Control Programs for Forest Tent Caterpillars & Elm Bark Beetles

Forest Tent Caterpillar Control Program

The City’s Insect Control Branch will begin its forest tent caterpillar control program on Sunday, May 14, 2017 at 9:30 p.m., weather permitting. Tree spraying will be carried out in Insect Management Areas 43 and 51. Throughout the program, surveillance crews will continue to identify areas of the city where trees require treatment.

The program will be treating City boulevards and focusing on City parks and cemeteries where forest tent caterpillars are starting to cause significant levels of defoliation.  Forest tent caterpillar larvae typically feed on American Elm, Manitoba Maple, Green Ash and ornamental trees.

A Public Service Announcement will be issued daily providing information on what areas of the city will be sprayed the following day. This announcement will also be posted at City of Winnipeg – Insect Control News/Public Notices. Until further notice, the forest tent caterpillar treatment program will occur nightly from 9:30 p.m. to 6:00 a.m., weather permitting.  Treatment will be conducted using Bacillus thuringiensis var. kurstaki (Btk), a biological, organic product which is sprayed from high pressure tree sprayers directly onto the foliage of the trees. two to three days later.

Homeowners are responsible for forest tent caterpillar control on their property:  Citizens can spray their own trees with Btk which is available at most garden centres or they can contract a tree spraying company by referring to the Yellow Pages under tree service or exterminators. If you are planning to spray trees on City property, you are required to use Btk or insecticidal soap in accordance with the City of Winnipeg’s guidelines for treating City-owned trees.   Homeowners are also reminded to remove tree bands as the band will damage the bark of the tree if left on throughout the summer.


Application for Buffer Zone

Residents can apply for a 30-metre buffer zone in order to exempt their property during a forest tent caterpillar treatment program. Property owners not wanting insecticides applied on or adjacent to their principal residence may register as “Anti-Pesticide Registrants”.

Those who wish to register must provide identification that ties the registrant to the address being registered for a buffer zone. A photocopy or scanned document like a driver’s licence, Manitoba Hydro, MTS or other utility bill will suffice as acceptable identification proving primary residence. A 72-hour turnaround time is required.

There are four different options to register:

  • In writing to the Insect Control Branch at 3 Grey Street, Winnipeg, MB R2L 1V2,
  • By emailing 311 at
  • By faxing 311, and
  • In person at 1539 Waverley Street.


Elm Bark Beetle Control Program

The elm bark beetle control program will begin on May 23, 2017, weather permitting, in Insect Management Areas 31 and 32. The program is intended to control elm bark beetles, the carriers of Dutch Elm Disease (DED).

Weekly public service announcements will be issued on Fridays throughout the program indicating which Insect Management Areas will be treated the following week.   Treatment will occur between the hours of 5:30 a.m. and 4:30 p.m. Monday to Thursday, weather permitting. Treatment will occur on an ongoing basis until fall.   Treatment will be conducted using Pyrate 480 EC® (Chlorpyrifos), a chemical product, which is sprayed from portable sprayers directly onto the lower 50 centimetres of the tree trunk.


More Information