The Larval surveillance program for York County consists of two separate strategies.

Monitoring Permanent Bodies of Water

Permanent bodies of water (ponds and permanent marshes or swamps) normally have populations of predatory species (fish, amphibians and other insects) which prey on mosquito larvae. York County monitors all permanent bodies of water for presence of fish. Gambusia holbrooki (mosquitofish) will be added if needed.

Temporary Bodies of Water

Temporary bodies of water (low depressions, residual ditches or artificial containers) usually, unless they are vernal pools, have no natural predators for mosquito control. Mosquito control uses our extensive GIS mapping system to monitor areas of low depression for the purpose of larval control. Stormwater drainage crews also monitor and report sightings of larvae to mosquito control for larvicide treatment.

Larviciding Products

The products used for larviciding in York County are specifically targeted against mosquito larvae. One of the products used is Bactimos Briquettes. This larvacide is a kitty-litter donut impregnated with a bacteria, Bacillus Thruingiensis variation Israelensis (BTi). The donut falls apart over time releasing the active ingredient.

When mosquito larvae eat this bacteria they become sick and die. This bacteria affects only mosquito larvae and its considered harmless enough to be used in drinking water. Mosquito dunks are provided to York County citizens free of charge and can be picked up at the Waste Management Center located at 145 Goodwin Neck Road.
Package of mosquito dunks