By Clint Thompson
Mancozeb’s uncertain future as a fungicide option for Southeast grape producers has researchers, including those at the University of Georgia (UGA), currently studying potential alternatives.
Phil Brannen, UGA Cooperative Extension fruit disease specialist, provided an update in the UGA Viticulture Blog and noted that mancozeb remains available for the 2026 season under current labels.
“It is on the chopping block, I’ll put it that way,” Brannen said. “Again, it might be two, three, four years before it comes off if it does come off. But as currently proposed by the EPA (Environmental Protection Agency), it would be taken off of grapes completely.
“It’s an old fungicide that’s been around for a long time, but it’s pretty dang active for a contact material and it’s very important to our program.”
Valuable Product
Mancozeb’s value is based on its effectiveness against certain diseases and its lack of developing resistance.
“It’s really good on phomopsis. It also controls downy mildew pretty well, as you know, and it’s part of our program for sure. And then it’s active on quite a few things like black rot, the collectotrichum ripe rot, that we have as well, and it doesn’t develop resistance. That’s the other thing that’s real critical about it,” Brannen said.
Brannen noted in the blog post that it still may be another couple of years before EPA makes a decision regarding mancozeb’s future. It may not be available at all or be available with certain restrictions. Its future is critical to the sustainability of grape production throughout the region.
“It’s one of our critical contact fungicides we utilize a lot on grapes. It would make it much more difficult to control diseases on grapes if that happens,” Brannen said. “And so, you know, go to California, the west coast, they don’t worry about downy mildew or black rot, for example, or ripe rot. They just don’t have enough moisture, and everything’s irrigated from below and they very rarely get rain during the season based on their climate. They just don’t have the issues we have.
“But when you get into a wetter climate trying to grow European grapes and hybrids and muscadines too, I mean, it’s a critical product even on muscadine grapes, which are native grapes. When you get into our environment, we just need every material we have, and especially some of these that don’t develop resistance.”