Home > 

European Gypsy Moth

If the corona virus pandemic and a drought is not enough for 2020 you can add in a Gypsy Moth infestation. 


From Sharbot Lake to Kaladar, from Bob's Lake/Crow Lake to Otty Lake this infestation has been spreading.  We now have confirmed reports of the Gypsy Moth on Mississippi Lake.


A Gypsy Moth infestation can create sever defoliation of all oaks and basswood, while also feeding on balsam fire, hemlock, elm, poplar, cottonwood and birch . (Source: Forest Health Tech MNRF)


The current infestation of gypsy moth is wide spread across southern Ontario, ranging from Niagara through to Eastern Ontario. It is confirmed on our Lake in numerous locations. 



Some Facts


  • The larvae (caterpillars) feed on foliage of a wide range of hardwood and some softwood trees.

  • The gypsy moth has over 300 known host plant species with oak, maple, birch, alder and hawthorn being some of their favourites.

  • Defoliation of the tree canopy in many areas across Ontario has been observed widely this year including close to home in the Otty Lake/ Bob's Lake and Crow Lake area.

  • Gypsy moth is most destructive in its larval stage. A single caterpillar can eat an average of one square metre of leaf material over its life span. 


Effect on Area Tress

  • Hardwood trees may try to re-foliate, but this will put a stress on their resources, especially given that most areas of Eastern Ontario are in drought-like conditions. These trees may suffer longer term consequences such as crown die-back or even death. 

  • Trees which were already weakened after three years of defoliation by Forest Tent caterpillar may be more susceptible.

  • Conifer trees may suffer more immediate consequences of defoliation, and may die within a year if all needles have been stripped from the trees.

What's Happening Now?

  • The current 2020 population is beginning to pupate, meaning that heavy feeding by the caterpillars will soon be over for this year.

  • The pupal phase lasts for 10-14 days and then the adult moths have less than 2 weeks to mate and reproduce before they die.

  • There is evidence from past outbreaks that natural control measures may kick in, including a natural virus, and a fungus (NPV). These usually help to bring the outbreak under control, but there is no indication of this at present in our area.


What You Can Do

  • Band your trees with burlap. Wrap a piece of burlap cloth around the trunk of the tree, tie a piece of twine around the centre of the burlap and drape the burlap cloth over the twine so there is room for the caterpillars and adult moths to take refuge during the day. Check the trap and remove and transfer the insects to soapy water for a few days and then dispose.

  • If you find pupating insects, place them in soapy water and dispose.

  • Find egg masses. These eggs are left to overwinter and hatch in the following spring. Scrape the masses off the tree using a putty knife, butter knife or a paint scraper and place in soapy water for two days. Then dispose.

  • Water your trees if you are not under water restrictions.

  • Protect the root zones of your trees.

Plan for Next Year


Although too late for this season, consider spraying trees with hand-held sprayers using Bacillus Thuringiensis Kustaki (BTK). This kills the caterpillars and is non-toxic to humans, pets, birds, fish and other insects. BTK is recommended, but will require multiple treatments during next year’s feeding phase.


Working together


Contract with service providers who may have larger equipment that can reach higher into the canopy of trees. Organize with neighbours or landowner associations to conduct aerial spraying of BTK.  If this option is being considered, planning for next year's season should begin almost immediately, as there are many logistical challenges including:

  • can you find a suitable spray contractor?

  • can you ensure a supply of the BTK product?

  • do you have a large woodlot of your own, or can you enlist enough neighbours to ensure that the spray blocks are of sufficient size for aerial spray operations?

  • speak to your town council or municipality and find out what they can do.

  • educate yourself.

  • prepare for next year.