2022 Season:
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.
The aerial treatment was very successful and staff believe that additional applications are not required on County-owned lands at this time.
Additionally, staff will continue to assist residents by directing them to aerial suppliers, conducting on-site assessments, providing educational assistance and monitoring County-owned properties.
Aerial Treatment Program
The aerial treatment program of County-owned lands and private residential lands to control the Lymantria dispar dispar (LDD) moth (formerly known as Gypsy Moth) outbreak was completed in Spring 2021. For more information on how to control LDD moths on your property, please see below.
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.
What is the County of Brant doing about the Lymantria dispar dispar (LDD) Moth Outbreak?
Some areas of the County of Brant have been negatively affected by a LDD Moth infestation. In spring 2021, the County of Brant will complete 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, please email moth@brant.ca or call 519.44BRANT (519.442.7268), 1.855.44BRANT.
The County of Brant is committed to protecting our local forests.
What can you do to stop the spread 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:
| May to July: Hand Pick Caterpillars |
 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. |
| June to August (Larger Caterpillar Stage): Burlap Banding |
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Required Supplies:
Step-by-Step Instructions:
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| July to August (Female Moth Stage): Burlap Wrapping |
| 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. |
| 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. |
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.Year-Round: Consult with a Professional
Consult an arborist for treatment options or contact your local garden supply store for the availability of materials.
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.
Other tactics:
| Traps: |
| Traps will attract and trap moths using pheromones and can be deployed in areas where outbreaks are occurring. This tactic is difficult for larger areas or large populations of LDD Moth. |
| Chemical Treatment: |
| Chemical insecticides can be sprayed on trees with caterpillar infestations. This is feasible for smaller trees or by tree services with high-pressure spray equipment, but is not feasible for larger woodlot areas. Please note, chemical insecticides can have health and environmental side-effects. |
| Biological Treatment: |
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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? |
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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 General Airspray Ltd., Lucan, ON
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 www.canada.ca/en/health-canada/services/pest-control-tips/gypsy-moths.html
Please note, LDD Moths and Tent Caterpillars are not the same. To learn more about Tent Caterpillars, visit the Government of Canada webpage.
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