Spectrum Technologies is monitoring the soil temperature in Plainfield and Naperville Illinois.
In northern Illinois and surrounding areas, three species of Magicicada emerge from the soil every 17 years for a brief above-ground visit. Brood XIII will emerge when soil temperature reaches approximately 65Â° F. Spectrum data loggers are busy tracking soil temperature near Spectrum headquarters in northern Illinois to estimate when to expect their arrival.
Spectrum wrote back and say they are measuring the temperature at 20cm depth. So I guess we’ll get to see if the 64F number works well in Brood XIII territory. Heath’s 1968 study was done on Brood V in Ohio. I’m guessing they will not come up exactly when the soil hits 64F at that depth, but when it averages 64F at that depth for a little while.
You bring up a very interesting question with regards to how long cicada nymphs can survive on roots
from a tree that has been cut down. In 2005 one of my favorite ash trees which yielded many T. lyricen
annual cicadas that year died at the end of the summer. By the time the summer of 2006 started the tree
was completely dead whether from disease or old age, I’m not sure. Anyway despite the fact that the tree
was dead, still many T. lyricens and T. canicularis cicadas still emerged. So despite the fact that
the tree was dead, maybe the roots still live on for a period of time. It will remain to be seen
if any emerge this year.
With regards to obstacles on the surface of the soil “blocking emergences” I think that cicada nymphs
are good diggers, so I don’t think they will have a problem finding a way above ground. (You can however
help their situation by temporarily remove the stones to make life easier for them)
I wonder how far down they are measuring that temperature. The original research that yielded the 64F (not 65) temperature reported it from 20cm soil depth using a steel probe. It is not a surface temperature — the surface will reach 64F before the soil at 20cm depth does. I wrote them to ask how they are doing the measurements.
I meant to give my location in my previous message. I live in Westmont,Il
Thanks for the info Roy! Would you know how far the nymphs will burrow sideways to get around an obstical? We have some stepping stones in our yard under a tree and i lifted one up and found at least 8 exit holes in the aprox 2sq foot area. Will they get out from under them? Also would you know how long the nymphs can survive on the roots of a tree that has been cut down? We had to cut down some diseased trees last summer. I took a rake and raked around the stumps of the trees and again saw numerous exit holes and nymphs last night 3-26-06 so they obviousley survived but was curious if that info was available. These guys have really stimulated a passion in me this year. I am anxiousley awaiting their incredable arrival. Thanks again, Steve
How long does the soil temperature have to stay at 65 for cicadas to emerge? It looks like it got close last weekend, and this weekend could be hot too…
It looks right now as if the emergence will start around May 24th if you live in north-central Illinois but there are other factors such as soaking rains that can affect the exact date of emergence. IMHO humidity affects the emergences too. In my past observations I have noticed that nymphs really like the warm & humid nights. Of course experts like Dr. John Cooley have observed magicicada stragglers emerging as late as early July.
Enjoy the emergence,
Has there been a determination as to when we can expect the grand emergence? Thank you.