At 22°C, time required for the false celery leaftier (FCLT),Udea profundalis(Packard), to complete the 5 larval stadia is 17.58 days. During this period, a larva usually consumes 14.67 cm2of leaf, about 79% in the last larval stage. FCLT are abundant on sugarbeets in August and September when the leaf area of the plant is too great for the feeding to make an appreciable impact. At the observed population levels in sugarbeets in Washington, the FCLT is not an economically important pest.