Moth Control

City moth control

In 2021, the City placed barrier bands on more than 1,200 trees and removed approximately 6,600 egg masses from over 900 trees. The City continued in 2022 to implement these control measures along with several other integrated pest management strategies. The moth populations collapsed in 2022 however the City will continue to monitor population levels. 

Egg mass scraping and vacuuming – January to May

• The City will manually remove accessible egg masses through scraping and vacuuming in known moth hot-spot areas.

Biological control product (Btk) application – April

• The City will perform some Btk sprays from the ground at select park and street tree locations and will inject TreeAzin™ in trunks of select high-value heritage trees.

Barrier band installation – May

• The City will install barrier bands on select high-value street and park trees.

Spongy moth population monitoring – Ongoing

• The City continues to track locations of outbreak populations in order to inform potential next steps.

Resident moth control

To help protect trees on your property from these invasive insects, the following precautions can be taken throughout the year:

Scrape and destroy egg masses – January to April

• Scrape off and destroy egg masses by submerging them in a bucket of water and soap for at least two days. After that time, discard of the solution and egg mixture. Doing this will help prevent more caterpillars from hatching in the future. It is important to look thoroughly on your property for egg masses as they can also be found on benches, firewood, outdoor furniture, swing sets and under the eaves of buildings.

Apply biological control products – April to June

• Applying biological control products to affected trees early in the season can also reduce infestations. Contact a licensed tree care company to discuss options for applying biological control products. There is a very tight timing window for some products.

Install burlap bands – May to August

• Trap caterpillars by wrapping burlap around tree trunks to make it easier to collect them. Check your burlap band daily, remove trapped caterpillars and place them in a bucket of soapy water for a day or two before disposing.

Handpick caterpillars – June to July

• Remove caterpillars by hand and place in a bucket of soapy water for a day or two.

Scrape and destroy egg masses – August to December

• Scrape egg masses off trees and place in a bucket of soapy water for a day or two.

Ensure you always wear gloves when handling caterpillars and egg masses to avoid an allergic reaction.

If you have concerns about a tree on your property, contact a certified arborist. For materials and supplies to help control the population, contact your local nursery or garden supply store. To help promote new leaf growth, water the trees that have been affected by spongy moths. Visit vaughan.ca/water for more information.