Tree management

The Great Cankerworm Count. Help us conquer the canker.

​​Where did the cankerworms go?

Ever wonder why Charlotte used to have so many cankerworms? Are you stumped over why, recently, we haven't had hardly any? So are we! 

​​Become a Citizen Scientist!

We think you can help us unravel the mystery. Become a citize​​​n scientist this winter and help us collect data on cankerworms. We will send your data to Clemson University to analyze​. With your help, we hope to better understand the cankerworm population in Charlotte and possibly predict the next infestation. ​Ready to get started? Just follow these steps.

​Measure the circumference of the tree trunk to determine how big around it is. Just wrap a string or measuring tape around the tree trunk at approximately 4 1/2 feet above the ground. Make sure it's straight and tight around the trunk. If you're using string, cut it where the string overlaps and then measure it. Enter the length in inches on the tracking form.

You have two options for entering your data:

Online form
This form will save your data so that you can come back to it each week to enter more data. IMPORTANT: You must use the same browser on the same device in order for the form to work properly. We recommend bookmarking this link if you choose this method: https://www.surveymonkey.com/r/Cankerworm​​ 

Printable form
Download this form​ and follow the instructions.​

​Start tracking only when you start seeing moths on your band. There are two ways you can track how many cankerworms are on your band.​

Method #1: Count all the moths on the band.
This method works well if you only have a few moths.

Method #2: Estimate using squares
If the band is covered with moths, it may be easier to estimate them by using 3-inch square holes cut out of a piece of paper.

How do I estimate using squares?
Print out this template and cut out the three-inch squares provided. Place the paper in random places on the band and count how many moths are inside the holes you just cut out. The number of squares you use depends on the circumference of your tree.

  • ​​​Less than 31 inches - Use three squares

  • 31 to 62 inches - Use four squares

  • More than 62 inches - Use six squares

Select different areas to count each week. To ensure you don't count the same moths twice, use a stick to mash or squish the moths.


START TRACKING USING OUR ONLINE FORM

IMPORTANT: You must use the SAME browser on the SAME device in order for the form to work properly. We recommend bookmarking this link if you choose this method: https://www.surveymonkey.com/r/Cankerworm​​ 

PRINTABLE FORM 

Just download, print and follow the instructions.

​​How to track cankerworms

Learn how to measure you tree and estimate how many moths are on your band.

​​How to band your tree

Assistant City Arborist Laurie Reid demonstrates how easy it is to band your own tree.
​​Be notified via email or text message about tree-banding season, where to find supplies and when to apply for tree-banding grants. Subscribe today!​ 

FIND TREE-​BANDING SUPPLIES

​​​​​​​Fall canker​worm​​ and tree banding​

Charlotte has a history of severe infestations of cankerworms. Homeowners can help control the population by banding their trees. Banding trees can prevent the cankerworm population from increasing to an unmanageable level.
 
Each November the City places special traps at scattered locations to monitor the fall cankerworm population. They also monitor the amount of defoliation in the spring to see if it affecting the health of our tree canopy.​ 

Do-it-yourself tree banding 

It's easy to band your own trees. The most common product used to trap cankerworms is Tanglefoot. Another alternative is the Bug Barrier Product. See retailers and resources​​
 
​​What is the fall cankerworm?

The fall cankerworm (Alsophila pometraria) is an insect native to North America. It is typically found from Georgia to Nova Scotia and west to Texas. It has a four-stage life cycle: egg, pupa, larva (caterpillar) and adult.

How does the fall cankerworm affect trees?

​After mating in December, the female moths crawl up trees to lay their eggs on twigs and small branches. As the trees leaf out in the spring, the eggs hatch leaving small green caterpillars to feed on the leaves. In most cases, the cankerworm will not kill the trees; however, repeated defoliation can weaken trees and make them more susceptible to other stresses, such as age, drought, other insects and disease.​ ​​​

What effect will tree banding have on the cankerworm?

Tree banding in November and December is an effective way of controlling the cankerworm.  By applying a glue barrier to the tree trunk, the wingless cankerworm moths are trapped as they climb the tree. 
 
For best results, trees should be banded around the last week of November. It is important to wait until most leaves have fallen from the trees so they don't get stuck to the tree bands. 

Why does Charlotte have a fall cankerworm problem?

For the past 30 years, the cankerworm population in Charlotte has continued to grow. Natural controls have not been adequate to bring the cankerworms to a level that isn't harmful to our tree canopy. Aerial spraying in 1992, 1998 and 2008, along with other natural factors, reduced the population for several years. The City started a banding program on street trees, while requesting homeowners and businesses to cooperate in 1990.  

The banding efforts have continued for the last 25 years. Entomologists cannot explain why the cankerworm populations continue to increase, but the City's large concentration of old willow oaks may promote the infestation. ​​

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​TRAINING RESOURCES

The information below provide instructions on how to band your trees and what to look for as you participate in the The Great Cankerworm Count.

What do cankerworms look like? 
Use squares to estimate how many moths are on tree bands that are full of moths.

 

Trapped moths often lay their eggs on the tree band


 

​​Why band your trees?
Find out how cankerworms threaten tree health ​and why banding protects them.

​An adult cankerwom on a crape myrtle

 

An adult cankerworm trapped in Tanglefoot on a tree band

 

​1. MEASURE YOUR TREE

Measure the circumference of the tree trunk to determine how big around it is. Just wrap a string or measuring tape around the tree trunk at approximately 4 1/2 feet above the ground. Make sure it's straight and tight around the trunk. If you're using string, cut it where the string overlaps and then measure it. Enter the length in inches on the form provided.​​


2. BAND YOUR TREE

You can hire a professional to install the band(s), or you can do it yourself. 

List of local retailers that sell tree-banding supplies​

Instructional video on how to band your trees

Tree-banding instructional brochure​​


3. CHOOSE YOUR FORM

You have two options for entering your data:

​​​​Online form  - This form will save your data so that you can come back to it each week to enter more data. IMPORTANT: You must use the SAME browser on the SAME device in order for the form to work properly. We recommend bookmarking this link if you choose this m​ethod: https://www.surveymonkey.com/r/Cankerworm​​ 

​​​Printable form - Download this form​ and follow the instructio​ns.​


4. START TRACKING!​

- ​Start tracking only when you start seeing moths on your band. There are two ways you can track how many cankerworms are on your band.​

Method #1: Count all the moths on the band.
This method works well if you only have a few moths.

Method #2: Estimate using squares
If the band is covered with moths, it may be easier to estimate them by using 3-inch square holes cut out of a piece of paper.

How do I estimate using squares?
Print out this template and cut out the three-inch squares provided. Place the paper in random places on the band and count how many moths are inside the holes you just cut out. The number of squares you use depends on the circumference of your tree.

  • ​​​Less than 31 inches - Use three squares

  • 31 to 62 inches - Use four squares

  • More than 62 inches - Use six squares

Select different areas to count each week. To ensure you don't count the same moths twice, use a stick to mash or squish the moths.

​​​​