There's a serious problem with my pecan tree; it appears to be black sooty mold. I would never have planted this tree since pecans need so water. Though it doesn't get as much irrigation as it would like, it has doubled in size during our 15 years here and offers lots of much needed shade. But in the last few years the leaves have had sooty mold. This year it got much worse. Everything under or near the tree (covered trash cans, outdoor furniture and their cushions, the fig tree) has been covered with the mold too! But the odd thing is that there is no evidence of aphids, scale, or any of the other insects that, according to my Rodale books on disease and insect control, should be causing the problem. The ant population was much reduced this summer too, due to the spraying I asked about here.

So, what is causing this awful mold? And what can I do about it? HELP!!!!!!!!!!

Jennifer,

I'm sure you did a thorough search on the mold problem (not the least of which was referencing the Rodale book), so a lot of this may just be redundant.

But, it appears, that sooty mold is endemic to pecan trees. According to what info I garnered,there doesn't seem to be any other reason for the mold but aphids. In particular, black pecan aphids, which emerge late in the season. They apparently "hide" themselves in the most dense part of the tree. All that mold is the result of the honeydew they secrete. Blah, blah, blah...you know all that already.

Are the leaves in any way damaged? There might be little yellow areas on them, where the aphids have sucked the chlorophyl:
http://www.uky.edu/Agriculture/Entomology/entfacts/fruit/pecanaph.gif

Anyhoo...just in case you missed these in your search:
http://www.uky.edu/Agriculture/Entomology/entfacts/fruit/ef210.htm
http://msucares.com/pubs/infosheets/is1432.htm

It's a shame, but it seems that many landscapers and nurserypeople are trying to disuade folks from planting the trees, due to this pervasive and chronic problem with the mold. My best suggestion is to mix yourself up a big batch of insectidal soap (homemade or store-bought), in a pump sprayer and douse the thing, making sure to get the underside of the leaves. Unfortunately, that could be an awfully big job and (probably) one that you'd have to repeat every so often.

gardenz

What would we do without you, Gardenz? And what a problem this tree is!!! It's ruined the cushion on the chaise lounge that we keep underneath it, it's all over the fig tree next to it, it's on the citrus that isn't even very close, and there's an unknown tree around the side of the house that's infested too. but that tree does have some type of white fly on it, whereas I can't find any aphids of any color on the pecan. Of course the tree is so tall they must be hiding way up there.

What possessed someone to plant the !!@#$%^& thing in the first place? It would cost hundred of dollars to remove it. And the squirrels eat the nuts. And it gives lots of shade.

Ok. The leaves are falling. I've been discarding them. Then when it's dormant I should start spraying soap (or maybe dormant oil first?) about once a month for about a year? Omigod!!!

After this first rain I started cleaning up the pecan tree leaves. What a mess. I was also able to see how badly the sooty mold has affected almost all the other plants around the tree. Even fortnight lily and succulents are covered with the mold. Not to mention the fig tree. I've just about decided to remove the tree. Now to shop around for a decent price.

If we planted a jacaranda on the parking strip juat outside where the pecan is now it might give some shade within a few years. It's depressing, such a beautiful and useful tree... but the fig will do much better. You can tell how ambivalent I am! It's almost like having to put down a beloved cat!!

Well, we think of our plants like they are our leafy children and yes, it's hard to chose to destroy one. I have a dogwood tree that has anthracnose. I've been keeping it sprayed with Soap Shield and it does a good job but this summer was soooooooooo rainy, I couldn't keep up. The tree is noticable more symtomatic now than in previous years. I also prune it every other year to keep it small enough to spray. I know some day I will have to decide to remove it and I will miss it as much as a beloved pet. What really bothers me about the whole thing is that a) it was sick when I got it and I was told it was OK, b) it is very nicely branched and has good symetry and c) it was FREE.