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Sustained SWD catch was obtained over the last couple of weeks in several counties — Dutchess 1 SWD, Herkimer 6 SWD, Livingston 18 SWD, Onondaga 16 SWD, Orleans at two farms 11 and 9 SWD, and Tioga 1 SWD. Last month, I missed reporting sustained catch in Erie County on June 6, 1 female SWD. Blueberries, raspberries, cherries, gooseberries, currants and many other fruits are being harvested and many will continue with harvests extending over the next several weeks.

Risk from SWD infestation will be high from this point forward in the growing season. Monitor your crops for infestation by taking a sample of fruit at each harvest period and doing a salt flotation test on it. Methods described in Guidelines for Checking Fruit for SWD Larvae in the Field by Laura McDermott, available on Cornell Fruit Resources Monitoring SWD page, fruit.cornell.edu/spottedwing/monitoring/.

Symptoms of SWD infestation in raspberry. The fruit receptacle is stained red with leaking juice, druplets are damaged and dimpled, and fruit melts off the receptacle.
Signs of SWD infestation on raspberry. The fruit receptacle is stained red with leaking juice, druplets are damaged and dimpled, and fruit melts off the receptacle.

Look for signs of infestation in fruit in the field -- look for symptoms of leaky fruit; tiny drops of juice on otherwise perfect fruit; red stains on raspberry fruit receptacles that would otherwise be white; flat, sunken, and dull spots or dimples on fruit surfaces; distorted and disintegrating fruit; leaves stained with juice that has leaked from infested fruit.

Protect ripe and ripening fruit crops from infestation with an insecticide program. Choose a material with excellent efficacy against SWD and an appropriate days-to-harvest interval. Download the Quick Reference Guide to SWD Insecticides at

www.hort.cornell.edu/fruit/pdfs/swd/berry-insecticides.pdf for berries

www.hort.cornell.edu/fruit/pdfs/swd/treefruit-grape-insecticides.pdf for stone fruit and grapes

Details about each County's sustained catch:

  • Dutchess: 7/16/2019, 1 female, raspberry – total 1
  • Erie: 6/6/2019, 1 female, blueberry – total 1
  • Herkimer: 7/15/2019, 2 females & 4 males, blueberry – total 6
  • Livingston: 7/25/2019, 7 females & 11 males, tart cherry – total 18
  • Onondaga: 7/16/2019, 7 females & 9 males, blueberry – total 16
  • Orleans: 7/29/2019, 10 females & 1 male, raspberry – total 11
  • Orleans: 7/29/2019, 7 females & 2 male, raspberry – total 9
  • Tioga: 7/17/2019, 1 female & 0 males, blueberry – total 1

The sustained catch in Tioga County of only 1 SWD in the blueberries after the prior week’s catch of 26 underlines the impact of an insecticide program on SWD populations.

Thank you for monitoring SWD in the Counties with sustained catch!

  • Peter Jentsch and Lydia Brown, Hudson Valley Research Laboratory (Dutchess County)
  • Sharon Bachman, CCE of Erie County (Erie County)
  • David Thorp, CCE of Livingston County (Livingston County)
  • Shona Ort and Barb Neal, CCE of Chemung County and CCE of Tioga County (Tioga County)
  • Elizabeth Tee, Lake Ontario Fruit Program (Orleans County)
  • Ryan Parker and Juliet Carroll, CCE NYS IPM Program (Herkimer and Onondaga County)

This wraps up monitoring for this year.

The ability for the SWD population to explode as summer rolls on was demonstrated last week in several counties where I have research projects. Per trap, 5 to 125 SWD were caught in raspberry, blueberry, and tart cherry in mid-July. The totals for the two to four traps set in the orchards and fields were 14 to 250.

