17 September 2023

The onslaught of invasive spotted lanternflies (Lycorma delicatula) continues in Pittsburgh until the first truly cold weather gives us a couple of frosts. This month the bugs are congregating on vertical objects, feeding on Tree of Heaven (Ailanthus altissima), and laying eggs.

On Friday in Schenley Park the sun broke sideways through the trees to a large Ailanthus along the Lower Trail coated in lanternflies, sooty mold, and white mold (highlighted in yellow). The lanternflies were actively sucking on the tree’s sap.

Sunlight illuminated small bugs flying horizontally near the tree and something falling that looked like rain.

Uh oh! That rain is watery spotted lanternfly poop called “honeydew.” The honeydew is sugary and the air actually smelled sweet.

So stand back when you see a tree coated in sooty mold and spotted lanternflies. You won’t want to get rained on.

Here’s more about sooty mold.

p.s. Don’t worry about honeydew dropping from buildings and utility poles. The lanternflies aren’t eating there so they aren’t pooping either.

(photos and video by Kate St. John)

13 September 2023

They aren’t very smart but they know what they like: warmth and vertical objects.

If you haven’t been to Downtown or Oakland lately you’re missing an insect phenomenon. Our plague of spotted lanternflies (Lycorma delicatula) is quite attracted to tall buildings and utility poles, especially when it’s hot.

Like moths to a flame, spotted lanternflies are visually drawn toward and seemingly captivated by vertical objects such as utility poles …

[They] turn and land on the poles when they are less than about 10 feet away. They remain on the pole for many minutes, even hours, while crawling up toward the top to try to take flight again.

However, a large proportion of those launching themselves from the pole are drawn back to the pole, which serves as a sort of “visual magnet” from which the insects cannot escape for a while. 

— Science Daily: Lanternfly’s attraction to vertical silhouettes could help monitor, trap it, April 2021

On hot days I see thousands above me, puttering toward the buildings, tapping along the structures as they try to find a place to land.

The bugs cling and fall off, leaving drifts of lanternfly carcasses on the ground below.

There’s a theory that the bugs like vertical objects because they are such weak fliers that they have to climb up and relaunch on their search for their host tree, the Tree of Heaven (Ailanthus altissima). According to Penn State Extension, they “land on buildings for warmth, height and other unknown reasons.” Other unknown reasons: Who can know the mind of a lanternfly?

Fortunately we can learn from Philadelphia where their spotted lanternfly plague hit in 2020 (during the pandemic). Here’s what happened at a taco shop on the ground floor of a high rise.

Eeewwww!

Note that Philadelphia had their lanternfly plague in 2020 and now, three years later, they are wondering where all the bugs have gone. I’m sure we can expect 2-3 summers of this nonsense. Certainly by 2026 spotted lanternflies will just be a bad memory in Pittsburgh.

(credits are in the captions)

24 August 2023

Spotted lanternflies (Lycorma delicatula) are everywhere in the East End of Pittsburgh and along our rivers and railroads. One even triggered a snapshot on the motion detection camera at the Pitt peregrine nest. Aaarrg!

Right now, while the invasion is getting worse by the day, it is hard to imagine a time without them but that day will come. The bugs have daily, seasonal and annual cycles and their population trend goes down, based on what happened in eastern PA where they were first detected. Let’s take a look.

Daily dispersal, nightly roost. During the day adult lanternflies disperse to the sky but at dusk they land on buildings and trees to “roost” overnight. Dusk is an unpleasant time of day as they aggregate near us but it’s a good opportunity to catch them with a water bottle (video shows how). [Put a lid on the bottle and the bottle in the freezer. They die in the cold.]

Seasonal disappearance of adults in late fall. Spotted lanternfly adults mate and lay eggs in late summer and fall. Winged adults started to appear in July in Pittsburgh but they did not reach a crescendo until mid-August. They’ll be present in September and October and completely die off at the first frost. I expect their presence to taper before they disappear.

I have not been able to find out if the individuals die shortly after mating and laying eggs but if so the population would taper quickly. I’ll know more in November.

Invasion lasts two to three years based on experience in Eastern PA.

Lanternflies were a plague in Berks County(*) in 2018 and 2019 but by 2021 they were hard to find. That year the Reading Eagle wrote “Where have all the spotted lanternflies gone?“

Similarly the bugs plagued Philadelphia in 2020 but reports went down 95% in 2022 and this month the Philadelphia Inquirer asks Should we still care about spotted lanternflies in 2023? and What should you do if you see spotted lanternflies?

Notice that Philadelphia is saying “IF you see spotted lanternflies,” not “WHEN you see spotted lanternflies!”

Based on these reports I’d say the infestation lasts two to three years and then drops to an unremarkable level. It seems to be a bell curve.

The Pittsburgh area has had spotted lanternflies since 2020. This summer we are in the first plague year (Year label 5). Next summer will be bad, too, but by 2025 or 2026 they’ll be virtually gone.

This, too, shall pass.

p.s. Great News! Two naturally occurring native fungi infect and kill spotted lanternflies in great numbers. Batkoa major and Beauveria bassiana decimated the spotted lanternfly (Lycorma delicatula) populations near Reading, Pennsylvania in 2019. Fingers crossed!

(*) Berks County in 2014 is the location where spotted lanternflies were first identified in the U.S.

(photo by Kate St. John and from the National Aviary snapshot camera at Univ. of Pittsburgh, graph by Kate St. John)

8 August 2023

Aaarrg! They’re everywhere! Pittsburgh is in the midst of a spotted lanternfly (Lycorma delicatula) invasion and it’s just plain creepy. These bugs don’t bite but they’re large, they leap and fly unpredictably, and there are just so many of them. Even when damaged like the one above, they’re disgusting. Make them go away!

So what kills them? I’ve seen a few birds attempting to catch the nymphs but those few birds can hardly make a dent in such an overwhelming insect population.

For now it’s up to humans kill them. Not with poison but by more ingenious means.

How about robots? Carnegie-Mellon’s Robotics Institute developed a robot that scrubs spotted lanternfly (SLF) egg masses off trees in winter so they can’t hatch the following spring. This is fascinating and useful in the long run for orchards but it doesn’t help us today. (1:29 minute video)

Another long term solution is to introduce SLF’s natural predators. Researchers in Delaware are studying two species of parasitic wasps from China that target spotted lanternflies but it will take years to make sure these tiny wasps are totally dedicated to SLF and will not attack North American species. If these wasps pass the test they’ll provide a long term solution for vineyards. (3:00 minute video)

And then there’s just plain killing them. The second half of this 2022 video shows how a woman in Gillette, NJ kills them in bulk. Favorite tool? An electric “tennis” racket! (Entire video here is 8 mins long. Excerpt is 4:00 minutes)

video from VICENews on YouTube

If you live in southwestern PA and haven’t seen a lot of lanternflies yet, just wait. Butler, Lawrence, Fayette and Somerset Counties were added to the SLF quarantine this year. Forewarned is forearmed … with an electric “tennis” racket!

Check out local answers you can use right now in this 1-hour-long Lunch and Learn about Spotted Lanternflies presented by Phipps Conservatory.

(photo by Kate St. John, map from PA Dept of Ag via Penn State Extension, video credits in the captions)