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City's Cankerworm Control Program

banding elm tree Cankerworms are a common insect pest in Regina. They can cause considerable damage to trees. There are 3 main components to the City's cankerworm control program:

  • Monitoring 400 traps are placed on various trees throughout the city to monitor the populations of adult male and female cankerworm moths in each area. Cankerworm counts are done on the bands during the spring and fall migration periods to determine which areas have the highest level of cankerworm concentration for a particular year, and require spaying to control these populations. In spring, visual inspections further assist in determining cankerworm populations.
  • Spraying City crews spray City-owned trees in areas with high concentrations of cankerworms. Areas identified as having higher population levels are sprayed first and as time allows we move to the next level of infestation, in decreasing order of trapped adult concentrations. Spraying is done from mid-May to mid-June when the worms are hatching and feeding on trees. A commercial product containing the bacteria Bacillus thuringiensis kurstaki (Bt.k.) is used. Bt.k. affects only worms and is non-toxic to other insects, birds, animals and humans. The worms eat the product, stop feeding in 2-3 hours and die in a few days. The City does not go out to an individual houses to spray the trees, nor do we spray private trees. Residents can view the spraying schedule. Those that have sensitivities can also call the Pesticide Advisory Line for information on where and when the City is spraying. Residents are asked to move their cars off the streets while their areas are being sprayed.
  • Public Awareness  You encouraged to band private and City trees during the spring and fall migrations periods. Tree banding can reduce or manage populations and reduce the need for spraying. Banding trees controls cankerworm populations by trapping wingless female cankerworms as they crawl up the tree to lay their eggs.  You should band your trees from late March to mid-May and again from early September to mid-November to catch the cankerworms moths at both the times they are emerging from the soil. It is important to band all trees in an area or else cankerworm larvae could move from unbanded trees to banded trees.