An innovative mosquito biocontrol method has been tested in Washington, D.C.

Article written by dr. Kathy Heinsohn, B.C.E. and published on 23rd of October, 2026.

How Wolbachia mosquito biocontrol works

The released mosquitoes are all males inoculated with Wolbachia, a bacterium that renders female eggs inviable (i.e., they do not hatch) when mated. This is an innovative biocontrol method for reducing Aedes and other species of mosquitoes, which can carry deadly diseases such as dengue, Zika, chikungunya, and yellow fever.

Regarding this biocontrol method, there are two important things to know:

• Male mosquitoes do not bite, they spend their time resting, mating and feeding on nectar only.
• Once mated, a female mosquito (and most female insects) is mated for life. The male's spermatophore, or package of sperm, remains in her ovaries to fertilize current and future eggs. If she mates again with a different male, the newer packet of sperm will be used instead. The female insect catalogs the received sperm so that the first in is the last out. However, if she is in a hostile environment where there are no males, she will remain mated for life. This evolutionary adaptation ensures the success of the next generation in hostile environments, such as deserts, or short-lived adult insects (a day or less).

The gut bacterium Wolbachia which is used for the inoculation, occurs naturally in six out of ten insects and is harmless to humans, animals, and the environment. When the mosquito dies, the gut bacterium dies as well.

From laboratory breeding to release

The mosquitoes must be mass reared in a lab, and the resulting eggs are inoculated with the bacterium. When the adults emerge, the males and females are culled out. The females are destroyed. The males are shipped to be used for this type of biocontrol method. Because of the specificity and time constraints of lab rearing the mosquitoes, the price tag goes up dramatically.

As it happens, Dr. Stephen Dobson, the manager leading MosquitoMate, the company behind the mosquito inoculation, was a student of mine at Clemson University about 35 years ago. He was bright and exceptionally talented back then, and I remember him very well.

Why community-wide treatment matters

This biocontrol method can cost $1,000 or more per property. While it is an innovative approach, treating an isolated yard offers limited protection.

To truly reduce mosquito populations and disease transmission, whole communities or municipalities need to be involved—an approach that has already proven successful in Singapore, parts of Mexico, Colombia, and other test sites.

Although the U.S. EPA has approved this technique, state and local regulations can vary widely, making it challenging for service providers to operate across different regions.

My view is that this should NOT be considered a standalone mosquito management treatment for a residential customer, so other pest management and homeowner measures to reduce mosquitoes remain particularly important.

Where in your yard is the water standing?

You don’t need to look far. Trash/recycle can lids that are off and turned over, pet water bowls, bird baths, kiddy pools, tire swings, toys/equipment in the yard. Bottle caps and cans are all candidates for holding stagnant water that needs tipping and tossing.

In fact, a single bottle cap can hold over 100 eggs, and if conditions are favorable, it is estimated that a single tablespoon (about 15 ml) of water can produce 200 to 300 eggs. (Source: blog.entomologist.net)

Other standing water areas of concern include abandoned swimming pools, backed-up gutters in need of cleaning, boats, tarpaulins, chain link fence poles with no caps, tires used in bulkheads and landscaping, ditches, ungraded land on property that allows water backup puddling and pools to accumulate, and naturally occurring forest and yard tree holes.