How We Operate

Mosquito control programs employ specialized equipment and treatment methods often unfamiliar to the public whose health concerns the program is working to protect. Take a few minutes to familiarize yourself with the activities of our environmentally conscious program, so you will know what we are doing when you see us at work in the field.

Placing Product in Drains

As early as March we begin placing long-term larvae control products in the drain system of Durango, the college campus, and outlying areas of our district. When the water recedes after periods of rain leaving static pools in the drain system that are not visible or accessible from the surface, this product is working for us all season long.

Placing Long-Term Abatement Products

Beginning in mid-March through April we place our extended duration abatement products focusing on the larger sloughs and bodies of water that would be producing the majority of the mosquito population. These products provide between 30 to 180 days of abatement depending on which product is used in a particular habitat.

Distributing Natular Tablets

We use Natular XRT to provide abatement all year in standing water or areas that will accumulate water due to the rise in the Animas River and irrigation in the coming season. 

Broadcasting Natular Granules

We broadcast Natural G-30 granules in the low areas of hay fields and other areas where we anticipate small pooling where it would be inefficient to place a tablet in each individual location we find water, i.e. water filled cow tracks, a rut in a a hay field, etc.

Sampling Water for Larvae

The majority of our summer activity and the basis of our abatement is sampling water for the presence of mosquito larvae. This involves simply using a dipping instrument to confirm that mosquito larvae are being produced. When present, larvae are collected to be identified in AMCD’s lab and the water habitat is treated with a larvicide.

Larviciding with Mineral Oil

When a mosquito larva population is discovered in a body of water, mineral oil is applied, which creates a thin film on the surface of the water. Since mosquito larvae are unique to other aquatic life in their developmental stages, in that they must rise to the surface to breathe through a tiny siphon tube, the thin film of mineral oil that we apply creates a barrier, suffocating the mosquito larvae. AMCD uses mineral oil because it not only very specifically targets mosquito larvae but has almost no environmental impact whatsoever.


From May 1st through September 30th AMCD maintains and monitors 15 mosquito traps throughout the district. A trap attracts mosquitoes throughout the night with light and CO2 and then draws them into a net with a fan. Captured mosquitos are taken to AMCD’s lab where they are counted, identified, and tested for West Nile. This information gives us insight into where adult mosquito populations exist and what type of habitat they are reproducing in. Each specie reproduces in a particular type of environment and identifying the adults alerts us to where to find and abate their larvae population.

Mosquito Identification and Testing

Through inspection under a microscope in AMCD’s lab, mosquitoes are counted, identified according to sex and species (among over 20 present in our district,) and this information is place in our daily log to give us a comparison of mosquito populations. This data give us a scientific basis for our mosquito abatement strategies.

Monitoring Routes

We systematically monitor the residential areas of our district for mosquito producing habitat like water-filled tires, buckets, bird baths, ornamental ponds, tarps and covers that are holding water, etc. 

Spraying at Night

Spraying for adult mosquitoes takes place when we observe or are alerted to adult populations by residents who call us and request spraying. We do not systematically spray for mosquitoes in our district. It is our policy to only spray at night when adult mosquitoes are active and bees and other pollenating insects are inactive.

Clearing Access Trails

In September and October we do the maintenance necessary to keep access open to mosquito producing habitats for the following year’s abatement. By doing this in the fall, we are able to remove that year’s growth after wildlife has already reproduced and before they arrive next spring.