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Mosquito BioControl for Farm and Yard Water

Mosquito BioControl uses Heterorhabditis entomopathogenic nematodes against mosquito larvae and is currently sold with garden and plant-area directions. Use in livestock troughs, farm ponds, rain barrels and yard water features requires label amendment and state acceptance and is in development.

Where mosquitoes breed on farms and yards

Container-breeding mosquitoes lay eggs in small volumes of standing water: troughs, tires, buckets, clogged gutters, tarps and rain barrels. Floodwater species use hoof prints, low pasture and lagoon margins. Larvae develop in one to two weeks in warm water. Removing water is always the first step, but troughs and ponds cannot be emptied, and that is where a larval treatment matters. A weekly walk of the property to tip, drain or cover containers removes most breeding sites.

How nematodes act on larvae

Heterorhabditis infective juveniles carry the bacterium Photorhabdus, which kills the host after the nematode enters. Most entomopathogenic nematode work targets soil insects; aquatic use is a more demanding setting because the nematode must contact larvae in open water. Published laboratory studies show infection of mosquito larvae by several nematode species, with results that vary by species and water conditions. We describe this program as aiding in the suppression of larvae, pending our own field data.

Status and use today

Nematodes are exempt from EPA registration as macroscopic biological control agents, but directions and state requirements still apply. Current directions cover garden sites. Livestock drinking water and wildlife ponds need specific trial data before directions are extended. Until then, pair source reduction with registered larvicides where required, and register farm or municipal sites for our trials. Trial sites will log larval dip counts weekly, alongside water temperature and any rainfall or refill events that dilute treated water.

Key facts

Heterorhabditis nematodes are symbiotically associated with Photorhabdus bacteria that kill the insect host (Kaya and Gaugler 1993, Annu Rev Entomol 38:181)
Container-breeding mosquitoes such as Aedes albopictus develop in small artificial water containers including tires and buckets (US CDC, Mosquito Control at Home)
Nematodes are exempt from FIFRA registration as non-microbial biological control agents (40 CFR 152.20(a)(1))

How our delivery technology applies

This is a live biological, not an encapsulated active. The delivery question is keeping infective juveniles viable and in the upper water column long enough to contact larvae. Development work covers carrier, water temperature limits and re-application interval, measured as larval suppression in real troughs and ponds.