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United States Department of Agriculture

Agricultural Research Service

Research Project: PROACTIVE MANAGEMENT FOR SUSTAINABLE RANGELAND PRODUCTION Title: Growth Regulator Herbicides Prevent Invasive Annual grass Seed Production Under Field Conditions

Authors
item Rinella, Matthew
item Masters, Robert -
item Bellows, Susan

Research conducted cooperatively with:
item Dow Agrosciences, Llc

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 12, 2010
Publication Date: July 1, 2010
Citation: Rinella, M.J., Masters, R.A., Bellows, S.E. 2010. Growth Regulator Herbicides Prevent Invasive Annual grass Seed Production Under Field Conditions. Rangeland Ecology and Management. 63:487-490.

Interpretive Summary: This research tested an approach for controlling invasive annual grasses with growth regulator herbicides under field conditions. It has been known for decades that growth regulators can dramatically reduce cereal seed production if applied for broadleaf weed control late in the growing season while cereals are developing reproductive parts. In a previous greenhouse study we found growth regulator herbicides reduced seed production of the invasive annual grass, Japanese Brome. In this paper we tested whether or not growth regulators have this same effect on seed production of Japanese brome in the field. Our results show that typical use rates of growth regulator herbicides can dramatically reduce invasive annual grass seed production providing additional evidence for the use of growth regulator herbicides for controlling invasive annual grasses.

Technical Abstract: Growth regulator herbicides, such as 2,4-D, dicamba, picloram, and aminopyralid, are commonly used to control broadleaf weeds in grasslands, non-croplands and cereal crops (e.g. wheat, barley). If applied to cereals at late growth stages, while the grasses are developing reproductive parts, the herbicides often reduce cereal seed production. We are researching methods for using this injury response to control invasive annual grasses by depleting their short-lived seed banks. In a previous greenhouse study, we found picloram and dicamba reduced seed production of the invasive annual grass Japanese brome by nearly 100%. However, this promising greenhouse finding needs to be corroborated in the field before growth regulators can be confidently recommended for invasive annual grass control. This research note describes a small study conducted in eastern Montana suggesting growth regulators may provide excellent control of invasive annual grasses. Specifically, we found typical use rates of aminopyralid and picloram reduced Japanese brome seed production by more than 95% (based on sample means) when applied at three different plant growth stages. This promising result contributes to the accumulating body of evidence suggesting growth regulators may control invasive annual grasses.

Last Modified: 10/23/2014