Phenology of <i>Euscelidius variegatus</i> (Hemiptera: Cicadellidae) reared under controlled conditions

X-disease is an agricultural pathogen caused by the phytoplasma 'Candidatus Phytoplasma pruni' and is responsible for significant economic losses to cherry production across the Pacific Northwest. Euscelidius variegatus (Hemiptera: Cicadellidae) (Kirschbaum) is a key vector of the X-disease phytoplasma, and the most prevalent vector species in cherry orchards in The Dalles, OR. Little is known about the phenology of this important vector species. To determine the phenology of this species, E. variegatus adults were collected from commercial cherry orchards in The Dalles and Hood River, OR, and placed on potted barley plants in the laboratory. Development time and longevity of the F1 generation was recorded. Development time from egg to adult was 35.3 ± 2.5 d (n = 125). Adult leafhoppers lived an average of 52.6 d (SD = 32.9 d) (n = 34). We fit the survival data to a Gompertz distribution that produced a probability curve that estimated 50, 80, and 95% mortality at 41, 81, and 104 d, respectively. We also measured egg production and placement. Over 3 d females (n = 10) laid from 11 to 47 eggs with an average of 24.5 (SD = 10.6). The distribution of egg height produced a bell curve, with the highest number of eggs (n = 26: 10.6%) laid at 9 cm. Most eggs were found between 5 cm and 17 cm (n = 219: 89.4%). Our findings provide essential data for future degree-day models, enhancing understanding of population dynamics, and informing integrated pest management decisions.