Justin McDaniel OSU Extension Educator
The Ada News
Pontotoc County has experienced much needed rain the last few weeks, along with the moisture, calls concerning mosquitoes and their control have increased.
More than 60 mosquito species occur seasonally in Oklahoma - from March through first frost in November. A few early species prefer cool weather, but the majority of adult mosquitoes are pests during April, May, and June, especially following spring rains. Culiseta mosquitoes first become active in Oklahoma in March with subsequent summer species usually appearing in April and May. Mosquitoes may be present even after the first frost because emerging larval and pupal populations may not be affected by a light freeze. Mosquito populations in Oklahoma are greatly influenced by the weather. Scattered rains may lead to higher populations of mosquitoes in certain areas and not in others. During hot, dry summers there normally are not enough mosquitoes present to cause pest problems.
The mosquito has four distinct stages in its life cycle: egg, larva, pupa, and adult. The adult is an active flying insect while the larvae and pupae are aquatic and occur only in water. Depending on the species, eggs are laid either on the surface of water or are deposited on moist soil or other objects that will often be flooded.
The adult mosquito is entirely terrestrial and is capable of flying long distances. Both females and males feed on nectars which they use for energy. Males and females mate during the first 3 to 5 days after they have emerged. Females mate only once. Males generally live for only a week. Only the females feed on blood which is what is occurring when they are biting. Females evidently gain little nourishment from blood meals but need them in order to develop eggs. Many mosquitoes feed on any warm-blooded bird or mammal. However, some prefer cold-blooded animals. Some species also prefer birds and seldom feed on mammals, which is the case with Culex spp. mosquitoes which are known to transmit the West Nile virus (WNV). Unfortunately many species feed on a wide range of warm-blooded mammals and humans are often attacked. Once a female has completely engorged, she flies to a shaded environment until her eggs are completely developed, usually 3 to 5 days. Once the eggs are developed, the female is called a gravid female and she begins to search for a desirable place to lay her eggs. If a female survives her egg laying activities, she will very soon start searching for another blood meal after which she will lay another batch of eggs. She does not need to mate a second time. Generally a female will only live long enough to lay 1 to 3 batches of eggs.
Most mosquito species are actively searching for a blood meal in the evening hours from just before dark until 2 to 3 hours after dark. During the daytime the females normally rest in cooler vegetated areas where the humidity is higher and they are protected from drying out. Females will often bite in the daytime if humans or animals invade the wooded areas where they are resting. However, Aedes albopictus is an aggressive biter which prefers to feed during the daylight hours and is often a nuisance in urban areas.
Very few mosquitoes in Oklahoma are able to transmit diseases. Of the 60 plus species present in Oklahoma, only 7 to 10 species are considered medically important because of their pest status to people. Disease transmission by mosquitoes is complex, and being bitten by a mosquito does not mean an individual will develop an illness. If a mosquito-borne disease is detected in Oklahoma, the mosquito species transmitting the disease must be identified. Control measures targeting the biology and behavior of that particular species are then implemented to reduce pest populations and prevent further disease transmission.
Most likely species of mosquitoes present in Oklahoma which could transmit the West Nile Virus:
One of the most effective tools available is awareness of mosquito biology so that you can eliminate future mosquito breeding sites from your yard. You should be aware of the life cycle of mosquitoes so you can take steps to avoid rearing mosquito larvae in water containers on your property. You should eliminate larval breeding sites such as discarded tires, beverage cups/litter, and unused children’s wading pools. Residents should clean and replenish pet water and bird bathes every 3 days, clean roof gutters to allow proper drainage, prevent standing water in flower pots, ensure good property drainage, and plug hollow tree stumps. Water gardens or small fountains should be treated with larvicides or contain mosquito eating fish to prevent emerging adult mosquitoes. Maintenance of screen doors and windows will prevent adult mosquitoes from entering homes. Remember, any container that will hold water for 5 to 7 days is a potential breeding site for mosquito larvae.
People can reduce their exposure to biting mosquitoes by wearing insect repellent when they are outdoors. They can also avoid being outside at dawn, early evening, and dusk when the majority of biting female mosquitoes are active. Wearing long sleeved clothing with long pants also provides protection. Repellants which contain from 10 to 30 percent DEET (N, N diethyl-m-toluamide) are most effective, but always read and follow label directions for proper application. Special care should be taken when applying repellants to children.