Module 15: Pests of the Acadian Forest

Lesson 4: A Quick Guide To Sample Collection

You may be fairly certain of the insect involved after consulting the field guide. However, if you are still unsure or if you want to confirm the identification you have made, you can send a sample to Nova Scotia Department of Natural Resources (NSDNR). Lesson Four covers what to do if you want to have an insect identified. This is done using a sample of the insect if available or a sample of the damage.

This lesson provides guidelines to help you collect and send the necessary information. This will ensure you receive accurate and timely feedback. Once the insect is identified, NSDNR staff can suggest some control options.

Insect is still on site

Let’s start with the easiest one. You have found an insect and used your field guide and this module to make an identification. You would like to make sure that your assessment is correct. Take the insect and a sample of the damaged tree part to your nearest district NSDNR office. A PDO will confirm identification or send it to the Forest Health group for further work. See Appendix A for contact details. They will ask you some questions about your woodland and get your contact information.

If you aren’t able to identify the insect, do not lose heart. There are approximately 30,000 different insect species in Nova Scotia. Even those who specialize in this field are stumped more often than they would like to admit.



Insect cannot be found

A more perplexing situation occurs when you see damage and are unable to find the insect that has caused it. This requires a bit more work on your part. A digital camera, notebook, pencil, and hand snips are good tools to take with you when trying to collect a damage sample.

Check the damage from a distaNce First look at the damaged tree or trees from a distance, far enough away that you can see most of the tree(s). Make a note of the overall appearance in your notebook and any of the following:

  • Thin crowns
  • Discoloured foliage
  • Damage only on one side of the tree or only on one part of the tree
  • Damage on the new growth or old growth





Also look at the terrain. Is the tree on a rise or in a hollow?

Take a photo that best shows what you see when you look at the whole tree.

As you walk closer to the tree(s), look for damage in the soil around the tree and also note:

  • Work done around the tree(s) that might have damaged the roots
  • Very wet or very dry ground
  • Damage from animals digging
  • Look at the other tree species. Are they healthy or are they looking discoloured or thin? Do you notice any fungus growing where the tree meets the soil? Again, take photos of the soil and area surrounding the tree(s).

Check the damage from close up

Next go closer to the tree(s) and look at the damage. Estimate how much of the tree(s) is damaged. Note if the damage is limited to a couple of shoots or a larger portion of the tree. Even if you don’t see the insect, you may see some webbing or evidence of feeding. A photo would be very helpful. Try to focus the photo as clearly as possible. Use the close up or macro function if your camera has one.








Collecting Samples

For your best chance at identifying the insect pest(s), collect a sample of the damage. Using your hand snips, clip off a section of foliage that has both healthy and damaged parts. It’s difficult to determine the exact size of a sample. Remember that this may have to be sent to the NSDNR Forest Health group, so a truckload of foliage is a bit impractical. Do your best to get a representative sample and fill in any gaps in information with your written notes and photos.

Don’t forget to review your photos before you leave your woodland. It’s not always easy to get good shots but clear, well-lit pictures help provide needed information to assess the damage.

There are also some standard questions that NSDNR staff may ask when you bring in a sample for identification. It helps if you can answer the following:

  • Where was the sample collected?
  • When was the sample collected?
  • What is the tree species?
  • What part is affected? For example: foliage, shoot, last year’s growth.
  • Where is the affected tree(s) located? For example: forest or woodland, yard or landscape, urban, barnyard or pasture, plantation, Christmas tree lot.
  • What is the approximate size of tree(s) affected, height and diameter?
  • What is the approximate age of tree(s)?
  • What is the degree of damage? For example:
    • none (you would use this if you found an insect that was not causing any noticeable damage but you wanted to know what it was)
    • trace (1-5% of leaves, needles, twigs, or branches affected)
    • light (6-29% of leaves, needles, twigs, or branches affected)
    • moderate (30-69% of leaves, needles, twigs, or branches affected)
    • have/severe (70-100% of leaves, needles, twigs, or branches affected)
  • How many trees are affected?
  • Any other notes or comments?
  • What is your contact information?



Now that you have your sample, notes and pictures, you can go to your local NSDNR office. Each district office has a Pest Detection Officer who is familiar with forest pests. They may be able to identify the insect damage or they may want to send it to Forest Health for confirmation.

Once the sample reaches the Forest Health group, you can expect a response within seven business days. If a successful identification is made, you will be told what the insect is and some options to choose from to deal with the insect.

Unless there is an invasive alien species involved, the choice to control or manage the insect is up to the woodland owner. We can provide information and options so that you can manage your woodland to best meet your goals.

Case Study One

Insect present but unknown. Softwood Trees

John and Marie LeBlanc, and their son Jeremy have a 20 ha woodland in Urbania, Hants Co. The family uses the woodland trails for recreation and harvest a few natural Christmas trees.

