Whether you have a backyard pond or you are out on the water in a kayak or canoe, you may have the opportunity to see some beautiful water lilies. When I was out kayaking recently I noticed that some of the smaller pond lily leaves had a lot of serpentine lines in them that looked typical of leaf mining insect damage. I snapped a couple of photos and made a mental note to look up the possible culprits later on.
I wish I’d grabbed a couple of leaves to see if anybody was still there and actively feeding for identification but that will have to wait for the next outing. Anyway, it turns out that there are a couple of midges that could be responsible. They are in the family Chironomidae and possibly in one of two genera: Chironomus (leaf-mining midges) or Cricotopus (false leaf-mining midges). The adults are mosquito-like and can be seen hovering around the water and lily leaves at dusk. They do not bite. Eggs are laid on the leaves and have a sticky coating that aids in adhesion. The tiny larvae hatch and begin to feed. Leaf-mining midge larvae tunnel between the leaf surfaces and the false leaf-miners chew trails on the surface. False leaf-miners are protected at the head end by shallow burrowing. Both types of feeding result in serpentine lines or trails that eventually rot and fall from the leaf. A heavy infestation will result in tattered looking leaves.