The City of Toronto is implementing its first round of its aerial spray program this weekend.
The spray is for tree-damaging European Gypsy Moth, and will protect the canopy and vulnerable trees from infestation.
According to the city, gypsy moths are an invasive insect whose caterpillars feed primarily on the leaves of oak and other trees species. The severe leaf loss created by these insects can make trees weak and susceptible to diseases and weather fluctuations. Untreated, those pressures can result in the loss of public and private trees.
During the aerial spray, two twin-engine helicopters with ultra-low-volume spray systems will fly about 15 to 30 metres above the tree canopy to apply “a biological insecticide.”
The City of Toronto used Foray 48B during its 2017 aerial spray program. The pesticide does not affect adult moths, butterflies, bees, fish, birds, or mammals. This is a biological control made from a naturally occurring bacterium found on dead or decaying matter in the soil that poses minimal risk to human health and is approved by Health Canada for urban aerial use.
The city says the product must be applied directly to tree foliage, as Gypsy Moth caterpillars must feed on the treated leaves for the insecticide to be effective.
Wards 1, 2, 3, 4, 11, 12 and 15 have been identified for aerial spray as they contain a large portion of the city’s oak trees and exhibit significant gypsy moth egg masses.
The first round of aerial spraying for Day 1 areas will take place on Sunday, May 26 between 5:30 and 7:30 am and spraying for Day 2 areas will take place on Monday, May 27 from 5:30 to 7:30 am, weather permitting.
As a result, specific spray dates are chosen 48 hours in advance and can be cancelled if weather conditions change. Residents within the affected spray zones are encouraged to check for and subscribe to updates on the city’s website.
Previously, the city has controlled gypsy moth caterpillar populations by using integrated pest management measures including tree banding and injections as well as egg scraping. However, those methods alone will not effectively control or reduce the population in the identified high-risk areas.
Toronto Public Health is not anticipating any health impacts associated with the aerial spray program.
A map of the designated spray areas which identifies each location’s specific spray date is available online.