Striped cucumber beetles over-winter in plant debris outdoors, and migrate into greenhouses to feed on cucurbits. Adult feeding on cotyledons and young leaves can delayed plant growth. The striped cucumber beetle vectors (Erwinia tracheiphila), the causal agent of bacterial wilt, and this can be more damaging than direct feeding injury. Cucurbit plants at the cotyledon and first 1-4 leaf stage are more susceptible to infection with bacterial wilt than older plants.
To prevent their entry, maintain a weed and trash free barrier around the greenhouse. Beetle numbers should be kept low, especially before the 5-leaf stage. Scout frequently and treat plants when beetles are observed.