Leafhopper Newsletter Archive - 2015/2016

The "Leafhopper Newsletter" is now the "Leafhopper Blog"

This year we're transitioning the Leafhopper Newsletter to a blog format in order to improve readability and create a better way for readers to send comments and feedback.

As part of this transition, we have transferred all newsletter subscriptions to the new blog. By now you should have received an email from "blogs-no-reply" with the subject "New Subscription to ANR Blogs" indicating that you've been subscribed to the "Leafhopper Blog". Please make sure to validate your email in order to confirm your subscription to the blog (otherwise you will not receive updates).

Like the Leafhopper Newsletter, these Leafhopper Blog posts will summarize data from the regional leafhopper monitoring effort in Mendocino and Lake County.

The full blog can be found here: http://ucanr.edu/blogs/leafhopperblog/index.cfm

This will be the final email sent through the "Leafhopper Newsletter" list-serve.

Happy New Year from the VCLH Area-wide IPM Team! Hope this finds you all well (and dry/safe, given the recent storms).

Annual Report for Crop Year 2016

Our Annual Report for Crop Year 2016 is now available on the project website. As in previous years, this report provides a review of our efforts in 2016, including a summary of the regional monitoring data, parasitoid release program, and grower outreach events.

You can access the report here: Annual Report for Crop Year 2016

Project Review and Planning Meeting on Jan. 24

There will be a team meeting in Ukiah to review the VCLH area-wide program to date and discuss plans for the 2017 growing season.

The meeting will take place on Tuesday, January 24 from 9-11am at the UCCE-Mendocino office in Ukiah (890 N. Bush St., Ukiah, CA 95482).

All are welcome to attend and we are actively seeking new collaborators for the regional monitoring effort and parasitoid release program. Please click here to RSVP.

MENDOCINO AND LAKE COUNTY

Densities of both VCLH and WGLH eggs and/or nymphs have declined at most sites while adult populations remain relatively elevated at some sites, and may even increase as remaining nymphs molt into adults. The leafhopper adults present at this time are most likely in reproductive diapause and will overwinter in the vineyard.

SUMMARY OF 2016 MONITORING AND PARASITOID RELEASE PROGRAM

This year overall leafhopper populations were relatively higher in Mendocino County than in Lake County. Early season insecticide applications for VCLH did appear to reduce densities, but later in the season VCLH populations increased again at most of these sites, this time with overlapping life stages (adults, eggs, and nymphs all present at the same time). A total of 15,342 Anagrus daanei (the parasitoid that attacks VCLH eggs) were released across 9 sites between April 23 and September 2. While these releases led to increased parasitism at 4 of the 9 sites, in most cases VCLH densities were still very high at the end of the season. See newsletter for further details and summary.

MENDOCINO COUNTY

Densities of both VCLH and WGLH eggs and nymphs have declined at most sites while adult populations remain relatively elevated, and may even increase as remaining nymphs molt into adults. The leafhopper adults present at this time are most likely in reproductive diapause and will overwinter in the vineyard.

LAKE COUNTY

VCLH adult densities are generally low and more variable across all sites (less than 3 adults per trap). No VCLH nymphs have been observed since mid-July, with the recent exception of Scotts Valley and Finley, but densities are still very low (less than 0.5 nymphs per leaf). WGLH adult and nymph populations have peaked at most sites with the exception of Finley, where no WGLH nymphs have been observed since June.

PARASITOID RELEASE PROGRAM

No further parasitoid releases are scheduled for 2016 in order to build up populations in our greenhouse colonies in preparation for the fall-winter period.

MENDOCINO COUNTY

Densities of VCLH adults remain elevated at most sites while WGLH adult populations have peaked and are now relatively low, with the exception of Potter Valley, where WGLH adult densities may be rising again. Nymph densities of both VCLH and WGLH appear to have peaked (or are currently peaking) as well.

LAKE COUNTY

VCLH densities are generally low and more variable across all sites (less than 3 adults per trap). No VCLH nymphs have been observed since mid-July, with the recent exception of Scotts Valley and Finley, but densities are still very low (less than 0.5 nymphs per leaf). WGLH adult populations have peaked at all sites and we are now seeing nymph densities peaking (or just passed peak) at most sites with the exception of Finley (no WGLH nymphs observed since June).

PARASITOID RELEASE PROGRAM

No parasitoids were released last week and no further releases are scheduled for 2016 in order to build up populations in our greenhouse colonies in preparation for the fall-winter period.

