Trees are raining! - Ask Extension
My white oaks - after pelting us with acorns last year - are raining caterpillars and now showering leafs bits like snow flakes. My love of trees is ...
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Trees are raining! #870817
Asked May 30, 2024, 4:35 PM EDT
My white oaks - after pelting us with acorns last year - are raining caterpillars and now showering leafs bits like snow flakes. My love of trees is waning …
What is up with them?
Calhoun County Michigan
Expert Response
Hi Laurie,
I suspect the caterpillars are spongy moth caterpillars (formerly known as gypsy moth). Their populations grow to noticeable levels every 20 years or so, and many areas of the state are experiencing what you describe. This will only last a week or two longer, then the caterpillars will morph into moths and begin laying eggs. Best defense is to kill any white, egg laying moths when you see them, to limit next year's populations. I've attached an information sheet that describes the life cycle of the moth, as well as some tips to deal with them.
As for the acorns, every so often oaks have a "mast" year, where acorn production is over the top. Mast is another word for the acorns, or wildlife food. The theory is that when oaks overproduce acorns, the acorns have a better chance of germinating and surviving as wildlife that eat the acorns are overwhelmed by the food source and could not possible consume it all. So, this is typical of a white oak from time to time.
Thank you,
-Julie
I suspect the caterpillars are spongy moth caterpillars (formerly known as gypsy moth). Their populations grow to noticeable levels every 20 years or so, and many areas of the state are experiencing what you describe. This will only last a week or two longer, then the caterpillars will morph into moths and begin laying eggs. Best defense is to kill any white, egg laying moths when you see them, to limit next year's populations. I've attached an information sheet that describes the life cycle of the moth, as well as some tips to deal with them.
As for the acorns, every so often oaks have a "mast" year, where acorn production is over the top. Mast is another word for the acorns, or wildlife food. The theory is that when oaks overproduce acorns, the acorns have a better chance of germinating and surviving as wildlife that eat the acorns are overwhelmed by the food source and could not possible consume it all. So, this is typical of a white oak from time to time.
Thank you,
-Julie