Use this summary as a wake up call! For the weeks ending on the date given:
7/11/2019, Schuyler County, blueberry, 4 traps, 22 SWD (11 males and 11 females)
7/11/2019, Schuyler County, raspberry, 4 traps, 108 SWD (64 males and 44 females)
7/22/2019, Herkimer County, blueberry, 4 traps, 30 SWD (12 males and 18 females)
7/22/2019, Wayne County, tart cherry, 2 traps, 14 SWD (1 male and 13 females)
7/22/2019, Wayne County, tart cherry, 2 traps, 24 SWD (4 males and 20 females)
7/22/2019, Wayne County, tart cherry, 2 traps, 57 SWD (9 males and 48 females)
7/22/2019, Wayne County, tart cherry, 2 traps, 85 SWD (19 males and 66 females)
7/22/2019, Wayne County, tart cherry, 2 traps, 250 SWD (60 males and 190 females)
7/23/2019, Wayne County, blueberry, 2 traps, 131 SWD (53 male and 78 females)
7/23/2019, Wayne County, blueberry, 4 traps, 29 SWD (14 male and 15 females)

In eight of the nine sites a spray program was in place to protect fruit. Fruit is ripe and being harvested – and it’s delicious! Fruit isn’t showing signs of infestation, which means insecticide programs can protect fruit from oviposition, even when SWD numbers are high. Download the Quick Reference Guide to SWD Insecticides at

Photo of the three instars of SWD.
The three instars of SWD will emerge from fruit immersed in a salt solution. The smallest instar is about 0.5 mm long, the largest about 2 mm long.

Salt flotation – What  these numbers also demonstrate is that trap catch numbers aren’t necessarily an indication of whether or not an insecticide program is working. A better indication is to sample fruit and run a salt flotation test. Two berry growers described their success last year using salt flotation to monitor infestations in blueberries, detailed on the blog, Use salt flotation to check for SWD.  A simple method is described in Guidelines for Checking Fruit for SWD Larvae in the Field by Laura McDermott, which can be downloaded from Cornell Fruit Resources SWD Monitoring pages, fruit.cornell.edu/spottedwing/monitoring/. Large scale berry growers will routinely run salt flotation at each harvest, because blueberries, raspberries, and blackberries ripen and are harvested over several weeks. For crops that are harvested all at once, like tart cherry, salt flotation may not be as useful.

Refrigeration – The high populations of SWD, coupled with later ripening of many crops this year, make it even more important to immediately cool fruit after harvest. Cold storage temperatures close to 32°F can greatly inhibit and even kill SWD in fruit. Raspberries, blackberries, blueberries, and tart cherries will all tolerate cold storage temperatures between 32°F to 34°F.

Diversified fruit farms – Protect your crops from SWD, if you’re growing susceptible fruit – June strawberries, day-neutral strawberries, sweet cherries, tart cherries, raspberries, blackberries, elderberries, blueberries, peaches, nectarines, plums, prunes, and thin-skinned grapes. If you have a diversified fruit farm, SWD can spill over from one crop to the next as they are harvested and especially when cull fruit remains in the field. Renovate strawberry fields promptly.

Photograph of high tunnel raspberries.
High tunnel raspberries.

Fruit becomes susceptible to SWD oviposition when it is ripening and is highly susceptible when it is ripe – raspberry, blackberry, blueberry, sweet cherry, tart cherry, elderberry. Fruit that is less susceptible will be attacked when it is at peak ripeness – peach, nectarine, plum, prune, strawberry, grapes. All fruit can serve as a resource for feeding and breeding when it is left for cull in the field. The good news is that, in degraded fruit, SWD doesn't compete all that well with other Drosophilas, like Drosophila melanogaster, our common vinegar fly, which often shows up in our kitchens in late summer or in the winery during press. SWD prefers nice ripe fruit — like we do!

Sustained SWD catch in Eastern NY — Columbia County 5 SWD, Clinton County 5 SWD, & Orange County 36 SWD — and Wayne County 4 SWD. Berries and cherries are being harvested and will continue ripening over the next several weeks. Risk from SWD infestation will be high from this point forward in the growing season.

