First Detection of Spotted Wing Drosophila in Wisconsin for 2019
The last DATCP Pest Bulletin of 6/20/19 reported that the first spotted wing drosophila flies (SWD; Figure 1) were detected in DATCP’s monitoring traps in La Crosse County on June 19. Our traps in Dane county have not yet collected any SWD so far. To put this in perspective, see the table below with the first SWD detections in Wisconsin since 2013 when we initiated an active monitoring program.
Figure 1. Spotted wing drosophila adults (males on left and female on right). Photo by Keith Phelps, UW-Madison.
The cool wet weather we have been experiencing this spring has led to a later first detection this year compared to recent years. However, this does not necessarily mean that we will experience a lower than average pressure from SWD this year. As the weather warms up and the humidity remains high, SWD populations are likely to surge once they begin to show up. If you have not done so already, we strongly recommend that all SWD-susceptible fruit growers begin monitoring for SWD as soon as possible. Commercial or homemade traps and baits are fine to use. Commercial traps and lures can be purchased from companies such as Great Lakes IPM. For more information on making your own trap and bait, please refer to the SWD website. Another option which should be implemented especially by strawberry and grape growers is to sample suspected fruit to look for the presence of larvae (see previous article here). We recommend checking fruit twice a week, crushing the fruit and looking inside for SWD larvae, or using the salt test method.
If you find larvae in your fruit, sanitation and harvest schedule methods should be implemented and were discussed in a previous article. Other management methods should also be implemented and were discussed in our article on organic management of SWD and this comprehensive organic management publication. Some insecticides and other strategies that can be used in conventional management are also discussed in a previous article.
| Year | Date of 1st detection |
| 2013 | June 24 |
| 2014 | June 30 |
| 2015 | July 8 |
| 2016 | June 10 |
| 2017 | June 5 |
| 2018 | June 1 |
| 2019 | June 19 |
Happy growing season!
This article was posted in Insects and tagged Berries, Grapes, SWD.