Stem miner (Undetermined) in Asclepias

I found a winding linear mine in the lower portion of a dead stem in winter, the mine having been constructed during the previous growing season while the stem was still alive. There was some indication of a central frass line, suggestive of Marmara sp., but the evidence was insufficient to make a clear identification. The mine appeared to proceed into the crown or belowground parts of the plant.