Monitor your crops for infestation by sampling fruit at each harvest period and doing a salt flotation test. Methods described in Guidelines for Checking Fruit for SWD Larvae in the Field by Laura McDermott, available on Cornell Fruit Resources SWD pages, fruit.cornell.edu/spottedwing/.

Picture of a raspberry fruit with tiny breathing tube threads where an egg is inserted under the skin.
Tiny threads of the SWD egg breathing tubes indicate where an egg was laid in a raspberry. Two eggs were found in 40 fruits examined.

Pay attention to SWD -- look for symptoms of leaky fruit; flat, sunken, & dull spots or dimples on the fruit surfaces; or distorted & disintegrating fruit. Protect ripe and ripening fruit crops from infestation with an insecticide program.

Details about each County's sustained catch:

  • Orange: 6/14/2019, 23 females & 3 males, raspberry & gooseberrytotal 36
  • Columbia: 7/8/2019, 4 females & 1 male, tart cherry – total 5
  • Clinton: 7/9/2019, 3 females & 2 males, blueberry – total 5
  • Wayne: 7/9/2019, 3 females & 1 male, raspberry – total 4

The sustained catch report in Orange County was a month ago! This report slipped my attention, but it underlines that SWD has been found in many fruit plantings for upwards of a month now.

The sustained catch in Columbia County of only 5 SWD in the tart cherries after the prior week’s catch of 32 underlines the impact of an insecticide program on SWD populations and trap catch.

Refer to the insecticide quick guides online. Choose a material with excellent efficacy against SWD and an appropriate days-to-harvest interval.

SWD Insecticides for Berries, www.hort.cornell.edu/fruit/pdfs/swd/berry-insecticides.pdf

SWD Insecticides for Stone Fruit & Grapes, www.hort.cornell.edu/fruit/pdfs/swd/treefruit-grape-insecticides.pdf

Thank you for monitoring SWD in the Counties with sustained catch!

  • Andy Galimberti, CCE Eastern NY Commercial Horticulture Program (Clinton County)
  • Natasha Field, CCE Eastern NY Commercial Horticulture Program (Columbia County)
  • Nate Mengaziol and Laura McDermott, CCE of Orange County and Eastern NY Commercial Horticulture Program (Orange County)
  • Ryan Parker and Juliet Carroll, CCE NYS IPM Program (Wayne County)

Four SWD, 2 females and 2 males, were caught in traps set in a blueberry planting in Onondaga County on July 10, 2019. Traps were checked by Ryan Parker and Juliet Carroll, NYS IPM Program.

This completes first catch for all locations in the SWD Monitoring Network. We'll continue to report sustained catch and provide updated management information to keep you up-to-date on SWD.

SWD distribution map picture.
SWD distribution map for New York. SWD has been found in all the counties in the network, as of July 10, 2019. Counties in white don't have traps or reports in.

Yikes! After catching nothing last week... First catch had 26 SWD caught in four traps set in a blueberry planting in Tioga County — 15 females and 11 males. These traps are being monitored by Barb Neal, CCE of Tioga County and Shona Ort, CCE of Chemung County.

I'd say it's time to protect the crop at this location! We want to bring in a good crop and protect it. For comprehensive information on protecting blueberries from SWD, download and read the new IPM guide from the SWD IPM Working Group.

Spotted Wing Drosophila IPM in Blueberries
neipmc.org/go/swdpub2

Also, refer to the insecticide quick guide to augment the information in the above IPM guide.

A picture showing two male SWD on a blueberry.
Two male SWD on a blueberry, photographed in early September 2013. SWD populations typically build to very high levels in late summer and early autumn.

A single female SWD was caught in a blueberry planting in Orleans County, in traps checked on July 9, 2019 by Liz Tee, Lake Ontario Fruit Program of CCE. While the number is low, it is likely that the SWD catch will be greater next week, but possibly not.

