PECAN TREE OVERVIEW
The pecan, Carya illinoensis, is a member of the plant family Juglandaceae. This family includes the walnuts and the hickories. Brison in his book Pecan Culture writes that the pecan is the most important horticultural crop native to the United States. The pecan is a large tree, often growing to 100 feet high or more and has a stately appearance. It has been proclaimed the state tree of Texas.
The pecan is indigenous to a large area extending from the Mississippi River Valley on the east to the western branches of the Llano and San Saba rivers of Texas on the west, and from southern Illinois in the north to northern Mexico in the south. Isolated populations also occur in Alabama, far west Texas, and Mexico. These may be important sources of diversity that can be used in pecan breeding. Unlike other horticultural crops, the native pecan is very important commercially.
Worldwide pecan production (nuts) generally exceeds 250 million pounds per year. The pecan has been introduced to foreign countries such as Israel, South Africa, Brazil, and Australia, as well as states on the Eastern Seaboard. Georgia, which had no pecans a few hundred years ago, has within the last 75 years become the #1 pecan producer in the U.S. Texas production averages about 35 million pounds per year. The transition from native to improved pecan production can be seen in the figure progressing from no improved production in 1919 to about 35% of the Texas crop consisting of improved pecans in 1990.
There are three insects that attack the pecan nut and may require management every year in areas of Texas where they occur. These are the pecan nut casebearer, the pecan weevil, and the hickory shuckworm. These nut feeders have coevolved with the pecan. Significant sections of this program are devoted to understanding their biology and management.
Texas is the 2nd leading producer of pecans behind Georgia.
The development of various pecan pests is usually closely related to the seasonal development of the pecan. Although the severity of insect problems cannot be predicted on a seasonal basis, producers should frequently determine tree and nut development to aid them in predicting insect problems and planning control strategies. The seasonal pecan pest profile indicates the possible insect problems associated with various developmental stages of the pecan.
The pecan is attacked by many arthropods and pathogens. The primary arthropod complex is shown here. This tutorial discusses these pests in some detail. A quick informational summary can be obtained by pointing the cursor to a pest and clicking on it. Pests are arranged as to when management decisions may be needed. This information will help you to anticipate problems and make management decisions.
Note that pecan arthropod pests can occur throughout the growing season. Fortunately, most of them are not a threat to pecan production most of the time because they are controlled by natural enemies, adverse weather, defensive or repair mechanisms of the pecan itself and other factors.
Regular pesticide application is not recommended to control these pests for several reasons:
1) too expensive
2) resistance to pesticides will develop
3) natural enemies may be killed
4) nontarget pests will become problems
5) unnecessary use of pesticides pose dangers to the applicator and to the environment
Pesticides should be used only when a pest is present in damaging numbers and no other management method will be effective. The ability to recognize these pests and their natural enemies will greatly aid in making these management decisions.