If these symptoms exist, split the stems apart with a sharp knife to look for the larvae. If several larvae have infected a plant, the plant may collapse and die. Once the larvae invade the stem, little can be done except to scrape the larvae out of the stem and cover the stem with dirt to promote possible growth of new roots. If the main root and stem are injured, this tactic may allow the plant to recover and continue to grow. Growers and gardeners, however, can be more proactive by looking for the adult moth flying around their plants from mid-June through July.
Growers can also monitor moth presence by placing pheromone traps near squash or pumpkins.
Since the pheromone may attract a variety of clearwing borer moths, identification and knowledge of clearwing borer moths will be necessary. The home gardener may put out large yellow pails filled with water. The moths are attracted to yellow and are trapped when they fall into the water. A spray is most effective just as the larvae are hatching from their eggs and before they burrow into the stem. Since insecticides such as carbaryl may kill bees, avoid spraying during flowering.