Cranberry Fungicide Update 2021
This article provides some recent updates on fungicides currently registered for fungal disease control in cranberries. Specific usage instructions such as rates, timing, and precautions can be found on the fungicide labels, the 2021 Cranberry Pesticide Chart from the Cranberry Institute, and the 2021 Wisconsin Cranberry Pest Management Guide. Please make sure you have the most up-to-date versions of these documents and get rid of older versions. If you notice an inconsistency between the product label and the UW spray guide or Cranberry Institute chart, always follow the instructions on the label. Check with your handler about rule changes and restrictions. REMEMBER, the label is the law, read and follow the directions on the label.
What is FRAC?
The Fungicide Resistance Action Committee or FRAC works to prolong the effectiveness of fungicides prone to resistance issues and minimize crop losses in the event of resistance. A FRAC group is a number and/or letter combination used to distinguish different fungicides based on their mode of action.
Mancozeb (FRAC M5) – In cranberry, mancozeb offers broad-spectrum control against fruit rot pathogens (efficacy comparable to chlorothalonil), however mancozeb can result in reduced fruit color if applied during bloom and/or fruit set stages, critical application timing for fruit rot control. Announced at the end of 2020, the European Union will be conducting a risk based maximum residue limit (MRL) review of mancozeb. At this time, no decisions have been made regarding changes and/or withdrawal of the MRL. As more updates become available, I will share them here in the Cranberry Crop Management Journal.
Propiconazole (FRAC 3) – In cranberry, propiconazole is found as a stand-alone fungicide (ex. Orbit/Tilt) and in a pre-mixture (ex. Quilt Xcel is azoxystrobin + propiconazole). Propiconazole fungicide is an option for cottonball control in cranberry. However, UW field trials over the years have demonstrated that Indar (FRAC 3) is just as effective if not more effective at controlling cottonball than propiconazole fungicides. Recently, the European Union made the decision to withdraw the MRL for propiconazole, this will go into effect on September 2, 2021. Fortunately, due to the infrequent use of products containing propiconazole in Wisconsin marshes and the availability of other effective control options for cottonball (i.e. Indar), this does not appear to be a major concern for Wisconsin cranberries.
This article was posted in Cranberry, Disease and tagged Cranberries, cranberry, FRAC 3, FRAC M5, Fungicides, Leslie Holland, mancozeb, propiconazole.