City beginning aerial spray program to address LDD Moth infestations in Hamilton next month

HAMILTON, ON – Beginning next month, the City will begin its aerial spray program to address the areas where significant LDD Moth (previously referred to as Gypsy Moth) populations are located in Hamilton. An organic biological insecticide - Foray 48 Biological Insecticide Aqueous Suspension (PCP# 24977) will be applied to wooded properties and residential streets in East and West Hamilton, Ancaster, Dundas and Waterdown, to help manage the infestation on city-owned properties.

The organic biological insecticide specifically targets LDD caterpillars and contains a naturally occurring bacterium that when ingested kills the caterpillar within one to two days. The product has minimal environmental impact and will have no health impact on humans, other types of insects, pets, other animals or bees.

City of Hamilton Forestry crews have been monitoring LDD Moth populations over recent years. Most recently, in the fall of 2021, the City engaged a contractor to complete egg mass surveys. The completed surveys showed 47 per cent of plots exceed 2500 egg masses per hectare, which is one of the factors used to determine spray locations.

The aerial spray program will reduce LDD Moth populations in Hamilton, but it will not eradicate the pest entirely. The City will continue public education efforts to inform residents about what they can do to limit infestations on their own property.

The Royal Botanical Gardens (RBG) will be working with City of Hamilton staff to complete aerial spray applications on affected lands adjacent to the RBG Arboretum.

The aerial spray program treatment period is scheduled between May 15, 2022 and June 15, 2022.The exact dates and time for the aerial spray are weather dependent and the City will share up to date details 48 hours prior to each application on www.hamilton.ca/LDDMoth and the City’s Twitter channel. Residents will also be able to use the interactive map on the webpage to search spray locations by address. Each treatment area will be sprayed twice, with the second application occurring seven to 10 days after the first application.

Quick Facts:

• As part of the City of Hamilton’s commitment to diversity and inclusion, the City has replaced the name Gypsy Moth with its Latin name, Lymantria dispar dispar (LDD) in its communications to help educate residents about the invasive pest while remaining sensitive to the negative connotations associated with its common name.
• In 2008, Council approved a by-law that directs control programs be implemented if populations of LDD Moth are above an identified treatment threshold. Monitoring completed in the fall of 2021 noted high populations of LDD Moth, which exceed this threshold.
• LDD Moth is an invasive pest that was introduced accidentally to the United States, from Europe in 1869. Since then, the LDD Moth has expanded its range over much of the eastern United States and Canada. It was first detected in Ontario in 1969 and quickly spread across southern Ontario. It is now well established throughout southern Ontario and as far north as Sault Ste. Marie.
• LDD moth larvae or caterpillars will feed on tree leaves and in some cases evergreen needles. If the larvae population is too high, they will defoliate entire tree canopies and forests in a short amount of time.
• Repeated consecutive defoliation of trees of three years or more has the potential to kill trees and cause a long-term negative impact to the urban forest.
• The City of Hamilton last conducted a similar aerial spray program in 2019. Program frequency is determined as part of the City’s Integrated Pest Management (IPM) program.

Residents can request 48-hour advance notice by contacting the Customer Contact Centre 905-546-2489 or 1-877-446-2424 toll free.