To help prevent alternate bearing, use sound cultural practices. These include disease and insect control, adequate use of fertilizer and zinc, and an extra application of fertilizer in late May or June in years when nutset is heavy. Drought also causes failure to fill, if it occurs late in the growing season. In many years lack of pollination causes the greatest loss of nuts. Weather conditions in some seasons cause the male and female flowers to mature at different periods, and pollination fails to occur.
Some cultivars shed their pollen before the female flowers are receptive.
To insure pollination, it is important to plant more than one cultivar in an area. Insects, such as pecan weevil and hickory shuck- worm, and diseases, such as scab mildew and blotch, also can cause premature loss of nuts. More information on pecan insects and pecan diseases is available by requesting fact sheets HGIC 2212, Pecan Insects , and HGIC 2211, Pecan Diseases . Drought and too little fertilizer often cause early drop of nuts. Prevent nut loss by harvesting early.