Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Plant Science

First Advisor

Dale L. Reeves


Weed control in oats {Avena sativa L.) is principally achieved by post emergence herbicide applications. The two most widely used being the amine salts of 2,4-D and MCPA. Both 2,4-D (2,4-dichlorophenoxy) acetic acid and MCPA (4-chloro-0-tolyl) oxy acetic acid belong to a class of compounds known as the phenoxys. Other compounds in this class include 2,4,5-T (214,5-trichlorophenoxy) acetic acid, 2,4-DB 4- (2,4-dichlorophenoxy) butyric acid, and the ester formulations of 2,4-D and MCPA. The phenoxys are auxin type growth regulators. The cause of death from phenoxy compounds is believed to be the physiological disfunction of the plant brought about by abnormal growth. MCPA and 2,4-D have similar herbicidal properties, residual toxicity lengths and human toxicities. One area in which the chemicals are dissimilar, is in crop tolerance. Oats are more tolerant to MCPA than to 2,4-D. It has been proven oats are more susceptible to 2,4-D at certain growth stages than at· others, and some varieties appear to be more susceptible to 2,4-D than others. Researchers have reported varietal differences in oats when treated with either 2,4-D ester or amine. The differences are usually much greater with the ester applications. It has also been theorized that varietal response to 2,4-D may be related to the genetic makeup of each variety. The objectives of this study were to determine the response of eleven oat varieties to 2,4-D amine and MCPA amine. Also, to determine if varietal response to 2,4-D is related to the genetic makeup of the varieties.

Library of Congress Subject Headings

Oats -- Weed control
Plants, Effect of herbicides on
Phenoxyalkanoic acids



Number of Pages



South Dakota State University


No Copyright - United State