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Wednesday, March 27, 2013

The future of the SWD*VMN for 2013 and beyond

Male (right) and female (left) spotted wing drosophila on a raspberry at the Upper Mountain Research Station, Laurel Springs, NC. Photo: HJB

For the last three years, we have coordinated the Spotted Wing Drosophila Volunteer Monitoring Network (SWD*VMN).  The goals of the SWD*VMN were:

1. To detect the movement of spotted wing drosophila (SWD) if or when it spread throughout the eastern United States
We began the SWD*VMN in 2010, when SWD had only been detected in Florida in the eastern US. The SWD*VMN facilitated the first detections of SWD in South Carolina, North Carolina, Tennessee, Virginia, Arkansas, Louisiana, West Virginia, and Maryland.

2. To determine when during the year SWD are active and relative population densities throughout the year
SWD have been detected earlier each year in states where the SWD*VMN has been active.  In 2012 and 2013, some locations in the southeast caught flies throughout the entire winter. Peaks in trap captures in NC appear to occur in mid summer (July) and fall (after September), with fall populations appearing the largest.  However, these trap capture peaks are subject to interpretation because the traps and baits we use are likely not as attractive to SWD adults as fruit. 

Dates of first trap capture for eastern states participating in the SWD*VMN. Table from Burrack, et al. Journal of Integrated Pest Management.
3. To communicate and display information on detections and trap captures with growers and extension personnel
All trap captures from the SWD*VMN are available here (click on a county to link to the sites in that county and then click on site names to view data from that site). Our policy has been to only identify sites to county.

Along the way to accomplishing these goals, we've been able to gather some additional information. During 2010, we compared different lures at SWD*VMN sites and learned that some baits need to be changed more frequently than others. Our relative trap capture numbers have suggested that some crops may either foster lower SWD populations or be less conducive to our trapping methods.  For example, we catch more flies in shady crops such as caneberries and some grapes and fewer flies in crops with open, sunny canopies such as strawberries and blueberries.  Importantly, this does not necessarily mean that we have fewer flies in theses systems.

Where does the SWD*VMN go from here?
We have accomplished the initial goals of the SWD*VMN and reached the end of the funding which supported the large statewide (in NC) and multi state efforts (much thanks to the Southern Region Small Fruits Consortium and the NC Tobacco Trust Fund, Inc. for their support).  We have also produced a journal article article to more widely share our findings from the SWD*VMN.

Moving forward, we will maintain, and improve the SWD*VMN site for use by our lab and partners in other states to collect, store, and display SWD trap capture data. Collaborators in OR, TN, AR, NY, and other states have expressed interest in continuing to use the site.  The improvements on the way for the site include incorporating graphs to display data for each site and, in the more distant future, incorporating degree day models being developed for SWD by folks in the western US.

In our lab, we will be using the SWD*VMN to collect data from our planned 8 to 12 trapping locations throughout the state, most of which will be at NCSU or NCDA & CS Research Stations. However, we will no longer be directly facilitating large scale SWD monitoring through our laboratory.  We've posting lots of "do-it-yourself" SWD monitoring information and will be posting a monitoring update for 2013 later today.  Please feel free to contact us if you have questions about the SWD*VMN.

More information
All SWD*VMN posts at NC Small Fruits & Specialty Crop IPM

Plan to monitor insect pests in berries in 2013

One of the most important pest management practices growers can impliment is montoring insect pest populations.  This allows management pratices to be targeted when damaging populations are present and also provides a wealth of information about future pest populations.
We’ve posted lots of information about monitoring methods for insects in berry crops, including a series of “do-it-youself” (DIY) posts.
Do-it-yourself insect monitoring:
One caveat to our spotted wing drosophila (SWD) trapping recommendations-many new baits and lures are in the process of being developed for SWD. We no longer believe that apple cider vinegar is the most appropriate bait for traps. Instead, we are suggested that interested trappers use a mixture of 4 Tbsp sugar plus 2 Tbsp active yeast dissolved in 32 oz water. Traps should be filled 1 to 2 inches deep with this bait and changed weekly! After one week, yeast baits become unusable.