At the Illinois Native Plant Society Central Chapter annual meeting in December, I heard Guy Sternberg from Starhill Forest Arboretum in Petersburg IL talk about our periodical cicadas and the potential for damage to small trees when they emerge this May and June. Below is what I sent to my gardening family about this historic gardening (and apparently culinary) event.
This year, two different broods (13 year and 17 year) will be emerging the same year for the first time since 1803 (it’s a prime number thing).
And for the first time EVER, the two broods will be emerging in the same location (roughly, ours here in Springfield, IL). This is because brood 19 (13 year) has been slowly moving north and brood 13 (17 year) has been slowly moving south (cicadas do fly, but not far), and our location is now anticipated to be at the union of both broods in a year when both will emerge together.
This will result in millions of cicadas coming up out of the ground and swarming up trees. They lay their eggs in branches between ¼ and ½ inch in diameter, weakening the branch, which will eventually die and fall off the tree. When the nymphs hatch, they fall to the ground and hibernate underground for 13 or 17 years until the cycle repeats. It’s thought that the prime cycles plus the massive synchronous brood emergence evolved to evade and overwhelm the ability of predators to consume all of them.
For large trees, non-woody plants or evergreens (cicadas don’t like evergreens), this isn’t generally a big deal. The large trees will loose many of their smallest branches in windy conditions and recover. And if you’re in a new subdivision where there are few trees or the soil has been deeply enough disturbed, you may not have them.
However, if you do, for small trees (like the 11 I planted last year in the lot) and for expensive or rare woody shrubs (tree peonies, beautyberry, are two that I plan to try to protect) the bugs can cause enough branches to die that the entire plant dies – or for single-leader small trees, they can kill the leader and ruin the appearance of the tree. They are also really loud.
Protective Netting
The only effective way to protect plants is to cover them during the emergence in May & June (timing dependent on the soil temp – 62-ish degrees at 8” deep) with netting that is fine enough – ¼” or less — that cicadas can’t get through it – and closed snuggly around the trunk so they can’t climb up the trunk and under the netting.
Here’s the link where I got mine, which is some kind of nylon or polyester: https://www.amazon.com/dp/B0CDV3Q6WQ?psc=1&ref=ppx_yo2ov_dt_b_product_details
It’s currently unavailable, but there are some alternatives listed.
Here are some additional links in case you’re interested in learning more:
Video from U of I Extension specifically about 2024
Cicadas talk picks up around 24:20.
On Wikipedia
https://en.wikipedia.org/wiki/Periodical_cicadas
Overview – University of Pennsylvania Extension
Read this overview of periodical cicadas from the University of Pennsylvania Extension…
All broods – from University of Connecticut
https://cicadas.uconn.edu/broods/
Brood 19 (13 year)
- first link doesn’t list Sangamon County, IL, but one of the comments specifically indicates Springfield, IL will be hit by both
https://www.cicadamania.com/cicadas/periodical-cicada-brood-xix-19-will-emerge-in-2024-in-fifteen-states/ - https://cicadas.uconn.edu/brood_19/
Brood 13 (17 year)
Culinary Cicadas
Cicadas are arthropods and bioaccumulators of mercury (toxins?), so if you are allergic to shellfish or live in an urban area, you might want to abstain from eating them.
Otherwise, enjoy:
Download the Cicada-licious Cookbook… (PDF)
I’ll plan to post an update with photos in May/June.