Mosquito Control

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The City of Prince George treats mosquito breeding sites with larvicide by ground and by air when larvae numbers reach certain levels. Residents can help further reduce the mosquito population during peak seasons in April, May, and June by removing all standing water from their properties.

The City also operates a Nuisance Mosquito Abatement Program to control mosquitoes. The Program is based on Integrated Pest Management principles that priotizes environmentally-sensitive methods.

Mosquito Treatment

A list of known breeding sites has been compiled and used for monitoring and implementing treatment activities. There are more than 350 identified treatment sites and the City continues to add to this list. Larvicide, an insecticide specifically targeted against the larval life stage of an insect, is commonly used against mosquitoes. The City treats breeding sites, both by ground and air, when larvae reach certain levels.

Flood plain treatment is regulated by the Department of Fisheries and Oceans. If the river level falls quickly, treatment occurs before mosquito larvae have time to develop into adults. If the river level falls slowly and disconnects slowly from other pools and channels, mosquitoes will have time to fully develop into adults. Treatment is more effective after pools and channels have disconnected from the main river channel.


Ants are an integral part of the ecosystem and are exceptional housekeepers, clearing the ground and turning litter and natural debris into valuable soil that is rich in essential nutrients.

The City of Prince George has discovered treating an active anthill with pesticides and/or natural controls forces the ants out of the active nest and, in turn, these ants rebuild up to five new nests in the same area. Because of this, the City of Prince George no longer treats ant hills in greenbelts or public parks.

Properties bordering on a greenbelt or natural area must not dump garden waste into these locations, as it is illegal and attracts ants. 


The City of Prince George is visited by tent caterpillars every year. Some years are worse than others, but while these caterpillars are unpleasant, they are a short-term nuisance in most locations. 

Caterpillars complete their life cycle in seven to eight weeks.  Around mid-June, they will crawl away from their natal tree and seek a protected place in plants, under leaves, or on structures to attach and spin their cocoons. Adult moths emerge from these cocoons about 7-10 days later. Tent caterpillars follow a boom-bust population cycle and the cycle varies, depending on weather and other factors.

Tent caterpillars eat the leaves of the branches of the trees they inhabit, but once they vacate the tree, the branches will usually grow new leaves.  This does not affect the overall health of a healthy tree.

Spraying pesticides to kill tent caterpillars on residential City-owned boulevard trees is not permitted. To find out if a tree is City property, for more information, or to report a problem, call 250-561-7600.


The City of Prince George employs qualified local contractors to control rodent populations at civic facilities. These contractors use rodenticides, which are pest control chemicals meant for controlling mice, rats, and other rodents. Common varieties include:

  • Bromadiolone
  • Chlorophacinone
  • Difethialone
  • Brodifacoum
  • Warfarin

Rodenticides are favored over mechanical traps because of their increased efficiency against rodent populations. Moreover, traps are more labor-intensive, as they need to be cleared out often and are generally less effective.

Tamper-resistant bait stations must be used when using rodenticide on City property.

The count of mosquitoes found in these traps determines the frequency of spraying. Complaints, questions or an exclusion form can be found on the State of Maryland Department of Agriculture's website (or by clicking this link).

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