Strategies You Can Use to Help Limit Fungicide Resistance

Fungicide resistance has limited the positive effects of many good disease control products over time, impacting yield and quality gains for growers.

DuPont Crop Protection has developed DuPont™ Zorvec™ disease control, a novel chemistry with a new mode of action that provides an unmatched combination of consistency and control for growers. The good news is that by developing resistance management plans and following label directions, growers can help prolong the efficacy of Zorvec™ technology, combating any fungicide resistance worries. 

Zorvec™ disease control helps growers of potatoes, tomatoes, cucurbits and grapes battle difficult and costly diseases. This new technology combats tough oomycete pathogens like downy mildew and late blight to help you realize greater, more marketable yields. Maintaining the efficacy of Zorvec™ technology will require an understanding of fungicide resistance and overall resistance management strategies.

How Fungal Pathogens Develop Resistance

Fungal pathogens are survivors, constantly fighting to overcome growers’ control efforts. Resistance occurs when pathogens change in a way that reduces or eliminates the effectiveness of fungicides designed to prevent or cure outbreaks. Initially, some varieties of plants can fight off pathogens. Over time, however, pathogens can change. They find new ways to overcome natural resistance and infect plants, often lowering yield potential or destroying entire fields or greenhouses of crops.

With crop rotation (planting a crop the pathogen can’t infest), tillage and other agronomic practices, growers can limit the ability of harmful pathogens to proliferate and attack crops. And above all, fungicides are extremely valuable in controlling these pathogens.

By controlling oomycete pathogens, Zorvec™ allows your crops to thrive and yield beautiful crops that help keep your operation profitable. However, a few pathogens inevitably survive. When they reproduce, the next generation can be less sensitive to that fungicide. If too many of these survivors reproduce, they can become the dominant type of the fungal pathogen. The solution is to use products featuring different modes of action to eliminate these survivors. This allows the continued use of fungicides, which can effectively control susceptible pathogens.

How to Manage Resistance 

Zorvec™ disease control technology offers a novel target site and new mode of action, which are unlike any current class of fungicide. While fungicide resistance challenges are always a concern, Zorvec™ targets oomycete pathogens using multiple modes of action, a critically important trait that helps put growers’ minds at ease.  

For growers who adhere to label recommendations on products containing Zorvec™, fewer, if any, spores will be left alive to multiply, resulting in long-term efficacy of valuable, effective fungicide technologies.

DuPont products containing Zorvec™ disease control should be used with a strategic approach to help ensure effectiveness well into the future. The keys to using Zorvec™ technology to limit fungicide resistance are:

  • Apply fully labeled rates at recommended spray interval for effective disease control
  • For best results, use in the first half of the growing season, which maximizes the benefit from Zorvec™ because of its strength in protection of new growth
  • Use in programs with different mode of action fungicides that provide effective disease control
  • Apply preventively before first signs of disease
  • Where possible, apply in a block of two (2) or three (3) applications
  • Where possible, follow Zorvec™ application(s) with a fungicide product that offers curative activity

Other Factors Impacting Field Performance 

Despite the challenges of fungicide resistance, sometimes it is not the sole cause of poor field performance. Additional examples of poor agronomic practices that could impact your crops aside from resistance include:

  • Delaying first application, which may result in a curative situation, allowing disease establishment
  • Poor application methods
  • Extended spray intervals
  • Reduced application rates
  • Weather conditions (favor disease or delay sprays)
  • Poor crop management practices

Modifying agronomic practices can reduce the risk of fungicide resistance associated with pathogens. This is why it is critical to read and follow all product label directions and precautions for use, as well as to put into place and practice a resistance management plan.

Talk with your DuPont Crop Protection representative for help in discovering more about Zorvec™ technology and how it can become the cornerstone of your crop management program.

DuPont™ Zorvec™ disease control (oxathiapiprolin) is not registered for sale or use in all countries. No offer for sale, sale, or use of this product is permitted prior to issuance of the required country level registrations.