Last Days Before the Invasion Begins

Last instar of the spotted lanternfly, Pittsburgh 14 July 2023 (photo by Kate St. John)

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 lanternfly red nymph, Schenley Park, 30 June 2024 (photo by Kate St. John)

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.)

Spotted lanternfly life cycle (image from Wikimedia Commons)

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.

embedded video by @GooglaNYC on YouTube

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.

Spotted lanternfly quarantine counties in Pennsylvania as of 2 July 2024 (map from PA Dept of Agriculture via Penn State Extension)

9 thoughts on “Last Days Before the Invasion Begins

  1. (Washington County) They were all over my cucumber plants, Neem oil seems to be working. Only saw 2 today.Also found on my sunflowers. Not found on any other garden plants, tomatoes, peppers etc.

  2. I’ve been trying to kill any juveniles/nymphs I’ve come across this past month under the delusion that it’ll make a difference. There’s just too many.

  3. I live in Brighton Heights, 2 miles from downtown Pittsburgh Pa and I have been killing the tiny red ones for a week now, so I’m always on the look out for those nasty bugs!! I will try to kill as many as possible?

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