Catkins buds are produced in late summer before they bloom the next year. Therefore, trees have to make all the year s growth before the crop of nuts is set. This is why it is so important to apply fertilizers approximately six weeks before trees bud. Trees in production should be fertilized to maintain a minimum annual terminal twig growth of six or more inches.
Optimum growth is approximately six to eight inches.
Because nuts do not appear until trees have most of their annual growth, the pecan crop is rarely killed from late spring frosts. If you observe a nut drop, it should be determined if it is from a natural shed or one of the following factors. Leaf disease such as scab, scorch, mildew, blotch, brown spot, and downy or vein spot also may cause nut shedding. The pecan nut casebearer probably causes more nut shedding than all other insects collectively. However, insects such as black aphids, May beetles, shuckworms, stink bugs, and pecan weevils may cause dropping.