Interaction of a bioherbicide and glyphosate for controlling hemp sesbania in glyphosate‐resistant soybean

Abstract

The bioherbicidal fungus, Colletotrichum truncatum (Schwein.) Andrus & Moore, was tested at different inoculum concentrations alone and in combination with, prior to or following treatment with different rates of glyphosate (N-[phosphonomethyl]glycine) (Roundup Ultra) for the control of hemp sesbania (Sesbania exaltata [Raf.] Rydb. ex A.W. Hill) in Roundup Ready soybean field plots. Colletotrichum truncatum and glyphosate were applied in all pair-wise combinations of 0, 1.25, 2.5, 5.0, and 10.0 ¥ 10 6 spores mL -1 (i.e. 3.125, 6.25, 12.5, and 25 ¥ 10 11 spores ha -1 ), and 0.15, 0.30, 0.60, and 1.2 kg ha -1 , respectively. Weed control and disease incidence were enhanced at the two lowest fungal and herbicidal rates when the fungal spores were applied after glyphosate treatment.The application of the fungus in combination with or prior to glyphosate application at 0.30 kg ha -1 resulted in reduced disease incidence and weed control regardless of the inoculum's concentration. At the highest glyphosate rates, the weeds were controlled by the herbicide alone.These results suggest that it might be possible to utilize additive or synergistic herbicide and pathogen interactions to enhance hemp sesbania control.

Weed Management in Soybean — Issues and Practices

“…Monitoring weeds in crop fields [90,91] Use economic thresholds to determine when to apply herbicides [91][92][93] Crop rotation [80,91] Using the biological and chemical control [94,95] Using cultural and chemical control [96] Using mechanical and chemical control [97] Using rotation of herbicides [90,91] Plant cover crops [90,98] Using the tillage, no-tillage or reduced tillage system [90,92] However, there are no more ready-made and generalized solutions without risk of errors. IWM is characterized by reliance on multiple weed management approaches that are firmly underpinned by ecological principles [89].…”

Effects of <i>Myrothecium verrucaria</i> on Ultrastructural Integrity of Kudzu (<i>Pueraria montana var. lobata</i>) and Phytotoxin Implications

“…MV effectively controls kudzu in the absence of a dew treatment over a wide range of physical, environmental, and field conditions [7]. Reports indicate significant performance improvements of several bioherbicides through additive or synergistic effects of chemicals [11] and we reported synergistic interactions of MV and glyphosate on kudzu and some other weeds [12][13][14]. MV host range tests on various tree species commonly found in natural kudzu infestations indicated most trees were not susceptible to MV [15].…”

Integrated weed management systems with herbicide-tolerant crops in the European Union: lessons learnt from home and abroad

“…For example, in arable crops, the most obvious targets for a biological control agent are perennial weeds, but the interest in biological control agents for perennial weeds would likely be reduced for GMHT crops. In contrast, research [76,77] has shown that sub-lethal doses of glyphosate can work in synergy with microbial biocontrol agents as the former temporarily stops the growth of the weed allowing time for the latter to establish and inhibit growth.…”