Black Stuff all over leaves

What's causing this black stuff all over the leaves in my center island? It's hideous! It doesn't rinse off with plain water. It's hard to scrape off too.

I have a few theories. I'll get to those in the next post. In the mean time.... here is the overall picture. It shows the island and the 2 or 3 humongous trees in the center. I don't know for sure what those trees are so included some bark photos.

Janet

This message was edited Aug 10, 2006 8:45 AM

Here are some close-ups of the leaves of the plants that have the crud all over them.

OK, here is my theory.

We burn refuse... such as dead leaves, and other ugly stuff in the chiminea on the patio. My husband was striping some untreated wood recently and decided to burn the remains in the chiminea. It's been raining pretty steadily for the past several weeks. The night he burned the wood, it started raining shortly after the blaze got going. Could it be soot?

The trees in the center of the island have been "weeping" lots of clear sticky stuff recently. Could this black stuff be something that's coming from the trees? The big elephant ears are coated in this black stuff. Even the smaller leaves under the waybigo leaves.

Do a Google search on "sooty mold"

We tried "washing" one of the leaves with some car wash mixture. Didn't do a bit of good and I really don't want to have to "wash" each individual leaf on EVERY plant. As you can see there are a whole lot of plants in the island.

Strangely enough, only the plants on the right sife of the island have this black stuff. Everything behind the island is fine and the plants on the left side are just fine too.

Good idea Kevin. I'll try that.

OK so I read about this. It's caused by sap-sucking insects. Could THIS then be the culprit? I've got these white things flying all over the yard. They land on a lot of different plants. They look harmless enough. Just tickle a bit when they land on arms or legs. There are bajillions of these things flying everywhere right now.

This is what I found when I googled Sooty Mold.

Sooty Molds and Global Climate Change

Because sooty molds are more common under warm conditions, the higher temperatures and increased drought stress brought on by a changing climate are expected to increase the prevalence of sooty molds. During drought, aphid populations and their honeydew production typically increase on foliage undergoing moisture stress. Also, under dry conditions, less rain would be available to remove or dilute honeydew concentrations suitable for sooty mold growth on leaves and other surfaces. During the extended summer drought of 1988, sooty molds were more prevalent throughout the Northeastern U.S.

Control

Sooty molds can be indirectly controlled by reducing populations of sucking insects that excrete honeydew. Outdoor furniture can be hosed down with water during periods of honeydew excretion, particularly during drought. The growth of sooty mold fungi is inhibited by preservatives used in treated wood in rustic outdoor furniture. Here is the recipe for a good cleaning solution for removing sooty molds from plastic or painted surfaces:

Powdered household detergent
Household liquid bleach
Trisodium phosphate
Water 1/3 cup
1 quart
2/3 cup
3 quarts

Be sure to wear rubber gloves when cleaning with this solution.

Author

Kenneth J. Kessler, Jr.
Principal Plant Pathologist

Here is the website.
http://www.na.fs.fed.us/SPFO/pubs/howtos/ht_sooty/ht_sooty.htm

That's the same basic recipe you would use to remove mildew from house siding. But don't use it on live plants. Can you move some of the plants out from under the affected trees until you can get rid of the aphids? If not, the mold isn't really harmful except aesthetically.

By the way, you were born a day too late. I was born on the third! Oh well, at least you're still a Scorpio!

Guy S.

I'm tempted to borrow the pressure washer from my brother in law. Ok I'm just kidding about that because I know it would tear the plants to shreds. I will try and move the plants, though only God knows WHERE I'll move them too. My yard has become a jungle this year.

I'm still a bit comfused about this stuff. So, is it the trees that are weeping this stuff? If that's the case, why aren't the plants on the left side of the island affected? Or is each plant being affected by the Sooty Mold. Those little white things are all over ALL of the plants out there. So maybe that isn't the problem. I also see a lot of THESE (see below) throughout my yard.

Janet

Are you sure you weren't born a day early??? Hmmmmmmmmmm

UniQue, the bug pictured is an aphid. You can verify this by searching for "aphids" at the top of the thread in the forum box. Most gardeners I know just blast the plant with water. If you use chemicals, you can purchase them easily. Aphids are real messy insects.

What kind are the trees? I have had a terrible case of black mold on the plants under my two Liriodendron tulipifera (tulip poplar) trees. These trees are known to attract aphids. I have not actually seen the aphids (the lowest branches are 20' off the ground) but I suspect they are up there creating honey dew. I have noticed some honey dew in the past, but only this year does it look bad. I have not really done anything about it other than try to wash off the hosta leaves with water (it did not work very well).

- Brent

Just an afterthought - check around to see if you see any ant activity. Ants love the honeydew. Down here, where we have fire ants, we will often see ant colonies spring up at the base of plants that aphids are feeding on. I don't think there is any year where we don't have aphid or white fly infestations. We saw white flies in April this year - that's very early - due to our early heat and drought conditions.