MENDOCINO COUNTY

At most sites, densities of VCLH adults remain elevated while WGLH adult populations have peaked and are now in decline, with the exception of Potter and Redwood Valley, where WGLH adult densities may be rising again. Nymph densities of both VCLH and WGLH appear to have passed peak, although at some sites densities continue to increase.

LAKE COUNTY

VCLH densities are generally low and more variable across all sites (less than 3 adults per trap). No VCLH nymphs have been observed since mid-July, with the recent exception of Scotts Valley, but densities are still very low (less than 0.5 nymphs per leaf). WGLH adult populations have peaked at all sites and we are now seeing nymph densities peaking (or just passed peak) at most sites with the exception of "Finley" (no WGLH nymphs observed since June).

PARASITOID RELEASE PROGRAM

No parasitoids were released last week in order to build up populations in our greenhouse colonies in preparation for the fall-winter period. The next release is scheduled for September 23 in Mendocino County, but this si contingent on parasitoid densities in the colony.

MENDOCINO COUNTY

Densities of VCLH adults remain elevated at most sites while peak WGLH adult populations are starting to decline. Nymph densities of both VCLH and WGLH continue to increase or remain high, with the exception of Potter and Redwood Valley, where WGLH populations have been declining. For the WGLH, the current nymph population represents the second brood whereas for VCLH the nymphs are likely third brood.

LAKE COUNTY

VCLH densities are generally low and more variable across all sites (less than 3 adults per trap). No VCLH nymphs have been observed since mid-July, with the recent exception of Scotts Valley, but densities are still very low (less than 0.5 nymphs per leaf). These VCLH nymphs represent the third brood.

WGLH adult populations have peaked at all sites and we are now seeing nymph densities peaking (or just passed peak) at most sites with the exception of "Finley" (no WGLH nymphs observed since June). These nymphs represent the second WGLH brood.

PARASITOID RELEASE PROGRAM

A batche of Anagrus daanei, the parasitoid that controls VCLH, was released on September 2 at a vineyard in Mendocino County in the Hopland area. The next release is scheduled for September 16 in Mendocino County.

MENDOCINO COUNTY

Densities of both VCLH and WGLH adults and eggs remain elevated at most sites while nymph populations of both species continue to increase. For the WGLH, this nymph population increase represents the second brood whereas for VCLH the nymphs are likely a mix of second and third brood (later instars are from the second brood and earlier instars are from the third brood)

LAKE COUNTY

VCLH densities are generally low and more variable across all sites (less than 3 adults per trap). While no VCLH nymphs have been observed since mid-July, if they do appear they will represent the third brood.

WGLH adult populations have peaked (or are currently peaking) at all sites and we have been seeing increased nymph densities at most sites with the exception of "Scotts Valley" (sharp decline this week) and "Finley" (no WGLH nymphs observed since June). These nymphs represent the second WGLH brood.

PARASITOID RELEASE PROGRAM

Two batches of Anagrus daanei, the parasitoid that controls VCLH, were released on August 26 at a vineyard in Mendocino County in the Talmage area. The next release is scheduled for September 2 in Mendocino County.

MENDOCINO COUNTY

Densities of both VCLH and WGLH adults and viable eggs are approaching (or just passed) peak density at most sites, while nymph densities of both species continue to increase. For the WGLH, this nymph population increase represents the second brood, whereas for VCLH the nymphs are likely a mix of the second and third brood (later instars are from the second brood and earlier instars from the third brood).

LAKE COUNTY

WGLH adult populations have peaked (or are currently peaking) at all sites and we continue to see an increase in nymph densities at most sites. These nymphs represent the second WGLH brood.

VCLH adult and nymph densities are generally low and more variable across all sites. Where present, VCLH adult densities are relatively low (less than 3 adults per trap). While no VCLH nymphs have been observed recently in the Lake Co. vineyard being monitored, if they do appear they will represent the third brood.

PARASITOID RELEASE PROGRAM

Two batches of Anagrus daanei, the parasitoid that controls VCLH, were released on August 19 at a vineyard in Mendocino County in the Hopland area.

MENDOCINO COUNTY

Densities of VCLH and WGLH adults, viable eggs, and nymphs are all increasing at almost every site in Mendocino County. For the WGLH, this population increase represents the second brood, whereas for VCLH the nymphs are likely a mix of the second and third brood (later instars are from the second brood and earlier instars from the third brood).