As she was walking in the woodland one August, Marie noticed one type of softwood was looking thin, almost like she could see through them. After taking a closer look, she found the branches were missing a lot of needles. She thought it was strange that the outer edge of the branch still had needles but the part closer to the tree had very few.

John and Marie were quite sure the trees were balsam fir. They checked in Module One of the Home Study series to confirm that it was.

The following year, they kept a close eye on their trees to see if the problem would continue. In June, they noticed caterpillars feeding on the needles. They knew that they could take a sample to the local DNR office for identification.

John and Marie found 20 trees with caterpillars on them. Jeremy took some pictures, collected a few caterpillars and some small branches, and put them in an ice cream container. They wrote down the information that DNR would need.


  • The insect was collected in Urbania, Hants Co.
  • Collection date was 15 June 2012
  • The tree species is balsam fir
  • The needles are being fed on by a caterpillar
  • It is in our woodland
  • Trees are about 3 m tall
  • Trees are about 10 yrs old
  • About 30% of the tree is affected
  • There are 20 trees with caterpillars feeding on them
  • We noticed last year in August that some of the balsam fir missing needles. Not the needles on the outside of the branch but the needles on the inside, closer to the trunk. We have not sheared the trees or done any work around them.
  • Name, Address, telephone and e-mail.

Armed with their information, they headed for the Natural Resources office to speak to the Pest Detection Officer (PDO). He looked at the insect sample and thought that the caterpillars were the balsam fir sawfly.

But,” he said, “I would like to send this sample to our Forest Health office in Shubenacadie. They will be able to confirm this and provide management options for your woodland. Once they receive it, they will respond within seven business days, so you should hear by the end of next week.

The following week the LeBlanc’s received an e-mail from the Entomologist at Forest Health. The insect was indeed the balsam fir sawfly. They found the reason the trees looked see-through was because this insect feeds on the previous year’s growth and leaves the new needles untouched. This leaves the trees with a silhouette appearance.

The entomologist provided several options to deal with the balsam fir sawfly. He wrote, “They are almost finished feeding so most of the damage is done. Control this year may lessen the population for next year but will not fix the damage already caused. A biological insecticide is available that may help. There are also natural predators and disease that affect balsam fir sawfly. If you’re not planning to use these trees right away, you may want to wait a year and see how the population looks then.”

John, Marie and Jeremy decided to continue to watch the population and see what happened in the following year.

Case Study Two

Insect not present, only damage. Hardwoods

Katherine Murray purchased a woodland five years ago in western Nova Scotia. While driving in Digby County in the early fall, she noticed clumps of tent- like webbing on some of the hardwood trees along the road. She then went back to her woodland to see if there were any of these clumps in her trees.

She found a mass of webbing on the outer end of an alder branch and then another one on a poplar. She noticed that some of the leaves looked like they were missing pieces. She was able to reach the web mass on the alder and pulled it down for a closer look. There were no insects inside the mass, only small dark coloured lumps and the remains of partly eaten leaves.

Concerned that this may impact her woodland, Katherine took some notes on the kind of trees that had web masses, where they were found on the trees, and how many of her trees had them. She also took a couple of pictures of the webbing she couldn’t reach. Lastly, she snipped off the web mass from the alder.

Returning home she looked in her Woodland Home Study Module and Companion Field Guide. She found out that what she was seeing was a tent made by an insect. According to the field guide, three types of insects make feeding tents in Nova Scotia. Number one was the ugly nest caterpillar which is seen much earlier in the season and only feeds on pin cherry. It wasn’t that one. Number two, the eastern tent caterpillar, is usually seen earlier in the year. Since she didn’t find any insects, she didn’t know when they were there. She also read that the eastern tent caterpillar builds its web where two branches meet (crotch) of the tree so it was probably not that either.

The last insect she looked at was the fall webworm. Its caterpillars feed in the late summer so the timing was right. They feed on the leaves of a wide variety of hardwoods – Katherine had noticed the tenting on five different kinds of trees. They make their tents on the outer part of the branches where she had originally seen them, encompassing some leaves within the mass. The book also said that the caterpillars leave the web mass to form pupa and overwinter, so that was why it was empty.

Satisfied that this was the insect that had caused the damage, Katherine did a bit more checking on the internet. She found that this insect, although unsightly, usually does not cause permanent harm to the tree. And the dark-coloured lumps that she saw in the web mass she collected—droppings from the caterpillars that had lived there.


A conclusive ID of the insect pest affecting your trees is necessary to help you to choose the best solution. Collecting a sample and noting various features of the damage are part of this process. DNR staff can assist you with the final identification and also suggest some treatment options.