What Every Homeowner Needs to Know About Their Aging Trees

Where did all the Cankerworms go in the spring of 2019


 Cankerworm Page

Winter/Spring 2010

May 11, 2010  

I have had another message from David Goforth and since I have driven on I -85 twice in the last month it appears that there is a pretty heavy infestation in Cabarrus County. It will be interesting to see if the cankerworm comes back to the Charlotte area and what it does in Cabarrus County. 

My guess on the infestation level in Charlotte turned out to be good.  I have six trees that I band normally, but this past year I only put a tar paper band up on one tree.  I watched the tree carefully when the insects first started climbing the trunk.  My thought was that if  there was a lot of activity, I would band the rest of the trees in my yard.  It worked and I saved my self considerable time and money.  Even if a person has 3 or more trees and is having a commercial firm do the banding, I think it would be economical to pay for banding one tree and if needed come back and pay for the rest of them if the infestation level is high.  The company doing the work would determine a price for making a separate trip.

Since I am no longer in the business I can say that but am not sure I would like it if I was still in the tree banding business.  The logistics might be very difficult.  If I had hundreds of customers and they all called three days after the first influx of crawling cankerworms and wanted me in their yards NOW, that would create a major problem.

Lets be realistic.  The amount of Tanglefoot and tarpaper in the various dumps around town is considerable.  As stated earlier Blackhawk Hardware sells lots of tar paper and has sold over a mile of it this season alone.  How long will it take for these materials to decay?  We used to buy 75 pails of 25 lb each of Tanglefoot prior to the season for banding.  It also took about a day as I recall to cut tarpaper with a powersaw.  There was lots of manpower preparing the materials and also applying the bands.  To make bad matters worse, if it was cold, the Tanglefoot became very still and difficult to apply.  As in any business venture, being able to plan in advance is critical.

I have not even discussed the amount of Bug Barrier that is being used for banding. (read Bug Barrier)  Unfortunately, the cankerworm is not something that will need to be treated every year in one specific area.  The city provided aerial spraying that really worked and that might have a lot to do with the fact that Charlotte in general saw little cankerworm activity.

April 15, 2010   As I suspected there are some hot spots around.  I got a report from David Goforth who is the county agent for Cabarrus County.  His report is below.  I do not disagree with anything he says but will add to his comments to say that we have such a long growing season, the cankerworm does less damage that if we had a shorter growing season like our friends up North.  We gain about a month in the fall and another month in the Spring for growth and recovery.

If the trees are healthy, they will survive however, it is getting very dry, and if we have a severe drought, along with defoliation from cankerworms then the trees can be weakened.  I also think the trees will leaf out before late June.  It will be helpful to water and make sure the trees are getting enough nutrient.


David Goforth <DJGoforth@cabarruscounty.us>

Date: Thursday, April 15, 2010, 7:14 AM
   We are running into a severe problem with spring caterpillars in several parts of the county in particular Robinson Church Road.  This has been a problem for several years in Charlotte but the first time we  have had much problem in Cabarrus  County.   At this point the homeowner will  have to take what Nature throws at them as far as the mature trees are concerned.  Unless they hire a helicopter for aerial spraying.   On lower shrubs and trees  they can use anything that will kill a caterpillar including  Dipel or the "thrins" (anything where the active ingredient  ends in thrin such as cyfluthrin, bifethrin, permethrin and  others).   In future years banding may be an  option.   The good news (if there is any good  news about this) is that one defoliation will not kill a  healthy tree.   New leaves will appear by  late June and the tree will get some growth this year.

April, 14, 2010 By this time if we were having a severe cankerworm problem, we would all be aware of it.  I have seen a few cankerworms on my car or on the driveway but just two or three on my trap since the last posting on April 7, 2010.

April 7, 2010  Upon checking the tree again today about noon I found 13 cankerworms.  12 were green and one dark gray with a small dark strip on the back.  I never have figured it this is another species which I think it is.  Years ago I thought it might be because the cankerworm fed on a different food and therefore was black.

I also lots of webbing today and a few cankerworms on the driveway. so there are definitely insects around.

