Wednesday, June 20, 2012

Tulip Tree Scale

Last year I noticed big shiny patches under some of our trees.   The shiny patches turned black and I figured it was some sort of blight.    I did a search and came up with nothing.   Over the winter, many of our small tulip trees died.  This year, it is widespread enough in the Midwest that it hit the news.

The blight is  Toumeyella liriodendri, Tulip poplar scale.

You may notice big dark wet looking patches along the roads under some trees.   If you walk on those patches they'll sound sticky.  

They are sticky.   It's honeydew, excreted in little droplets from the bodies of the scale insect. 

The honeydew looks like rain falling from the tree if you look at it from the right angle in the sunshine.  The lower leaves look very shiny.    Any cars parked under those trees will have little sticky dots all over them. 

In Indiana, black sooty mold feeds on the honeydew and it's common to see lower leaves, and the grass and plants under an infected tree turn black with this stuff. 

The scale is not new.   There are dozens of kinds of scale. [Who knew?]   It's all over the place all the time.   It spreads on birds, which is why it's everywhere in the first place.  The question is what allowed it get out of control? 

Turns out our mild winter didn't kill a lot of it and the dry weather has stressed and weakened the trees, which means there's more of it around and the trees aren't fighting it the way they usually do.

What can be done about it?    You can treat the trees with Neem oil or some other dormant oil, but that gets pricey and you'd need to be careful of all the other things that live on and around the tree. 

You can also make sure your trees are well watered and fertilized so that they're in a strong healthy condition.   The scale may get to them, but not kill them.   That's what we're going to do with the trees around the house. 

We will lose more of our trees in the woods.  Even the huge tulips look pretty bad.   There's not a lot we can do except pray for rain.

Firewood will be cheap for the next few years.  


  1. So that's what those sticky drops were on my car every time I parked under a friend's tulip tree...I thought they just leaked sap, which didn't quite make sense (why would a tree bleed spontaneously?) Thanks for the info! I luckily have no tulips, but am hoping that it doesn't affect other things as well...

  2. I live in Indy and dreamed it rained last night. I was very disappointed when I woke up. I'm just worried about flowers and my small vegetable garden. I can't imagine what it must be like for field farmers.


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