In many years lack of pollination causes the greatest loss of nuts. The male flower and female flower on pecan are separate, but they are on the same tree. The female flower is produced at the end of the current season s growth. Since pecans are wind-pollinated only, excessive rain during bloom prevents pollination and the unpollinated nuts fall. 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 shuckworm, 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 HGIC fact sheets 2212 and 2211 respectively. Too little fertilizer and drought often cause early drop of nuts. Prevent nut loss by harvesting early.