New SWD Trap Is Available
August 8, 2012 
Since the emergence of the spotted wing drosophila (SWD) in the Pacific Northwest a few years ago, growers have complained to entomologist Alan Knight that the traps used on the pest didn’t seem all that effective. The most common type of trap
was made out of just simple clear plastic, and seemed like it would be easy to improve upon, says Knight, who is based at the USDA-Agricultural Research Service Laboratory in Wapato, WA.
Esteban Basoalto, an entomology researcher from Chile who has been working with Knight, took a particular interest in the project and began testing various types of alternative traps. “Monitoring for SWD is very important as it is a new pest in our region and growers may or may not have it in their crops,” says Basoalto, explaining why he’s so interested. “The most widely used trap was reported to be poor, and the use of a clear plastic water cup seemed to be something which could be easily improved.”
Basoalto found that the use of color on the trap was important in attracting SWD. “The use of visuals is important because they are day fliers,” explains Knight, “so we looked at many different colors when considering the design.”
“Red Zorro”
After a great deal of experimentation, Basoalto determined that SWD was most attracted to dark colors, with red and particularly black being the most attractive of all. He also found that having two colors was better than one, which is why they paired red with black. “Our research found that alternating red with black was the best use of color,” he says.
In the design they settled on, the top of the trap is red with a black band over it that looks something like a black mask, thus the trap’s nickname: “Red Zorro.” Its official name is CAPtiva. A side benefit to the “Red Zorro” is that growers like the look of it, says Basoalto. “The CAPtiva trap is attractive to humans, is a convenient size, and is easy to use,” he says.
One other change they made was that many of the traps now commonly used have just two holes. That doesn’t provide the SWD with convenient access, so they put 10 holes in the CAPtiva to increase fly capture, says Basoalto.
Now Online
Knight says they were fortunate in that they were able to find a manufacturer almost immediately, and the CAPtiva is already available online. Growers interested in ordering traps should go to the website of Marginal Design in Oakland, CA, which is simply marginaldesign.com.
The traps cost $6 apiece. Basoalto says he thinks they are worth the price, because an early warning system is the best defense, so trapping is absolutely critical. Otherwise, SWD often doesn’t show up until it’s already inside the fruit.
“This year has been a very bad year for this new pest,” he says. “Growers are going to have to develop an effective monitoring program.”
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