By Clint Thompson
University of Georgia (UGA) Extension pecan specialist Lenny Wells cautions growers about a fungal pathogen that primarily affects Stuart varieties.
Wells noted in the UGA Extension Pecan Blog about leaf drop that is associated with a dying or browning of the terminal leaflets of compound leaves which progresses backward toward the base of the leaf. It eventually moves into the main stem of the compound leaf, and the entire compound leaf may die.
The pathogen has been identified as Neofusicoccum, but Wells refers to it as terminal dieback.
“It’s a disease that we saw show up, probably 10 or 15 years ago. It’s just one of those minor foliar diseases that can pop in on them when conditions are right. Usually, that’s going to be cool, wet conditions. We had that a couple of months ago,” Wells said. “The problem with this disease is the time that you see it, it’s too late to do anything about it. Normally your scab sprays are going to take care of it. That’s why we generally don’t see that disease being too much of a problem because everybody is spraying for scab anyway. But in a situation like we’re in this year, you’re trying to save some money and stretching those sprays, even back a few months ago, that’s the kind of situation you can get into.
“For some reason, this particular disease, Stuart seems to be susceptible to it. When we first started seeing it years ago, we saw it mostly on Stuart. That seems to be where it’s popping up the worst now.”
UGA plant pathologist Tim Brenneman recommends the use of a strobilurin or a DMI/strobilurin mix like Absolute or Quadris Top when weather conditions favor infection; usually extended cool and wet conditions.
This year’s yields should not be impacted too much since most of the Stuart trees are in an off year for production.