Fungicide selection can be a challenging process, and growers often need to take into account many factors in deciding on a product. Disease history, variety susceptibility, cost, and performance are important factors that go into the overall equation for selecting a product. One statement you may hear sounds something like this:
“I’m going with Product X because it has more of triazole1 than Product Y, which has a lower amount of triazole 2 for this price”.
Let’s change that statement around, but this time let’s say the individual is in the demolition business. “I’m going with black powder over plastique because I get less plastique for this price.”
That statement is true, but the amount of powder needed to do the same job as a given amount of plastique is much greater. Thus, the comparison doesn’t really make sense.
The same goes for our fungicides. Potency can vary significantly within a fungicide class. Thus you may only need to go out at a 6 oz rate for one product to achieve the same level of disease suppression that you may achieve at a 10 oz rate for another product. In addition, the inactive ingredients play vital roles in the performance of fungicides. Premixes are another issue, as sometimes synergism occurs-the activity of the actives in a mixture are greater than what would be expected if they were applied solo. Keep this in mind going into the field season.