In addition to the Town of Caledon information regarding Gypsy Moth https://www.caledon.ca/en/news/gypsy-moth-in-caledon.aspx#How-can-I-protect-my-trees this information is from the Inglewood Garden Club:
It has been brought to our attention that perhaps many in our village and surrounding areas are not aware that our trees, both deciduous and coniferous, have become infested with the Gypsy Moth invasive species. Many other close by areas, such as Halton, are similarly infested. When not kept under control, the caterpillar or larva stage of the Gypsy Moth eats and, in some cases, completely defoliates the leaves and needles of trees, causing them to be more vulnerable to disease, attack from other insects, and eventually die. Many municipalities, such as Etobicoke, conduct aerial spraying to control this pest, but to date neither the CVC nor the Town of Caledon have similar plans. It will be up to each resident to try to mitigate the damage on their own property.
Therefore, we recommend that between now and the end of April, you remove and destroy egg masses found on tree trunks and branches. One egg mass contains about 300 eggs. By destroying them you will reduce the number of caterpillars that emerge in May. These egg sacs are easily identified as light brown, oval shaped mounds, approximately 1” in length.
Scrape off egg masses with a dull knife and place them in a bucket filled with soapy water. After a few days, discard them in your garbage.
If this is not possible, you can also use a commercial horticultural oil that can be sprayed on the egg sacs to prevent the eggs from hatching in the spring. This oil can be found in most garden centres or stores.
Further measures will need to be taken throughout the growing season. Refer to these websites for detailed instructions
Late April to early May: Place sticky barriers or bands on the tree trunk
Late May to August: Replace sticky bands with burlap bands https://fyi.extension.wisc.edu/gypsymothinwisconsin/pest-management-2/management-guide-for-homeowners
For caterpillars that cannot be trapped in this manner, or for which you cannot pick by hand, this is an organic spray that will kill them. https://www.saferbrand.com/safer-brand-caterpillar-killer-ii-with-bt-concentrate-16-oz-5163-6
September 2021 to April of 2022
Capture and destroy female Gypsy Moths to aid in preventing the laying of egg sacs. Repeat the procedure for destroying any egg masses on your trees.
Websites for Additional Information
We hope you find this information useful. If you would like to contact one of our members for more information, or to join the Inglewood Garden Club, please contact us at firstname.lastname@example.org