Project Overview
Commodities
- Agronomic: soybeans, kochia
Practices
- Pest Management: integrated pest management, electrical weeding, glyphosate followed by electrocution
Abstract:
The proposed project, entitled ‘Integrated weed management of herbicide resistant kochia in North Dakota’ developed and evaluated efficacy of a novel electrocution system in conjunction with single glyphosate application to control glyphosate-resistant kochia in North Dakota. Glyphosate-resistant kochia (Bassia scoparia (L.) A. J. Scott.) proliferation in North Dakota agricultural systems has raised concerns about potential crop yield losses and continued efficacy of chemical weed control. Addressing this issue requires the implementation of integrated weed management strategies for the control of kochia in soybean (Glycine max L.), a crop for which kochia control options are quickly dwindling. A greenhouse study was conducted to evaluate a small-scale electrocution device, used alone and in combination with glyphosate, to control inter-row glyphosate-resistant kochia in soybean. The electrocution device consisted of a mobile platform mounted with a negative terminal to ground electrical current into the soil, a positive terminal to pass current into weed plants via contact, and a glass cover to protect crop plants. An initial experiment evaluated two voltages (9kV or 18kV), travel speeds (20 or 40-seconds tray-1), and kochia biotypes (resistant vs. susceptible). A second experiment evaluated seven treatments: 9kV, 18kV, glyphosate followed by 9kV, glyphosate followed by 18kV, glyphosate only, weedy check, and weed-free check. The travel speed was 40-seconds tray-1. Glyphosate was applied at 1680 g ae ha-1 with AMS at 2.5% v/v. Glyphosate-tolerant soybeans (AG009X8) were planted in the center of the tray. In the initial experiment, kochia control at travel speed of 40-second tray-1 (84%) was greater compared to 20-second tray-1 (70%). In the second experiment, glyphosate followed by 9kV and glyphosate followed by 18kV treatments provided greater kochia control (99%) compared to 18kV, 9kV and glyphosate only (88%, 80% and 25%, respectively) in the first run, with similar pattern in the second run. No soybean injury occurred and glyphosate followed by 18kV produced greater soybean biomass compared to weedy check. Overall, electrocution combined with glyphosate maximized control of inter-row glyphosate-resistant kochia and soybean biomass. The combination of electrocution and glyphosate offered a highly effective weed management strategy, enhancing the overall weed control efficacy in soybean systems.
Project objectives:
The objective of these experiments was to develop and test a novel electrical weeder (a prototype) capable of targeting inter-row kochia in soybean within greenhouse trays. Electrical weeding alone or in combination with a single glyphosate application was evaluated to control inter-row glyphosate-resistant kochia. The results of this study will benefit both organic and conventional farmers who are interested in reducing herbicide applications to control kochia and other weeds by using proposed integrated weed management strategy. Although we evaluated electrical weeding and glyphosate combination on herbicide resistant kochia in greenhouse trays, we plan to use the results as preliminary data to apply for a larger grant to extend the results to many other crop species at field scale. The proposed project resulted in scientists/researchers and students learning about integration of electrocution and glyphosate to control kochia in soybean production systems at two conferences (North Central Weed Science Society Annual Meeting and Western Society of Weed Science Annual Meeting). These studies also provided a PhD student with training in developing a research proposal, designing and conducting weed science experiments, managing a research grant, writing reports, and presenting findings at two professional conferences that contributed substantially to his doctoral training.