Weed Control in Safflower in the United States Northern Plains Region

Neil R. Riveland

Abstract

Many herbicides have been tested and evaluated for broadleaf weed control in safflower during 30 years of weed control research conducted at the North Dakota State University Williston Research Extension Center (WREC).  Most herbicides tested were rejected because of excessive crop injury, inconsistent weed control or both.  Post emergence herbicides that show promise for controlling broadleaf weeds in safflower include the sulfonylurea herbicides chlorsulfuron, thifensulfuron and metsulfuron.  Safflower varieties grown in the Northern Plains are quite tolerant to these herbicides but safflower injury can occur at excessive use rates.  Thifensulfuron was the least injurious to safflower.  Each of these herbicides controlled Russian thistle satisfactorily but kochia was best controlled by chlorsulfuron and metsulfuron.  Sethoxydim, quizalofop and clethodim herbicides that control grassy weeds including volunteer cereal grains showed good potential for grassy weed control in safflower.

Key words: Russian thistle, Salsala iberica, Kochia, Kochia scoparia (L.), Redroot pigweed, Amaranthus retroflexus L., Common lambsquarters, Chenopodium album L., Safflower, Carthamus tinctorius, weed control.