SLF has an appetite for a wide variety of plants, however, the favorites are grapes, hops, maples, and other trees. It’s most favorite is tree-of-heaven or Ailanthus altissima. More on that later.
While the adult may remind you of a butterfly, it is not. It is a planthopper that has piercing, sucking mouthparts. It has incomplete metamorphosis meaning it goes from egg to nymph, through several nymphal stages and then to the adult.
Both nymphs and adults pierce the phloem of the plant and suck the juices. This feeding doesn’t usually kill a plant. However, significant feeding on grapes and hops can reduce production.
The annoying part of these planthoppers is the honeydew that they excrete. Because they are phloem feeders, they get a lot of sugar through the sap. Their excretion is high in sugar content and thus sticky.
On top of that, a black sooty mold grows on the honeydew, leaving a black sticky mess wherever SLF is feeding.
This is what struck me the most when I was in Pennsylvania observing their feeding and egg-laying stages. The honeydew and sooty mold were everywhere. On sidewalks, cars, the forest floor, and anything else that was near or under a tree where they were feeding.
So, if you have a maple in your landscape, I guarantee when they arrive in force in the Miami Valley, you won’t be happy. They won’t kill the tree, but the mess is incredible.
Now is the time to be on the lookout for the adults and nymphs. Their favorite tree is the tree-of-heaven, mentioned above. Look around your neighborhood to see if these are around.
It’s easy to spot these trees in the landscape. They have foliage like walnut and sumac (pinnately compound), but their seed clusters are very easy to spot and are different from these two.
The seeds are held in large clusters that are obvious on the trees currently. When you see a bunch of trees and see yellowish, reddish masses in the tree, it’s likely tree-of-heaven.
In addition, the leaflets, while like walnut and sumac, have one or two bumps or glandular teeth at the base. The other two don’t have these bumps.
Some say when the foliage is crushed, it smells like peanut butter. I just get a strong odor – not the peanut butter smell!
These are invasive trees and what I call a scrub tree. They grow in disturbed soils and in areas around train tracks and fields. I have seen them along bike trails that were once a train track.
Learn more about these trees and these pests and if you find them, contact your local extension office or the Ohio Department of Agriculture. They haven’t been confirmed in the Miami Valley but it’s likely they will be soon.
Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at bennett.27@osu.edu.
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