Spongy Moth 101: Everything You Need To Know About Spongy Moths (Formerly Gypsy Moths)

The Lymantria dispar dispar (LDD Moth) or as it is more commonly known Spongy moth (formerly the European Gypsy Moth) is a non-native defoliating insect that feeds on a variety of tree species found in the Greater Toronto Area. They are an invasive insect from Europe that were accidentally introduced in North America in the 1860s during an attempt to rear an alternative silk-producing insect. They feed on a wide range of hardwood trees, as well as evergreen trees, but show a preference to oak trees.

Before you start running for the hills because these pests are invading your green spaces, we have put together a quick 101 on everything you need to know about Spongy Moths.

What You Need To Know About Spongy Moths

What Do Spongy Moths Look Like?

Single Spongy Moth Caterpillar

The Spongy Moth (previously known as Gypsy Moths) caterpillars are 50 to 60 millimetres in length. They are dark and hairy, with five pairs of blue dots and six pairs of red dots on the back.

Why Are Spongy Moths A Threat?

Lymantria dispar dispar (LDD Moth) or Spongy/Gypsy moth caterpillars usually congregate in large numbers, eating leaves off your tree over a 1 to 2 month span during the spring/early summer. They can be blown from tree to tree for over a kilometre by the wind, thus spreading these pests across a wider area and creating a larger issue for you to manage. 

Each Spongy moth caterpillar can eat an entire square metre of foliage off a tree. This can result in a tree becoming defoliated. A defoliated tree can be weakened substantially and over repeated invasions or combined with other environmental stresses, can result in the tree dying.

 Spongy moth caterpillars may also cause allergic reactions, as the small hairs on their body can pierce skin. This can result in a moderate stinging sensation and the pain associated with being stung. Welts or blistering may also be common, but this is dependent on the individual, as everyone reacts differently to being stung.

These pests can also become nuisance when they move onto or lay egg masses on outdoor household items, contaminating the item in the process. Their droppings, which are gooey/sticky, can be messy and unsightly to deal with, making outdoor activity unpleasant especially on paved surfaces, decks or yards. 

What Are Common Signs Of Spongy Moths?

Egg sacs and Spongy moth caterpillars on a tree

From late August to early May, you may see the yellowish cottony looking egg masses on trees in your yard. Each egg mass can contain between 100 to 1000 Spongy moth eggs that will be ready to hatch.

Spongy Moth damage on a leaf

The damage from the caterpillars in early May to mid-July is the most noticeable, as it starts with small holes in the leaves and over time, the leaves are soon completely eaten. The most sign of Spongy moths (formerly Gypsy moths) on your property could be the seeing the caterpillars feeding on tree foliage or you may also notice droppings on leaves and the ground. The early instars (the stage in between hatching and moulting into a moth) feed during daytime, so they will be visible on the trees.

How To Prevent Spongy Moths (Formerly Gypsy Moths) On Your Property

Removing as many egg masses as possible during the August to May period can help to significantly reduce the Spongy moth population on your property. It is important to note that it may be difficult to find and access the egg masses, depending upon the height of the tree and the location of the egg masses. 

Any kind of burlap sack/material can be wrapped around the tree trunk to capture some Spongy moth caterpillars. Once these pests are on the burlap sack/material, you manually pick them off and place them in soapy water.

If the Spongy moth issue on your property is beyond what you can handle, don’t hesitate to reach out to Orkin Canada. Your experienced Orkin Canada technician will implement a customized Spongy moth program for your trees and property that will ensure your trees are safe. Contact the local pest control experts at Orkin Canada for professional Spongy moth removal you can trust.