Optimizing Foramsulfuron for Weed Control and Corn Tolerance

Foramsulfuron is a new sulfonylurea herbicide for postemergence control of grass and some broadleaf weed species in corn. Field studies were conducted to evaluate weed control and corn tolerance from postemergence applications of foramsulfuron in sequential and total postemergence (POST) herbicide programs. Foramsulfuron provided good control of giant foxtail, fall panicum, and redroot pigweed, which was comparable to the standard treatment of nicosulfuron. However, control of common cocklebur, velvetleaf, and common lambsquarters with foramsulfuron was superior to nicosulfuron. Tank-mixtures with atrazine antagonized giant foxtail and fall panicum control, however improved control of several broadleaf species. This antagonism was reduced when methylated seed oil (MSO) was used as the adjuvant. In field and greenhouse studies MSO also increased control of several grass and broadleaf weed species when it was compared with a nonionic surfactant (NIS) and crop oil concentrate (COC). The addition of a nitrogen source 28% urea ammonium nitrate (28% UAN) or ammonium sulfate also improved control of certain species. Foliar absorption of radiolabeled foramsulfuron was also greatest when MSO and 28% UAN were used as the adjuvant. However, this adjuvant selection did not improve control of woolly cupgrass. Foramsulfuron is formulated with a crop safener, isoxadifen-ethyl, to enhance corn tolerance. Field, greenhouse, and laboratory studies were conducted to determine what effect this safener had on corn tolerance. Application timing and hybrid selection had a major impact on corn tolerance with and without isoxadifen-ethyl. The corn hybrid N58D1 was more sensitive to foramsulfuron applications than N59Q9. Averaged across all application timings, the addition of isoxadifen-ethyl decreased corn injury of the more sensitive corn hybrid, N58D1. Corn injury generally occurred from foramsulfuron applications to 6- and 8-leaf corn (visible collars). However, there were very few cases of reduced corn yield and these generally occurred when foramsulfuron was applied without isoxadifen-ethyl. Differences in hybrid tolerance were primarily correlated with differential herbicide metabolism. Foramsulfuron metabolism, with or without isoxadifen-ethyl, was similar at 4 h after treatment for both the sensitive and tolerant hybrids. However, by 24 h the addition of isoxadifen-ethyl significantly increased foramsulfuron metabolism.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Bunting, Jeffrey Alan

Contributors dc:contributor

• Christy L. Sprague

• Biology, Plant Physiology

Language dc:language

eng

Identifier

(MiAaPQ)AAI3130887

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85014