Pecan

January 6, 2018

Back in the summer I googled spraying for worms in pecans, it said to spray in August and September with 5 ounces of Sevin in 10 gallons of water under the drip line of the trees and do it several times through the two months and put some stickum on the trunk of the trees. It stated that the worms come out from the ground and climb the trunk and bore into the nuts. I did as they said and still had about 50% nuts with worms that bored through the husks and into the nuts. I thought that next year I would I would just spray the nuts with the Sevin throughout those months. What are your thoughts on doing this and skipping the ground spraying? I would like your input on this.

I visited with our pecan expert and here is her answer: there are different types of worm pests in pecans and the first step would be to identify the true issue. I am going to guess it is two things, weevil and hickory shuck worm. For hickory shuck worm control you would spray a BT (Bacillus thuringiensis) product starting in July. I would make 2 applications 10 days apart. I would also get circle traps up by July 1 to begin monitoring for weevils. You can send infested nuts to your county extension office for pest identification if needed. There is a great fact sheet on circle trap construction (http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2367/F-%EE%80%807190%EE%80%81web.pdf) or you can buy them from Great Lakes IPM. It sounds like you are trying to prevent pecan weevil infestation. I have heard others try this and it does not work. The weevil pupae are located 16-18 inches in the ground so ground sprays are not effective. About 80% of weevils emerge from their soil cell and then crawl up the trunk of the tree, the other 20% fly up to the canopy. I suggest that homeowners put circle traps on trees to intercept the 80% that crawl up the trunk. This is a good alternative to spraying and you will have minimal damage, but if you want to maximize nut production, spraying the tree directly, starting when the first weevil is captured in the circle trap and thereafter when they are trapped, can also be done for great control with Sevin or a synthetic pyrethroid. Sprays tend to begin in July/August but are very weather dependent, hence the importance of monitoring.  One more point from me—pecan trees are huge trees at maturity and thorough spraying can be difficult for home gardeners.  Thus, I say for home gardeners, treat them as a shade tree and if you get quality nuts that is a bonus.

(September 2015)

I am attaching a couple of photos of the nests of worms that we have in so many trees in our area. I live in Scott. The tree I am most concerned about is the pecan tree although I guess we need to control them everywhere. Is there something that we can spray on the trees? When should we spray?  How often?  Is it safe on pecan trees?

You have a nice case of fall webworms.  In the spring we get tent caterpillars for a few weeks, but in mid to late summer we start with fall webworms, and we can have several generations per season.  The webs are a tad unsightly, but there is very little damage that occurs to the trees.  With webworms, they feed inside the web, making the web larger over time.  They primarily eat the leaves, and this late in the year, that doesn’t hurt the trees—look at how many leaves are already falling.  If you really dislike them, you can try to use a high powered spray at the end of your hose and spray with BT (Bacillus thuringiensis) and organic spray.  The key is to spray around the web and into it, getting the spray on the leaves.  The caterpillars have to eat the foliage to ingest the BT for it to work.  If you have small trees with webs close to the ground, you can use a rake and pull the webs out of the tree and dispose of them, but don’t hurt yourself trying to climb up into the tree to remove them, and don’t use the old-fashioned method of burning them out of the trees, of you can damage your trees.  The insects (or the BT) will not affect the safety of the pecans themselves.  While webworms can attack a wide range of tree species, pecans are one of their favorites.   But look on the bright side, Halloween is just around the corner, and you could pretend they are Halloween decorations—they look a bit spooky!

(January 2012)

We live in Walnut Ridge, Arkansas . We have 5 big pecan trees all different varieties. One is a very good tree and the pecans are always good. Our question is can we plant the pecans from this tree to grow more like it, or do pecan trees have to be grafted to some other kind of plant?

Pecans do not breed true from seed—they cross pollinate.  You actually need two different trees to get nuts.  Planting a seed may give you  something similar, or totally different, and it will take a good 7-10 years before you see a fruit.  Grafting is by far the preferred method.  Other good varieties to try include: Oconee, Pawnee, Desirable, Kanza or Lakota.