LAKE COUNTY

WGLH adult populations have peaked (or are peaking) at all sites and we are now starting to see an increase in nymph densities at most sites. These nymphs represent the second WGLH brood.

VCLH adult and nymph densities are generally low and more variable across all sites. Where present, VCLH adult densities are relatively low (less than 3 adults per trap). While no VCLH nymphs have been observed recently in the Lake Co. vineyard being monitored, if they do appear they will represent the third brood.

PARASITOID RELEASE PROGRAM

Two batches of Anagrus daanei, the parasitoid that controls VCLH, were released on August 12 at a vineyard in Mendocino County in the Talmage area.

MENDOCINO COUNTY

Densities of VCLH and WGLH eggs and adults are increasing at all sites, with the exception of "Hopland2" where densities of both species slightly declined. VCLH and WGLH nymph densities have increased at all sites as well. Most nymphs are 1st instar (stage) which means they are likely from the third brood, but we are also starting to see 2nd - 4th instars.

LAKE COUNTY

Densities of WGLH adults continue to rise (or remain high) while VCLH densities are generally low and more variable. We are seeing VCLH and WGLH nymphs of second brood, most of which are 3rd - 4th instar (stage).

PARASITOID RELEASE PROGRAM

Another batch of Anagrus daanei, the parasitoid that controls VCLH, was released on August 5 at a vineyard in Mendocino County in the McDowell Valley area.

MENDOCINO COUNTY

Densities of VCLH and WGLH adults are increasing at all sites, with the exception of "Hopland2" where WGLH densities slightly declined. VCLH and WGLH nymph densities have increased at all sites, most are 1st instar (stage) which means they are likely from the third brood. 

LAKE COUNTY

Densities of WGLH adults appear to be peaking (or approaching peak) while VCLH densities are generally low and more variable. We are seeing VCLH and WGLH nymphs of second brood, most of which are 3rd - 4th instar (stage).

PARASITOID RELEASE PROGRAM

Two batches of Anagrus daanei, the parasitoid that controls VCLH, were released on July 29 at two sites in Mendocino County near Hopland.

MENDOCINO COUNTY

VCLH adult populations are low or in decline and the peak of the second flight is most likely over. Densities of WGLH adults continue to increase, especially in Redwood and Potter Valley and at the "Hopland2" site. Third brood VCLH/WGLH nymphs are present, most of which are 1st - 3rd instar (stage). Some 4th - 5th instar nymphs were seen at the Potter Valley and "Talmage2" site and are likely from the second brood.

LAKE COUNTY

Adult populations continue to level off and we are seeing second brood nymphs which are mostly 3rd instar (stage).

PARASITOID RELEASE PROGRAM

A batch of Anagrus daanei, the parasitoid that controls VCLH, was released on July 21 in Lake County near Kelseyville.

MENDOCINO COUNTY

Adult populations are beginning to decline and the peak of the second flight is most likely over. Densities of WGLH adults continue to increase in Redwood and Potter Valley and at the "Hopland2" site. Second brood VCLH/WGLH nymphs are present, most of which are 4th - 5th instar (stage). Some 1st - 2nd instar nymphs were seen at the "Hopland2" site, which are likely from the third brood.

LAKE COUNTY

Adult populations are also beginning to level off and we are seeing second brood nymphs which are mostly 2nd instar (stage).

PARASITOID RELEASE PROGRAM

A batch of Anagrus daanei, the parasitoid that controls VCLH, was released on July 15 in Mendocino County near Hopland.

MENDOCINO COUNTY

Adult populations continue to increase, although 2nd - 3rd instar (stage) nymphs of the second brood are present as well, so we are beginning to see overlapping leafhopper generations.

LAKE COUNTY

Adult populations continue to increase and a majority of the remaining nymphs are 5th instar (stage). As in Mendocino County, we are also seeing 1st-3rd instar nymphs of the second brood, which indicates overlapping leafhopper generations.

PARASITOID RELEASE PROGRAM

A batch of Anagrus daanei, the parasitoid that controls VCLH, was released on July 8 in Mendocino County near Talmage.

TAIL GATE MEETING ON JULY 7
UCCE Area Wide Virginia Creeper Leafhopper Project Research Update
Date: July 7, 2016
Time: 8-10:00 AM
Place: South Gate of the Sundial Chardonnay Vineyard (across from the Fetzer winery in Hopland), located on Old River Road north of Old Hopland.
Details: 2CEU’s APPLIED FOR

MENDOCINO COUNTY

Remaining nymphs are 5th instar (stage) and adult emergence is well underway. We project that this week (July 3-9) most of the remaining nymphs will molt into adults and we will continue to see increased adult emergence and egg deposition.