I've heard of aphids all of my adult life, but never seen one... that I knew what it was. I did check the bugguide index and searched for aphids. Sure enough, there was my little guy (or one of 'em) I have several different kinds of those orange bugs. I haven't seen them doing any damage. At least not on the Lantana where I've seen them most frequently. I just thought they were eating other bugs and left them alone.

I can't tell if the aphids are in those trees (not for sure about what kind they are, but hubby says the one on the right is a sweet gum tree), but I'm sure they are up there somewhere (uninvited, I might add). The trees are much fuller, lower to the ground this year than they've ever been before. We've always keep them pruned up pretty high because there used to be a small pond under those trees, before hurricane Rita buckled the pond in half. This is the first year we haven't pruned them at all.

I was able to move a whole lot of the plants (in pots) out from under the trees. Those that remain, will just have to stay there. It's too hot to be working that hard right now. The humidity is horrible. On top of all that, about 20 minutes after I moved the plants, it came down a gully washer and that prevented me from doing much else anyhow.

I guess I'll just have to live with the disgusting black stuff on the leaves until things die off for the winter, because I'm surely not going to scrub each individual leaf on all of those plants. You can bet that I'll be more vigilant in spraying something out there for aphids and hope this never happens again. I'm glad I found out what it was and was able to move some of them before they were affected. I'd just placed a bunch of potted bromeliads under those elephant ears the other day. They had not been affected... yet. Whew!

Thanks everyone for your input on this. I'm glad I had someplace to go to find out what I needed to know.

Janet

I went to Lowe's and bought a hose end sprayer and 2 things. Spectracide Immunox and Bug Stop. Was told that one would treat the fungus and the other the cause. Both of these are concentrates that kill on contact with guaranteed results.

The guy there assured me that my bajillions of lizards wouldn't be affected by this stuff and that only BAD bugs would bite the dust. I don't want the dragonflies and butterfles, etc. to be killed as well. Actually, I broke my little toe Friday night and am procrastinating getting this job done so I thought I'd come here to the experts to make doubly dern sure I wouldn't murder my GOOD GUYS before I did the spraying.

Janet

I dunno. Read the label very carefully, and it that doesn't tell you and no one here replies with any confidence then contact the chemical manufacturer. The doofus at the discount store probably will tell you whatever he thinks you want to hear!

Guy S.

I'm not familiar with those particular products, but pretty much any insecticide, even many of the "friendlier" natural/organic ones (which I don't think these are!) is going to take out most bugs it comes in contact with, not just the bad ones. Typically the more selective products are biological controls such as parasitic wasps, Bt, etc, and even those may sometimes take out good species that are similar to the bad species you're trying to get rid of, but at least they're more selective than the chemical insecticides. As far as the lizards, I don't know if these would kill them or not, but I doubt they'd be good for them. The safest thing to use in this case, since I think your problem was aphids? would be some kind of insecticidal soap--these will typically only kill soft bodied insects so you may get rid of a few good bugs along with the bad but overall you're less likely to do broad-scale damage (so if the products you mention above are insecticidal soaps, I feel a bit better about them--my earlier comments were assuming they were regular insecticide type products)

I use Spectricide Bug Stop on some of my plants that get most often attacked by aphids and ants. Sometimes the ants are worse. It works pretty good but I'm not sure about it lasting for 4 weeks like it says on the bottle.

Starhill you could be right. I happen to know that fella personally and well.... you hit the nail on the head there.

I don't see anything on the packaging about it being soap Ecrane. And we have had some problems with ants, which hubby has been treating with something or another... not sure what, but it may be Amdro.

I think the thing that worries me most is the statement on both the Immunox/Fungicide and the Bug Stop for Gardens:
Hazards to Humans and Domestic Animals

I have 2 dogs that like to hang out back there along with me and my husband. I see them munching on leaves all the time. In addition to the dogs, the grandkids come over all the time. Both are toddlers (1 & 2) and we all know that their motto is "Let's put it in our mouth to see how it tastes!" They are still learning to keep their hands off of Maw Maw's plants.

I think I had better call the manufacturer ... just to be safe.

I'm wondering also if I should cut back anything I can that's been affected, or will these things "clean" the affected leaves. Cutting things back wouldn't make much of a dent in the foilage, and truth be told, it's needed anyway.

Thanks everyone for your input.

Janet

Do you winder how "Spectracide" got it's name? Does it kill the whole spectrum of life? I forgot to mention that you might try making a local call to your extension office first -- good luck!

Guy S.

Good Point on the Spectracide, Guy! Also good advice on calling someone local. I'll give them a call in the morning.

I do enjoy the "good" wildlife out there and me and my camera would be quite bored if I lost my dragonflies, etc.

