Evaluating Monitoring Tools for Spotted Wing Drosophila

Erica Pate & Hannah Fraser

Last week at the Berry Growers of Ontario meeting we introduced a project we are working on evaluating new monitoring tools for spotted wing drosophila (SWD).

Since we began monitoring for SWD in Ontario we have been using liquid bait traps to monitor for SWD. These traps are effective tools, but they are also time-consuming and labour-intensive to process, and impractical for on-farm use.  Recently, solid matrix baits have become available on the market. With these baits comes the potential to pair them with dry, solid traps, such as a sticky card or sticky sphere. These dry traps are easier to use and require less maintenance than the liquid traps we have been using. We are hoping that these traps are more practical for on-farm use, so in 2018 we began a project evaluating different combinations of sticky card traps and lures (Figure 1).

This project compared yellow sticky traps, red sticky traps, and liquid bait traps. We also used different lures in combination with these traps, using Scentry lures and Trécé lures.

We set these traps up at a blueberry farm and a raspberry farm and collected the traps weekly to ID and count SWD. With the sticky card traps only the adult males are easily identifiable by the spots on their wings (Figure 2).

From our monitoring it appears that the Scentry lure paired with the yellow sticky card is a good choice for a monitoring tool (Figure 3.)

 

We had more success with the Scentry lures than the Trécé lures, and the yellow sticky traps appear to have better results than the red traps.

 

We also found these sticky cards much faster to use, SWD can be identified in the field, and the traps did not require the same amount of labour and maintenance the liquid traps did. We are continuing our project in 2019 to further evaluate these different trap-lure combinations and gain experience with using different lures.

2019 Grower participatory survey

Monitoring is important for growers to do on their own farm. Every year SWD emerges at a different time and emergence is very challenging to predict. By monitoring on their own farm growers can ID SWD and begin a spray program before the population rises, or growers can hold off on spraying for 1-2 weeks and save these limited sprays for the end of the season.

This season we are hoping to conduct a grower participatory SWD survey with growers across the province, using this lure + sticky card trapping system for early detection on their own farm.

We will work with growers to set up and manage traps. Hannah Fraser and I (Erica Pate) will be able to help confirm ID of SWD on the cards. If growers have a smartphone they will be able to send us pictures to help with identification in real time. The picture in figure 2. was taken on a smartphone- you can see that the picture is good enough quality to confirm ID remotely.

If you are interested in participating please contact me at Erica.pate@ontario.ca or Hannah Fraser at Hannah.fraser@ontario.ca . We don’t yet know how many growers will be able to be a part of this project, but we will support other growers who are interested through confirmation of SWD ID. Growers must be able to take pictures with their cell phones to participate.

Thank you to the growers whose fields we used for monitoring. The project was funded by Horticulture Crops Ontario.

See the next blog post for a list of suppliers for SWD monitoring tools (Part 2).