The Pecan Nut Casebearer is one of the most important nut infesting insect pests for pecans. The Pecan Nut Casebearer completes two to four generations per year with the first generation having the greatest potential for damage. Adults of the overwintering generation emerge in April and lay eggs on the nutlets soon after pollination.
The best way to determine when or if to spray for the casebearer is to scout for eggs. Most casebearer eggs are found at the tip of the nutlet, either on top of or just under the tiny leaves called sepals. A good hand lens is necessary to identify casebearer eggs and determine their development. The eggs are white when laid and turn pink as they near hatching. Also look just below the nut cluster to detect the presence of newly hatched larvae.
Scouting for casebearer eggs should be taking place right now. Depending on the pecan nut load, usually around 5% nut entry warrants an application of insecticide. However, if trees are really loaded, spraying may not be necessary for light casebearer infestations.
Once again, several pecan growers throughout the county and region are monitoring the activity of adult casebearer moths using pheromone baited traps. Over the past couple of weeks these “pecan scouts” have begun catching adult moths. Based on this information, the estimated spray “decision window” time for De-Witt County will range from May 4th through May 11th. However, because moth catches have been sporadic, treatment may still be effective if continued beyond May 11th.
Products with significant residual control like Intrepid should be applied toward the beginning of this time period, possibly even a few days earlier. Products with very little residual control like Bacillus thuringiensis (Bt) should be applied toward the end of this time period. Please refer to product labels for rates and grazing restrictions. It is very important to remember that it is difficult to determine an exact spray day for the entire county; therefore, it is important for growers to scout for themselves.
If you have any questions about the Pecan Nut Casebearer, please contact the DeWitt County Extension Offi ce at (361)275-0816.
