Mosquito control keeps outdoor activities healthy

Mosquito infestations can ruin outdoor community activities and chase away potential business. But more importantly, the pests may also transmit a variety of life-threatening diseases, including malaria and yellow fever in humans and heartworms in dogs.

Because of budget tightening, mosquito control activities, once the province of mosquito abatement districts, are increasingly coming under the direction of city, county, municipal governments and public works departments. Most conventional control techniques rely on adulticides, agents that kill adult mosquitos yet do not affect the pre-adult mosquito eggs, larvae and pupae.

And often, those techniques were not the most environmentally sound.

But a substance called methoprene, the active ingredient in Des Plaines, Ill.,-based Sandoz Agro’s Altosid line of products, is a larvicide, which prevents mosquito larvae from growing into adults, while leaving other aquatic and non-aquatic creatures completely unaffected.

That is why the Cape May County, N.J., Mosquito Control Commission uses larvicides for open marsh water management on the Jersey shore.

And it is also the reason larvicides were the mosquito control technique employed after a major earthquake in California’s San Fernando Valley left more than 1,500 pools abandoned or damaged, creating ideal breeding grounds for mosquitos. The Greater Los Angeles County Vector Control District controlled the infestations by adding long-lasting larvicidal briquets and pellets to the pools.

Indeed, geography makes a larvicide preferable over an adulticide. While in the larval stage, mosquito populations are concentrated and easily located in ponds, puddles and other stagnant bodies of water.

Adult mosquito populations, on the other hand, are airborne and constantly migrating, necessitating a great deal of time and manpower to track them down and kill them.

Additionally, while adulticides often provide instant relief, the results are short-lived. Repeated applications and the cost of manpower and specialized equipment make some adulticidal treatment programs cost-prohibitive.

Increasing concerns over airborne sprays is also reducing the use of such measures in many programs.

But with larvicides, an insect growth regulator disrupts the actual normal mosquito metamorphosis, turning the mosquito’s own biology against itself to prevent emerging larvae from developing into breeding, biting adults.