Life Cycle

• Adult casebearers are dark gray, 1/3-inch-long moths. After mating, each female deposits 50 to 150 white eggs near the blossom end of the nut over a period of five to eight days and then dies. Before hatching, the eggs gradually turn red. When the larvae emerge they bore their way into the base of the nuts where they feed for four or five weeks, emerging as adult moths. Pecan nut casebearers produce two or three generations per year.
  
  

Detection

• Pheromone traps capture adult moths, signaling the beginning of the mating process. The eggs are very tiny, so use a hand lens to examine the blossom ends of the nuts for eggs. If you find black excrement and silk at the base of the nuts instead of eggs, the eggs have already hatched and the larvae are inside the nut.
  
  

Pesticides

• Begin looking for eggs on the tips of nuts in mid-spring and spray when the eggs are pink in color for best results. If you have trouble finding the eggs, but the traps indicate the presence of moths, spray as soon as the nuts begin to form and again six weeks later. Choose an insecticide that contains Bacillus thuringiensis, spinosad, malathion or carbaryl and is labeled for use on pecan trees. Read the label and follow all mixing and safety instructions. Avoid spraying on windy days when the insecticide may drift.
  
  

Additional Measures

• Good sanitation helps reduce populations of pecan nut casebearers. Pick up debris under pecan trees and destroy infested nuts that fall from the tree to prevent emergence of adult moths. Parasitic wasps belonging to the genus Trichogramma lay their eggs inside casebearer eggs, turning them black. You can purchase trichogramma wasps to release in your pecan trees, but, according to Texas A&M University Extension, they aren't as effective as insecticides.