Sunday, February 5, 2023

Spotted Lanternfly Control

The spotted lanternfly (SLF) is an invasive insect first detected in Pennsylvania in 2014 and is currently spreading through the eastern United States. It feeds on many kinds of woody plants including grape vines and other fruit crops, maple, walnut, and birch trees, and more. SLFs use piercing-sucking mouthparts to suck sap from their hosts, which is stressful and damaging to the plants. They also excrete sticky honeydew that promotes the growth of sooty mold fungus on plants (or anything else -- like patio furniture). Click to enlarge.

This is a SLF egg mass on the side of a tree. I recently spent a few hours with local county park staff and USDA educators learning how to spot egg masses and remove them to help reduce the spread of SLF in my area. A typical egg mass contains 30 to 50 eggs and has a protective coating which cracks like this as it ages.

Scanning the branches in the park revealed many SLF egg masses. The only hard part was differentiating them from lichens and the other kinds of tree bark blobs and blotches.

Here are a few uncovered masses from a previous year from which the insects have hatched. Note the exit holes.

We used complimentary SLF egg-removal cards to scrape and crush egg masses. A credit card will do fine for impromptu SLF egg-scraping whenever the urge arises. An alternative method to crushing is to scrape the eggs nto a plastic baggie filled with alcohol.

We removed egg masses from beyond arm's reach with scrapers on poles. There were a lot of them on the structural supports of this wooden gazebo in the park. 

I estimate that our squad of three people removed about 100 egg masses during the two hours we spent scraping. I think there were 5 squads altogether so our whole group dispatched as many as 500 egg masses that day. At 40 eggs per mass, that's 20,000 fewer spotted lanternflies that will be sucking on that park's trees come spring.

Click here for a recent report on the state of the SLF invasion from the Penn State Extension Service.

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