Spring is prime time for initial injury to pecans by the pecan nut casebearer (PNC). This is also the best tome to begin looking for this destructive pest in your pecan trees. Here are some helpful tips on identifying pecan nut casebearers and minimizing their damage to pecans.
Casebearer adults are rather dull looking brownish moths, which can be distinguished by a dark stipe running across their wings just behind the head. Female casebearers emerge from their winter sleep in spring and begin producing a scent that attracts males. The moths are active at night when they mate and lay eggs on pecan nuts.
Up to one-hundred-fifty eggs can be deposited by an adult female moth during her lifetime. The eggs are usually placed very close to young tender buds on pecan trees. They will hatch in four or five days. Once they hatch, PNC larvae will enter immature pecan nutlets and begin feeding for about a month depending on the temperature.
After about four to six weeks full grown larvae will change into a pupal form within the nut. After one or two weeks they emerge from the nut in their adult moth form and start the process all over again. Pecan production can be seriously reduced by the pest. Tress with shriveled pecans are an almost certain sign of casebearer presence.
The PNC can produce between two and four generations a year. It is the first generation which is most damaging to pecans. Later generations find it too difficult to penetrate the harder shell of maturing nuts.
Sticky traps with a scent that mimics the female moth can be purchased through many different suppliers and used to determine when the casebearer is active. Once a casebearer moth is trapped, tree owners should begin scouting clusters of nuts for the presence of eggs. Two to five days after hatched eggs are spotted on the nutlets, sprays of carbaryl, malathion, spinsad, Bacillus thuringiensis or other properly insecticides can help reduce the loss of pecans.
