New chemistry to fight early blight in potatoes

For potato growers battling early blight, brown spot and black dot, BASF has introduced a new disease management tool. Provysol fungicide is an isopropanol azole fungicide, making it a solution for disease control. Provysol fungicide not only controls key diseases, but also provides a new mode of action to manage resistance and has excellent tank-mixing capabilities, according to company officials.

The uniqueness of the product lies in the innovative molecular structure of Revysol fungicide, the active ingredient in Provysol fungicide, said Curtis Rainbolt, a technical service representative for BASF. “The unique isopropanol azole bridge allows the Revysol molecule to customize its shape for tighter binding at the enzyme site of action for excellent efficacy of even the toughest diseases,” he said. Used as a foundational tool, it can strengthen the overall spray program and reduce risk of resistance development.HS9A5228Tim Parry product manager for Provysol, with Curtis Rainbolt.

Rainbolt added that Provysol fungicide controls important foliar diseases, including Alternaria, brown spot and black dot. “These are diseases that, at least in Idaho, we can find in pretty much every field,” he said.

“Provysol fungicide is really delivering a level of performance that we haven’t seen in a while,” he continued. “In addition to the high level of control, there is a long duration of control and it tank-mixes well with a lot of other products that growers might use on their fields, so it’s really got a nice all-around fit.”

To determine control of disease pressure from Provysol fungicide, Dr. Jeff Miller, owner and operator of Miller Research LLC, based in Rupert, ID, tested Provysol fungicide on his research farm.

Miller Research has been testing Provysol fungicide for several years with positive results. Miller shared his experience with the product during a BASF field day in August. “We first began testing Provysol fungicide several years ago, and it has been very impressive from the start. There’s only been a few products that have come along that have been very effective at almost eliminating early blight. Provysol fungicide is in that category.”

Provided such use is permitted by the relevant label, Miller recommended that fungicides be used preventatively, not as a rescue or a curative treatment. Miller also recommended incorporating Provysol fungicide in the early part of the grower’s program with “two applications around row closure to two weeks later,” noting that, “When you look at the level of protection you get from an early application, versus late, you get so much superior disease control, and you have much less blight later on.”

Miller is concerned that while growers may be rotating products, that does not necessarily mean they are rotating between Fungicide Resistance Action Committee (FRAC) groups, which can lead to resistance.

The SDHI fungicides, which are members of FRAC Group 7, are critical components of many potato growers’ disease management strategy. Recently, there has been a push to use SDHI fungicides not only as foliar treatments for managing white mold and early blight, but also in-furrow and early in the plant’s growth cycle, when plants are six to eight inches tall, to target nematodes.  

“Where I’m using a Group 7 in the furrow, I want to minimize the amount of times that I would put it on the foliage now. So, if I have a different group, a Group 3 fungicide like Provysol fungicide, it would be a perfect fit now to put that in the early part of your fungicide program,” said Miller.  

“With Provysol fungicide we have a triazole, which is in a completely different category of fungicide, which has high efficacy. Now growers have something that they can rotate to, so they don’t have to use the same FRAC groups. They can use Provysol fungicide, which should extend the life of all the fungicides involved, not only Provysol fungicide, but the other chemistries as well,” Miller added.

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