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Research & Regulatory Update

Research & Regulatory Update   

Steve Salisbury

MIRC Research

The MIRC’s Scientific Affairs Committee (SAC) had a full slate of proposals to discuss during their January annual meeting. It is encouraging to have more interest in mint research by several researchers, agencies and associations, and it creates a healthy competitive grant situation. This is a good thing for the mint industry. However, the unfortunate reality is that the MIRC can only fund so many proposed projects each year. That said, the SAC maintained its primary focus on agronomic research and varietal improvement.  

In the area of agronomy, several projects were funded in the areas of weed science, Verticillium wilt, nematodes and entomology. Weed management continues to be an on-going effort to pursue new active ingredients that are usable and effective in mint. This year’s multi-regional weed research trials will focus on pyridate (Tough) post-emergence treatments to control difficult weeds and new developing weeds in each region. A few of the weeds on the hit list include Russian thistle, field violet, sulfur cinquefoil, common groundsel, waterhemp, white cockle and Palmer amaranth. This work goes hand-in-hand with the current regulatory efforts on Tough for mint.

The SAC continued its support of Verticillium wilt research developing a quick bioassay test to detect and quantify the mint strain of VW in field via soil samples. Researchers are refining quantitative Polymerase Chain Reaction (qPCR) techniques to make this determination. qPCR is essentially the technical way to say they are looking for genetic/DNA differences between VW strains present to differentiate between the mint strain and others not affecting mint. If developed, this technique could be a tool used by commercial agriculture labs to assist growers in making field planting decisions.

In addition to the qPCR Verticillium efforts, a new project to the MIRC this year is studying the genome of the pathogen (VW) itself. This project fits nicely with the genome work going on with the varietal improvement project. As with any disease, there is an interaction between the pathogen and the host. The better we can understand both the pathogen and host, the better we should be able to manage the disease. In our case, the better we understand the genome of VW along with the genome of mint, the better chance we have to develop VW resistant mint and/or developing VW management strategies. This project was initiated by the Oregon Mint Commission last year, but due to the fact that it can potentially have an industry-wide impact, the MIRC considered and supported it this year.  

Nematodes continue to be a challenge in several production areas, and there are still many unanswered questions regarding this pest. The MIRC’s priority at this time is to find effective products to control nematodes that we can get registered for use on mint. There are a few materials that are being evaluated in trials, and recently there have been more candidate materials proposed for use on mint. In addition to finding effective options, it is also a challenge to determine the best application strategies to optimize the materials’ effectiveness while maintaining acceptable crop safety. At the end of the day, the mint industry needs options outside of Vydate, which is still not available, and Mocap. These research efforts are key to developing those options.  

With regards to entomology, the SAC supported the continued efforts to research the use of pyrethroid insecticides on mint, and they supported a new project to study acaricide resistance in spider mites infesting peppermint. The pyrethroid research will bring to light which material has the best fit for use on mint, while evaluating pest control performance as well as what impacts the treatments may have on beneficial and predatory mites. It is the MIRC’s intention to review this data and consider pursuing a new registration of a pyrethroid for mint. 

As for the acaricide resistance, this research will not only evaluate the efficacy of miticides on mites, but will also develop and expand molecular diagnostics to predict miticide resistance in the field. It will clearly be a benefit to the grower to be able to identify if populations of pest mites are resistant to specific acaricides.  

As for the MIRC’s continued efforts in varietal improvement, the SAC remains focused and supportive of the non-transgenic (traditional breeding) efforts. This research continues to develop key genomic knowledge that will lead to selections for possible crosses and improved lines. The goal remains to improve mint cultivars by integrating Verticillium wilt resistance, preferred oil characteristics and yield. Recently, Dr. Kelly Vining has reported she has successfully sprouted the first crosses of longifolia x suaveolens lines. Those seedlings will be evaluated for wilt resistance and oil properties once they have developed into big enough plants.  

Overall, the MIRC’s research efforts remain busy and focused on pest management topics and varietal improvement. However, there are two key pieces missing from our program at this time: irrigation and distillation. Efforts are being made to initiate studies in both areas, as both have great potential of benefiting the industry by improving production efficiencies and reducing energy consumption. 

Thank you to our SAC members who dedicate a significant amount of time to review reports and proposals, as well as discuss the several proposed projects. There is a lot of time invested to make the recommendations as to which research projects to fund each year. The industry appreciates your time and interest.  


A brief update on pesticide news: If you had not heard, Aim herbicide is now registered for use on mint as tolerance was established by EPA through the IR-4 program. However, by the time this update is published the window of application will have past for most or all of you. The labeled use is only for application to dormant mint. An e-announcement was sent out via the Mint Insider from the MIRC office. If you did not get that, then please let us know your email address so that you will get important announcements in the future. 

We continue to work on obtaining a Section 18 request for Tough herbicide (pyridate) through the states and EPA. As excited as we are to have a possible solution for our urgent post-emergent weed control situation, it is still a significant challenge to navigate through this process. In other words, if we get an emergency exemption then that is fantastic, but you should not make plans expecting it to happen. The best news on the Tough front is that the registrant has applied for a full federal Section 3 label. That application was submitted at the first of the year and is now under review at the EPA. Keep in mind this process takes approximately 18 months and has to withstand the rigors of the review.  We are hopeful that there will be an approval in time for the 2018 crop.  

If you have not heard, Vydate remains unavailable to the U.S. market. DuPont has commented that they are targeting the fourth quarter of 2017 for having material available again. Let’s keep an eye on that and hopefully there is relief in the foreseeable future.  

Gowan Company has improved the formulation of Onager and is pursuing new registrations and labels for Onager Optek. The labeled rate still contains the same amount of hexythiozox (active ingredient), but the new form has significantly less volatile organic compounds, which results in an improved environmental profile. Additionally, the new formulation has better translaminar properties, which improves its performance in mite control.  

Also in the world of mite control, we are working with Bayer Crop Science to obtain registrations again for Oberon (spiromesifen). We had a few 24C SLN registrations for a brief time back in 2015 before they were cancelled due to a dispute between Bayer and the EPA. It appears that the “air has been cleared” and we may be able to get labels again. In fact, this time we are hopeful to obtain a full Section 3, which would allow for use in all states. 

As always, I welcome your questions, comments and thoughts. Your support of the MIRC efforts is always appreciated. I wish you all a safe and productive year.