Janet

Just to point out... the bug in the pic isn't an aphid. It's an assassin bug (there are many related bugs called assassin bugs though). This one is pretty much harmless to people and will run or drop from the plant if you get too near. It eats other insects, though, so it is beneficial. Juvenile assassin bugs (of this type) look just like the adults, only smaller (ranging from teeny-tiny to adult size) and without wings.

Edited to add, this looks like the Milkweed Assassin Bug, Zelus longipes.

This message was edited Aug 22, 2006 11:35 AM

Hi Carter,

Boy oh Boy! Now I'm really confused! Here I've been thinking I've got aphids for about a week. And I don't????

There are several varieties of that particular bug hanging out back. Some are solid orange. Some have black and orange. They range from 1/4 of an inch in length to about 1 inch.

I looked up aphids on the BugGuide and would have sworn that the bug I showed before was in that group. Now that I just checked again, you are absolutely right. I do have the Milkweed Assassin Bugs. There are a lot of similarities in the aphids and the assassins. I haven't really seen that they have done any "damage" to the leaves that I've found them on.

So if not these guys, what else could be causing the black sooty mold on the leaves?

I do have some of these guys hanging out in the yard. They look like snowflakes that are about the size of a gnat.

The sooty mold still makes me think of honeydew and aphids, the white bug you're showing above could be a wooly aphid although I'm more familiar with the non-wooly sort so it may not be. Assassins don't leave anything behind that would create the sooty mold so there's definitely something else at work here besides them, based on my experience it would most likely be either aphids or scale.

Ya, the assassin bug doesn't have anything to do with your "sooty" problem. Just wanted to point out it was a beneficial bug and not an aphid. As to the smaller orange ones, those are probably juveniles. They are pretty wicked looking, but they eat lots of other insects.

I guess I'll need to go back through the aphid photos again to see what to look for.

I'm really glad that the assassin bugs are good guys. I liked them until I thought they were a problem. I haven't been "ugly", but I have been more apt to blast them when watering this past week. I can only imagine what they were thinking because they'd always been "sweetie" before that. I've apologized this afternoon and was rewarded with a beautiful butterfly on my lantana for several minutes. Long enough for me to get about 30 photo shots of it. Don't know exactly what it is at this point. Until I came here, I wouldn't have been interested enough to find out. It's funny how this place makes me want to know more about the world I live in. :-)

BTW, this is the very first time a butterfly has ever hung around long enough for me to photograph him. Isn't he a beaut??!!

Janet

You know about their life cycle right?

That males are not needed at a certain point.

Here's some notes at a page on my site. You already found a lot of info, this has some life cycle stuff.

http://www.mdvaden.com/aphids.shtml

Pesky little critters, but they must have a purpose in nature.

This message was edited Sep 8, 2006 11:11 PM

Thanks for the link. Very nice page you have there. I bookmarked it for future use after reading about the aphids and the walking sticks. My cousin in Virginia used to gather sticks with vines around them to make walking sticks with. I still have one of them that my nephew brough back from a trip up there.

Janet

I thought the very same thing when I read that! WOW! Frightening, isn't it!

OK, I just couldn't figure out any way to make the announcement "ALL LIZARDS AND GOOD BUGS PLESAE MOVE TO THE LEFT SIDE OF THE YARD!!!" and know that they'd follow instructions.

So, I "weasled out" on the BugStop and Immunox. I took them both back to Lowe's and got my money back. I bought, instead, an insecticidal soap. Home Depot had that on sale so I bought 2 containers of the concentrate for less than either of the other containers I took back to Lowe's. I used it early this morning and will hope for the best, expecting to have to re-use it again. I was very pleased with the sprayer thingamabob that I bought that hooks to the hose to shoot up into the trees. I do hope that the black stuff goes away using this stuff, but I'm prepared to cut things back if I have to.

I've been watching throughout the morning and haven't seen any "strangeness" with the lizards or dragonflies.

Thanks again to everyone for your input and your expertise.

Janet

It might or might not solve the problem, but that was a good thing you just did, for all the right reasons.
Guy S.

Thanks Guy. I felt good about it too. Almost like I'd pardoned a whole bunch of bugs. Definitely made me feel like "queen of my fifedom"!! HAHAHA

I watered with a feed this morning. Things "looked" a bit better and strangely enough, it "felt" better too. I used that same sprayer this morning with the feed and it worked very well. That wandy tree/shrub sprayer thingy was a great investment!

I haven't completely cut back all of the black leaves, due to the broken toe issue, but I can see that it's NOT getting any worse.

Thanks again everyone for letting me pick your brains. It's nice to know that y'all are here.

Janet

Just thought I'd post an update here. I've sprayed the area twice now and really gave everything a good watering/'washing the other evening. The black stuff is finally starting to wash off! YEAH!!!!!!!!!!!

Some of the leaves were just too far gone and I had to cut them back. But everything is looking much better now.

Thanks again to all of you for letting me pick your brains about something that I had no knowledge of.

Janet

And thanks for the feedback -- good to know it's working!

Guy S.