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Keep an eye out for these winter shapes
Published: 1/6/2022
It's winter in Novi, and the leaves are off the trees. If you happen to do some healthy outdoor walking this winter, you may see some peculiar shapes in nature that you hadn’t noticed before, and wonder what they are.

Here are a few to hopefully answer your questions:
  • Willow Pine Cone Gall: This looks like a normal part of a willow, like a seed ball or something, but it actually a deformed branch, caused by the Willow Pine Cone Gall midge, who injects an egg and possibly chemicals into the tip of the stem. Then the plant forms deformed leaves around the egg to protect it as it develops into a little insect called the Willow Pine Cone Midge. See the photos of the fully formed gall, what it looks like inside, and what the adult midge looks like.
  • Goldenrod Gall: Instead of being at the end of the plant, this insect lays its egg and injects hormones into the stem of a goldenrod which gradually forms a growth (gall) around the egg and gets as large as a golf ball. Sometimes birds or other insects will dig into the gall to eat the larvae, but the lucky larvae will develop into the fly in the photo.
  • Oak Gall: Oaks actually have a number of galls, some on the leaves and some on the stem. As the leaves have mostly fallen you’re likely to be seeing a stem gall. They are an adaptation that, while not necessarily symbiotic (mutually beneficial to both plant and insect), do not cause long-term damage to the plants, as galls or as adult insects. So, get out, enjoy the bug-free fresh air and take a walk in the woods or field. You may find one or all of the above, and know what the heck they are.