Vector Control Policy

City of Wahpeton Vector Control Policy
Purpose: To reduce the adult mosquito population and reduce the risk of mosquito-borne disease.
Control Method: The primary preference for controlling adult mosquitoes is to use environmentally sound techniques such as the methods used in an Integrated Pest Management (IPM) program. When threshold limits have been reached, adult mosquito control may be initiated using public health pesticides that have been registered and approved by the U. S. Environmental Protection Agency (EPA) and the State of North Dakota. The EPA has determined that public health pesticides developed for mosquito control can be used successfully to kill mosquitoes without posing unreasonable risks to human health, wildlife, or the environment.

Principals of IPM:

  • Knowledge of mosquito biology and the epidemiology of the mosquito-borne diseases known to occur in the region.
  • Surveillance and monitoring mosquito population, species diversity, mosquito-borne disease, and pesticide treatment efficacy.
  • Mapping the mosquito control district to identify known mosquito habitat that will be inspected and treated with pesticides.
  • Physical control (when possible) by eliminating or modifying known mosquito habitat.
  • Establish action thresholds based on surveillance to determine the need for larval and adult mosquito control.
  • Larvaciding mosquito habitat with pesticides designed to prevent mosquitoes from reaching the adult flying stage while having little or no negative impact to non-target organisms and the environment.

Educate the public about mosquito control protective measures, current mosquito issues, and possible threat levels associated with mosquito-borne diseases: maintain professional training for staff through continuing  education training and /or attendance at professional conferences.

Adulticiding in Populated Areas: The decision to spray mosquitoes in populated areas will be based on evidence collected by surveillance. Establishing a threshold for adult mosquito control is based upon professional surveillance and monitoring efforts for immature and adult mosquito populations using several types of indicators. No one factor is always decisive for determining action. Often times a combination of quantitative or objective data must be evaluated to make “spray/no-spray” decisions. Some of the factors considered prior to citywide spraying include; mosquito population, species diversity, mosquito-borne disease activity, community events, specific (public) events, weather conditions (short term and future weather conditions) and environmental factors. Service requests and public complaints are helpful indicators but do not provide sufficient justification to spray. Service requests and complaints will result in increased surveillance.

Threshold: Citywide spraying will be considered when threshold criteria have reached the minimum action level. The numeric values for thresholds identified below are subject to further refinement or modifications as circumstances or new information warrants. Population density (daily trap count) is generally determined from data collected through a network of New Jersey Traps.

CDC/C02 Trap:
Nuisance species: 130 – female mosquitoes in an overnight trap collection.
Culex species: 5 – female mosquitoes /trap-night.
New Jersey Trap:
Nuisance species: 35 – female mosquitoes in an overnight trap collection.
Culex species: 2 female mosquitoes/trap-night.
Landing Rates:
Nuisance species: 2 – female mosquitoes per minute.
Culex species: 1 – female mosquito per site inspection.
Mosquito-Borne Disease Activity:
Any positive identification.

1. Public Service Announcement issued as soon as decision to spray is made.
2. Notify the staff required to work during the scheduled spray.
3. Prepare equipment for spray operation.
4. Notify staff with any special instructions pertaining to the scheduled spray.
5. Check weather status to assure conditions are acceptable to begin operation.
6. The citywide spray will commence at sunset unless there is reason to advance, delay or suspend the spray.
7. If wind speeds are greater than 10 mph or calm, operations shall cease.
8. If the citywide spray has not been completed by 1:00 A.M., operations shall cease unless it is determined conditions are favorable to continue.
9. If the outside temperature drops below 50 degrees, operations shall cease unless it is determined conditions are favorable to continue.
10. All pesticides used within Wahpeton shall be applied according to label instructions.