Even though mosquitoes are a natural part of Colorado’s landscape, there are many human activities that can increase their populations to levels that are significantly higher than they would be otherwise. One of the activities that can dramatically increase local mosquito populations is agricultural irrigation. With its widespread use in Colorado, agricultural irrigation has the potential to create thousands of additional acres of mosquito breeding habitat every season. Not only do these areas have the potential to produce millions of nuisance mosquitoes, but data from the last few years of Colorado’s WNV surveillance suggests that there is also a link between higher WNV activity and irrigated lands. The areas of the state that consistently experience higher levels of WNV activity also have large amounts of irrigated lands near populous areas.
Anytime that water is allowed to sit and stagnate for 5 days or more it can become a source for mosquito breeding. Along with the typical mosquito breeding areas found around the home (see our Mosquito Tips for the Home web page), agricultural users often have additional areas on their properties that can produce mosquitoes. Farm impoundments, seepage from irrigation pipes or ditches, standing water in control structures, irrigated pastures and clogged ditches are also potential mosquito breeding areas.
To help us in our nuisance mosquito and WNV reduction efforts, we urge land users to help us control mosquitoes on agricultural lands by:
- Scheduling irrigation water delivery to avoid excess watering.
- Draining water within 24 hours following irrigation (proper drainage can be achieved with good slopes that encourage runoff to collect in properly flowing drainage ditches).
- Inspecting fields for drainage and broken checks (broken checks create cross-leakage that can provide habitat for mosquitoes).
- Eliminating standing water from pastures and fields. Fields may need to be graded to allow for proper drainage and low-lying areas should be filled or leveled accordingly
- Having ditches repaired to prevent seepage of water.
- Maintaining weed free margins in drainage channels to reduce standing water and the opportunity for mosquito breeding.
- Making sure ditches and laterals are not clogged or blocked.
- When possible, using sprinklers to apply water rather than flood irrigation.
- Not over fertilizing. Excess fertilizers can leach into irrigation run-off, making mosquito production more likely in ditches or further downstream.
- Making sure containers or drums are not holding water (including puddles on the lid formed by the lip around the edge of the container) by discarding unused ones or by storing on their sides or indoors.
- Filling or leveling tire ruts in lane ways.
- Disposing of tires at a proper disposal facility or store indoors where they won’t collect rainwater.
- Draining or flushing animal watering troughs on a weekly basis or adding Bti mosquito ‘dunks’ (or similiar products) for monthly mosquito control.
- Making sure current and old farm equipment/machinery doesn’t hold water by discarding, covering or storing indoors.
If you have any standing water on your property that you are not able to eliminate, or know of any stagnant water in nearby fields or ditches, please report it to OtterTail by leaving the information on our
Mosquito Control Hotline at 303-273-2878 or (1-888-774-2161)