Larvicide Information

Increased Habitat Inspections, Remediation Efforts, and Larviciding

We will be providing additional field technicians and training to bolster breeding habitat identification and larvicide treatments. Mosquitoes lay their eggs on damp soil and standing water and develop during 5-10 days of aquatic juvenile stages. Therefore, eliminating or treating breeding habitats is the safest and most efficacious method for mosquito mitigation. 

VDCI will use methods such as rain gauges, standard dipper, and locating and mapping known breeding sources. Mapping of the mosquito breeding sites will be aided by Global Positioning System and GIS technology.  This will allow them to record and catalog breeding sites to make it easier for the technicians to use their truck mounted computers to quickly return to these sites after rain events. The breeding sites will be inspected as well as samples collected and tested. 

Bacillus thuringiensis israelensis (B.t.i), a natural bacterium, is our primary larvicide and a widely used industry standard. When applied as directed by the label, B.t.i does not cause harm to water supplies or crops and is non-toxic to humans, animals, aquatic life, or even other insects such as honeybees. For more information, visit the Bti page on the United State Environmental Protection Agency (EPA) website.  

Biological control is another target-specific and environmentally conscientious approach to mosquito control. Mosquitofish (Gambusia affinis) are small fish in the guppy family that are natural predators of mosquito larvae and pupae. Local mosquitofish are collected and continuing populations are reared at our lab and placed in appropriate ecosystems as an eco-friendly alternative to chemicals.

When a breeding habitat cannot be eliminated and historically is known to produce multiple if not continuous broods of mosquitoes through the season and natural predator populations are not consistent, Methoprene can be used. Methoprene is a growth regulator which prevents the larvae of mosquitoes and other insects from becoming adults, by imitating insects' natural juvenile hormone. The residual capacity of this chemical can provide mosquito control for up to 28 days with one application and therefore is a valuable resource for breeding habitats such as catch basins, swampland, and marshes common in our region. More information (PDF) is available from the EPA.