LAKE COUNTY

Leafhopper populations are developing more slowly in Lake County relative to Mendocino County, where a majority of the nymphs are 4th-5th instar (stage), although we continue to see many more newly molted adults, indicating that adult emergence has begun.

This week (July 3-9) we expect to see some 5th instar nymphs along with many more adults, whose population will continue to increase in the following week (July 10-16).

With the start of adult emergence in Lake County, the ideal period for leafhopper control measures has ended for most vineyards in this region.

PARASITOID RELEASE PROGRAM

A batch of Anagrus daanei, the parasitoid that controls VCLH, was released on June 30 in Mendocino County near Hopland.

TAIL GATE MEETING ON JULY 7
UCCE Area Wide Virginia Creeper Leafhopper Project Research Update
Date: July 7, 2016
Time: 8-10:00 AM
Place: South Gate of the Sundial Chardonnay Vineyard (across from the Fetzer winery in Hopland), located on Old River Road north of Old Hopland.
Details: 2CEU’s APPLIED FOR

MENDOCINO COUNTY

Most of the remaining nymphs are 5th instar (stage) and adult emergence is well underway. The newly emerged adults are beginning to oviposit higher up in the vine canopy.

We project that this week (June 26 - July 2) we will continue to see increased adult emergence and most of the remaining nymphs will have molted into adults. Adult populations should continue to grow in the following week (July 3-9) in Redwood and Potter Valley.

LAKE COUNTY

Leafhopper populations are developing more slowly in Lake County relative to Mendocino County. We are currently seeing 1st – 5th instar (stage) VCLH and WGLH nymphs, although a majority of the nymphs are 4th - 5th instar and we have been seeing many more newly molted adults, indicating the beginning of adult emergence.

We are now seeing the start of adult emergence in Lake County and the ideal period for leafhopper control measures has ended for most vineyards in this region.

PARASITOID RELEASE PROGRAM

A batch of Anagrus daanei, the parasitoid that controls VCLH, was released on June 24 in Mendocino County near Talmage.

TAIL GATE MEETING ON JULY 7
UCCE Area Wide Virginia Creeper Leafhopper Project Research Update
Date: July 7, 2016
Time: 8-10:00 AM
Place: South Gate of the Sundial Chardonnay Vineyard (across from the Fetzer winery in Hopland), located on Old River Road north of Old Hopland.
Details: 2 CEU’s APPLIED FOR

MENDOCINO COUNTY

In Mendocino County, we are seeing mostly 4th - 5th instars and many newly molted adults. At this point most of the Virginia creeper (VCLH) and Western grape leafhopper (WGLH) eggs have emerged.

We project that this week (June 19-25) we will continue to see mostly 5th instar nymphs and increased adult emergence. Adult populations should continue to grow in the following week (June 26 – July 2) and most of the remaining nymphs will have likely molted into adults.

We are now seeing the start of adult emergence and the ideal period for leafhopper control measures has ended for most vineyards in Mendocino County.

LAKE COUNTY

Leafhopper populations are developing more slowly in Lake County relative to Mendocino County. We are currently seeing 1st – 5th instar (stage) VCLH and WGLH nymphs, although a majority of the nymphs are 3rd - 4th instar and we have started t observe newly molted adults.

Now is the time to monitor your vineyard to determine if control measures are warranted.

We are now including data for sites in both Mendocino and Lake County.

MENDOCINO COUNTY

In Mendocino County, we are seeing mostly 4th - 5th instars and many newly molted adults. Approximately 98% of the Virginia creeper (VCLH) and 88% of the Western grape leafhopper (WGLH) eggs have emerged.

We project that this week (June 12-18) we will continue to see more 4thand 5th instar nymphs as well as increased adult emergence. Adult populations should continue to grow in the following week (June 19-25) and most of the remaining nymphs will have likely molted.

We are now seeing the start of adult emergence and the ideal period for leafhopper control measures has ended for most vineyards in Mendocino County.

LAKE COUNTY

Leafhopper populations are developing more slowly in Lake County relative to Mendocino County. We are currently seeing 1^st – 4^th instar (stage) VCLH and WGLH nymphs. Although a majority of the nymphs are 2^nd – 3^rd instar, we are still seeing many unknown 1^st instars as well (Fig. 8c). We have not yet observed any newly molted adults.