This picture shows the SWD females ovipositor which can slice the skin of ripening fruit and gently place an egg within.
Detail of the spotted wing Drosophila female's abdomen showing the extended ovipositor and the dark, saw-toothed edge used to cut into fruit to lay her eggs inside.

That's one of the things that makes this insect so unnerving — it can explode when you least expect it.

Make sure you keep an eye on how ripe your crop is. No-choice lab tests proved SWD females can lay eggs in blueberries that are pink.

Take the time to carefully plan out your management strategy now. Review resources available online to help you learn how to protect ripe and ripening fruit crops from infestation.

First catch was obtained on July 8, 2019 in Herkimer County. Nine SWD — 3 females and 6 males, distributed both within and on the edge of the planting. Numbers of SWD being caught are starting to escalate.

Photo of a male SWD on a blueberry.
A male spotted wing drosophila (SWD) on blueberry; another likely SWD is in the background.

It's time to get an insecticide program geared up for ripening and ripe fruit. This season will be demanding and all tactics should be brought to bear on SWD to keep it in check!

Refer to the quick reference guides for:

Other tactics that can help are:

  1. Sanitation – pick off and remove all cull fruit from the planting.
  2. Mowing – keep the environment hot, sunny, and dry.
  3. Weed management – keep the environment hot, sunny and dry, and provide no alternate hosts.
  4. Pruning – keep the environment hot, sunny, and dry, and improve spray penetration and deposition.
  5. Cold storage – immediately after harvest, place harvested fruit into a cooler at 32°-34° F and hold it there, to kill larvae and eggs, until sold.

One female SWD was caught in two traps placed in a small raspberry patch in Livingston County. Traps were checked on July 3, 2019 by Dave Thorp, CCE Association of Livingston County.

Only four counties in the network, two added just last month, have not yet caught SWD — Herkimer, Onondaga, Orleans, and Tioga. All these counties have traps set in blueberry fields. In Orleans a second site has traps set in raspberry.

Picture of a Scentry trap for monitoring SWD that is set in a raspberry planting.
Scentry trap for SWD set in a raspberry patch.

Fruit that is ripe is at risk of infestation. Consult Cornell Fruit Resources SWD Management, fruit.cornell.edu/spottedwing/management/.

More information on SWD is online:

Review the Quick Guide to SWD Insecticides at

www.hort.cornell.edu/fruit/pdfs/swd/berry-insecticides.pdf for berries

www.hort.cornell.edu/fruit/pdfs/swd/berry-insecticides.pdf for stone fruit and grapes

 

32 SWD were caught in four traps set on the edge of and within a tart cherry orchard in Columbia County. Fruit is ripe in the orchard. These traps, checked on July 1, 2019, are being monitored by Natasha Field, Cornell Cooperative Extension Eastern NY Commercial Horticulture Program.

A trap to monitor SWD set in a tart cherry tree.
Scentry SWD trap set in a tart cherry. Fruit are coloring and will soon be ripe for harvest. When ripening and ripe, cherries can be infested by SWD.

Numbers caught in traps, especially in Eastern NY, are climbing, with totals in the double and triple digits. Typically, we don’t see numbers climb up this rapidly in the SWD trap monitoring network. Fruit that is ripe is at risk of infestation. Consult Cornell Fruit Resources SWD Management, fruit.cornell.edu/spottedwing/management/.

Things to consider regarding insecticide programs for SWD, with specific emphasis on materials registered for cherries:

