Spongy Moth

Spongy Moth Caterpillar Control

Spongy Moths (formerly known as Gypsy Moths) are a European species of defoliating moth that feeds on deciduous tree species, especially oaks and maples. In 2021, many people became aware of these pests as their populations rose to damaging levels and spread across the province. The population is expected to continue rising and could potentially cause stress and damage to our native trees. Most broad-leaf trees are somewhat resilient to defoliation, but multiple years of attacks can seriously stress the tree, making it more susceptible to fungus, further infestations and other pathogens. This over time can lead to the tree decaying and ending in a costly removal. 

In May once the caterpillars hatch, our team will be able to use a biological control known as Bacillus thuringiensis (Bt). Bt is a naturally occurring bacteria found in soil that is used for targeted caterpillar control. It is widely used across Ontario for Spongy Moth control as it is not harmful to humans. Bt is mixed with water and can be sprayed directly on a tree without harm. Bt needs to be directly applied to the foliage for caterpillars to ingest. After it is ingested the caterpillars will begin to stop eating within a matter of days.

The window for control of Spongy Moth runs from mid-May to mid-June, depending on the weather and the caterpillars themselves. This short period is crucial for control as they will begin to mature and lay their eggs in August and repeat the cycle again. Contact us to get a free quote for Spongy Moth caterpillar control.

Additional At Home Care

The burlap bands that can be provided to you can aid in the decrease of the caterpillars.The caterpillars prefer to eat when it is cooler and will descend the tree during the hot afternoon hours. Before it cools off again, you can fold your burlap down to create an umbrella shape to trap the caterpillars and prevent them from accessing the leaves. At this time, the caterpillars may be removed and placed into a bucket of soapy water and disposed of after a few days. 

Unfortunately, not all the Spongy Moth caterpillars will be able to be controlled. They will mature and begin to emerge as moths in July and August and will lay their eggs for the next season. At this time, if you see any egg masses, they can be scraped off and disposed of to prevent more hatching the following season.