The hatched early, they hatched hungry, and they attacked Power County in swarms. Vector Disease Control, Inc. is fighting back against the mosquito invasion and has completely fogged American Falls twice, plus sprayed trouble spots in town and the surrounding areas.
Ochlerotatus increpitus is the smaller mosquito that has been seen in Power County, while the gigantor type, called culiseta inornata, can grow up to half an inch in length. They are strongly attracted to lights, which is what drew them to town from the river. Both types are very aggressive mosquitos. Fortunately, neither type are carriers for West Nile virus.
The bloodsuckers are biting their way through defenses on both sides of the river, from Pingree to Aberdeen, American Falls to the Pocatello Airport. “Bannock County is getting hammered, too,” said Tim Bennett of Vector Disease Control, Inc.
The high water and early May warmth, plus the large runoff, are partly to blame for the invasion. “The spring weather tapped an egg base that hasn’t seen water for years,” said Bennett. “We tried, but we couldn’t get all the larvae in time.” Some mosquito eggs have been viable even after 18 years of dormancy.
Bennett is pretty sure that the mosquitos came from Willow Bay into town. They like the shallow water with a lot of vegetation such as willows, cattails, drainages, etc. Mosquitos generally won’t go out on the open water.
Although the flying parasites are more active at dusk and dawn, they are still around during daylight hours. Therefore, although they would prefer not to, Vector has been doing some daytime spraying. The pesticide they are using breaks down rapidly in sunlight and also causes harm to beneficial insects. Most spraying is done in the late evening.
When the mosquitos go to roost, they prefer hiding in places where they are safe from the wind and predators, such as in trees and bushes, under carports, under decks, and up in the eaves of houses. Cedars and junipers are especially bad for harboring mosquitos.
“We will get a call from a residence, and if we go and shake a juniper or cedar on the place, swarms of mosquitos will come flying out,” said Bennett. When the temperature is under 60 degrees outside is when the plague slows down.
Culex tarsalis is the West Nile carrier. They’re a warmer weather mosquito, and their hatching has more to do with temperature than water levels. The area should start feeling their bite in mid- to late June, when migratory birds bring the West Nile virus back into Power County.
When c. tarsalis bites an infected bird, the insect increases the virus inside themselves, but doesn’t get sick. When a carrier mosquito then bites a human or animal, it can pass along the virus.
“This is an abatement program, not an eradication program, unfortunately. We can’t get them all, but we do the best we can,” Bennett said. “Take precautions, but don’t become a shut-in.”
Some things residents can do to help are:
• keep property clear of standing water. Rinse out bird baths every five days, and don’t let standing water accumulate in irrigated pastures. Mosquitos can go from egg to adult in as little as five days.
• keep household screens in good shape
• avoid going outside at dusk and dawn
• if mosquitos are noticed under decks, carports and eaves, go ahead and spray them
• apply mosquito repellent containing DEET
• wear long sleeves and long pants made of tightly woven fabrics. Jeans and t-shirts are barely a barrier, especially for the huge proboscus of the c. inornata.