Have you seen this caterpillar? If you have, it’s likely you’ve seen more than one. This is the second year the watershed has experienced a severe Lymantria dispar dispar (LDD) moth* infestation. Here are some facts and quick tips for managing infestations on your property.
Fact: LDD caterpillars can eat up to one square metre of leaf material before cocooning. They prefer oak but will also eat the leaves of more than 400 other plant species, including maple, poplar, cherry, willow, birch, and spruce.
Fact: A healthy deciduous tree can withstand LDD feeding, but repeated infestations over several seasons may kill it. Unhealthy trees and conifers are less resilient.
Fact: The hairs on LDD moth caterpillars and in egg masses can cause irritation or allergic reactions in some people. Consider using gloves and other protective wear when managing eggs or caterpillars.
Tip: For small infestations, hand-pick caterpillars off trees, buildings or other hard surfaces. You can also wrap trees with burlap to create a space where caterpillars will congregate. The best way to kill the collected caterpillars is to squish them.
Tip: For larger, more severe infestations, TreeAzin injections and ground sprays are effective. If your property is large and the infestation persists next year, consider organizing aerial sprays with neighbours.
Tip: The best time to tackle LDD moths is between the end of April and mid-May before eggs hatch. Add a note in your 2022 calendar to scrape egg masses off trees into a bucket of soapy water. Natural controls such as viral and fungal diseases that typically kill LDD moths after 2-4 years of outbreak may also bring relief next season.
Report LDD moth sightings to 1-800-563-7711 or www.eddmaps.org/Ontario.
*In our efforts to lead an inclusive organization, we are transitioning away from the use of gypsy moth and using the term LDD moth going forward.