）: 2018,（8）
• 页码范围: 1660-1676
• 页数: 17页
• 分类号: R73

摘要

Protoporphyrinogen oxidase (PPO) inhibitors are one of the few remaining postemergence herbicide options for controlling Palmer amaranth in soybean growing areas of Mississippi, USA. Most Palmer amaranth populations in Mississippi are resistant to both glyphosate and acetolactate synthase inhibitors. Resistance to PPO inhibiting herbicides in Palmer amaranth has very recently been reported in Arkansas, Tennessee, and isolated pockets of Mississippi. A significant proportion of reports of PPO inhibitor failures in Mississippi are not considered to be resistance-related at this time. Therefore, the objective of this research was to evaluate factors affecting the efficacy of fomesafen on Palmer amaranth including: quality of spray carrier (water), formulations, adjuvant, rainfastness, and nozzle type. All water samples and formulation combinations provided >95% control of Palmer amaranth 3 WAT. Some combinations of water samples and formulations did not result in complete control of the treated plants, with one or two individuals surviving 3 WAT. Formulation 1 provided 99% control compared to 95% from formulation 2. Irrespective of combinations of herbicide, adjuvant and height, control of Palmer amaranth was ≥91%. Formulation 1 provided 94% control compared to 88% from formulation 2. The adjuvant x height interaction was significant, owing to a 10% reduction in control of larger plants (86%) compared to smaller plants (96%) in presence of COC. COC provided better control (93%) than NIS (88%). Simulated rainfall applied ≥60 min after herbicide application did not adversely affect efficacy on Palmer amaranth when formulation 1 was applied in combination with NIS, with control ranging from 94% to 100%. Formulation 1 with COC provided ≥93% control at all rainfall application times, except 30 min after herbicide treatment, which resulted in 79% control. Formulation 2 provided better control with COC (79% to 100%) than NIS (71% to 90%), in general, across the rainfall treatments applied at various times following h