Angela Mech responds to the news stories about stopping browntail moths with buckets of water and glow sticks.

If you’ve seen or heard some recent local news stories, such as on Bangor’s Classic Rock Station 95.7’s website, you might have heard that it’s a great idea to use buckets of water with glow sticks in them to attract the browntail moths and drown them.  Maybe friends have told you how many they see caught this way each night.

But not so fast, per our resident browntail moth expert, Dr. Angela Mech: “Any light source trap would not have an effect on BTM populations because the majority of what is caught are males—their mortality won’t impact next year’s population density. Someone could kill hundreds or even thousands of moths using light traps, which looks really satisfying, but they may actually end up with more BTM nests on the trees around that light source than someone who simply turned their lights off. As far as other species, if [the light source trap] is attractive to browntail moth, it is most likely attractive to other insect species [so you may be catching and harming other insects that pose no threat].

Mech also pointed out:

“The Maine Forest Service just posted about this today! I agree with their assessments and notice the same trends. If folks don’t want to turn off their lights, we have preliminary data to suggest that the moths are more strongly attracted to white bulbs, especially those that emit UV or blue parts of the light spectrum (e.g., compact fluorescent or ‘cool white’ bulbs), so changing your bulbs to yellow or red should reduce browntail moths.”
This is what the Maine Forest Service wrote:

Around the same time that browntail moths start showing up on lampposts, posts abound on social media, encouraging the use of a light trap to “eradicate” BTM. We often get asked if light traps or bug zappers are effective at controlling adult moths, and the answer is a resounding no. Why?

  • Bright lights will draw in more BTM dispersing from other areas.
  • People who have tried this method report noticing more BTM winter webs in their trees, particularly those around the lights, the following winter.
  • Many parasitic flies and wasps that attack BTM are also drawn to light, reducing their impacts on browntail moth populations, not to mention other non-target effects.
  • Females attracted by lights generally hang out on the host foliage nearby, with more males drawn directly to the light.