Cut 'em down and burn them for firewood because they aren't good for anything else. :-)

I'll take a stab at it from what I gleaned off of the Net:

Aphids.
Aphids are small (1/16-1/8 inch long), soft bodied insects commonly called plant lice or ant cows. Virtually every plant has at least one aphid species that attacks it. These small insects are masters of reproduction and are often found in great numbers on stems or leaves. Some species even feed on the roots of plants. They range in color from green to brown, red, black or purple. Some species may even have different color forms in the same colony. Most have the soft exoskeleton exposed, but some species produce waxy, cottony strands which cover the body. These are often called woolly aphids.

Aphids excrete a sugary liquid called honeydew. This honeydew drips onto plant foliage or other structures and provides a suitable place for black sooty molds to grow. Ants often tend or care for aphids in return for the honeydew. Therefore, if ants are running over a plant, look carefully for aphids.

Probably the most common disturbance caused by aphids is their never-ending production of honeydew. This sweet liquid drips onto plant foliage and stems and is soon covered with black sooty mold. Cars, sidewalks, and lawn furniture under trees with aphids are also covered with this sticky fluid. Ants, flies and wasps appreciate the sugary meal and can become a nuisance of their own. Even though plants may look bad from the growth of sooty molds, these fungi do not damage the plant tissues. Once the aphids disappear, the sooty mold often dries up and falls off the plant.

For most aphid problems, particularly those associated with leaf curls, insecticides that move systemically within the leaf or plant provide the best control. The most common systemic insecticide available to homeowners is Orthene (acephate). Cygon (dimethoate) also may be available as a spray for use on evergreens.

Some insecticides can be applied to the soil and taken up by the roots of the plants. These are called systemic insecticides. The most recent, Imidacloprid, is sold under the trade name Bayer Advanced Garden Tree & Shrub Killer Concentrate. (Merit is the trade name of imidacloprid used by professional tree care companies.) It is applied as a drench over the root zone. An olderand much more toxicÂsoil systemic insecticide that is still available for some ornamental plant uses is DiSyston (disulfoton). DiSyston is sold as granules or in plant food mixtures for soil application.

There are several insecticides effective for aphid control when sprayed on plants. Perhaps most effective are those with systemic activity that allows them to move through the plant. Acephate (Isotox, Orthene) is the most widely available systemic insecticide.

I still stand by the cut and burn method! Get rid of them and plant some nice trees!!! Come to The Middle Tennessee Plant Swap at Henry Horton State Park in Lewisburg on Saturday, October 18th! I'll have several Peach tree saplings.

Check out or website at http://www.midtnplantswap.com/

Jeff

Jeff,

What is this hatred you have for Celtis all about? They are attractive, relatively disease-free, drought resistant, tolerant of a variety of soils and conditions, have very strong wood/branches, extremely cold tolerant, and excellent for wildlife. If it's the seedlings you are worried about, all you have to do is mow and keep the flowerbeds mulched and weeded.

Your aphids is almost certainly correct. Your hatred hasn't completely blinded you yet. LOL

"They are disease-free, drought resistant, tolerant of a variety of soils and conditions, extremely cold tolerant, and excellent for wildlife."
So are a big pile of rocks or a wrecked car up on blocks but I dont want them in my yard either! :-)

Let's see, just for starters...

They are garbage trees.
They give you no Fall color.
Aesthetically they are worthless.
They CONSTANTLY drop limbs.
They grow fast but die in 40-60 years.
Their wood is weak and almost useless.
They are VERY susceptible to root fungus.
Don't forget the infestations by Jumping Plant Lice, Hackberry Aphids, Nipple Gall and Witches Broom Gall.
Because they grow quickly, they block out the sun to inhibit the growth of nice trees and shrubs that ARE worth something.

The only tree that is worse is the Box Elder.

With a plethora of nice trees available why tolerate junk? That's my story and I'm sticking to it!

I dont like the Celtics either; past or present. Never cared for Hondo, Cowens, Cousy, Nelie, Chaney, Silas, Jones, Westphal, Russell, JoJo, Heinsohn, Bird, Chief, Tiny, Maxwell, McHale, DJ, or Auerbach. I was more of a 76ers and Laker guy.

