Last years pecans had holes in them. The problem is caused by pecan weevils. The weevils spend the winter, spring and most of the summer in the ground as a grub. The last of August through the first week of September the grubs change from the pupal stage into adults, mate and head up the pecan tree. About 90 percent crawl up the trunk while the rest fly. The weevils eat a hole in the undeveloped pecan and lay one or more eggs inside. The pecan continues to develop closing the hole. The hole found later on is the hole chewed by the grub on its way out of the now hollow pecan. Tree trunks can be dusted with Sevin the last of August through the first week of September to catch the 90 percent that crawl up the tree or the ground beneath the tree can be drenched with diazinon to kill the adults as they emerge. Sevin dusted or sprayed beneath the tree will kill beneficial earthworms.

There are tent caterpillars in my pecan trees. The tent caterpillars are fall web worms. Eggs were laid, where the tents appear, by a female moth in March or April. The moth may have flown for several miles before laying eggs. Caterpillars will come down out of the tree to spin a cocoon in late summer. Control is practical only in commercial orchards with spray equipment or where tents can be reached with a pole or garden hose sprayer. Liquid Sevin or any other insecticide labeled to kill fall web worms will work in the sprayer. Poles can be used to pull tents apart or to burn nests. Use care not to damage main branches with fire. Dusting the trunk with Sevin will kill caterpillars coming out of the tree before they hide under lawn furniture or under the house. Control may be impossible except with repeated preventative sprays due to the distance moths travel and the unpredictability of population explosions. Fertilization will help the trees restore food supplies lost with the leaves. Trees will recover.

Limbs are falling off pecan trees. Small limbs - finger sized - are probably being cut off by an insect or by squirrels. The insect is either the hickory twig girdler or the cicada (July fly). Twig girdlers chew around the twig leaving only a small section of wood in the center. Cicadas leave rough edges and cut marks on the twig. Squirrels leave clean cuts at an angle across twigs. Control of the insects is not practical. Twig loss on large trees will not severely damage the tree. Although unsightly, the tree will actually benefit from some pruning. Squirrels must be shot, trapped, or given an alternative nesting site. Squirrel nesting boxes will not reduce twigs cut, but will reduce twigs coming from open nests. Boxes must be cleaned. Large limbs breaking off can be the result of poor pruning in the past or dry wood. Pecan wood in late summer can be extremely dry and therefore brittle. Commercial orchards rely on heavy irrigation to keep wood well supplied with water. Pruning selected one to two inch diameter limbs will reduce weigh on long, leggy limbs and therefore reduce the chance of breakage in dry times or during storms.

Lines of oval shaped holes in the bark of pecan trees are caused by sapsucker woodpeckers. Damage is not a problem. Shooting the offender is a violation of federal law not to mention being unnecessary.

Trees bear well every few years. Weather, such as late frosts, is partly to blame. Improper fertilization is usually the main cause. Pecan trees need two to four pounds of 8-8-8 or 10-10-10 fertilizer per inch of trunk diameter in January and May of each year. Fertilizer encourages leaf growth. The resulting leaves manufacture sugar which is stored in the roots as starch. This starch is used to grow the nuts the following year. Broadcast the fertilizer under and slightly outside the branch spread. Poking holes is not necessary unless centipede grass is present. If so, poke holes an inch in diameter, six to eight inches deep at two foot intervals in the above mentioned area. Place about a tablespoon of fertilizer in each hole. Leave the hole open for water and aeration.

DISCLAIMER: Recommendations for use of chemicals are included in this newsletter as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services does not imply endorsement by the N.C. Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical.

Revised 2/16/2006.