- Author: Pratap Devkota
The Southwest US Herbicide Resistance Listening Session was hosted by the Weed Science Society of America (WSSA) on February 15, 2017 at the UCCE office in Tulare, California. This was one of seven regional sessions hosted by WSSA and it included attendees from California, New Mexico, and Arizona. This was a half-day event and participants represented various agricultural sectors with a primary focus on weed management. Growers, PCA's, representatives from industry, government agencies, land managers, right-of-way managers, and farm advisor and specialists from universities were the primary attendees at the session. The session provided an opportunity for the attendees to provide input to WSSA by discussing their issues, challenges, and suggestions which will help to establish research, extension, regulatory, and government priorities in moving forward for tackling the threat posed by herbicide resistance (HR) in the southwest region.
The listening session was fruitful in providing the diverse group of attendees a platform to discuss their issues, challenges and barriers, experiences and successes, and wants and needs related to HR weed management. In general, attendees from Arizona and New Mexico mentioned that HR weeds are a major problem in their cotton cropping system where they rely on glyphosate based weed management programs. Some of the participants from these states also mentioned that HR weeds are not an issue at present but they are concerned about the spread of HR weed in upcoming years. Attendees from California mentioned that there are some HR cases in rice and perennial crops but HR weeds are not a significant threat in vegetable and specialty crop production because of crop rotation and hand weeding practices.
Some of the common issues highlighted by the attendees during this session included the economic barriers where they have higher cost of input versus low return from the crop commodity. Lack of development of new herbicide chemistry and heavy reliance on some of the existing chemistry was also noted as a challenge. Shortage of farm labor and switching to herbicidal weed control has exacerbated the HR issue in some crops. Limited research, extension, education outreach, and some of the technical barriers to gain knowledge were listed as challenges for HR management. Several participants also pointed out that there is a lack of collaboration between various public and private agencies, and lack of stewardship incentives for growers and PCAs for addressing HR weed problem. In California, stringent rules and regulations on herbicide registration and applications in specialty crop was pointed out as critical constraint for addressing HR weeds.
The session also focused on nailing down some of the key aspects for effectively addressing the HR weed issue. Some of the suggestions made to the growers were to take proactive measure for scouting fields, identifying weeds, and applying management tools at the early stages of weed growth. Additionally, implementing best management practices: integrated weed management, implementing automated cultivation technology, stale seed beds, crop rotation, incorporating PRE herbicides in weed control program, rotating chemistry, and tank-mixing multiple modes of action POST herbicide programs were pointed out as critical practices for managing HR weeds. Ag-retailers and consultants were advised to focus on proper application of pesticides, record keeping, and selecting herbicide products unbiasedly from various companies while making herbicide recommendation. Some of the suggestions for the grower's organization included targeting and focusing outreach program to the growers, strengthening grower's accessibility to the resources, and voicing support for CDFA and federal grant funds for HR research and extension programs. For the university personnel, there was a call for more applied research, unbiased research on the herbicide performance, strong collaboration among the campus-based specialists and county based farm advisors. The Government agencies were suggested for serious consideration for weed control on public right of way, irrigation canals and ditches; funding for the cost-benefit researches; and visiting grower's fields, university research and extension centers; and making the policy appropriate for grassroots level. The lenders and bankers were suggested for understanding and considering HR issue as a factor for assessing risk management in the agriculture production. Last, but not least, investment on new herbicide pipeline products and their commercial development was considered the critical contribution from the agricultural chemical industries.