In scouting my garden for fungal and insect problems, many of the heart shaped leaves on all three eastern redbuds, Cercis canadensis, were folded and browning. When peeling back the folds with my fingers, I noticed the edges of the leaf were sealed with sticky white threads. A trail of black frass was inside the leaves. One leaf had a translucent larva.
Knowing redbuds could be a host to butterflies and/or moths, I consulted a field guide to find out what might be folding and eating the leaves. Redbud is host plant for Henry’s elfin butterfly, the redbud leaf roller moth, and the grape leaf roller moth.
The common name of leaf roller helped put me on the track of the culprit. The black and white dotted moth, Fascista cercerisella, only eight mm in length lays eggs on redbud leaves from April to October here. A tiny black and white striped caterpillar (larva) hatches from each egg. The larva constructs a tent in which to live and eat by folding the leaf in half while simultaneously spinning bundles of silk fastener threads at the base of the leaf to draw sides together. The larva then seals up the tent with small silk bundles around the folded leaf margin as if using a caulking gun filled with silk instead of silicon.
Fascista cercerisella is a suspect in the leaf rolling mystery on redbuds.
Inside the supple swinging green tent, the larva is protected from predators and inclement weather conditions. The larva feeds on the softer leaf tissue leaving veins uneaten. This feeding pattern gives the leaf its skeletonized look.
The grape leaf roller moth, Desmia funeralis, also lays eggs on redbud leaves. Its translucent larva follows the same scenario of making a tent with silk, feeding on soft leaf tissue, and skeletonizing the leaf. I checked my grape vines, and sure enough some leaves were rolled as well, but no larvae were found. The initial translucent larva was a clue to the grape leaf roller, but not all leaves had a larval clue.
Leaf folders do not defoliate the plants and will not cause serious injury. I am not looking for a chemical solution, just a positive identification.
Leaf roller larvae at work on grape leaves too.
How can I find out if I have one or two different leaf rollers at work? One resource for all Richland County residents is the Clemson Extension Office where Don Carter, Don McInnis, or Jackie Jordan use their experience and resources to answer plant, soil, and insect questions. Certain insects and diseases show up in gardens across the Midlands at the same time. There is a good chance other redbud and grape leaves look like mine.
As you scout your garden and find unsolved mysteries, bring the evidence to the horticulture agents at Clemson Extension at Sandhill or give them a call at 865-1216 ext. 127.
White silk stitches of leaf roller larva on redbud leaf.
Folded and browning leaves were clues to insects at work.
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