These pin oaks are shedding leaves, and large parts of some of them have leaves that look white from the ground. The culprit is scarlet oak sawfly larvae.
I have never seen damage quite like this from this insect. It’s unusual for it to reach such a high population that it defoliates the tree like this, and there ARE natural predators that usually keep it in check. But in this case it could impact the tree’s health, so control would be justified. Control, by whatever method, would need to be done soon. Otherwise the larvae will pupate, and later in the year the adult wasps will emerge and lay eggs and there will be another generation!
I really need help judging the Jacobs Tree Surgery Photo Contest. Somebody’s going to win a nice prize, and I want the winner to be determined in a more democratic way than just relying on the opinionated perspective of me and my Jacobs Tree Surgery associates. Note in the paragraph below the suggested judging criteria, follow the link to see the entries and vote for your favorite. Thanks in advance. Results will be posted Tuesday June 26.
Topic: Most Ridiculous Mulch Volcano
About the Contest: The idea here is to raise the level of public tree awareness. I picked the volcano topic because it’s the biggest, nastiest tree problem out there. Mulch volcanoes are a bigger threat to the trees of suburbia than any insect, even the dreaded emerald ash borer! All are welcome to enter, whether you are an ordinary citizen with just the slightest interest in trees, or a green industry professional. You don’t need to be a skilled photographer either. We’re going to judge these photos on lots of different criteria. Photographic composition might be one of them. “Artiness.” But also anything that makes the photo interesting. Maybe the perps caught in the act. Maybe the root injuries or girdling roots depicted. Maybe something about the location, that it’s somewhere that you’d think they’d know better. Maybe just the sheer outrageousness of the volcanic mass. Some little detail that makes it humorous. Be creative… If you are a serious gardener or plant person, you know about the mulch volcano problem. If you don’t know, Google it. And marvel at the number of hits! And then read the articles I’ve posted on my website.
The deadline to vote is Tuesday June 26, 2012.
This weeping willow in Harleysville has adult imported willow leaf beetles feeding on its leaves. They won’t cause much damage. But the population of beetles is rather high, and they will soon lay eggs. When the larvae of the next generation emerge from the eggs, they will feed on the leaves in a skeletonizing pattern, and there will be enough of them to defoliate the tree. The client is aware, and he will probably spray them.
The way this client found me is a little bit strange. He found my website by googling “bacterial leaf scorch” (I have articles posted about my experiences with BLS). That’s what another “arborist” told him was wrong with his ash tree. And that the disease would kill the tree, so he should remove it. Well, ash trees have a few problems around here of late, but bacterial leaf scorch isn’t one of them. Anyway, the tree didn’t look good and we talked about the true ash ailments – ash anthracnose (which the tree did have) and emerald ash borer (which hasn’t been found close to here yet). In the end, he agreed we should inspect the tree for EAB, just to be sure.
Today, Ricky and Dave climbed the tree, and the one next to it, and checked it thoroughly. Good news – negative for EAB.
The ailing ash
Holes in leaves: from the ground you can’t see them in detail, can’t tell if it’s insect feeding damage; close up it doesn’t look like it. More likely caused by damage to buds from our late frost
We look for any clue – here you can see the wood pile contains ash firewood
While we were getting started, this hackberry emperor butterfly came by and took a liking to the minerals on Dave’s hardhat strap. (Click the image to see a nice big version!)
Dave and Ricky each went up a tree
…and did a good, closeup inspection of the crown.
If you have ash trees and are concerned about emerald ash borer now that it has been discovered in Bucks County, right now is the best time to have them checked. This is the peak time for emergence of the adult insect.