John from Roanoke Va writes
You should always rotate fungicides after every 2-3 applications of one from one group to prevent resistance issues. Propiconazole 14.3 Fungicide is a Group 3 Fungicide. So you should rotate to one that contains a group 1 such as Clearys 3336F or a combo of group 3 and 11 such as Pillar G or Headway G depending on the target disease and area treating. It's possible that you just may not have had the right conditions for diseases to thrive in your area all this time but repeated applications of the same product does cause resistance.
Answer last updated on: 08/11/2021
