By Staff
April 11, 2019
BURLINGTON, ON
As part of an Integrated Pest Management (IPM) Program, the City of Burlington will be using a low-flying helicopter to apply a bio-pesticide over four wooded areas to control gypsy moth populations which causes significant defoliation and potential long-term impact to the City’s urban forest.
Gypsy moth undergoes four developmental life stages: these are the egg, larva (caterpillar), pupa, and adult. Gypsy moth females lay between 500 to 1,000 eggs in sheltered areas such as underneath the bark of trees. The eggs are covered with a dense mass of tan or buff-colored hairs. The egg mass is approximately 1.5 inches long and 0.75 inches wide. The eggs are the overwintering stage of the insect. Eggs are attached to trees, houses, or any outdoor objects. The eggs hatch in spring (April) into caterpillars.
The areas include:
• Forestvale/Kerncliff Park
• LaSalle Park
• Lowville Park
• Mountainside Park
The exact date of the spraying is expected to be during the third and fourth weeks of May in the early morning. Weather conditions as well as insect development will determine the exact date.
Spray dates will be posted on the City’s Twitter and Facebook accounts @CityBurlington and online at burlington.ca/gypsymoth at least 48-hours before the spraying.
Residents can also use the website to enter their address to see where the spraying will occur in relation to their home or work.
The City’s contractor will be applying a Class 11 biopesticide, Foray 48B, REGISTRATION NO. 24977 PEST CONTROL PRODUCTS ACT, with active ingredient Bacillus thuringiensis ‘kurstaki’.
Application of the pesticide with be completed between 5 and 7:30 a.m.
About the Biological Pesticide
Bacillus thuringiensis ‘kurstaki’ (Btk) is a soil-borne bacterium that is applied to the leaves of affected trees while caterpillars are in their early stages of development. Once ingested, the bacterium disrupts the caterpillars’ digestive system with cessation of eating within 24-48 hours. Within days, caterpillars that have ingested Btk will succumb to its effects.
Btk does not have any negative effects to humans, birds or bees. Btk will affect other caterpillar species (known as non-target species). Due to its low residual nature and the narrow spray window due to larval development, the non-target impact is expected to be low.
Individuals who have concerns should take reasonable precautions to avoid exposure during a spray program in the same way they would avoid pollen or other airborne materials during days when air quality advisories are issued. Residents can also reduce exposure by staying indoors with windows and doors shut during the spray period if spraying is taking place in their area, although this is not required by health officials.
About Gypsy Moth
European Gypsy moth, Lymantria dispar, is a non-native invasive pest that was introduced in the late 19th century. It was first discovered in Ontario in the 1960’s and has been a major defoliator of deciduous and coniferous trees across Southern Ontario.
Integrated Pest Management
As part of Burlington’s Integrated Pest Management (IPM) program, Forestry staff assess sites annually across the city and conduct egg mass surveys to determine areas that have exceeded an action threshold, whereby natural processes can no longer maintain pest population levels on their own. Although healthy trees can generally withstand defoliation several years in a row, trees which are already in distress from problems such as acute drought, compacted soils, diseases or other pests, may decline and die. Generally, healthy trees which are defoliated in spring, will leaf out again by mid-summer.
Gypsy moth populations tend to be cyclical, with peaks every 8-12 years, followed by dramatic population decline of the pest.
The City of Burlington conducted a similar program in 2008.
For questions or concerns, please contact Brianna Thornborrow, Supervisor of Forest Planning and Health at brianna.thornborrow@burlington.ca or 905-333-6166, ext. 6145.
Steve Robinson, Manager of Urban Forestry explained that: “We need to take action to reduce the gypsy moth population in order to maintain the health of our valuable urban forest. Currently, populations are expected to be too high for their natural predators to keep them in check. By applying a biological pesticide with a measured approach, we will be able to reduce pest populations to manageable levels. Protecting our urban forests is a priority for the City as it greatly impacts our health, homes and recreation.”