Pecan tree maintenance

Published 3:39 pm Tuesday, July 25, 2017

From mid-August through early September, the destructive pecan weevils emerge from the ground. They begin their short journey climbing up the trunks of pecan trees to bore holes into the shucks of the young nuts and destroy the kernels. If the weevils are detected in time, a suitable insecticide can be applied to the ground before the majority of the weevils emerge. The active ingredient of one insecticide that is commonly used is carbaryl, which is found in Sevin (apply only as directed on the label). To detect the weevils, a section of burlap cloth with a partial back-fold is usually wrapped around the tree trunk 3-4 feet from the ground. For the necessary daily monitoring, the burlap serves to make the weevils more visible as they climb up the trunk.

The life span of a pecan tree is well over 75 years and can reach heights well in excess of 50 feet. To the average home gardener, it is difficult, if not impossible, to apply any possibly needed insecticides and fungicides once the trees get to be more than 25 feet.

Starting in late August, there are three main reasons why pecans drop from trees prematurely. They are lack of sufficient pollination, insects and diseases and stress conditions.

  • Having adequate pollination requires having two varieties of trees (typically the Cape Fear and the Stuart) and good weather during the pollination period in the spring.
  • The insects that mainly cause premature drop during the summer are the pecan weevil, nut casebearer and shuckworm, which bore holes into the base of the nuts. Other insects causing damage to the nuts include the stink bug, aphids and the twig girdler that girdles the twig ends of the branches. Once identified to be present, weevils and other insects can be controlled by using appropriate insecticides. Of the diseases, scab is the most prevalent and damaging in causing defoliation that also can lead to some premature nut drop.
  • Stress conditions can be caused by many conditions, including successive humid, sunless days that limit essential photosynthesis. Severe stress, however, occurs mainly from lack of proper watering, particularly during dry periods. Late July through the middle of August is the critical period for beginning kernel formation when uniform and thorough watering is essential. Too much water (storms) and too little water (droughts) will severely stress the trees and cause considerable premature nut drop, as much as 50 percent. Since incorrect fertilization can also be a cause of some premature nut drop, getting periodic soil tests that are free (April through November) through the North Carolina Cooperative Extension is recommended. With pecan trees growing to be very large, they need to be planted in well-drained, deep fertile soil (sandy loam preferred) and typically spaced 60 feet apart.

Dan Bergbauer is a Master Gardener volunteer with the Beaufort County Cooperative Extension. This information is given courtesy of Extension Master Gardeners who are volunteers under the direction of the Extension. Volunteers are available through the hot line to answer your questions concerning lawns, vegetables, trees, ornamentals, fruits, plant problems and diseases, pests, soil and many other horticulture issues relating to gardening in North Carolina. The hotline telephone number is 252-946-0111, and the hours are Mondays and Wednesdays from 10 a.m. to noon. You can leave a voice message at that number, or email the Master Gardeners your question at and a volunteer will return you call on the next hotline work day.