Spotted Wing Drosophila Spray Protocol for 2010

LIVE Spotted Wing Drosophila Spray Protocol for 2010 Growing Season

Due to the relatively unknown impact that the spotted wing drosophila (SWD) will have on LIVE’s Region I growing area this year, the LIVE Technical Committee has put together a SWD treatment protocol for the 2010 growing season.  The protocol is based on integrated pest management (IPM) and therefore puts the burden of proof on the grower to provide recorded evidence of a SWD infestation and resulting damage.  Please read the protocol carefully and contact a member of the Technical Committee or Chris Serra if you have any questions about how to proceed.  This is very important, as LIVE inspectors will be looking for valid records to justify any applications made for SWD.

Of further importance is the need for LIVE members to stay up to date with the latest knowledge of SWD interactions with grape vines.  A research team comprised of competent scientists from California, Oregon, and Washington, with heavy involvement from our own Oregon State University, has been assembled to work on furthering our understanding of how this potential pest will impact our industry.  A webpage containing all current knowledge of SWD can be accessed at: http://swd.hort.oregonstate.edu/information_growers.

As wine grape growers, we are potentially immune from the cosmetic damage caused by SWD due to the processing our fruit receives.  This allows us to approach the problem using true IPM, whereby we establish thresholds for damage and resulting treatments once those thresholds are reached.  There has not been a lot of information published regarding economic thresholds for processed grapes, but we have developed a protocol that we feel will get us through this unknown pest evaluation period.  In a cooler than normal season where fruit will hang longer than normal and in potentially wet, disease conducive weather, we could not ignore the fact that damage caused by SWD is prone to secondary infection.  Evidence to date, supports the idea that under normal season conditions, damage from SWD would most likely be benign to the winemaking process, but further information in this area is needed and research is ongoing.  Thank you for your patience as our program continues to develop our strategy for this potential pest.                                                            

Sincerely,

Chad Vargas

LIVE Technical Committee Chair

 

 Spotted Wing Drosophila Protocol

 

Pest Detection:  Growers will need to show evidence of SWD damage this season by testing randomly sample berries for presence of pupae.  The burden of proof is to document one positive field sample for presence of SWD pupae.  The protocol for this test was recently provided to growers via the OSU monthly grape growing newsletter, and is preformed as follows: 

•Collect approx 20 to 40 ripening berries evenly distributed through an area where traps showed adult SWD flies.

•Drop fruit into 1qt Ziplock bag and lightly crush.

•Add ¼cup sugar and 4 cups water.

•Larvae float to top, smaller larvae may require a hand lens to see.

•Alternatively leave fruit inside the Ziplock bag at room temperature for a few days and larvae will emerge due to warmth.

 

Treatment:  Foliar ground applications of Entrust (spinosad) at 1.25 to 2.5 oz per acre.  This OMRI approved insecticide is used for suppression of adult SWD.  To avoid the development of resistance, LIVE is allowing for no more than three consecutive applications of Entrust applied in a 30-day period and no more than 5.6 oz for the season (per label).  No more than four applications for the 2010 season.  Applications must end 7 days before harvest (per PHI).  Remember that the label is the law.

 If more than one sample comes back positive for damage and cool wet weather is prevailing, it may be a good idea to tank mix a botryticide with Entrust to prophylactically treat for secondary infection.

Precautions:  Spinosad is toxic to both fish and honeybees.  Please do all you can to avoid contamination of fish holding watersheds by acknowledging appropriate buffer zones.  Mowing cover that contains a lot of pollen producing flowers before application will help reduce honeybee exposure.

 

 

 

 

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