Category: SWD info

No SWD has been reported, as of June 11, 2014, from any of the monitoring locations in New York. Any confirmed first trap catch SWD findings will once again be posted on the blog.

Current guidelines for managing SWD are to begin insecticide applications on vulnerable crops when fruit are ripening. Late-season blueberries, blackberries and fall raspberries are especially vulnerable to attack. Less vulnerable, but also at risk, are late season plums, peaches, cherries and grapes, and late harvest summer raspberries, early to mid-season blueberries, and early harvest day-neutral strawberries.

Insecticide table quick guides are linked below and available on the Spotted Wing Drosophila website on Cornell Fruit Resources, www.fruit.cornell.edu. If you are reading this from outside of New York, keep in mind that NY State may be more restrictive on labeling insecticides and there may be additional insecticide options available in your state; contact your local Extension Service for more information.

2014 Labeled insecticides for berry crops

2014 Labeled insecticides for stone fruit & grapes

As we emerge from the clutches of a long and very cold winter, we’re pondering if SWD was killed off…as were many fruit buds in New York. A study in Japan (Kimura 2004) investigating cold and heat tolerance of fruit flies included SWD. Interestingly, SWD is distributed in all three of the climatic regions in Japan from which drosophilid flies were collected for the research, the cool-temperate region (January mean temperature 23 F, August mean temperature 71 F), the warm-temperate region (January mean temperature 39 F, August mean temperature 80 F), and the subtropical region (January mean temperature 64 F, August mean temperature 82 F). Progeny from SWD females collected from each of these regions showed little variation in the range of heat and cold tolerance; the conclusion being that populations don’t gain much improved heat tolerance in the subtropical region or much improved cold tolerance in the cold-temperate region.

To test SWD’s temperature tolerance, flies were held at constant temperature in dark for a 24-hr period to determine the lethal temperature (LT) at which 25%, 50%, and 75% of the flies died. 75% of females die at 28.7 F and 75% of males die at 30.7 F.

 

 

 

Can we start celebrating? With low temperatures dipping into the negative teens this winter, was LT 100% reached? -17 F is certainly well below the LT 75% of 28.7 F. I would argue that a distinct possibility exists that a majority of SWD attempting to overwinter in the New York died this winter. However, remember how small SWD is and that microclimates do exist near buildings, compost piles, etc. where temperature may not drop as low as the recorded air temperature. Also, research has yet to determine if SWD overwinters in New York, so maybe the argument is irrelevant?

Another take home message from the lethal temperature table for SWD is that they die at and above 90 F. Last summer was hot and SWD damage seemed not as severe to many of us as in 2012. Perhaps adult flies died off during periods of 90 F and above this summer. As June nears its end this year, invest in an accurate thermometer and keep track of how hot it gets.

Masahito T. Kimura. 2004. Cold and Heat Tolerance of Drosophilid Flies with Reference to Their Latitudinal Distributions. Oecologia, Vol. 140, No. 3 pp. 442-449.

The Southern and Northeastern SWD IPM working groups developed the 2013 SWD Economic Impact Survey to assess the impact SWD is having on farmers and fruit production in the Eastern US. Survey results will support the prioritization and justification of research and extension efforts on SWD. Participation is voluntary and anonymous—the more farmers completing the survey, the more accurate the results. To address the overwhelming loss that can result from SWD infestation, we must work together to find sustainable solutions. Complete the 2013 SWD Economic Impact Survey, swd.ces.ncsu.edu/2014/01/swd-impacts-2013/. Results available mid-March 2014 at swd.ces.ncsu.edu. Questions about this survey? Want to know when the results are in? Contact Hannah Burrack, Assoc. Prof, Entomology, NC State Univ., hjburrac@ncsu.edu or 919-513-4344. Thank you, in advance, for participating!

Now that spotted wing drosophila is here to stay, berry growers in NY need radically different plans to grow a healthy crop. Marvin Pritts, Professor and Chair, Department of Horticulture, Cornell University, shares strategies for berry growers in his recent article, published in the NY Berry News, Horticultural Strategies for Living with SWD. Details on pruning, trellising, and sanitation to encourage open canopies and early fruiting are a "must-read" for growers developing plans for next year's battle with SWD.

