Skip to main content
ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #342278
Title: Field dodder (Cuscuta campestris) control with flumioxazin

Author
item Anderson, Treva
item Boydston, Rick

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2017
Publication Date: 10/17/2017
Citation: Anderson, T.L., Boydston, R.A. 2017. Field dodder (Cuscuta campestris) control with flumioxazin. Weed Technology. 31(6):847-851. https://doi.org/10.1017/wet.2017.76.
DOI: https://doi.org/10.1017/wet.2017.76

Interpretive Summary: Field dodder is an important parasitic weed of alfalfa grown for seed, requiring stringent control to keep the alfalfa seed free of dodder seed contamination. Pendimethalin has been the primary herbicide used to control dodder in alfalfa seed production for over 25 years. Another preemergence applied herbicide, flumioxazin, was recently registered in alfalfa seed crops, but activity on field dodder was unknown. Control of field dodder with flumioxazin and pendimethalin was compared by counting the number of emerged dodder seedlings able to twine on a simulated host over a 4-week period following herbicide application. Flumioxazin applied at the alfalfa field use rate completely controlled dodder over the 4-week period. Dodder seedlings either failed to emerge or emerged and died without twining on the simulated host. When reseeding additional dodder after the initial 4-wk period, flumioxazin was less effective indicating the herbicide had largely dissipated or was leached out of the surface layer of soil. Flumioxazin offers alfalfa seed producers a new herbicide with a distinct mode of action to manage field dodder.

Technical Abstract: Field dodder is an important weed in alfalfa grown for seed production, requiring stringent control to keep the alfalfa seed free of dodder seed contamination. Pendimethalin has been the primary tool used to control dodder in alfalfa seed production for over 25 years. Flumioxazin was recently registered in alfalfa seed and forage crops, but activity on field dodder was unknown. Control of field dodder with flumioxazin and pendimethalin was compared in greenhouse trials on a loamy sand soil. The number of emerged dodder seedlings able to twine on a simulated host were enumerated weekly for an 4-week period following herbicide application. Flumioxazin applied at the alfalfa field use rate of 0.14 kg ai ha-1 completely controlled dodder over the initial 4-week period. Dodder either failed to emerge or emerged and died without twining on the simulated host in the 4-week period. When dodder was reseeded after 4 weeks in flumioxazin treated soil, the number of twined dodder was reduced by 56% in one trial, but was unaffected in a second trial compared to nontreated checks. In the initial 4-week period following herbicide application, flumioxazin controlled field dodder similar to pendimethalin applied at 2.2 and 4.4 kg a.i. ha-1 in both trials. However, after replanting additional dodder seed at 4 WAT, dodder was suppressed more by pendimethalin than flumioxazin in the additional 4-week period. Flumioxazin offers alfalfa seed producers a new mode of action to manage field dodder.