Lake Bluff hears West Nile surge; village discusses larviciding and targeted adult spraying

Lake Bluff officials on Dec. 8 received an update on the village’s integrated mosquito management program from George Balas of Clark, the contractor now overseeing abatement after the Lake Bluff Mosquito Abatement District disbanded.

Balas told trustees the village runs larval surveillance from May through September, inspects ~2,000 storm drains and uses several trap types to identify mosquito species and West Nile virus prevalence. He said the program detected positive mosquito samples beginning in late June and through July; Lake County had 12 human West Nile cases this season and the contractor reported 177 positive mosquito samples statewide with 15 positives within Lake Bluff.

Because vector indices rose above established thresholds, staff recommended and implemented an overnight adult mosquito control treatment using a natural pyrethrin-based product and continued larviciding through the season. Balas said applications were performed overnight to reduce human exposure; he also described EPA and CDC guidance indicating that, when used properly, these products are considered safe for people and pets and that the application rates break down rapidly in the environment.

Trustees asked about risks to pollinators and exemptions for private properties that do not want treatment near their homes. Balas said exemptions (shutoffs) reduce local efficacy and that adult spraying is timed to minimize pollinator activity; he said barrier applications that remain on plants have greater risk and are not the technique used here.

The board noted it had approved an extension with Clark to continue the program and will continue to work with staff on resident concerns and notification.

Next steps: staff to continue surveillance and larval control in 2026; the village will maintain an email list and community communications about treatments and exemptions.