This article is a follow up to Carl Mansfield, tree consultant for MLF farm visit on September 7, 2019. On June 22, 2020, Deb Pella Keen, Executive Director, MLF visited the MLF farm with Ken Jewett, founder of MLF. We again observed the Lymantria dispar dispar or LDD moth (also known as European Gypsy Moth) larvae feeding on several trees, and one unusual host tree, a larch. Digging in the internet we found some interesting information on LDD moths. There are now two known species of LD moth invaders in North America: the LDD moth introduced to Canada over 130 years ago and now the Lymantria dispar asiatica / LDA (aka Asian Gypsy Moth) which while not known to be established in Canada, was first recorded in 1991 in North American at the port in Vancouver, BC according to the US Department of Agriculture (see PDF).
2022 Note: It has been decided by the Entomology Society of Canada that the new common name for LDD/Gypsy moth is now Spongy Moth. Visit their website for more information. In future, MLF will refer to this moth as the Spongy Moth.
Although in many ways similar to the LDD, the discovery of the LDA moth in Canada has raised new concerns. According to Health Canada, the LDA prefers coniferous trees, is better adapted to colder climates, and the female is able to fly longer distances. These traits make the LDA moth a serious threat to Canadian forests.
The spread of the LDD moth has been largely attributed to the movement of firewood, as well as outdoor recreational and household articles. Knowing how to detect, report and manage LDD moth could significantly reduce and limit the spread of LDD moths to new areas. So if you find LDD moth larvae (caterpillars) this summer, do your part for citizen science and download this app (EDDMapS Ontario) and report your finding.
EDDMapS is a web-based mapping system for documenting invasive species and pest distribution. It was developed by the Center for Invasive Species and Ecosystem Health at the University of Georgia, and since its launch in 2005 has now expanded to include the entire US and Canada. As of June 2020, EDDMapS had over 4.9 million records.
We did our part in reporting our finding of LD moth larvae at the MLF farm and while it is highly unlikely (we certainly hope!) that the moth we found was an LDA, it is important that we all learn more about these destructive invasive species.
For more information on LD moths in Canada and how you can control and prevent their spread see these links: