The pecan crop in Georgia produced a little over 60 million pounds in 2013. Steady rainfall and pecan scab disease decimated pecans last season, especially in south Georgia. Pecan scab disease is the most destructive disease of pecans. Scab severity is mainly influenced by rainfall during the growing season.

The fungus that causes pecan scab attacks young leaves in the spring and then shucks throughout the summer. Without treatment, infections can defoliate the tree and nut shuck infections can reduce the crop and quality.

You hear folks say, “If this season was bad, the next will also be bad.” This is because pecans are a perennial crop. Therefore, management and environmental conditions often affect the following year as well as the current year. Physiologically, our pecan trees determine what type of crop they will produce next season in August of this season. This is because the female flowers are induced during this time.

University of Georgia Extension Pecan Specialist Dr. Lenny Wells said, “Too much rain and disease is not just bad for the year it happens, it’s bad for the next year, too. All of that disease pressure, all of those cloudy conditions and some late-season pressure from some insect pests put a lot of stress on those trees at the wrong time.”

The rain and effects of environmental conditions play major roles in pecan production. The past few weeks, I’ve gotten questions pertaining to leaves dropping. Many of these questions come from homeowners that have a few pecan trees in the backyard. This is occurring in commercial orchards as wells as residential settings. What causes this and what can we do?

Weather this season has essentially continued from last season — lots of rain. Growers made sure to start their scab fungicide programs early. Once late June set in this year, we went through a dry period. We stayed dry through the Fourth of July but recently picked up rain. These rains have saturated the soil at once,  essentially “drowning” some of the pecan’s roots. The wet soil has created an anaerobic soil profile. As a result, the trees are dropping leaves.

I looked at a few backyard pecan trees while visiting a homeowner recently Most of the leaves dropping had black spots on the leaves. These black spots are remnants of pecan scab disease. Scab disease cannot be managed in a residential setting and consequently is another influence on leaf drop.

Unfortunately, there is nothing we can do about leaf drop. We will have to let it run its course. We manage our plants and crops for pests, but pests are influenced by the environment also. In this case, the environmental conditions are playing both a direct and indirect role.

So far, our pecan crop is about 7-10 days behind. Growers are just now completing their leaf tissue analysis. Last season, the later boost in pecan production came mostly above Highway 280 (Crisp and Sumter counties). Everything south of this line struggled do in large part to scab pressure.

For additional questions, contact Thomas County Extension office at 225-8952.