  • Population growth models for SWD theoretically calculate that using the most efficacious insecticide first will more successfully lower SWD numbers by knocking the population back to close to zero and delaying population growth. (This is strikingly similar to classic tactics in plant disease epidemiology – think knocking back primary apple scab infections.)
  • Insecticides with probable excellent efficacy include – Exirel (3 days), Minecto Pro (21 days), Danitol 2.4EC (3 days), Mustang Maxx (14 days), and Imidan 70W (7 days). Of these, choose first those with the longest pre-harvest interval (given in parentheses) that you can accommodate; some may be out of the question at this point. (Remember – Imidan can’t be used on sweet cherry.) Rotate to other insecticides with shorter pre-harvest interval for later in the season, closer to harvest.
  • Research on berries has shown Mustang Maxx isn’t very rain fast, so plan to re-cover if significant rain occurs during the spray interval.
  • Rotate use among insecticides with different IRAC groups to reduce selection pressure for resistant populations of SWD. (In a Finger Lakes vineyard last year, insecticide-resistant Drosophila melanogaster (SWD = D. suzukii) were identified. D. melanogaster is targeted with insecticide for controlling sour rot in grapes.)
  • For the second insecticide application, switch to a product with Good to Excellent or Moderate efficacy – Entrust 80WP (7 days), Entrust 2SC (7 days), Delegate (7 days), Asana XL (14 days), Lambda-Cy EC (14 days).
  • The spray interval column in the Insecticide Quick Reference Guide table relates to use of the same product back-to-back. When switching to another mode of action, weekly applications are OK and are suggested against SWD.
  • Don’t stretch intervals between sprays more than about seven days.
  • Make sure you are getting excellent coverage. Spray every row (no alternate row spraying.)

Review the Quick Guide to SWD Insecticides at

www.hort.cornell.edu/fruit/pdfs/swd/berry-insecticides.pdf for berries

www.hort.cornell.edu/fruit/pdfs/swd/berry-insecticides.pdf for stone fruit and grapes

Sustained SWD catch in Eastern NY with some site totals in the double to triple digits — the Capital District, Mohawk Valley, and Champlain Valley. Berries are being harvested and will continue ripening over the next several weeks. This will create an SWD paradise for fruit infestation.

Farms with trap catch in the double to triple digits should sample fruit and do a salt flotation test to assess fruit infestation. Methods described in Guidelines for Checking Fruit for SWD Larvae in the Field by Laura McDermott, available on Cornell Fruit Resources SWD pages.

It's time to pay attention to SWD and protect ripe and ripening fruit crops from infestation with an insecticide program.

Details about each County's sustained catch:

  • Essex: 7/2/2019, 22 females & 9 males, blueberrytotal 31
  • Montgomery: 7/1/2019, 40 females & 24 males, raspberrytotal 65
  • Rensselaer: 7/2/2019, 1 female & 2 males, blueberry – total 3
  • Schoharie: 7/1/2019, 67 females & 44 males, raspberrytotal 111
  • Washington: 6/24/2019, 4 females, blueberry – total 4
Photo of a female SWD on a raspberry.
Female SWD laying eggs in a raspberry.

Re-set raspberry and blackberry fields:
Because raspberry and blackberry continue to flower and set fruit over a protracted period of time, it is possible and advisable to “re-set” the field. When fruit infestation is found via salt flotation or high numbers of SWD are caught in traps in the field, clean pick all ripe and cull fruit. Remove this fruit from the planting and solarize it or freeze it to kill SWD. Solarize in sealed, clear plastic bags set in the sun. After clean picking, spray insecticide. Choose a material with excellent efficacy against SWD and an appropriate days-to-harvest interval.

See insecticide quick guides online:

SWD Insecticides for Berries, www.hort.cornell.edu/fruit/pdfs/swd/berry-insecticides.pdf

SWD Insecticides for Stone Fruit & Grapes, www.hort.cornell.edu/fruit/pdfs/swd/treefruit-grape-insecticides.pdf

More information on SWD is online:

Thank you for monitoring SWD in the Counties with sustained catch!

  • Andy Galimberti, CCE Eastern NY Commercial Horticulture Program (Essex County)
  • Natasha Field, CCE Eastern NY Commercial Horticulture Program (Montgomery and Schoharie Counties)
  • Crystal Stewart, CCE Eastern NY Commercial Horticulture Program (Montgomery and Schoharie Counties)
  • Laura McDermott, CCE Eastern NY Commercial Horticulture Program (Rensselaer and Washington Counties)
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