GRCA to treat gypsy moth caterpillars at two properties

The Grand River Conservation Authority (GRCA) will be spraying an organic pesticide at two of its properties this spring to control growing populations of gypsy moth. Aerial applications are planned over susceptible forest areas at Pinehurst Lake and Brant conservation areas. Control of the current outbreak is required to protect and maintain affected forest areas and to reduce future hazard tree removals.

The organic insecticide Foray® 48B, whose active ingredient is a widely distributed soil bacteria called Bacillus thuringiensis kurstaki (Btk), will be applied by airplane. Two applications will occur approximately three to seven days apart. Timing depends on insect and tree development, as well as weather conditions. It is expected that applications will occur between May 21 and June 10, 2021.

It is important that people are not present during aerial spraying for safety and regulatory requirements related to low level flying. Appropriate measures will be taken to close affected areas and park guests will not be permitted on the property for several hours while the spraying occurs.

Btk insecticide is not considered a human health risk and is not toxic to bees and other insects, birds, fish, mammals or adult moths and butterflies. Its application won’t impact moths and butterflies, like monarchs, whose caterpillars develop later in the season. Btk insecticides have been in use for over 30 years in Canada and around the world. Their use is approved by Health Canada including for aerial applications over urban areas.

About gypsy moth

Gypsy moth (Lymantria dispar) is a highly cyclical, non-native forest pest. Their caterpillars eat the leaves of a wide variety of trees. High populations of gypsy moth result in tree defoliation with significant potential impacts on tree and forest health. Ecological impacts result from tree declines and mortality, especially in oaks and hickories, which provide valuable food and habitat for a wide diversity of species. The current gypsy moth infestation is also having a cumulative forest health impact on areas that have recently undergone significant tree losses due to emerald ash borer.

More information and updates on the project can be found online at www.grandriver.ca/gypsymoth.

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Media contacts:

Cam Linwood, GRCA Supervisor, Strategic Communications
Phone 519-621-2763 x2251  |  Email clinwood@grandriver.ca 

Lisa Stocco, GRCA Manager, Strategic Communications and Environmental Education
Phone 519-621-2763 x2316  |  Email lstocco@grandriver.ca