Temecula GWSS monitoring - Mid October

October 20, 2025

GWSS activity continues to decline, but remains high for this time of year. In the most recent round of trapping a total of 105 GWSS adults were collected among 131 traps in citrus groves and select vineyards throughout the valley

28 traps captured at least one GWSS adult, with up to more than 20 on an individual trap. Again, just 3 traps collected 10 or more GWSS, from the same areas that have had high activity over much of the Summer

Overall, the seasonal pattern of GWSS activity in Temecula has been substantially delayed compared to historic patterns for the region. That includes this slow decline thus far in the Fall. Yet, although high GWSS counts this late in the year are unusual (one of the few exceptions being last year), treatments or other interventions are not necessarily needed due to high overwinter recovery rates for grapevines becoming infected this late in the year. More details about that phenomenon can be found here

Contact Matt (mattd@ucr.edu; 951-255-2807) with any questions

Sharpshooters & Pierce's disease in Southern California

Temecula GWSS monitoring - Mid October

Matt Daugherty