(formerly “Gypsy Moth” Lymantria dispar dispar)
The adult male moths have lighter brown coloration with darker designs on the wing. They also have large antennae which look like feathers. Since only the males can fly, it is quite easy to distinguish the genders, however, the females look quite different being a very light tan colour. The female moths can lay between 500-1000 eggs, and they usually lay them in between tree bark cracks. These eggs are very noticeable as they look like a big tan yellow fluff on the side of the tree. They can also lay them elsewhere such as on yard items and on vehicles. When the eggs hatch the caterpillars have 5 blue and 6 red spots running down parallel down the back. They also have large hairs which stick out and these hairs can irritate your fingers if you touch them. This moth is native to Europe Asia and Africa but came to America around 130 years ago. The spread of these moths is likely due to the movement of firewood.
The LDD moth inhabits Ontario, Quebec, New Brunswick, PEI and Nova Scotia as an invasive species.
Impacts & Control
The larva stage has the highest impact on ecosystems as they will eat foliage, thinning out the canopy of a tree. This can ultimately lead to the tree’s death if enough of its foliage is eaten away. The caterpillars feed on a wide variety of trees, most often oak. Economic and social impacts follow as dead trees can be costly to remove and our forestry industry loses valuable resources. The caterpillars have been known to cause skin irritation when touched.
Surveys are conducted to measure populations and identify target areas. Once this is done then there are different techniques to control them.
- Manually scraping away egg sites
- Banding trees with sticky barriers
- Chemical sprays to kill larvae
- Helicopters also spray pesticides in identified areas if the issue is prominent.
Property owners should regularly inspect their trees and outdoor equipment during late spring and early summer for signs of egg sacs. If they find one, then soak the sac in water with soap/bleach for 3 days to kill the eggs. As a property owner, you can also be wary when transporting firewood.
Inspect your vehicle and equipment after travelling to infested areas.
One method for property owners is to wrap a band of burlap near the base of their trees, as the day gets warmer the moth larvae will move down the tree and take shade under the burlap. At the hottest part of the day, remove the burlap and soap it in soapy/bleached water for a few days.