This should kill any overwintering insects as they emerge. Hopefully, this can control your problem. We recently moved to a house with two pecan trees. They were loaded with pecans, but they all fell off around September, before they matured. I would like to know why they fell off early.
Several things can cause pecans to shed early.
First, consider how hot and dry it was in August and September this past year. If there was no supplemental watering done, that could be a factor. Then, there are numerous insects and diseases which can attack pecans if a complete spray schedule is not followed. Incidentally, we really don t recommend spray schedules for home gardeners on pecans. The trees grow too large for thorough coverage to be possible.