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Iowa) -- Insects are becoming active earlier this year due to unseasonably warm temperatures, which could lead to an early spread of oak wilt, a fungus that's potentially deadly to oak trees.
Tivon Feeley, Forest Health Forester with the Iowa Department of Natural Resources says, "We have insects in Iowa commonly called pygmy bugs, that feed on the fungus first, and then they'll go feed on the sap of a wound in the tree. The fungus grows in the vascular system and plugs it up so water can't move up and down, and the tree quickly wilts out and dies.
The DNR usually recommends Iowans stop pruning oak trees around March 15th, but recommends stopping early this year due to the warmer than average temperatures statewide. Feeley says to be on the safe side, Iowans should stop pruning oaks by the end of this week or next week and wait until after the first hard freeze in the fall to resume pruning. He says if you have to prune an oak during the growing season, use latex or acrylic house paint to seal the wound in the tree to make sure insects carrying the fungus that causes oak wilt can't get in.