Public Education Meetings

Gypsy Moth Public Workshops - Experts Share Advice On How To Protect Trees On Private Property 


Gypsy Moth open house to be held on Saturday April 12th, 2014 from 1-4pm at the Lorne Park library.1474 Truscott Drive


Staff will discuss:   


  • Steps residents can take to treat Gypsy moth on their own property

  • hands-on demonstrations (may be outside, please dress for the weather)   

  • an update on the City's proposed plan for manageing this pest for 2014




The European Gypsy moth is a pest found in many locations throughout North America. The caterpillar eats the leaves of trees which damages the overall health of the tree. Gypsy moth is most commonly found on species such as maple, elm, oak, willow, birch and aspen.  Gypsy moth will always be present in the City of Mississauga.  Treatment will not eliminate the Gypsy moth population but will reduce its population and the destructive loss of leaves on trees.


More Information          

Pre-registration is not required.  Participants will receive a free moth trap (one per household).   To learn more about Gypsy moth, go to or call 311 (905-615-4311 if outside city limits).



The GWHA is well aware of the Gypsy Moth problem in Gordon Woods and we have been in constant contact with the City.


We have been informed by the Forestry group that the numbers were not as significant as in past years, so there will be no spraying this year.


Traps have been hung on some public trees in the neighbourhood as the City monitors the situation.  We encourage residents to contact Aaron Schmidt, Mike Maloney, or Gavin Langmuir (Manager) at the city and let them know of the situation.  Contact number is 311 or 905-615-4311.


We understand that some residents have had success with a company called Arbor Valley Urban Forstry (905) 773-7912.  They used Treeazin which is a product that is injected into the tree.  The chemical is carried to the leaves of the trees and the Gypsy Moth caterpillers eat the leaves and are killed.  It works in 2 days.  If the moths have pupated already it will not affect them as they will not inject the product.


There are other companies that also have gypsy moth traps which we suggest here or make your own here.


For more information - check here.


Gypsy Month Update Oct 2013
Adobe Acrobat document [213.1 KB]

Gypsy moth populations will always exist in the City. In 2005-2006 there was a significant rise in the population; resulting in substantial defoliation of a large number of trees throughout specific areas in the City containing the highest proportion of Oak trees. This resulted in the need to conduct an aerial spray program throughout those locations in order to try to bring the population back down to a more manageable level.


Since that time, the City has continued to monitor the population. In 2012, we noticed a few spikes in the populations but only in very specific areas within the City; so specific that even some streets would have one or two trees that were targeted by the species and the rest were not. The increases in general were mostly due to the fact that the spring and summer of 2012 were very hot and dry. The natural pathogens that exist in the environment only thrive in cool damp springs, and given we did not have that kind of weather, the existing population of Gypsy Moth had ideal conditions to thrive, hence the isolated population increases. Last year, the City conducted a very extensive monitoring program including installation of over 200 pheromone traps in effected neighbourhoods as well as individually monitoring all city owned trees in these areas and conducting egg mass counting and removal, in order to estimate populations for 2013. A report was taken to General Committee March 15, 2013 outlining findings and proposing mitigation measures the City was going to undertake in 2013 in order to ensure population levels remained manageable.


In 2013 the City has undertaken numerous types of integrated pest management on City owned trees that were identified as having higher than normal egg masses through our 2012 monitoring. We conducted egg mass removal, sticky band installation, burlapping, and ground spraying of BTK on trees that had difficult bark to remove egg masses from and injected some trees with TreeAzin as part of a trial with BioForest technologies. We are currently installing pheromone traps, and are currently working with the consultant we worked with in 2006 to  analyze our data from this year to help us with projections for next year. We are also currently planning workshops to be held both this fall and next spring with residents associations regarding Gypsy moth populations, what we as a City will do and what residents can do on their own property.


With that said, the population, albeit a bit higher than usual in some select areas, it is nowhere near in the infestation levels of 2005-06. Although there are signs of feeding in some canopies within select neighbourhoods, we are not seeing anywhere near the defoliation issues we were having a few years ago. Fortunately we have had a very wet and cool spring and early summer. We have confirmed, with the help of the Ministry of Natural Resources that the natural pathogens are very present this year (E. maimaiga & NPV) which has resulted in very high mortality rates in caterpillars. Although some trees appear to have high numbers of caterpillars, the majority of them are dead, which means they will not being laying egg masses for next year, and that nature really is taking its course and as of now, given what we have seen, we don’t anticipate having issues next year that require an aerial spray program.


Should you require any further assistance, please do not hesitate to contact the Councillor’s Office or direct your specific questions to Jessica McEachren M.ES, MCIP, RPP, Ecologist, Parks & Forestry Division 905-615-3200 x 5378;