April 6, 2010

The pollen has been coming down for a week or so and the leaves are out to the point where you see more green top than open branches, and yes the cankerworms are showing up.

On the same tree that I trap cankerworms on in the fall, I found 12 very young green-cankerworms.  I looked yesterday and saw none, but today there were twelve.

What is rather interesting is that the worms were crawling up the tree which I believe means they came down by their silken threads from the ground.  This indicates to me that they have migrated from other trees in my yard or the neighbors.  I will try to examine the foliage of all of my trees and decide if certain trees are being more heavily damaged than others. 

This season, I only banded one tree because I thought we would have a lean year.

March 28 2010

It is time to take a serious look again at what our late spring will hold.  Will the cankerworm infestation be small to nonexistent or will it be a serious problem for the young buds and leaves of our trees.  Mostly willow oaks are what we observe although many other trees are affected.  If you have flowering cherries close by, keep an eye on them.

The willow oaks are almost out and any day now the young cankerworms will be emerging and feeding on the buds and leaves.  I suspect the infestation will be light because I see few insects in the trees I visit.  In the one tree in my yard which I have trapped for many years, I had only 43 female cankerworms in the trap in 2010 whereas in 2008, there were 1141 females  captured.  During the season which is around late November to late January to early February, I actually mash the insects that get on my trap.  This way I can have an accurate count by totaling the daily destroyed insects.

Look for the tiny green worms as they emerge on your trap.  If you have a tar paper trap, you will probably have egg masses deposited by the female.  The males are attracted to the band because of the presence of the female and egg clusters are laid.  These “worms” will be very small and will show a light green color normally.  They will be looking for something to feed on and will not find it on your band and will starve or get trapped in your Tanglefoot.

March 4, 2010  Do not take the bands down.  The bands need to stay up until early April.  I will post ahead of time what you should consider.  To be well prepared, acquire some Tanglefoot in a small pail.  Many hardware stores sell it.

February 22, 2010  I believe the fall migration is over.  There have been no new females climbing the tree.  As I went through Freedom Park yesterday (Sunday) I saw wide bands of Tanglefoot on the trunks of several trees and not a sign or a single worm.  I do not intend to report much until late March prior to the hatching of the fall cankerworms.

On February 14, 2010 (Valentines Day) I started posting information about what will be happening in the Spring of 2010.  In early April, the new crop of cankerworms will emerge, and we will try to anticipate what will happen and what you might need to do.  Do not remove your cankerworm traps but plan to replenish with Tanglefoot or whatever type of sticky stuff you have. I will post more about this later. 

 If you want to go back to what has transpired from fall 2009 to February 14, 2010 go to this page Fall 2009 to Feb 2010.  As a word of explanation that page was called Cankerworms current info.  To get to the beginning of the page you will need to scroll to the end since daily entries are added at the top of the pages.

As a little recap of the fall migration, here are the highlights.  The migration started December 22, 2009.  That is quite late based on years past.  We used to say that the first hard frost was around Thanksgiving day.  So to start about a month later is interesting. About the 15th of February 2010, I observed the last cankerworm on the trap.

The cankerworms looked exceptionally large and healthy in the early days, but the migration was down compared to most years. On January 17, 2010 there were 25 cankerworms trapped.  That is a small number compared to 361 insects captured on January 13, 2007.  There were four days during the 2007 when the number of insects captured was above 100, and three days when there were over 200 insects captured in the trap.

The total cankerworms trapped in 2006 were 5941.  I have a monthly count for this but seemed to have misplace the daily records.  I believe they were lost when I had to release my old web site www.arborman.com to the company that bought my business.

The total cankerworms trapped in 2007 were 2522.
The total cankerworms trapped in fall 2009 and early winter of 2010 were 167.

I made the decision to only band one tree in my yard.  It will be interesting to see how bad the defoliation is in the spring.

As time allows, I will see if I can make more sense out of some of the other information I have gathered over the years.  The worse year was 2006.  Certainly, spraying the trees in the spring has helped, but that is not going to happen this spring.