Now is the time to monitor your vineyard to determine if control measures are warranted.

PARASITOID RELEASE PROGRAM

A batch of Anagrus daanei, the parasitoid that controls VCLH, was released on June 10 in Lake County near Finley.

We are seeing 1st - 5th instar (stage) nymphs, although most are 3rd - 4th instar. Some freshly molted adults were also observed, indicating the beginning of adult emergence. Approximately 92% of the Virginia creeper and 77% of the Western grape leafhopper eggs have emerged.

We project that this week (June 5-11) we will continue to see more 4th and 5th instar nymphs as well as increased adult emergence. Adult populations should continue to grow in the following week (June 12-18) and most of the remaining nymphs will likely be close to molting.

If you have not done so yet, this is the week to monitor your vineyard to determine is control measures will be necessary.

Parasitism of Western grape leafhopper has been consistent at all sites since May 5, indicating that the regional population of Anagrus spp. parasitoids have colonized the vineyards. There is practically no parasitism of Virginia creeper leafhopper.

A batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, was released on June 3 in Mendocino County near McDowell Valley.

We have been seeing mostly 2nd, 3rd and 4th instar (stage) nymphs and expect more 4th and 5th instars to appear this week. Some additional leafhopper nymphs will continue to emerge in the coming week as well. Approximately 79% of the Virginia creeper and 48% of the Western grape leafhopper eggs have emerged.

This is the week to monitor your vineyard to determine is control measures will be necessary.

Parasitism of Western grape leafhopper has been consistent at all sites since May 5, indicating that the regional population of Anagrus spp. parasitoids have colonized the vineyards. There is practically no parasitism of Virginia creeper leafhopper.

A batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, was released on May 26 in Mendocino County near Hopland.

We have been seeing mostly 2nd-3rd instar (stage) nymphs and expect 4th-5th instars to appear this week. Additional leafhopper nymphs will continue to emerge in the coming week as well.

This is the week to monitor your vineyard to determine is control measures will be necessary.

Parasitism of Western grape leafhopper has been consistent at all sites since May 5, indicating that the regional population of Anagrus spp. parasitoids have colonized the vineyards. There is practically no parasitism of Virginia creeper leafhopper.

A batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, was released on May 20 in Mendocino County near Talmage.

Leafhopper egg deposition continues but we are also starting to see more first instar nymphs. We expect to see additional leafhopper nymphs emerge in the coming week.

Parasitism of Western grape leafhopper is now fairly consistent at all sites being monitored, indicating that the regional population of the parasitoid Anagrus spp. has colonized the vineyards. There is practically no parasitism of Virginia creeper leafhopper.

A batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, was released on May 13 in Mendocino County near Hopland.

Leafhopper egg deposition continues and first instar nymphs have now been observed. We expect to see more leafhopper nymphs emerge in the coming week.

A batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, was released on May 9 in Lake County near Kelseyville.

Leafhopper egg deposition continues. We have not seen any leafhopper nymphs yet. Some of the Virginia creeper leafhopper eggs are almost fully developed, so we may possibly begin to see VCLH nymphs this week. 

A second batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, was released on April 28 in the McDowell Valley.

Leafhopper egg deposition continues. Some of the Virginia creeper leafhopper eggs (<5%) are almost fully developed, so we may possibly begin to see VCLH nymphs this week. 

A batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, were released on April 23 in the McDowell Valley and Hopland area.

We continue to monitor egg deposition and are seeing early stages of parasitism. No leafhopper nymphs have been observed yet.

This is the first edition of the "Leafhopper Newsletter" for the 2016 growing season.

VCLH Announcement for Aug 12 2015

VCLH Announcement for Aug 5 2015

VCLH Announcement for July 29 2015

VCLH Announcement for July 22 2015

VCLH Announcement for July 1 2015

VCLH Announcement for June 24 2015

VCLH Announcement for June 17 2015

VCLH Announcement for June 11 2015

VCLH Announcement for June 3 2015

VCLH Announcement for May 27 2015

VCLH Announcement for May 21 2015

VCLH Announcement for May 13 2015

VCLH Announcement for May 6 2015

VCLH Announcement for April 29 2015

VCLH Announcement for April 22 2015

VCLH Announcement for April 15 2015

VCLH Announcement for April 6 2015.