DuPage to target adult mosquitoes in forest preserves

DuPage County has a new tool in its ongoing battle against mosquitoes that spread West Nile virus and other diseases.

The Forest Preserve District of DuPage County this week approved a revised policy that will allow insecticides to be used to target adult mosquitoes on district land. Officials say the policy was updated "to better address potential threats from newly emerging mosquito-borne diseases."

"The changes that were made to the policy reflect the goals and purpose of the forest preserve while recognizing the health risks and issues that exist," Commissioner Jeff Redick said.

The forest preserve will continue its long-running efforts to control the Culex mosquito, which is the type known to carry West Nile virus. In addition to doing regular testing at preserves, the district uses larvicides made from a natural bacterium to kill Culex larvae when they are found.

Under its previous policy, the district allowed for "adulticide" to be used during a public health emergency. However, that policy was vague, officials said, and the district never used insecticides to kill adult mosquitoes because those products also could kill other insects.

But with the emerging threat of illnesses such as the Zika virus, health department officials started working with the forest preserve several years ago to update the policy.

"It's a situation where we all came together and did the right thing," forest preserve President Joe Cantore said.

Under the revised policy, the district will consider using sprays or fogs to kill adult mosquitoes if certain criteria are met. They are:

• The county health department's personal protection index for West Nile virus reaches its top level.

• Data conclusively shows the source of target mosquitoes is on district land.

• The delivery of insecticide must be able to effectively target specific areas.

• No other reasonable alternatives (such as closing a forest preserve) exist to protect public health.

Officials said the district will only use fogs and sprays to kill adult mosquitoes as a last resort. The chemicals dissipate after only 48 hours but can kill any insects they contact, including butterflies, moths and lightning bugs, they said.

Redick said the use of insecticides on district land will be done "in a very controlled and monitored way so it doesn't abandon our goals."