Growth Regulator Herbicides Prevent Invasive Annual Grass Seed Production Under Field Conditions

Abstract

Growth regulator herbicides, such as 2,4-D, dicamba, picloram, and aminopyralid, are commonly used to control broadleaf weeds in rangelands, noncroplands, and cereal crops. 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 in rangelands 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 (Bromus japonicus Thunb.) 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 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. Resumen Los herbicidas reguladores del crecimiento tales como el 2-4D, dicamba, picloram y aminipyralid se utilizan comúnmente para controlar las malezas de hoja ancha en pastizales, en cultivos de cereales así como en no cultivos. Si se utilizan en cereales en las etapas finales de crecimiento, cuando los pastos están desarrollando las partes reproductivas, estos herbicidas reducen a menudo la producción de semilla de los cereales. Estamos investigando métodos para utilizar esta respuesta de lesión para controlar pastos invasivos anuales en pastizales por medio de la disminución del banco de semillas de corta duración. En estudios previos de invernadero encontramos que el picloram y dicamba disminuyen las producción de semilla del pasto anual invasivo el bromo Japonés (Bromus japonicus Thunb.) casi en un 100%. Sin embargo estos estudios en el invernadero que son muy prometedores necesitan corroborarse en situaciones de campo antes de que los reguladores del crecimiento puedan recomendarse con la finalidad de controlar los pastos anuales. Esta investigación describe un estudio realizado en la parte oriental de Montana que propone el uso de los reguladores de crecimiento para control efectivamente los pastos anuales invasivos. Específicamente, encontramos que niveles típicos de aminopyralid y picloram disminuyen la producción de semilla del bromo Japonés en más de 95% (basándose en el promedio de las muestras) cuando se aplicó en tres estados diferentes de crecimiento. Estos resultados son prometedores y sugieren que los reguladores de crecimiento pueden controlar las gramíneas anuales invasivas.

Litter Reduction by Prescribed Burning Can Extend Downy Brome Control

“…Aminopyralid was included in the tebuthiuron treatments as an experimental tank mix. Due to lack of downy brome control by aminopyralid in previous field studies and for the sake of brevity, this treatment will be referred to as tebuthiuron (Rinella et al 2010). Imazapic treatments included 1.3% v·v -1 methylated seed oil, while glyphosate and tebuthiuron treatments included 0.25% v·v -1 non-ionic surfactant.…”

The influence of habitat conditions on the performance of two invasive, annuals — Impatiens glandulifera and Bidens frondosa

“…Research on annual invasive plants focuses on various sexual reproduction aspects, shaping the dynamics of the population. At present, the number of studies concerning flowering phenology (Suzuki et al 2007), fruit and seed production (MolinaMontenegro et al 2008;Rinella et al 2010), propagule size (Fumanal et al 2007) and seedling recruitment (Fumanal et al 2008). Despite growing interest in the aforementioned issues, the present state of knowledge on numerous taxa remains unsatisfactory.…”

Scientific Opinion addressing the state of the science on risk assessment of plant protection products for non-target terrestrial plants

“…Overall, the data presented in the study (from literature and experimental components) showed that, for 19 species of seven families sprayed with glyphosate, there is an effect on vegetative parts as well as on the next generation. Rinella et al (2010b) investigated the possibility of using plant growth regulators to control invasive annual grasses by depleting their short-living seed banks. It was reported that reduced cereal grain yield was observed when plant growth regulators were applied in cereal (Triticum aestivum, Hordeum vulgare, Zea mays and Avena sativa) fields at late growth stages (Friesen et al, 1968;Sikkema et al, 2007;Rinella et al, 2010b).…”

“…Rinella et al (2010b) investigated the possibility of using plant growth regulators to control invasive annual grasses by depleting their short-living seed banks. It was reported that reduced cereal grain yield was observed when plant growth regulators were applied in cereal (Triticum aestivum, Hordeum vulgare, Zea mays and Avena sativa) fields at late growth stages (Friesen et al, 1968;Sikkema et al, 2007;Rinella et al, 2010b). In two greenhouse studies, Rinella et al (2010a) investigated the effect of 2,4-D (at 1.12 kg a.i./ha), dicamba (at 0.56 kg a.i./ha) and picloram (at 0.42 kg a.i./ha) on the invasive annual grass Bromus japonicus at four different developmental stages (seedling, initiation of internode elongation, boot, and heading; Rinella et al, 2010a).…”