(October 2007)

The vacant lot right next to my west property line fence has four huge  pecan trees.  They are 25 to 30 years old or more, with no one taking care of the pruning.  When Oklahoma storm winds blow hard (45-60-70 mph) from the west and southwest, large and small limbs fall.  My question is about the concentric circles going completely around the trunks (2 to 3 inches apart) and going all the way up into the high tree limbs. Do these rings mean anything? Are they slowly weakening the trees and will it kill them?  I have heard about girdling, but do not  know  what that means. I do not know anything about pecan trees.

Concentric circles of  holes in pecan trees is fairly common.  Certain trees become favorites for woodpeckers or sapsuckers and they return again and again to the same trees.  Usually the damage is mainly cosmetic with little actual damage—especially if the trees are large and well established.  If you want to deter the birds, try hanging an inflatable eye from a branch or you can band them with Tanglefoot—an extremely sticky substance.  You would put the Tanglefoot onto a band that you wrap around the tree, don’t paint it directly to the tree of you will end up with a mess.  Once you deter them for a while they may move on, but it also may be a temporary fix and they will return.  The holes should not have any bearing on the dropping branches, which is a common problem with old pecan trees.

(Nov. 2009)

I'm new to Arkansas and have bought some acreage north of Batesville.  It includes bottomland and a raised meadow (the grassy knoll) which I fear is a huge gravel pile covered with a little topsoil.  Don't know that, but I fear it.  When I dig, I immediately hit marble sized rocks. I have mail ordered some pecan and chestnut trees.  Both say plant in well drained, moist soil.  I'm guessing that the grassy knoll will drain well, but I don't know if it is suitable for my nut trees.  By the way, the adjoining land is covered in cedar and oak trees.  What do you think?

Just looking at soil and the lay of the land, really doesn't indicate internal soil drainage.  You need to dig a hole as deep as you plan to plant your trees then fill it with water until the water stands.  See how long before the water drains.  That should give you an indication of drainage.  Planting, much less digging, and then growing can be a challenge in extremely rocky soil, but much of Arkansas is in the same boat, and we have lots of plants, so it is doable.  Get a soil test, test for drainage and see if you can amend the soil in an area at least three times the width of the planting hole with compost, incorporating that with the existing soil. Give your pecan trees plenty of room to grow, since they are large trees at maturity.

(Feb. 2010)

I have a pecan tree that is about twenty years old.  It is twenty feet high and has a six inch trunk.  It is about 600 yards away from two 50 year old pecan trees, which should provide the cross pollination.  It has never had any pecans.  There is a spider web sort of thing in the limbs every year.  My brother says they are web worms.  Will they keep it from producing?   What do you recommend to get this tree to produce?

Consider the site.  Pecans need full sun to produce flowers and nuts—if they are in competition from other trees that could be shading them, that is a possibility.  Also, the size of the tree may be an issue: twenty feet after twenty years sounds a bit small to me.  Usually pecan trees are fast growing.  Does the tree appear healthy and thriving?  The only other thing I can guess is that the three pecan trees are all the same variety.  Pecans have to have two different varieties that bloom at the same time to set nuts.  There are early, mid season and late season bloomers. Pecans can take up to seven to ten years to begin to bear, but at age 20 you should be seeing some nuts.   Webworms can be a nuisance, but they would not prevent pecans from forming.  They look worse than the damage they cause.

(May 2006)

I have sprouted some pecans. When these plants are mature enough will they produce fruit that is the same as the one the plants were grown from?

Pecans cross-pollinate to set nuts. That means the resulting pecans, if planted, will have genetic characteristics of both parents. They may be similar to what you had to begin with, or totally different--you won't know until they begin to bear nuts in 7-10 years. However, you can graft cuttings from the tree where you harvested the pecans onto the seedlings next year and you will be guaranteed the same quality nuts--provided insects or diseases don't alter that, or you can spray during the growing season.

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