On October 30, 2013, in Bridgeton, NJ at the Rutgers Agricultural Research and Extension Center, the Northeast Spotted Wing Drosophila IPM Working Group Meeting will be held from 8:00am to 5:00pm to provide updates on this invasive insect and to set and rank priorities for research, extension, education, and regulatory needs to address its impact on agriculture in the Northeast. Funding from the NE IPM Center will defray a portion of travel expenses to support attendance by commercial growers, industry, extension, and research personnel. A Spotted Wing Working Group block of rooms for October 29 and 30 with a discounted rate of $109.00 per night is being held until October 8 at the Courtyard Marriott, 325 Rowan Boulevard, Glassboro, NJ 08028. If you plan to attend the meeting, contact Laura McDermott, lgm4@cornell.edu. The agenda includes speakers from the academic and grower communities from Michigan to North Carolina, with information on

• Status, monitoring and management in Michigan
• Status, monitoring and management in North Carolina
• Overwintering biology and alternative hosts
• Olfactory cues and chemical control
• Trap improvements, phagostimulants and behavioral control
• Visual cues and behavioral control
• Biological control
• Monitoring and management in caneberries

Review the SWD 2012 Priorities and send jec3@cornell.edu input before the meeting. Your hosts are

• Greg Loeb, Dept. of Entomology, Cornell University, gme1@cornell.edu, 315-787-2345
• Cesar Rodriguez-Saona, Dept. of Entomology, Rutgers University, crodriguez@aesop.rutgers.edu, 609-726-1590 Ext. 4412
• Dean Polk, Rutgers Cooperative Extension, Rutgers University, polk@aesop.rutgers.edu, 609-902-1134
• Julie Carroll, NYS IPM Program, Cornell University, jec3@cornell.edu, 315-787-2430
• Laura McDermott, Eastern NY Horticulture Program, Cornell Cooperative Extension, lgm4@cornell.edu, 518-746-2562
• Anne Nielsen, Dept. of Entomology, Rutgers University, nielsen@aesop.rutgers.edu, 856-455-3100 Ext. 4110

 

Suggested ways for checking fruit for SWD infestation, include looking for egg breathing tubes, finding leaking pinholes, and floating out the larvae.

Egg breathing tubes You'll need a good pair of eyes and 20x magnification. Fruit on which this technique works fairly well include blackberry, cherry, black raspberry, dark plum and grape varieties, and probably nectarines. Looking for breathing tubes on fruit that is fuzzy (peach, red raspberry), has a waxy bloom (plums, grapes), or is light yellow in color may not be worth the effort. Blogs with breathing tube pictures: SWD in plums, Monroe County - first report, and Oviposition in blackberry.  A word of caution – I've noticed that once the egg has hatched (12 to 72 hours after laying) the breathing tubes may be shed from the fruit and, therefore, won't be visible. After hatch, what remains on plum, blueberry and other relatively thick-skinned fruit is a pinhole through which the larva periodically breathes as it pauses from feeding. The soft skin and drupelets of blackberry and raspberry collapse in response to larval feeding and the pinhole is less apparent.

Leaking pinholes  On tougher skinned fruit (plum, blueberry, cherry, grape) gently squeezing the near-ripe to ripe fruit may cause a dewdrop of juice to leak through the pinholes that are associated with oviposition and larval development. Fruit that appears sound but from which leaking juices are noticed can be a sign that SWD may be developing in the fruit. Dried drops of juice seen on leaves below a fruit cluster or on fruit in the field are also signs of possible SWD infestation, especially if no bird damage, cracking or other obvious signs of damage are seen on the fruit.

Floating out the larvae  The salt floatation method can be used to quickly assess larval infestation in fruit. This method works better with the soft-skinned fruit, such as blackberry and raspberry. It can be used on blueberry, though the skins may trap the larvae and possibly affect the test results. On larger fruit, such as cherry, peach, and plum, this technique may not work very well. Dissolve 1 Tbsp (~15 cc) table salt in 1 cup (~250 ml) water. Place about 100 fruit in a Ziploc bag or a crisper-type container and add the salt solution. Gently crushing the fruit may help release the larvae. After one hour, examine the salt-solution-immersed fruit for the presence of larvae (white, ~2-4 mm long). The fruit sample may be split into two parts. One part used immediately in a salt floatation test. The other part kept for 3 days to allow eggs to hatch and larvae to develop prior to doing the salt floatation test. (Keep the fruit covered during the 3-day incubation, so it is not contaminated by ambient vinegar flies, and keep it on paper towels or a sponge to absorb liquid, so the larvae don't drown.)