Starting Wednesday, Nov. 13th, Berthoud Parkway (LCR 17) will be closed for one day for asphalt overlay from Mountain Ave to Welch; please follow provided detours; this work will be completed weather permitting.

2017 West Nile and Mosquito Information

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Town of Berthoud Mosquito Control Policy for 2017

To mitigate the potential effects of West Nile virus on residents, the Town of Berthoud adopted Resolution 16-15 regarding mosquito control spraying in July of 2015. This resolution was updated in June of 2017. 

Vector Disease Control International (VDCI) is the Town's contractor for mosquito control measures. Their role includes treating mosquitoes at the larval stage, trapping mosquitoes and sending for testing at CSU, and activating emergency control measures if necessary.

Larvicide Program

VDCI will devote the majority of its staff and resources to eliminating larval activity for the Town of Berthoud. Larvicide measures include treating standing water for the incidence of mosquito larvae prior to maturation into full adults. It is an important control method because it reduces the overall mosquito population. See map below for larvicide boundary areas.

2017 Larvicide map

Adulticide Program

The Town of Berthoud uses a metric called a Vector Index (VI) to determine when to trigger adult mosquito control measures. If the WNV disease is present, it's imperative to stop the disease cycle as quickly as possible to ensure public safety.

In simple language, a Vector Index is is a number calculated by combining measures of the abundance of Culex mosquitoes (the species that carries WNV) and the rate of infection in those mosquitoes.

In conjunction with Larimer County, the Town of Berthoud has adopted a VI trigger of 0.5 to commence adult control measures.

Mosquito Control Measures

The process for activating adult mosquito control in the Town of Berthoud is as follows:

  • Vector Disease Control International (VDCI) places four traps in town and collects mosquitoes in those traps weekly
  • Traps are sent to Colorado State University to determine the presence of WNV in these traps
  • If the Vector Index (VI) is over 0.5 when averaged between all four traps, adult control operations will commence
  • minimum of 48 hours notice will be given to the residents
  • City-wide control measures will take place over two consecutive days after 10 p.m., weather permitting

Please note: Residents must opt in to be notified about control measures.

To receive a text regarding West Nile Spraying - Text 'Go Berthoud' to 888777 or to opt-in for Community Alerts & West Nile Virus Notifications sign-up at

Berthoud Spray Zones

More information:

Learning more


 2017 Data

In an effort to reduce the risk of human West Nile virus infection, and with the support of the Larimer County Department of Health and Environment, the Town of Berthoud will spray for mosquito control on August 30 and 31.

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