Growing Pecans Along the Gulf Coast
Growing paper shell pecans along the Gulf Coast is a challenge due to our high humidity, fungus problems, numerous bugs, and large animal population. Paper shell pecans require a lot of spraying because of these problems, so a lot of people have gone back to growing the native pecans that have become resistant to the fungal and bug problems such as Prilop. I am growing paper shell Choctaw, Forkett, and Podsednik - Forkett being my favorite, but it can sometimes not fill out completely. It does have a very thin shell and can get rancid quickly if not harvested from the ground.
Left to Right - Podsednik, Forkett, and Choctaw
Podsednik is probably the biggest pecan that I know of. About 22 pecans weigh about 1 lb.
Podsednik Pecans from my 2007 crop.
Fungus: Fungus is a major problem for pecan trees, and it is my number one problem. In late July through August a fungus forms due to Stem End Blight (fungus - Botryosphaeria ribis). Diagnosis for the fungus is made by cutting the nut in half (see below) and examining the developing nutlet in the later water stage. A fungus infested nut will be brown with an accompanying brown liquid. In contrast, a fungus-free nut will be white in color with a clear liquid. As a preventive step and not a cure (if the pecans already have the fungus, it is too late), one can spray a fungicide called Enable 2F. To prevent the fungus from destroying the pecans, one should spray Enable on the pecan trees in early July. The fungus shows up again when the pecans start to fall, and the shuck sticks to the pecan. This is known as Sticky Shuck.
Stem End Blight Pecans
The cut pecan on the left is normal and the three on the right have Stem End Blight.
Scab: Another problem with growing pecan trees in the Gulf Coast area is another fungus called scab. Scab is cladosporium caryigenum. It attacks the leaves and nuts, leaving little black recessed spots on the nuts and leaves. Some varieties are more susceptible than others. The three varieties that I am growing seem to be resistant, and I have very little scab. Fungicide has to be applied as a preventative method against scab, but, again, this is not a cure and most of the fungicides that prevent scab are restricted from the homeowner. One interesting note is the University of Alabama has found a reduction in scab by using the same bacteria (bacillus thuingiensis) that kills hickory shuck worms and tent caterpillars (see moths below). So this is about the only preventative for the homeowner.
Stink Bugs: Once the pecan nut forms a hard shell, one then has to contend with the leaf-footed (stink) bugs. This bug has the ability to drill through the shuck and also drills through the harden nut shell with his proboscis. The insect uses his proboscis to dissolve and to suck out some of the nutlet. If one finds black spots on the nutlet about the diameter the size of a b-b pellet, then stink bug damage is evident. The stink bug is hard to kill because it sits high off the nut and doesn’t get insecticide on its body. For the stink bug to be killed, it must come into direct contact with the spray and or its vapors. Lorsban is about the only spay that can kill the stink bug and is restricted. Also, Sevin will work, but is not as affective, and the dust or liquid spray has to come into direct contact with the stink bug.
Podsednik with Stink Bug damage.
Moths: Tent caterpillars and Hickory Shuck Worms are other insects that cause damage to pecan trees. Tent caterpillars make the web “tents,” and hickory shuck worms eat only the shucks of the pecan usually in late August and September. Tent caterpillars make the familiar web tent that protects them from predator -the red and paper wasps - during the day. At night the tent caterpillars eat pecan leaves and expand their tents. These insects can be controlled organically by using bacillus thuingiensis (BT) which is sold under a number of brand names - B-T, Dipel, Javelin, and Thuricide. BT is a stomach poison to insects that have an alkaline stomach and is harmless to humans who have an acidic stomach. Also, Confirm 2F and Provado Pro are other products that work, but they are real expensive. If you want to determine if you have a lot of shuck worm moths and need to spray, you can purchase sticky tent lures that capture the male moths. Ants may attack shuck worms, so having ants around pecans at this time may be beneficial.
Varmints: Animals can also cause damage to pecan trees. The heavy infestation of squirrels, raccoons, opossum, and crows create an animal problem for pecan trees. Squirrels strip the tender bark on new limbs during the growing season and can girdle and kill the stripped limb. Then, when the nuts begin to evolve from the water stage into the white nutlet stage, the squirrels start testing the pecans to see if they are ripe. They will go though several dozen pecans a day just trying to find a ripe one. When the pecans begin to ripen, the squirrels become satisfied more quickly; thus, fewer pecans are lost.
Squirrel damage to Pecan Tree.
The second limb on the right is totally girdled and dead.
About the only way to prevent animal damage is to isolate the tree by first creating a barrier near the base of the tree. Then pecan trees have to be far enough away from power lines, buildings, and other trees because the animals can use these structures as jumping points to leap into the pecan tree. The best method I have found to create a barrier is to use aluminum printing sheets that one can obtain from a local newspaper printing office. The newspaper printers only use the sheets one time, and then they recycle them. Our local newspaper printer sells the used ones (they have printer’s ink on one side) for 25 cents, and sell unused one for about $1.00 each. They are the size of a two page newspaper sheet. The aluminum should be stapled to the trunk of the tree at eye level. Because these aluminum sheets are slippery, they will stop squirrels, raccoons, cats and opossum from climbing the tree.
Aphids and Mites: Black aphids and scorch mites can also create problems for a pecan crop. Black aphids can really be bad; it just depends on the year, and the general conditions conducive for black aphids. Just three black aphids per compound leaf can cause pecan leaves to drop off. Black aphids can easily defoliate a tree if they get out of control. Green aphids are less damaging, and the tree can have about ten per compound leaf. Green aphids are known for the sticky “honey dew” they excrete which can cause sooty mold to build up on leaves, blocking the sunlight from reaching the leaves and leaving a sticky mess on parked cars under pecan trees. The best remedy to use for aphids is Lorsban, but it is a restricted chemical. Additionally, scorch mites attack pecan leaves similar to the method used by black aphids. Damage to leaves by scorch mites is seen when one finds a patch of leaves that look like they have been torched. To remedy the problem, a mitacide has to be applied to control them.
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