gypsy moth caterpillar     gypsy moth   

  • The Gypsy Moth (Lymantria dispar dispar) is native to Europe and is a defoliating insect found in Ontario.  The first detection of gypsy moth in Ontario was in 1969 and had spread noticeably across the Province by 1981. 
  • This insect is considered to the "invasive" due to the fact that it has moved outside of its native habitat and threatens local ecosystems. 
  • Although it is believed the gypsy moth prefers oak trees, the moth actually feeds on a wide variety of trees, including oak, birch, aspen, and various hardwood and softwood trees.

Life-cycle of a Gypsy Moth

  1. Over the winter, the egg stage is often found on the bark of trees, outdoor furniture, or the sides of buildings.   The egg masses are covered with tan coloured hairs and are about the size of a loonie and may contain anywhere from 100-1,000 eggs.
  2. Eggs hatch in the spring and the larvae ascend the trees to feed on new foliage, generally during the day. 
  3. As the caterpillars mature the feeding then occurs mainly at night. The mature caterpillars are roughly 50mm long, dark hairy colouring, with a double row of 5 pairs blue spots, followed by a double row of 6 pairs of red spots down their back. 
  4.  Feeding is completed around July.
  5. Male gypsy moths are light brown and slender bodies and female gypsy moths are white and heavy bodied. 

Report Gypsy Moth Issues

Gypsy Moth Defoliation Map 2020

It is believed gypsy moth outbreaks occur every 7-10 years.  The Township's annual spray program occurred in late spring 2020, but due to the COVID-19 pandemic, the informational Public Meetings were unable to occur.  There was also a widespread shortage in the insecticide spray that is used by the company for the aerial spray program. 

West Lincoln, specifically in the area of Caistor Centre and Caistorville, has been significantly impacted by the infestation of gypsy moths in 2020.  

If you wish to be contacted to receive information for the 2021 Gypsy Moth Spray Program please e-mail or call 905-957-3346 ext. 5134.  For additional information regarding the 2021 Gypsy Moth Spray Program, please see below.   

Alternatively, if you wish to report a citing or issue of gypsy moth infestation directly to Early Detection & Distribution Mapping System, who partners with Ontario Federation of Anglers and Hunters, Invasive Species Centre, Ontario's Invading Species Awareness Program, and the Province of Ontario, please visit their website,

The above pictured map is generated each year through the Forest Health Monitoring Program.  The information is collected through aerial surveys across the province and data is collected to produce forest disturbance maps.  The final map for each year is generally available later in the year once data has been collected and ground verified.   

2021 Gypsy Moth and Gypsy Moth Spray Program Information 

"Spring is upon us (thankfully) & we are preparing for our spring aerial spray program. Trees Unlimited (TU) & Zimmer Air Services (ZAS) have agreed to provide a E. gypsy moth aerial spray program across the Niagara Peninsula into Brant County. As in 2020, TU, ZAS & our municipal partners are very confident that we can provide a private foliage protection program that is both cost effective & successful. We deeply understand the importance our homes and backyards will be playing this spring & summer and we want make it as enjoyable as possible.

The latest 2020 gypsy moth defoliation mapping (1.4 million acres) from the Ministry of Natural Resources & Forestry illustrates the extent in which the gypsy moth infestation has grown in acreage & range in southern Ontario. In the Niagara Peninsula, the ground searching & mapping confirms increased levels of gypsy moth in the southern portion of the Peninsula. Egg masses are large & free of any parasitic wasps entry holes.

If you are interested in aerial spraying, please do not hesitate as the spray acres & participants are likely to be provincial records. 

Due to the COVID-19 crisis, a signed Spray Notification & Objection Waiver from adjacent non-participating landowners WILL NOT be required, unless instructed by TU or ZAS. Instead, the property will be posted at the property’s major access points with spray notification signs. As in the past, if your forested acres have not been measured by TU, please confirm with TU before sending in your Agreement. ZAS & TU appreciate your patronage, but due to circumstances possibly out of our control, we may not be able to treat all properties.

Our preference is to receive the signed Agreement online as well as the payment via an Etransfer. Our farm/office in Cooks Mills is open & Agreements & payment can be left in the mailbox. The deadline for Agreements is April 2, 2021 which is only 3 weeks away, so please do not delay.

TU & ZAS are carefully monitoring information from the Ministries and local public health units. We do not anticipate interruptions to our spray program, though there may be slight delays. I will provide further updates, when necessary. If you need to communicate with us for any reason, you will still be able to reach us by phone or email.

Over the winter, there have been many webinars that included gypsy moth & other stewardship activities. I have added a few links that you may find insightful. I have also the Ontario Woodlot Association’s December issue of their Ontario Woodlander. The Woodlander is on the benefits of firewood. The March issue that will be coming our shortly is on foraging in the forest. What makes the Woodlander special is it is entirely written by woodlot owners. I encourage you to review the publication & consider membership.

Stay well & take care. And don’t forget that this is also the beginning of tick season!!"  - Paul Robertson, Trees Unlimited

Forms and Information 

2021 Gypsy Moth Aerial Spray Program Backgrounder

2021 Gypsy Moth Spray Agreement with Cost Formulas

MDMS - Gypsy Moth Spray (Foray 48B) 

Helpful Websites

Please visit any of the following websites for useful information and tips when dealing with a gypsy moth infestation. 

Province of Ontario

Government of Canada

Ontario's Invading Species Awareness Program  

Town of Erin (useful tips for protecting your trees)