JEFF AND BRANDON.

I think you need to answer the question.Not
chop down all the hackberry tree.BRANDON is right
about the birds they love the berrys in the fall.
I once had a flock of 50 or more ceder waxwing in
mine at one time.

Burwoodbelle, see above. Jeff thoroughly answered the question in the first reply to this thread, and (for what little it's worth) I concurred.

In rereading my first post, I realize I left out the word diagnosis. My sentence was supposed to be:
"Your aphids diagnosis is almost certainly correct."

Here's what appeared on Rose Forum, with my answers, from experience in TN, as to how to handle the problem.
A low tech, but effective solution

:-O Ann posted a link to bug porn!

Ann, the ladybugs are great, but if the infestation is very bad (it it wasn't this thread probably wouldn't exist), it's gonna take a big swarm of them to make a dent in a tree full of aphids. Buying normal size batches of ladybugs from the various supply companies usually won't make a big difference. Within a few days, the ladybug population will likely be near what it was before the release.

Here's a link to some organic solutions. I have no idea how well many of them would work, but I'll post the link anyway. There are many similar list on the web.

Brandon,
It will take two years. Year one: infestation is digusting.
Year two: infestation is ingested.

You can't imagine the black on all of our outbuidling roofs. I could tell wind directions from where the gray was accumulating. And even the first year, I could see the glisten of a few lady bugs up in the trees starting to eat. My husband left his very ugly, very old Ford Pickup under a hackberry that year. The paint was turned from blue to a coating of ugly mold-gray. And he went through quite a few single edged razor blades to strip the c##p off of the windshield. Because it wasn't water, alcohol or bleach soluble.

I don't use insecticides, even with the monocultural rose gardens we grow. I depend on the Lady Bugs (spring version) for aphid control. And the fall ones aren't going to go away; now at least they are doing some good.

East Tennessee has this huge hackberry population. At least they give us shade and they burn fairly well in wood stoves.

Now Privet that's 25' high and horse nettle...I'm still looking for good in both.

"They CONSTANTLY drop limbs. "

I'm mostly with Jeff on this one. I have lived around many hackberries large and small, and in addition to their disease problems they have all shared an annoying habit of dropping limbs everywhere. My previous next door neighbor had a very large limb dropped on their CAR a couple of years ago.

I can live without them!

The studies I've read generally conclude that buying ladybugs and releasing them in a small area is frequently ineffective. Some studies have shown that releasing ladybugs during certain times and/or during certain phases of their life (eggs or very young) is more likely to do some good than randomly timed releases or releases of adult ladybugs. According to what I've read, the problem with them (at least the adult ladybugs) is that even with a food source, they usually quickly migrate away from the release area; they are highly mobile.

I tried ladybugs once. I bought the maximum number recommended for my yard's area. I think it was 2 baggies full. I even splurged for the ladybug food that the company recommended to keep the bugs happy. Before I released the ones I bought, I could go out into the yard and find 1 or 2. When I released them, there were plenty of aphids in my flowerbed for the ladybugs to eat. The first day, I had ladybugs everywhere. The second day, there were noticeably fewer, but I was in hopes they were just getting distributed and hiding where I wasn't looking. As time went on, the population decreased. After about a few weeks, I was back down to 1 or 2 ladybugs visible when I walked around the yard. All the money I spend on ladybugs had absolutely no long term effect. The money and effort did nothing to get rid of my aphid problem.

The companies that sell predator bugs are not going to tell you the down side of buying from them. So, if you do decide to use this method, it might not be a bad idea to check into how to keep the bugs at home. I've never talked to the bug people over at the UT ag college about this, but I bet they could give you information on this topic. There may be a "right way" to use ladybugs that works, but there at least seems to be a "wrong way".

Well fed bugs have no reason to roam.

And although I've no love for hackberries, mature hackberry trees came with our house, provide shade and cooler temps in the summer and windbreaks in the winter.

If we were to cut them down, our summer utility bills would soar.
But go ahead and cut yours down, if you feel so inclined. It is a world in which we are free to do as we choose.

"Well fed bugs have no reason to roam."

