There is a wide array of fungicides available for disease control. However, there is the ever-present threat of resistance from overuse or misuse.

Doll believes this concern is being heightened by the marketing of pre-mixed products with different active ingredients in the mix.

“They are great fungicides mixed together, but my concern is how to manage resistance with these pre-mixes,” according to Doll. “It is not effective resistance management if you follow one of these pre-mixes with the same active ingredient as one of the two products in the tank mix.

“Following a strobilurin and DMI tank mix with a single mode of action strobilurin or DMI is not good resistance management.”

He recommends following a pre-mix with sulfur, copper, sulfur or chlorothalonil.

“I do not blame farmers for using these pre-mix products, but I would highly recommend they rotate with something completely different,” he added.