Cotton-like Substance covering Oak

[LivefromFlorida]

It's only been two weeks since I paid any attention to the trees in my back yard... and in that short time frame, the leaves on one of my oaks has become completely covered in a cotton-like substance. It looks like it's mostly UNDER the leaves, and when I pulled a leaf off, I noticed bright yellow (squishable) pellets ingrained in the cotton stuff. I have a feeling its an aphid of some sort (??) I'm just trying to find out what this is and if there is a way to salvage the tree (preferably natural).

I'm in Orlando. I have Meyers Lemon tree that lives about 7' from this oak, and another oak another 7' beyond that (both of which appear to be unaffected currently).

Help, please!

 

[S Mc]

These appear to be oak woolly aphids. They produce copious amounts of cotton-like substance. From one website listed below, it is pointed out that horticultural oil will destroy the eggs and that natural predator insects are important in keeping the population at bay. Using chemicals is always a last choice as these kill the beneficial insects as well as the problems, causing further imbalance in your home landscape.


http://www.ext.colostate.edu/pubs/insect/05511.html

Sylvia

 

[ATS/TexasTree]

They are very tiny bugs after all. Yes, you can use an oil or a soap spray and clean it up right away.

The first line of defense should be just a hard jetting of water from the garden hose.

I'm always surprised at how fast people revert to even "safe" solutions when a hard stream of water will ruin most insects' day.

A daily hosing of the plant will greatly reduce the amount of infestation with no chemicals (or cost) at all.

 

[LivefromFlorida]

Water from the garden hose with a jet stream nozzle was exactly the course of action I took two days ago after Sylvia's response (and what a mess it made of the grass!) I checked in on the tree this evening and noticed that there are still a few fuzzy leaves, so I'll take your advice and spray it down again.

I was also encouraged to see a couple of lady bugs on the leaves. Wahoo!! Munch up those aphids, little "ladies"!!

I also noticed when I was spraying down the tree on Sunday that there are several spherical "nodes" in the branches - at first I thought they were acorns, and then I noticed that they're in the middle of the branch. If I remember correctly, that is a sign that the tree was starting to suffocate (right? I think I read that somewhere a long time ago?) Is there anything I can do to help the tree recover? The leaves look a little blue-ish compared to its companion 20' away...

Thank you for your help!

 

[S Mc]

Could you get a picture on these spherical nodes for us? Many things/bugs cause galls or cankers so would pretty much be guessing here.

Thanks.

(Glad the water is working. )

Sylvia

 

[ATS/TexasTree]

When Nature is allowed to run it's course, most insect problems come back in balance.

As one insect population builds, a predator population builds up 10 to 14 days later to bring back into balance.

By helping with the water jetting, you're allowing the lady bugs to bring the situation back into balance a little quicker.

Another thing to consider when worrying about insect damage on plants is when to intervene.

Most damage people see on plants doesn't ever reach the threshold of causing serious or lasting damage to a plant - yet they panic and spray everything in sight.

Knowing when to intervene is better for the environment and will save you a lot of money wasted on chemicals. I suspect you were able to spray off more than 90% of the insects with water alone.

 

[LivefromFlorida]

Branch Bumps

The woolly aphids definitely appear to be under control now. I finally got the chance to take some pictures of the nodes I was talking about. These bumps are all over the tree, mostly in the upper half of the branches. They're solid like the rest of the branch...

 

[treeseer]

I've seen these in live oak before, but don't recall in them causing problems. I looked for it in Johnson/Lyon but did not see it. How bout you Sylvia? O and posting person, how about slicing one in half and posting a pic of that?

 

[S Mc]

There are an amazing amount of gall wasps; there are more than 50 species of gall wasps in scrub oaks alone. They are normally identified by the type of gall they make.

The closest I come up with is the Horned oak gall and the Gouty Oak Gall. This insect produces woody swellings, as opposed to the cynipid wasp whose galls are more thin-skinned and fleshy.

The problem with the Gouty and Horned oak galls is that they do cause economic damage and can cause dieback if they girdle the stems. And physical removal of the gall (preferrably in the spring when eggs are inside) is the only viable option of control listed in the websites I came across.

There are fungal galls such as that caused by Sphaeropsis tumefaciens but I am not seeing oaks listed as a host species.

I would take a cutting to your local extension office to get a positive id on these growths. Many times galls are inconsequential and aesthetically disturbing only; however, with the caveat I read on the Gouty and Horned oak galls being potentially damaging, and this being a small tree, I would rather be safe than sorry.

I do hope you keep us posted if/when you get a positive id.

Sylvia

 

[LivefromFlorida]

Well, I contacted my local extension office (thank you one more time for the great advice!) They said that the galls are most likely Elongate Twig Ants.

This was the best online reference I could find: http://edis.ifas.ufl.edu/pdffiles/IN/IN75200.pdf

The advice of the office was to leave them be. They said that despite the nasty appearance of the ant, "it doesn't really do much harm, and the tree does very well without all of the pruning that would be required to remove them." I will probably try treeseer's advice this weekend and slice one of the galls in half (wearing gloves to avoid any upset insect stings, of course) because now my curiosity is up. I'll let you know what I find.

Thank you again for all of your help!

 

[S Mc]

I will be very interested to see what you find. The literature states that the Elongate Twig Ant is actually considered a beneficial insect, so those are always good to keep around. What I am not seeing in the literature is that they cause gall formation during any of their life cycles or nesting.

Very interesting...:monkey:

Sylvia