Budworm now within 25 miles of Maine’s border

Budworm defoliation 2016
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Rivière-du-Loup - Google Maps-1
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Last year, spruce budworm was about 50 miles from Maine’s border. This year it “seems to be getting closer,” said Dave Struble, Maine state entomologist.

Defoliation by spruce budworm, even pockets of severe defoliation, were seen less than 25 miles from the border.

“A small spot has appeared to our northwest, between  Riviere du Loup and Kamouraska. That’s probably less than 30 miles. Quebec’s situation continuing to intensify on the south shore.” See map.

Spruce budworm populations in Maine are being monitored in Maine using a combination of pheromone traps to monitor adults males and branch sampling to determine densities of hibernating larvae (aka “L2’s”).  At current population levels the trap network is being coordinated by the Maine Forest Service and the L2 sampling is being coordinated by the Cooperative Forestry Research Unit (CFRU) at the University of Maine. Struble reported that 94 percent of L-2 sites were negative last winter and the winter before. Numbers of larvae found  in the same order of magnitude:   .04 larvae/br in 2014/15 and .05/br 2015/16. Pheromone traps are showing a slow increase.

Average number of moths per trapMaine’s budworm population is “building up from within and will continue to build up (even if there are no moth flights) unless some factor causes the population to collapse,” Struble said. “There’s no indication of collapse next door. I take all of this to support our earlier forecast:  Detectable summer larval populations in parts of northern Maine in 2-3 years; significant defoliation thereafter.”

Read more: Forests of Maine health highlights 2015

Are you seeing large amounts of moths around your porch or street light in northern Maine? They might be spruce budworm and could provide valuable information about the dynamics of the current outbreak.

Over the past few days, there have been numerous reports of moth swarms throughout Atlantic Canada and there are possibly some in Northern Maine as well,  according to MFS. You can see a progression of weather radar imagery from July 25th, which indicates that these are very likely immigrants coming on wind currents from Quebec. There are many questions about these moths: Are there many female moths (with eggs) migrating or are they mainly males?  Are the females that migrate carrying many eggs or have they already unloaded them? The Healthy Forest Partnership and the Spruce Budworm Tracker program in Atlantic Canada are requesting help to answer these questions, and in doing so helping us to better understand how spruce budworm outbreaks spread.

Foresters in Northern Maine are asked to collect moths near lights at homes or woods camps. Follow these steps:

  1. Look for moths (live or dead) beneath your porch or street light. They may be on the ground or wall.
  2. Sweep these moths into a paper or plastic bag.
  3. Add a piece of paper that has your name, address, GPS Lat/Long. (of collection), and the date.
  4. Put the bag into your freezer (this is important to preserve the eggs for counting).
  5. Repeat using a fresh bag and label as often as you can for the next three weeks – check once per day or a couple times per week, whatever works for you.
  6. Contact Emily Owens (Budworm Tracker Coordinator) via e-mail (emily.owens@canada.ca) to arrange a pickup or shipping of moths.

For information about the SBW outbreak in Maine and the State SBW preparedness report, please visit sprucebudwormmaine.org .

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