ESTIMATION OF THE LOWER AND UPPER DEVELOPMENTAL THRESHOLD TEMPERATURES AND DURATION OF THE NYMPHAL STAGES OF THE MEADOW SPITTLEBUG, PHILAENUS-SPUMARIUS (HOMOPTERA, CERCOPIDAE)

The upper and lower thresholds for nymphal development of the meadow spittlebug, Philaenus spumarius (L.), were estimated using a coefficient of variation (C.V.) technique. The combination (upper and lower threshold) with the lowest C.V. were accepted as the theoretical developmental thresholds. These values were 2.8°C for the lower threshold and 26.7°C for the upper. Heat unit (HU) calculations based on these thresholds were used to estimate the duration of various nymphal stages. Once hatching began, an accumulation of 670 HU (°C) resulted in 50% adult emergence. The lengths of the nymphal stages were 225, 190, 190, 190, and 290 HU for the 1st through 5th nymphal stages, respectively. The nymphal density in the field during the period following final hatch to 1st adult emergence was found to adequately fit the Poisson distribution. © 1979 Entomological Society of America.