Seasonal phenology and activity of spotted lanternfly (Lycorma delicatula) in eastern US vineyards.
Spotted lanternfly (SLF) is an invasive insect pest in the northeastern USA, and current projections suggest global spread of this insect. SLF is particularly damaging in grape; however, little is known about SLF activity and phenology in vineyards. In 2018-2019, adult SLF populations were monitored in 7-9 Pennsylvania vineyards using weekly visual assessments of vines. Additional studies were carried out in 2019 to identify the daily activity (e.g., feeding, mating, flying) of SLF adults in vineyards. Weekly monitoring data revealed that adults infested vineyards in late summer and populations peaked in early to mid-September. Nymphs were observed on vines in the spring, but nymphal populations did not persist at high levels throughout the season (< 5 SLF/vine). Prior to harvest, SLF was predominantly found on the shoots, but after harvest, greatest proportions of SLF were found on the trunk. Both feeding and dispersal activity increased throughout the day with greatest proportions of these activities observed in the afternoon and evening compared to morning observations. Daily increases of SLF on vines were positively correlated with SLF dispersal, suggesting high input from the surrounding landscape and potential need for area-wide management of this pest. Understanding seasonal patterns of SLF may improve management of this pest through timing control measures with population influxes both diurnally and seasonally.