Influence of Stem-boring Insects on Common Lambsquarters (Chenopodium album) Control in Soybean with Glyphosate

Abstract

Control of common lambsquarters with glyphosate in Michigan soybean fields has been inconsistent. Stem-boring insects and evidence of insect tunneling were found inside the stems of common lambsquarters plants not controlled with glyphosate. In 2004 and 2005, field surveys and studies were conducted to identify and evaluate the prevalence of stem-boring insects in common lambsquarters in Michigan and Indiana soybean fields to determine whether tunneling by insects occurred before or following POST glyphosate applications and to evaluate the effect of glyphosate rate, application timing, and insect tunneling on the control of common lambsquarters with glyphosate. Two insect species, the beet petiole borer (Cosmobaris americana) from the Curculionidae family and an unidentified leafminer fly larvae from the Agromyzidae family were found inside common lambsquarters stems. Leafminer larvae were present in Michigan soybean fields in mid- to late-June, when most POST glyphosate applications are made in Michigan and Indiana; however, beet petiole borer larvae were not found in common lambsquarters stems until mid-July and would only be present in common lambsquarters plants if glyphosate applications occurred at that time. Results from three field experiments in East Lansing, MI, demonstrated the variability in common lambsquarters control. Control ranged from 79 to 98%, 75 to 99%, and 49 to 97% from glyphosate applied at 0.84 kgae/ha to 10-, 25-, and 46-cm common lambsquarters, respectively. In general, applying glyphosate to common lambsquarters plants 10 cm or less, or increasing the glyphosate rate beyond 0.84 kgae/ha, improved common lambsquarters control. Insect tunneling by leafminer and beet petiole borer larvae did not contribute to reduced common lambsquarters control with glyphosate applied to 10- and 25-cm common lambsquarters.

Influence of Glyphosate or Glufosinate Combinations with Growth Regulator Herbicides and Other Agrochemicals in Controlling Glyphosate-Resistant Weeds

“…Common lambsquarters is the fourth most problematic weed in the world and one of the most widespread species in Indiana (Heap 2012;Westhoven et al 2008). (Harder et al 2007;Kniss et al 2007;Loux et al 2005;Schuster et al 2007). Populations of glyphosate-resistant horseweed are widespread across the United States (Davis et al 2008;Heap 2012;Westhoven et al 2008).…”

Characterization of Selected Common Lambsquarters (Chenopodium album) Biotypes with Tolerance to Glyphosate

“…Biotypes with tolerance to glyphosate have been identified in eight states (Curran 2005;Harder et al 2007;Kniss et al 2007;Loux et al 2005;Schuster et al 2007). Research has been conducted to investigate factors aside from glyphosate tolerance that may reduce common lambsquarters control with glyphosate, including stem-boring insects (Harder et al 2007), large plant size (Boerboom et al 2006;Schuster et al 2007), short photoperiods (Kniss et al 2005), low glyphosate rate, rainfall following application, and dust (Boerboom et al 2006). Boerboom et al (2006) observed up to 8.9-fold greater tolerance to glyphosate when applied to 20-cm-tall common lambsquarters plants, compared to 10-cm-tall plants.…”

Management of Glyphosate-Tolerant Common Lambsquarters (Chenopodium album) in Glyphosate-Resistant Soybean

“…Hite et al (2008) observed a 2.8-fold difference in response to glyphosate between two Virginia biotypes. Researchers in Delaware, Michigan, Nebraska, North Dakota, Ohio, and Wyoming have observed variable levels of glyphosate activity among common lambsquarters biotypes (Curran 2005;Harder et al 2007;Kniss et al 2006;Loux et al 2005;Schuster et al 2007). Common lambsquarters became the dominant weed species in long-term experiments to evaluate weed species shifts in glyphosate-resistant cropping systems.…”

“…Widespread adoption of glyphosate-resistant cropping systems has been accompanied by a proclivity for growers to apply glyphosate to large weeds (Green 2007;Johnson et al 2007;Johnson and Gibson 2006;Young 2006). Previous research has shown that small common lambsquarters plants, less than 10 cm tall, are more sensitive to glyphosate than taller plants (Harder et al 2007;Loux et al 2007;Schuster et al 2007). Delaying application until plants are large, results in reduced mortality and increases the likelihood that plants will develop to maturity.…”

“…Application to large plants might also allow a common lambsquarters population to become more tolerant to glyphosate over time (Kniss et al 2007). The effectiveness of glyphosate on common lambsquarters can be reduced under any of the following conditions: plants are infested with stem-boring insects (Harder et al 2007); short photoperiods (Kniss et al 2005); low glyphosate rate; rainfall too soon after application; and dust (Boerboom et al 2006).…”