Most of you know I live in DeLeon, Texas, in one of the few concentrated pecan areas of Texas. Because I live and work closely with pecan growers, I hear their observations (complaints!). Here we had a great deal of rain in the fall of 2018 and again in the spring of 2019, which is great for trees, all trees. Our pecan trees are very healthy, but we have pecan scab issues on leaves and fruit because of difficulty spraying with so much rain. Also, we started out with a huge amount of nutlets on the trees, but slowly they are disappearing and a common question is WHY?
This is a complicated problem but the basic answer is one that Dr. Sparks addresses in his book, Pecan Cultivars. The first big nut drop occurs after bloom (remember all that pollen on our cars) and is related to weak pistillate flowers. This drop is related to tree stress from 2018 and happens so early most people don’t see it, except growers. The second drop is happening now and is related to poor pollination. This happens 14 - 40 days after pollination or now and is basically the result of no pecan nut fertilization. There are a number of factors such as calm days, rainy days, nutlets not being receptive when pollen is available, or maybe we just don’t know why!