Implementation of Aerial Spray Program for Control of European Gypsy Moth Outbreak in Ward 2

European Gypsy Moth (Lymantria dispar) (EGM) is an invasive alien pest that was first found in Ontario in 1969. This pest cannot be eradicated. If left unchecked, populations can grow to outbreak levels, which can lead to tree defoliation and ultimately affect the health of the urban forest canopy. The EGM population fluctuates in relation to environmental and biological controls. In 2007, 2008, 2013, 2017 and 2019 Toronto implemented aerial spray control programs when EGM populations attained outbreak levels. Those measures were successful in reducing the population to acceptable levels. Survey data collected in the fall of 2019 indicate that the EGM population is at a high level in the area defined as the Princess Margaret Spray Block and requires intervention in order to mitigate the impact to forest health and to alleviate the nuisance caused by this pest. This report presents the results of the survey along with recommended control measures, which include an aerial application of Bacillus thuringiensis subspecies kurstaki (Btk) to manage the infestation. At present, aerial spraying is proposed to treat a total of twenty-six (26) hectares of land in Ward 2. Ground-based spraying, systemic tree injection and mechanical egg mass removal is also proposed for various locations within multiple other wards to treat approximately 900 additional individual trees. This control strategy is expected to reduce the EGM populations as well as mitigate potentially severe canopy defoliation from occurring in the targeted areas. The control strategy would result in the significant decline in the health of the trees and/or the prevention of tree loss in the area to be treated.

3. City Council authorize the City Solicitor to introduce a bill to implement a control strategy for European Gypsy Moth (EGM) infestation through aerial spraying of the biological control agent, Bacillus thuringiensis subspecies kurstaki (Btk) in Ward 2.