That's what I thought until I tried it, heard from others that had the same experience I did, and read a few studies on the subject. Apparently there may be more to it than that.

Can someone PLEASE, once and for all, tell me how to distinguish the Common Hackberry from the Southern Hackberry (Sugarberry). Both are common to the TN valley. All I understand is that Southern has smoother bark and smaller, smoother leaves. Do the two species also hybridize? Distinguishing is about as fun as the case with Scarlet, Southern Red, and Cherrybark oaks:(

Also, C.occidentalis has serrate leaf margins, C.laevigata have mostly entire (smooth) leaf margins with only an occasional tooth or very few teeth.

From various studies about Celtis hybridization, I think it's clear that they don't hybridize nearly as rampantly as many of the oaks, but the degree to which this occurs seems uncertain. Some studies, mostly older, indicate that hybridization is common. Many newer studies indicate that hybridization is uncommon.

My field guides also identify a third species, commonly called the Georgia or dwarf hackberry, that is found in the TN valley. Is this the smaller multi-branched "grove-forming" specimen that I have observed in limestone barrens or was I merely observing a variation of one of the other two species? Do C. occidentalis and C. laevigata prefer different conditions? I seem to remember reading that laevigata is more tolerant of moist conditions, while occidentalis is almost entirely xeric in habitat. Am I correct?

Sounds like you have everything pegged pretty well, except I wouldn't classify C.occidentalis as "almost entirely xeric". Although it occurs more frequently in upland areas, it is adaptable to a wide range of conditions including occasional flooding.

It's unlikely that the possible C.tenuifolia was laevigata. They vary considerable in multiple factors including leaf type, bark, and habitat. You could have either tenuifolia or occidentalis. Two differentiating factors between laevigata and occidentalis are leaf margins and fruit.

C.tenuifolia's leaf margin is nearly entire on the basal third of the leaf and it's fruit is orange-red when fresh and smooth when dry. C.occidentalis' leaf margins are toothed all the way to the leaf's base and it's fruit is dark purple when fresh and wrinkled when dry.

I will attach a link below to the eFloras key to the Celtis genus. I just LOVE eFloras! Maybe one day it will be complete.

I took a look at some Celtis herbarium leaf samples of occidentalis and tenuifolia. On average, there's a small difference in leaf margin between them, but I think it would be an unreliable indicator out in the field. Maybe if a large sample was used and averaged, there would be a noticeable difference, but it wasn't that clear to me looking at individual leaves.

Is the hackberry black mold harmful to humans? We have three large hackberry trees in the yard next door and across the street. Our house and cars are covered with this black mold. It is even inside the house and my wife is very sick with a breathing issue. The dust is black also. No visible mold produced inside. Could these trees cause such a problem?

Need help !

As far as Hackberry trees go... they may not the best looking tree in the neighborhood, but they provide shade. And living in south Texas shade is a good thing. I would have preferred a different variety of tree where several are growing, but I wouldn't cut them down and start over with a small tree. And the deer seem to like the leaves too. I have live oaks and red oaks as well, so the more shade the better. Just my 2 cents.

Hackberry trees are EXCELLENT for the right people. If you have killed every tree that you have ever planted, then you can grow a Hackberry.

Since most garden stores don't stock this persistent tree, here is the best way to grow one.

Buy a 6 foot length of chain link fence and place it in the center of your yard. Don't edge around it. In about two or three years a Hackberry will start growing through the fence. Allow it to grow for two years and get some wire cutters and cut the chain links off the tree.

Then you'll have a nice tree that you can never kill.

BTW, Brandon... I made a bunch of "primitive" bird houses with Hackberry wood. It's really is fun to work with... I'm talking about not very thick branches. They are not completely primitive since I use a nail gun to quickly assemble them, and then I tie them up in other trees. I've challenged a number of friends to find them when the trees were actively growing and they hardly ever found them. Only in the winter when the leaves are gone are they easier to find. They last about 2 or 3 seasons.

It's not a decoration but a 'where is waldo' thing for me. I don't know if the birds like them, but I do. LOL!

The only food snout butterfly larvae eat are hackberry trees,so please leave some for them,pollinators are good for the rest of your garden!