By Brendan Henry
The Surveyor

Berthoud’s town board held a special meeting to discuss mosquito spraying on Tuesday. This meeting was presented as a result of the vector index being a concerningly high 3.0.

Mosquito tracking is done by collecting insects using traps in different locations, with many of the mosquitoes getting tested for diseases such as West Nile virus. The vector index takes both abundance and infection rates into account and is calculated by multiplying the average number of mosquitos collected per trap night by the proportion of the infected. Berthoud’s board adopted a policy in August 2022 to not use pesticides unless the vector index exceeded 0.75 in two consecutive weeks, which is what spurred the special meeting.

The board discussed the potential use of adulticide – a pesticide that targets adult mosquitos – to curb the high infectious rate. With this in mind, the board had to decide whether to spray the whole town, spray certain areas of town or not to spray at all.

Public concern at the meeting was polarizing, with multiple locals approaching the board with their concerns about the potential harm of pesticides and also the potential spread of viruses. Two Berthoud residents were against spraying pesticides, while another felt that prevention of disease outweighed the unknowns of spraying adulticide.

The adulticide the town is considering using is sprayed as a mist into the air, which is when the pesticide is most effective. After the mist dissipates, the effectiveness of the adulticide decreases exponentially as it breaks down in sunlight.

Trustee Tim Hardy equated using adulticide to thin the mosquito population as “fighting fire with fire,” as his concerns lay in chemical inhalation being as bad for the elderly population as “non-pandemic levels” of West Nile virus as he put it. Hardy wishes to avoid adding a second health issue to the town.

Trustee Jeff Butler echoed similar concerns as Hardy, who feels uncomfortable by voting in favor of spraying without knowing everything about adulticide.

Trustee Sean Murphy challenged Hardy in his knowledge of the pesticide and asked if he knew of any negative effects it may produce on humans. Murphy asserted that without taking action to minimize the mosquito population, the board would be neglecting the public health and safety of Berthoud’s citizens. The new policy, according to Murphy, has made the decision to spray less clear.

“I question the necessity of this meeting tonight because we are coming up with a policy on the fly here. Nobody knows whether we want to spray tonight or not,” Murphy said. “I feel like the communication failure with this new policy is on us because nobody in this town knows what we are going to decide tonight.”
Mayor Pro Tem Mike Grace felt that the decision should be made after further discussion.

“I just can’t kick the can down the road anymore,” Mayor William Karspeck said. “To me, a 3.0 is high enough to take action, so we should.”
Karspeck agreed with Murphy that although spraying could have potentially negative effects, not spraying could lead to a higher public health concern.

“I am in favor of this, reluctantly. I don’t think I’m going home patting myself on the back, but I feel I have to vote in favor here,” Karspeck said.

Murphy moved to apply adulticide via truck spraying after a minimum of 24-hour notice to town residents via available communication outlets. The motion failed as Butler, Hardy and Grace all voted against it with only Murphy and Karspeck in support.

Grace moved to make the motion hybrid by moving to apply adulticide via truck spraying for the whole town after a minimum of 24-hour notice to town residents via available communication outlets as of July 24 conditional on results being higher than 0.75 on the vector index. The motion passed with the assumption that the city attorney allows the vote to stand as both Trustees Karl Ayers and May Albrecht were not present, with both Murphy and Hardy voting against it.

The board must give a 24-hour notice to the town before adulticide spraying takes place.