Emerald Cedar Bugs/ Damage


Wondering if anyone can help to identify the bugs I captured off of my emerald cedar trees. The branches seem to be drying out and dying off in sections / limbs of the tree.
I applied Cygon to the trees 2 days ago and seeing these still feeding. I was pretty sure of spider mites prior to this may be in addition to the mites.


Thank you for your question. The first thing I want to say is that you shouldn’t be using Cygon. The active ingredient in Cygon, dimethoate is very toxic. It has been shown to cause mutations, birth defects and cancer in laboratory animals. It is rapidly metabolized in animals and humans and can be virtually undetectable in the body within 24 hours of ingestion. Cygon can be absorbed through the skin and lungs. The species most affected are fish and birds. Birds are especially susceptible to toxic affects and will die if exposed. Honey bee populations can be decimated by single organism contact as the chemical is brought back to the hive and affects the whole population. This website will give you information on pesticide use in Ontario. Some chemical pesticides can be used but must be applied by a licensed operator.


It’s hard to identify the insect in the picture you sent. I wonder if it is a boxelder bug, see photo below. The shape is right, but I don’t see any orange in your photo. Boxelder bugs feed almost entirely on the developing seeds of boxelder (Manitoba maple), maple and ash trees. They are not classified as an agricultural pest and are generally not considered injurious to ornamental plantings. During certain times of the year boxelder bugs cluster together in large groups while sunning themselves on warm surfaces near their host tree.

Emerald cedars can be vulnerable to such insect pests as aphids and spider mites, and these do cause browning and death of foliage, but unless you are certain that this is occurring, the application of insecticides is not necessary; indeed, often light insect infestations can be removed with a strong spray of water, or with insecticidal soap.  Here is some information on identification of and treatment for mites from another Toronto Master Garden post:  https://www.torontomastergardeners.ca/askagardener/newly-planted-emerald-cedar-tree-turning-brown-from-the-outside/

The Cygon should have taken care of the spider mites, so it may be that you do have an additional insect pest but I can’t identify it with certainty.

Boxelder bug

Image result for boxelder bug