Critical Time to Protect Against Scab Disease

Web AdminPecan

Photo courtesy of UGA Extension

By Clint Thompson

It is a critical part of the production season for Southeast pecan growers. Producers should be diligent in their fungicide sprays against scab disease.

Lenny Wells, University of Georgia Extension pecan specialist, stresses why this is an important time for farmers in protecting this year’s crop.

“It’s a super critical time because those nuts are growing so rapidly right now. They’ll do most of their sizing probably within the next two to three weeks. They’re growing so fast right now,” Wells said. “Because they’re growing so fast and now that we’re getting these rains like we’re getting, they’re very vulnerable right now to scab.

“All the way through June, for the most part it was pretty dry. That was the time to try to stretch the sprays. Now there’s no option for that. If you’re going to make some of those really susceptible varieties like Desirable and Pawnee, you’ve got to be spraying right now.”

What to Use?

Wells noted in the University of Georgia Extension Pecan Blog, that rotating Miravis Top with Elast/Tin will provide the best protection during the nut sizing period. Growers should tighten their spray applications to 7-to-10 day spray intervals on susceptible varieties.

“A surfactant applied with Miravis Top (Group 3 + Group 7 fungicides) or with materials like the Group 3 + Group 11 mixtures can help under these conditions,” Wells wrote. “No surfactant is necessary with Elast because it has surfactant activity itself.”

According to Thursday’s release of the U.S. Drought Monitor, the dry conditions are starting to lessen in Georgia due to increased rain activity throughout the state. But most of the rain is occurring in the evening which keeps the nuts wet throughout the night.

“It’s the worst possible time of day to get those rains because they get wet, get soaked late in the afternoon and they just stay wet all night long. Of course, that’s what drives that scab. The longer those nuts stay with free moisture on them, the more likely scab is to develop,” Wells said.

Scab is a fungal disease that infects the leaves or nuts of pecan trees. If it affects the nut early enough, scab can cause the pecan to blacken and fall from the tree.