HWA Detection & Prevention


Will these kids get to camp under hemlocks with their children?  

With over 35,000 acres of Nova Scotia's hemlock forest infested with the Hemlock killing bug HWA, we are at a critical point in the fight to save our hemlocks.

Right now (early May) is a very important time of the year.  Momma HWA has been busy making babies all winter.  And the cotton-like sacs where she lives are at their largest and most easily seen.

As the weather warms this month, her babies will come out of their protective home and start looking for a new source of food.  Called "crawlers", there can be MANY of them.  100s per sac.  

At the peak, scientists have counted 1,000s of crawlers falling from a single, infested tree.

How do you find HWA?

HWA are tiny -- about the size of a pencil dot.  

But they create a protective cotton-ball like sac around them that is visible and tells us that HWA is present.

The most common way to find the cotton balls is to grab a hemlock branch, flip it over and if infested, you will see the sacs where the needle meets the stem on the underside.

But what about branches higher up in the tree?  Here are a couple of options:

  • wind and ice storms will break off hemlock tips and branches scattering them on the ground where it is easy to inspect (this was a banner year for windfall where I live in Lunenburg County)
  • just before dark, shine a powerful light (greater than 2,000 lumens) with a focusable beam up into the branches.  The cotton balls will pop in the light
  • The pros use a pole saw that will reach up into the canopy where they can cut off branches and bring them down for inspection.

Please report any sightings (with a pic and location if possible) to hwa@nshemlock.ca

What do I do if I find it?

If you find HWA (or something that looks like it), please get a pic, the location and report it to hwa@nshemlock.ca

If this is a place where HWA has not been previously reported, someone from the Canadian Food Inspection Agency will visit the site to confirm the infestation.

VERY IMPORTANT : Early detection means there are more options for dealing with HWA.  Please let us know if you find any.

How do I prevent it from spreading?

HWA is most easily spread when the babies emerge from the cotton balls and start looking for food.  Called "crawlers", this happens from mid May thru until the end of August.  Over 1,000 can fall from an infested tree onto anything below.  And unfortunately, this is when lots of people are heading into the forest for serious R&R.  :-(

Crawlers are tiny -- about the size of a pencil dot.  So what can you do to prevent spreading them :
  • the picture above is the sign that will be going up in locations known to have a HWA infestation
  • please do not assume that the sign is in all locations where there is HWA!  It is found in all seven Western Counties and is moving eastward.  Best to be wary if you are in hemlocks
  • when you leave the forest, use a lint roller on your clothing and pets to remove any crawlers that may have fallen on you, your gear or your pets
  • avoid leaving an infested hemlock stand and visiting another hemlock forest (ie: awesome party weekend at Keji and then go directly to Victoria Park in Truro)
  • if you are headed for another hemlock site, please change your clothes.  5 minutes in a dryer will kill any crawlers
  • please do not remove any hemlock foliage from the forest
  • avoid parking your vehicle or ATV under hemlock trees

We all can help save our hemlocks by taking simple actions.

If you know what HWA looks like and report your sightings --> we can act early to contain it.

You can help minimize the spread if you take steps during HWA's active period from May to August -- use a lint roller to remove crawlers, change your clothing after visiting a hemlock forest, avoid parking under hemlocks, do not remove hemlock foliage --> we can slow the spread

And maybe, just maybe the children in the first picture will get to share the joy of camping in a hemlock forest with their children