They have mouthparts that look like a straw, and they insert their mouthparts into plant tissue and drink the sap.
Planthoppers have incomplete life cycles meaning they go from egg to nymph to adult. Nymphs usually have a different appearance than adults. In their final stage they are mature adults with wings.
The adult SLFs are large, approximately one inch long, and have grey wings with black spots. When they open their wings, they have a bright red underwing which really makes them standout. The adults are hard to miss.
The nymphs go through five stages and are black with bright white spots. They are approximately the size of a pencil eraser. They are a little harder to spot.
The egg masses are found this time of the year and are distinctive. You will see a gray mass that looks like a patch of mud or putty on the trunk and branches of trees. Under this gray you will find the eggs that are laid in rows and look like a rectangle block of chains laying side by side.
Native to Asia, SLF is thought to have come into Pennsylvania into Berks County in 2014. I had a chance to visit this county in 2019 in the fall, during egg laying time. I was able to see the adults and egg masses firsthand and believe me, this is going to be an annoying pest.
At this point, if you are a wine drinker, you may want to pay even closer attention. SLF is very fond of grapes and can kill grapevines. Owners of vineyards around Ohio are paying attention to this invasive pest.
SLF also likes about 70 different plant species. It may not kill a tree immediately, but heavy feeding damage stresses the plant, which can lead to problem with the overall health of the tree.
In my opinion, the biggest problems we will have in our landscapes is their secretions. Because they suck sap, they secret a sticky substance called honeydew. Sooty mold (a fungi) takes advantage of honeydew and grows on it.
The resulting sticky blackish substance could be found on anything underneath the trees where SLF was feeding. In other words, porches, toys, swing sets, houses, etc. were covered in sticky sooty mold.
Sooty mold in not harmful to people, but it a nuisance which can make outdoor recreation impossible in areas where there are large outbreaks.
SLF prefers grapes but also likes another invasive species, the tree-of-heaven, or Ailanthus altissima. SLF spotters are inspecting sites with these trees to find early infestations and to attempt eradication.
Research is ongoing regarding control of this invasive species. I will be sharing more and more about this pest as it nears the Miami Valley. In the meantime, educate yourself about SLF and be on the lookout for it and report it to your nearest extension office.
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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