With the this growing season nearly 3 weeks ahead of normal, we got way behind in our normal spring work and failed to get pheromone traps up early enough to capture the flight of first generation adults. However all is not lost. From our experience of monitoring casebearer and pecan nut development for more than 30 years we can predict that first nut entry will occur next week most likely, May 22. Since all northern pecan areas experienced the same early spring this year, The normal differences we see in the timing of budbreak, nut development, and insect appearance from south to north have been nearly erased. As a consequence, everyone should expect first nut entry sometime next week.
The nuts cluster on the left is pollinated but the pollen tube has yet to grow down to the ovary to fertilize the egg. Note the small size of the nutlet and the fact that the 4 leafy bracts just below the stigma stick outwards. The nuts pictured on the right are fertilized. The small nuts have enlarged and the 4 bracts are now sticking straight up. The nuts in our grove are nearly all fertilized and are now ready to for egg laying by female casebearer moths.
This decision tree was developed for native pecans. Improved cultivars most likely have a higher cluster size threshold for not treating than native trees. However, with the nut set I'm seeing on all our trees, I won't be spraying anything for casebearer this year.