It’s too late to help us for this year, but there is a new fungicide labeled for pecans that provides a totally new chemistry for us to use in our arsenal of weapons to fight pecan scab and its performance on nut scab in UGA Plant Pathologist Dr. Tim Brenneman’s trials has been excellent.
Syngenta’s Miravis Top recently received its label and will likely be a significant component of next year’s spray programs. This fungicide combines difenoconazole (a group 3) and pydiflumetofen (group 7), the latter of which is a new chemistry for pecans, which should strengthen our resistance management programs.
Dr. Brenneman’s work has demonstrated very good results on nut scab with as much as 98%-100% reduction under heavy pressure situations. The best fit for the material will be in the June-August nut sizing period, used in rotation with other strong nut scab materials like Elast or Elast/Tin combinations. It is recommended to use no more than 2 sequential applications. The rate will be 13.6 oz/acre. Word is that pricing will be very competitive at somewhere around $17/acre.
As with any fungicide we strongly urge growers to rotate these materials. The key to helping all our fungicides work better and longer is to continuously rotate them and not rely too heavily on any one material.
Photographs below show one example of the results of Miravis Top on Wichita, one of the most highly susceptible scab varieties.