Stress and Pests Lead to Poor Pecan Crop

Many calls have come in from people concerned about this year’s pecan crop.  The common question I hear is “why didn’t my pecan tree produce any good pecans this year”.  Many claim that their old pecan tree has always produced good pecans until now.   Well, I don’t know about why they did so well in the past, but I can tell you that it is quite difficult for homeowners to grow pecans. You cannot just plant a pecan tree, do nothing to it, and expect pecans to rain from it each fall.

“Pecan trees tend to have “on” and “off” years”, Goff says. “In “on” years, like this one, the crop load is heavy and trees are under a great deal of stress trying to develop the nuts.” 

Among the additional stresses adding to the crop load stress Goff lists:

• Scab and other diseases. The rainy June-July period created an environment for serious disease problems. Nuts are attacked directly, and leaves and twigs are also affected, reducing the trees capacity to manufacture foods.
• Aphids, mites and webworms. These all attack foliage and serious outbreaks occurred this year. When foliage is damaged, the trees ability for photosynthesis is reduced. Pecans without sufficient photosynthesis can’t manufacture the carbohydrates necessary to fill the nuts properly.
• Too much water, then not enough water. The rainy June-July period occurred as pecans developed size, so nuts were large, demanding even more energy. Then as the large crop of big pecans needed water to fill the kernels, in late August through early October, the weather turned dry, increasing stress.
• Overcrowding. Plenty of sunlight, and lots of room for root growth are needed for pecan trees. If a grouping of trees has more than 50% of the area occupied by tree canopies, it’s too crowded and pecan production will suffer.

So what can you do to have pretty trees and good pecans? Goff suggests the following:

Consider replanting to better cultivars. “Young trees stand stress better”, he states, and ‘there are much better varieties available now which have natural resistance to pests”. He recommends the varieties ‘Gafford’, ‘Excel’, ‘Carter’, ‘McMillan’, and ‘Kanza’. Check alabamapecangrowers.com for more information and availability.

Water trees in September. “Applying 1-2 inches of water a week in late August through September is an effective practice proven to improve pecan quality dramatically”, Goff says.

Reduce overcrowding. Cutting down the worst-performing trees and replanting resulting skips with resistant varieties is an effective practice. This deals with overcrowding, and converts the planting to younger trees of better varieties.