Contributed by: Dr. Chip East, Regional Extension Agent
We get many questions about pecan trees each year. It is a popular crop for many home producers and commercial farmers as well. There are several pests that pecan trees can get including pecan scab, downy spot disease, fungal leaf scorch, pecan phylloxera, and black pecan aphids. These pests can greatly decrease the productivity of the tree. Producers with small plantings can not spray big pecan trees like the commercial growers. However, proper management practices such as planting disease resistant trees, along with proper fertilization, will help your pecan production.
Some of the recommended pecan trees that are scab resistant are hard to find at nurseries and may need to be ordered a year in advance. Some pecan scab resistant cultivars recommended for the home planting include Amling, Adams 5, Miss L, Prilop, Kanza, Headquaters, and Gafford. These pecan cultivars do not produce the largest pecans. It is difficult for homeowners to properly manage pest problems so that large pecans can fill out properly. Pecan nurseries and much more information on pecan trees are listed on the Alabama Pecan Growers Web site at www.alabamapecangrowers.com.
Cross-pollination should be considered when planting pecan trees. A particular pecan cultivar does not receive pollen at the same time the tree sheds pollen. Generally, the more different cultivars (types) of trees in the planting, the greater the chance for cross-pollination.
If you already have an established pecan orchard, fertilization is a great way to increase production. Of course a soil test is the best way to know for sure how much to fertilize your pecan trees. It would be much easier to tell someone what nutrients the crop needs if we begin by knowing what nutrients are already present. But if you have not had a soil test done, there are some general guidelines to follow for fertilizing your pecan trees.
You should apply the following: 1 pound of 13-13-13 per tree per year of age up to 25 pounds per tree. Plus 1 pound of 34-0-0 per tree per year of age up to 20 pounds per tree. Plus 1/10 pound of zinc sulfate per tree per year of age up to 2 pounds per tree. Plus 5 pounds of dolomitic limestone per tree per year age up to 100 pounds per tree.
That may sound confusing. Basically, if your trees are more than 25 years old you need 25 pounds of 13-13-13, 20 pounds of 34-0-0, 2 pounds of zinc, and 100 pounds of lime per year per tree.
For large trees, apply all of the fertilizer in April. For younger trees, apply all of the 13-13-13 fertilizer, lime, and zinc in April. Apply half the 34-0-0 in April and the remainder in June.
The use of a mechanical spreader may help ensure an even application of the fertilizers. Do not disturb the soil before applying the fertilizer. Spread it under and around the tree in an area twice the branch spread of the tree. The dolomite lime is the cheapest, but pelletized lime is easier to spread.
Remember that many pecan trees tend to be alternate bearers. That means if they produce a heavy crop one year, they may produce a light crop the next year. A proper fertilization program is very important, but there are other things you can do to increase production.
Overcrowding can be a problem. When the trees are close together and the limbs begin to overlap you may want to remove a few limbs. This will increase air circulation and sunlight in the canopy of the tree. If you are planting new trees the spacing should be about 60 feet apart.
A large weed-free/grass-free zone of about a 10 foot radius or more around the trunk is desirable. Mulching the trees in that weed-free zone will also help. It may be hard for a small grower to irrigate, but irrigation during any dry periods and especially during the months of August and September would be beneficial.
We usually teach a hands-on grafting class each April. Some pecan cultivars or types are hard to find and grafting your own trees is the only way of getting the cultivar of pecan you desire. If you have questions about pecans or any other horticulture topic, just give us a call here at the Extension office, 334.361.7273.