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Sharpshooters & Pierce's disease in Southern California

Department of Entomology

glassy winged sharp-shooter
Sharpshooters & Pierce's disease

The purpose of this site is to provide information on the biology and management of sharpshooters and Pierce's disease, with a focus on Southern California vineyards and surrounding areas.

The blog will be used to post regular updates on the results of the Temecula glassy-winged sharpshooter areawide monitoring program and to occasionally share other information relevant to sharpshooters, Xylella fastidiosa, or Pierce's disease.

For more information, contact Matt Daugherty (matt.daugherty@ucr.edu; 951-827-2246)

Updated Temecula GWSS monitoring - early October

Based on the most recent trapping, GWSS activity in Temecula increased slightly. This is consistent with a Fall peak we get in many years, but also might be in part attributable to unusually warm temperatures the last week or two and a sampling issue due to the loss of some traps this time around A...

Updated Temecula GWSS monitoring - late September

Two rounds of sampling were conducted since the last update. GWSS activity has declined sharply as is typically the case this time of year. However counts remain higher than usual in most years In the most recent sampling, collected last week, a total of approximately 140 GWSS adults were caught on the 112 traps deployed...

Scouting for Pierce's disease

Although things are busy this time of the year with harvest, it is also a good time to keep an eye out for Pierce's disease. Symptoms are strongest this time of year. Try to scout the vineyard as time allows and flag suspected diseased vines for later removal. The following document has some additional details...

Updated Temecula GWSS monitoring - late August

GWSS activity remains high, but has come down substantially since the last update. Such declines this time of year are typical, and we'd normally expect to see them decline substantially further in the coming weeks. However, this unusually late heat wave may delay those declines a bit A quick note about sharpshooter trapping. The yellow-sticky...

Updated Temecula GWSS monitoring - mid August

GWSS activity remains high since the last update, but may have plateaued. Typically, we start to see declines in activity at this time of year A total of nearly 700 GWSS adults were caught on 65 of the 112 traps deployed. This included two dozen traps that collected 10 or more sharpshooters. High GWSS activity...

Temecula GWSS activity continues to increase

GWSS activity increased sharply again since the last update. Although increased counts at this time of year are not unusual, and are likely attributable in part to the ongoing warm weather, counts this high are unusual. For context, the last time this many GWSS were captured in Temecula was the Summer of 2017 A total...

Updated Temecula GWSS monitoring - mid July

There has been a sharp increase in GWSS activity since the last update. The last time counts were this high was in July 2022. Although such an increase at this time of year is not unsual, and is likely due in part to the current heat wave, it is worth keeping an eye on as...

Updated Temecula GWSS monitoring - late June

Since the last update, there have been two rounds of glassy-winged sharpshooter trapping. Counts are back right where they were this time last year, which were low or at least delayed compared to historic averages A total of 7 GWSS adults were caught on just 4 of the 112 traps deployed. With the recent warm...

Updated Temecula GWSS monitoring - late May

After a fairly unusual spring, with higher than typical GWSS activity, captures have declined to near historic averages for Temecula in the late Spring A total of 11 GWSS adults were caught on 6 of the 115 traps deployed. Just one trap captured more than a single sharpshooter, a trap in the same northeast part...

New restrictions on neonicotinoid use for glassy-winged sharpshooter?

At the beginning of the year the California Department of Pesticide Regulation ( https://www.cdpr.ca.gov/) placed restrictions on the use of neonicotinoid insecticides, the goal of which are to reduce pollinator exposure. This policy change has the potential to impact the use of certain insecticides (e.g., imidacloprid, dinotefuran, thiamethoxam, clothianidin) that are commonly used for the...

Updated Temecula GWSS monitoring - early May

GWSS activity ticked up a bit since the last census and remains a little high compared to historic averages for this time of year. As a reminder for those vineyards planning to do a soil application of a systemic insecticide, that application should occur soon if it has not already happened A total of 24...

Updated Temecula GWSS monitoring - late April

Fortunately, since the last update, GWSS activity has declined to levels that are more typical for this time of year A total of 18 GWSS adults were caught on 12 of the 115 traps deployed. Just three of the traps caught more than a sigle GWSS

Temecula GWSS monitoring - early April

Since the last update, GWSS activity has continued to climb. Trap counts are high for this time of year, which is something to keep an eye on in the coming weeks as it can be a predictor of a busy GWSS summer season A total of 40 GWSS adults were caught on 13 of the...

Updated Temecula GWSS monitoring

Since the last update, two rounds of trapping for GWSS have occurred. Over this period, GWSS activity has increased to levels approximately matching historic trap catch in the area In the February census a total of 26 GWSS adults were captured on 10 traps. In early March, the number captured increased to 31 GWSS adults...

Updated Temecula GWSS monitoring - early 2024

Since the last update, around Halloween, GWSS activity in the Temecula area has declined back down or slightly below where it typically is late in the year. Early 2024 counts also remain low Fortunately, as of early 2024, there's not much to see with respect to GWSS activity. Of the 106 traps that were recovered...

Temecula GWSS monitoring - Halloween edition

GWSS activity is up a bit since last time. 23 GWSS were captured on a total of 115 traps. Keep in mind that traps were out approximately twice as long, nearly a month, as earlier in the season. Some of this uptick is likely attributable to that longer deployment rather than a marked increase in...

Updated cooperative vineyard pest monitoring

GWSS captures are up slightly from a couple of weeks ago. However, this apparent increase in activity is solely attributable to one of the seven sites that reported counts All six GWSS captured were at this single site, on three of the 4 traps. As you can see in the lefthand map below, all other...

Updated Temecula GWSS monitoring

GWSS activity remained low despite the recent warm weather. Just 14 total GWSS were captured on a total of 115 traps. The secondary peak in activity that occurs in some years is clearly not happening this year Few GWSS captures were the norm throughout the area. Of the 11 traps capturing any sharpshooters, only 3...

Updated cooperative vineyard pest monitoring

GWSS captures are up slightly but still remain fairly low as is typical this time of year for most years. Records were reported for a total of 21 traps spread among 7 vineyards in Riverside and San Diego counties. Collectively, 5 GWSS were collected, which is consistent with the most recent Temecula GWSS areawide monitoring...

Updated Temecula GWSS monitoring

GWSS activity seems to be shutting down, which isn't too surprising given the (pleasantly) cool weather recently. Just 17 total GWSS were captured on a total of 115 traps. More of what's been a strange year, albeit a good one from the perspective of GWSS and PD - a very delayed start and somewhat early...
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