Drowning in Problems (AKA: Got water?)

Continuing with Mosquito Madness (day 2)! When we talk about mosquito control, it’s common for people to think of the spray or the fog. We picture the adult mosquito—the one currently buzzing or biting and ruining the outdoor patio seating. But we also need to look at the source. We talk about larvicides but do folks really understand them and how they work? 

Starting with the basics - every mosquito starts its life as a "wriggler" in a stagnant pool of water. Manage the larvae, the adults never happen. It’s that simple (and that difficult).

Mosquito larvae are fascinating little creatures. They don’t breathe underwater like fish. They hang upside down from the surface of the water, breathing through a snorkel-like tube called a siphon. This is one reason they can survive in very polluted water. If the food source is there, they are happy little insects. That food source is anything from algae, bacteria, and other organic detritus that is common in dirty water. They are incredibly sensitive to vibrations; if you walk up to a stagnant bucket and see a bunch of tiny larvae diving for the bottom, you’ve found the mosquito nursery.

So, how do we get to this part of the life stage and deal with the larvae? It’s easy. Just eliminate every water source in the area.

Okay, we know that’s impossible. Not every water source can be identified. Larval habitat may be on a neighboring property. We don’t control the weather. Considering mosquitoes can develop in about 14 days, most models don’t have technicians going back that often for control efforts. Assuming that in some magical world we could do that, it still doesn’t stop neighboring adults from flying in and taking advantage of the area we just cleared.

When we can't just "tip and toss " (which we all know should always be step one!), we turn to larvicides. There are a couple options and a couple different ways they work. Choosing the right one can be the difference between success and continued bloodshedding.

Bti (Bacillus thuringiensis israelensis): This is a naturally occurring soil bacterium. It’s the "gold standard" for targeted control because it only affects mosquito, blackfly, and fungus gnat larvae. It doesn't hurt the bees, the birds, or the fish. The Bti spores are ingested by larvae and they release toxins into their guts. This then causes the larvae to stop eating and basically starve to death. The Bti has to be ingested, and since the eggs and pupae don’t eat, those life stages escape death.

Insect growth regulators (IGRs): These are the "stop growing" potion for insects. Since adults don’t grow anymore, IGRs again affect the immature stages. They don't kill the larvae instantly, but they prevent them from ever molting into adults. IGRs mimic the hormone that tells larvae, “hey, you are getting bigger, you better molt so you don’t get stuck in this little shell”. There are also mimics that mess up their exoskeleton as they grow, again trapping them. They get stuck in the immature stage and, since they can’t make it to adults, eventually die. The adult is the stage that mates and reproduces so no adults, no babies!

Botanicals: These work by putting down an oily barrier on the water and clogging that "snorkel" tube so the larvae can't breathe. Or, they mess with the surface tension of the water and the larvae can’t break through to breathe.

Spinosads: These are relatively new and are based on a bacteria species. It messes with the insects’ nervous systems and disrupts their nervous system, especially the ACH transmission.

Chelle’s Soapbox

As convenient as it is, we really should stop relying on regular treatments. Mosquitoes don’t follow our calendar of every other month service. Timing services around temperature and weather can make treatments way more effective and often result in fewer overall treatments.

There are also a few formulations that may make a difference. The “dunks” and other solids are very convenient and easy to dose for different-sized water sources. Botanicals might be labeled for adult control and water treatments. Mosquitoes show resistance to many common pesticides so rotating products is important.

You can’t spray your way out of a stagnant water problem. You also can’t deal with EVERY water source in the area. When things get tricky, contact us for training, recommendations, troubleshooting, and more to help you soar above your competition!

Lagniappe – some mosquitoes are really pretty.