Currently no proven monitoring or trapping method exists for the harlequin bug (Murgantia histrionica), a pest of crops in the genus Brassica. However, a new study that has identified the insect’s color preference may help in developing such a lure. (Photo credit: Russ Ottens, University of Georgia, Bugwood.org)

By Josh Lancette

Ever wondered what a harlequin bug’s favorite color is? Some researchers from Virginia Tech and the USDA-Agricultural Research Service now have an answer.

Josh Lancette

To help improve trapping of the harlequin bug (Murgantia histrionica), a pest of crops in the genus Brassica (such as cauliflower, broccoli, turnips, mustard, and cabbage) and a member of the stink bug contingent, the researchers tested which colors the bug responded positively to through two different tests. The results of the study are published today in the Journal of Economic Entomology.

The first test was performed in a laboratory and used a hexagonal arena to test which of six colors the bugs were most attracted to: green, black, white, red, yellow, or purple. In the second test, different traps of the same six colors were deployed throughout a field to test if the bugs were more attracted to some colors.

And what did the researchers discover about harlequin bug color preference?

In the laboratory test, green was the most attractive color for males, females, and nymphs. Females were also attracted to red.

In the field test, green won again, with black taking the silver medal.

“A positive attraction to green in harlequin bug may be associated with their attraction to Brassica host plants of high nutritional quality,” the researchers write. “The addition of red color components to a green or black trap could perhaps enhance attraction to harlequin bug females, but this idea still needs testing to confirm.”

This finding is important because the harlequin bug can be hard to monitor and trap.

“To our knowledge, there is no monitoring device or proven trapping system for this pest,” write the researchers. “Thus, an effective monitoring tool would be useful to assess the presence and abundance of this stink bug to determine the need for and timing of control tactics.”

Josh Lancette is manager of publications at the Entomological Society of America.