Coloring of both loopers varies with population density. Female moth laying eggs. Photo by John H. Ghent Spring cankerworm trap stick band. Photo by Bill Carothers Fall cankerworm larva. Photo by E. Bradford Walker Identifying the Injury.
Older larvae consume the entire leaf, except the midribs and major veins.
They overwinter in the egg stage. The spring cankerworm adults emerge in February and March to lay their eggs. For both species, the eggs hatch at about the time of bud break, and the young larvae begin feeding on the new foliage. Feeding continues for approximately 6 weeks, after which the mature larvae enter the soil and pupate. Other natural enemies also help in control.