What Every Homeowner Needs to Know About Their Aging Trees

Where did all the Cankerworms go in the spring of 2019


 Cankerworm Page

Additional Photos 2007

I see a lot of Bug Barrier traps put up like this.  Note that two white strips of batting material are placed side by side.  That means that four inches of the total six inches of sticky stuff are wasted.
In my  opinion, these types of traps, when they are installed properly, will only work when there is a low level of infestation of cankerworms


Below is a the old style Tanglefoot trap.  The tarpaper is wide enough to allow for more Tanglefoot later in the season as dust, leaves, and cankerworms clog up the trap.

The band of Tanglefoot is about 6 inches wide and is applied at the lower part of the tarpaper.  This is good except that early in the season the Tanglefoot will gather a lot of leaves.  If you are doing this yourself, then you should just put on a narrow band of Tanglefoot until the leaves are down and/or the cankerworms are active.


Below is a photo which shows a tree in April where the Tanglefoot is not working anymore.  There are at least two reasons.  In the fall the Tanglefoot was not thick enough.  Secondly, the tarpaper tends to absorb the Tanglefoot after a period of time.

The solution is to add more Tanglefoot to trap the caterpillars that have hatched and are moving around looking for food.  There are often thousands of insects moving up the trees in the spring and they can defoliate a tree in a few days.

Copy of cw_tarpaper_not_working_300

Below is an amazing photograph of a willow oak in the spring where the worms are going up the tree.  The owner has taken duct tape and put it around the tree backwards to catch insects.  I do not think this is a better solution than the Tanglefoot but it sure does demonstrate the quantity of insects that are out there.


The significance of the photo below is that the center willow oak is banded with the old style Tanglefoot and tarpaper band. This tree is not adversely affected by the cankerworms.   There are four other willow oaks in the yard and one elm on the planting strip which is to the left of center.

Cankerworms do not like the winged elm, but all the four other willow oak trees which were banded with Bug Barrier are totally defoliated.

Also the city trees which were banded with Tanglefoot came through quite well last year (spring 2007).  It is for these reasons that I prefer the Tanglefoot banding.  It is still necessary that the traps be monitored throughout the season and especially in later March and very early April.


In the spring this past two seasons there have been thousands of cankerworms coming out of the trees either by parachuting on silken threads or crawling down the trunk  It  has become very important to trap these insects also as they move either up or down on the trunk.  

The photo below shows many cankerworms on a tassel that has fallen out of a willow oak.  Since the tassel tends to fall straight down it easily makes a bridge for the cankerworms to crawl over.