28 August 2024

I was beginning to think we were safe this year but now I’m not so sure. After surprisingly few spotted lanternflies (Lycorma delicatula) in July and August, there are suddenly more of them in the air and on buildings and trees. Uh oh!

Have you seen more spotted lanternflies, too? I think I know why.

• Their peak population was in September last year so we probably haven’t reached the peak yet. But it’s coming.
• Spotted lanternflies love heat and it has been hot this week. Yesterday’s high was 94°F –> 13° above normal.
• Why do I see them fly by my 6th floor windows? They love height as well.

Last year I mused on their love of height and heat. I sure hope their population doesn’t get so bad this year!

16 August 2024

Though the number of adult spotted lanternflies (Lycorma delicatula) is growing this month in Pittsburgh, their population does not match the invasion we saw a year ago. Among the many reasons for this happy news is that local bugs are eating them.

On Wednesday Kalehism Kheshgi found a small praying mantis eating a spotted lanternfly on Carnegie Mellon’s campus.

Several species of praying mantids were imported for pest control: Green ones are from Europe, brown ones are from China. If the brown mantids have deep ancestral knowledge, they will recognize the lanternfly as food from home. 😉

Spiders, yellowjackets, wheel bugs and birds (including northern cardinals!) all eat spotted lanternflies. For photos of the devouring, see this 2022 article.

7 August 2024

Spotted lanternflies (SLF, Lycorma delicatula) were a plague in Pittsburgh last year. This month their adult population is ramping up again. What’s their status now and how do their numbers compare to last summer?

I didn’t pay attention to the first adult spotted lanternfly in 2023 but this year I was ready. My first 2024 sighting was on 18 July. Interestingly I haven’t seen a whole lot of red nymphs and adults compared to last year so I went to a place that was swamped with them in 2023.

On Saturday I visited the Three Rivers Heritage Trail at Herrs Island back channel, a place that was overrun by red nymphs in late July 2023 and had so many winged adults in August and September last year that it was impossible for cyclists and pedestrians to avoid them. The bugs flew into us. It was creepy.

This year on 3 August I found adult lanternflies at the same place but not in an overwhelming number. I counted 16 red nymphs and 68 adults at the most densely populated location. The fact that they were countable is a sign there weren’t that many … yet.

This one tried to avoid being counted. Hah!

What I couldn’t count were the bugs above my head sucking sap from invasive vines and ailanthus trees. Their “honeydew” coated the leaves below and “rained” on me at one point. Yuk.

Last year the worst of the invasion ran from late August to mid September so we still have more to come. Will it be as bad as last year? CBS Pittsburgh provides some expert opinions.

As usual we’ll just have to wait and see.

18 July 2024

They’re back. Well, actually, they never left but they haven’t looked like this since last fall. Up until now spotted lanternflies (Lycorma delicatula) in western Pennsylvania have been present as egg masses or nymphs.

Yesterday a winged adult lanternfly landed on John English’s window feeder in Homestead. This is the first report I’ve received that adults have emerged.

Their population will follow a well known arc. A smattering in mid July, lots more in August, an invasion in September.

Have you seen an adult spotted lanternfly yet? Leave a comment and let me know when you saw the first one.

p.s. I just got back from a week in Virginia where I learned that spotted lanternflies are indeed in Virginia wine country. They are really bad for grapes. Yikes! Here’s the 2024 map from New York State Integrated Pest Management and Cornell University.

2 July 2024

In late June friends of mine wondered why they hadn’t seen any spotted lanternflies this year. Are the invasive bugs gone? Not at all! The nymphs are present but they can’t fly yet. Last weekend I saw the first warning that we’re in the last days — a week, maybe two — before the spotted lanternfly invasion begins. I saw a red nymph.

Spotted lanternflies overwinter as egg masses that began hatching in Pittsburgh this year in early June. The first nymphs appeared around 3 June but were hard to notice because they’re so tiny and dark. From first instar to winged adult takes about 6-8 weeks. (This statistic is my best guess. It’s hard to find the data online though I’m sure scientists have timed it.)

The first three instars are black while the fourth and final one is red, an early warning of things to come. Here’s a red nymph morphing into a winged adult.

Expect to see the first flying adult by mid-July. Let me know when you see your first one.

The invasion will ramp up slowly, explode in September, and then we’ll have to wait for winter to kill them.

p.s. It’s been 10 years since spotted lanternflies were first recorded in PA. Now the bugs are in every county in southern PA and all of the eastern border counties. Greene County, the last holdout in southwestern PA, crossed the threshold this year. Read more about their 10-year siege in this article from WESA.

6 June 2024

When we think of spotted lanternflies we remember the flying adults that plague us from July through early autumn. But these annoying insects don’t start out in flying form.

In May-June their eggs hatch into tiny black nymphs, 1/4″ long, with white spots. If the nymph manages to pass through four instars it becomes a winged adult.

On Monday 3 June, Bob Donnan saw a couple of the black-spotted early nymphs in Washington County, PA. Oh no! They’re already here. The tiny nymphs are hatching.

Smashing them doesn’t work. As Bob remarked, “They jump fast!”

Check out last year’s article on alternatives for trapping spotted lanternflies.

If fewer nymphs make it to the next stage we’ll have fewer annoying winged adults.

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)