Moths
2022 Season
The aerial treatment in Spring 2021 was very successful and staff believe that additional applications are not required on County-owned lands at this time. In Fall of 2021 and Winter 2022, staff surveyed and performed egg mass counts on all treated county-owned properties, as well as, a number of untreated county-owned properties. Egg mass counts where deemed low with light to moderate infestation with minimal defoliation forecasted for Spring 2022.
In the Spring of 2022, staff will continue to conduct egg mass removals and banding of trees. Affected trees in County parks, specifically newly-planted trees, will be targeted, along with tree species that are known to be preferred feeding hosts for the Lymantria dispar dispar (LDD) (formerly known as Gypsy Moth) including Oaks, Basswood, Cherry, Poplars, Birch, Elms, Sugar Maples, etc.
What is a Lymantria dispar dispar (LDD) moth?
The Lymantria dispar dispar (LDD) is a major forest pest concern because the caterpillar, or larva stage of the insect, eats the leaves of trees, defoliating them which makes them more susceptible to disease and damage from other insects, like tent caterpillars. Continued defoliation of trees can lead to their decline and eventual death. While this pest can consume the leaves of most trees, it tends to feed mostly on Oak, Cherry, Birch, Beech, Spruce, and Pine.
View the LDD Moth Brochure (PDF)
What is the County of Brant doing about the Lymantria dispar dispar (LDD) moth outbreak?
The County of Brant is committed to protecting our local forests.
In spring 2021, the County of Brant completed an aerial spray program of County-owned lands affected by severe outbreaks.
The County is also assisting landowners to determine the severity of the infestation on their property and provide education on how to manage it. For more information:
- Email moth staff
- Call 519.44BRANT (519.442.7268), 1.855.44BRANT
How to manage an infestation on your property
LDD Moth outbreaks tend to occur every 7-10 years, with the last major outbreak in the County of Brant being estimated around 2008.
Help manage LDD moths by following these techniques
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May to July: Hand Pick Caterpillars |
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Handpicking caterpillars is most effective on small newly planted trees, shrubs and plants infested with LDD moth. If possible, gently shake the tree so caterpillars fall from the leaves. Thoroughly inspect the remaining foliage, branches, and trunk for caterpillars and using gloves, pick them off your tree. Fallen and collected caterpillars should be placed and left to soak in soapy water to destroy them. |
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June to August (Larger Caterpillar Stage): Burlap Banding |
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Once caterpillars grow to about an inch (2.5 cm) in length by mid-June, they will move down the trunk to seek shelter from predators and heat during the day. Reduce the number of larvae on the trees in your yard by trapping them. Required Supplies:
Step-by-Step Instructions:
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July to August (Female Moth Stage): Burlap Wrapping |
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To trap female moths, wrap burlap lower on the trunk of the tree to trap the female moth (which are unable to fly) before it crawls up the tree and lays eggs. This is the same method used for the larger caterpillar stage. Once captured, drown the moths in soapy water. |
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August to May: Egg Mass Removal |
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Survey your property for egg masses and scrape them off surfaces into soapy water to destroy them. Required Supplies:
Step-by-Step Instructions:
Egg masses can be located high up in trees. Care needs to be taken if trying to access anything up high, especially if using ladders. Some private tree care companies can be hired to provide this service at heights. |
Other tactics
Are your neighbours trees infested with LDD moths?
LDD moths can travel by wind up to one kilometre in distance, easily taking over urban neighbourhoods. Working together to manage the infestation is often the best solution.
Biological treatment
The most common approach to dealing with large infestations of LDD moth is to treat the populations with a biological pathogen called Bacillus thuringiensis kurstaki (Btk) which is a naturally occurring organism found in soils. If sprayed into the tree canopy, Btk is consumed by LDD moth as they feed and will kill the caterpillar a few days after consumed. While Btk can be applied from the ground, it is most commonly applied from the air using aircraft which allows the material to be evenly spread into the feeding zone of the LDD moth caterpillar. Aerial treatment is the only feasible way to treat LDD moth in woodland areas or larger urban settings.
Bacillus thuringiensis kurstaki (Btk) is a naturally occurring bacteria that affects the digestive systems of caterpillars. Since Btk does not specifically target LDD moth, there are some native caterpillars that will be affected by aerial spray operations. Btk is not harmful to humans or other wildlife as it is a bacterium only found in insects.
Aerial suppliers - who can help?
It can be expensive to complete an aerial spray program and if not done properly, it may not be successful. Encouraging your neighbourhood to participate will alleviate the cost for you and result in a higher success rate for everyone.
Companies that aerial spray Btk include:
Zimmer Air Services Inc., Blenheim, ON
T: 519.676.9550, TF: 1.800.665-5485
F: 519.676.9552
Email Zimmer Air Services
General Airspray Ltd., Lucan, ON
T: 519.227.4091
Email General Airspray
Please note: The County of Brant does not endorse or recommend a specific vendor. All procurement follows the County of Brant Purchasing Policy #45-13
For more information, visit Health Canada's Spongy Moth webpage