Mosquito season not over yet as late summer hangs on

University of Illinois Extension

Summer is in its final days but warm weather and rainfall is still with us in early days of September.

And with that comes mosquitoes.  They will be with us for some weeks into the fall as long as the weather conditions are conducive for the resilient pest.

If you scooped a pond, you would find the infamous mosquito larvae but you would also find dragonfly and damselfly nymphs, tadpoles, and fish feeding on them. The larvae of these mosquitoes love cleaning stagnant water of bacteria, algae, and fungus. However, states University of Illinois Extension Horticulture Educator Kelly Allsup, “nothing ruins a summer outing by being bitten by a female mosquito.” 

Adult mosquitoes eat nectar, pollen and honeydew (insect droppings full of sugar). However, the adult female needs the protein from your blood to produce her eggs. Allsup says, “she finds you while you are innocently gardening, injects her saliva to make your blood thin, and numbs the area before she begins to fill up with your blood. It is unclear why she chooses to bite me and not my husband, as some scientists believe it has something to do with the bacteria that live on our skin, your blood type, and the makeup of the lactic acid you produce when you sweat.”

The female mosquito leaves behind saliva that causes your body to produce histamine. This histamine causes that infamous swelling and itching.

If you are tired of being bitten, there are some steps you can take to prevent the mosquito populations in your yard. Retired Extension entomologist, Phil Nixon, says “treating the adult mosquito is not as effective in controlling the population as treating the larvae is.” He predicts more spraying will occur to control adult mosquitoes throughout the state but says the chemical rates used to kill mosquitoes will be low and most likely will not have a negative impact on other insects. Chemicals used to treat mosquitoes by cities may be pyrethroids, insect growth regulators and Bti.

Controlling mosquitoes

  1. The number one task a homeowner should take to reduce the number of mosquitoes is to remove the areas in your yard that could be breeding habitats. As little as a half-inch of standing water can be the ideal breeding habitat. Nixon said abandoned swimming pools can be large breeding areas, and state officials are looking for areas of concern. It is suggested to empty and clean anything that you want to hold water every week. In rain barrels, homeowners can use mosquito dunks containing Bacillus thuringiensis israelensis (Bti) to control the larvae.
  2. Clean the gutters. Some mosquitoes breed in stagnant, even putrid, water, so cleaning gutters is one of the best things a homeowner can do.
  3. Add goldfish and bait minnows to ponds. Nixon said that to use bate minnows for effective mosquito larval control, the shallow pond must be at least 39 inches deep.
  4. Forget bug zappers. Mosquitoes are not attracted to light and many other good bugs may be killed instead.
  5. Citronella candles can be somewhat effective if used in large numbers on calm days. Citronella-scented geranium plants are not effective because the essential oils of the leaves are not released into the air.
  6. Sit in front of an oscillating fan combined in addition to personal protection can help. Mosquitoes cannot fight the wind current.

 Personal Protection 

  1.     Wear light-colored clothes, long-sleeved shirts, and long pants when possible. Mosquitoes are attracted to dark objects.
  2.     Avoid being outdoors when mosquitoes are looking for a meal. Mosquitoes tend to bite at night.
  3.   Use personal bug sprays. The Illinois Department of Public Health recommends DEET as the most effective chemical to use to combat mosquitoes. DEET is the abbreviated name for N, N-diethyl-meta-toluamid, often found in common bug sprays. DEET in its concentration of forty percent is effective up to four to six hours. DEET confuses the mosquito and blocks the females’ ability to detect carbon dioxide, heat, moisture, and human sweat. This product should be sprayed liberally on open skin and should not be used on children less than two years old. A ten percent DEET product should be used for protection on children and will last around two hours. Retired University of Illinois Extension Horticulture Educator Sandy Mason reported that “natural repellents containing essential oils like citronella are not as long-lasting as DEET.” They may only be effective for 20 to 30 minutes and have shown to be poor performers in preventing mosquito bites. However, according to recent consumer reports, oil of lemon eucalyptus at thirty percent showed higher effectiveness and lasted more than seven hours, making it more effective than other natural products.
  4.     Make sure window screens are in good shape to prevent mosquitoes from invading the home. 

Taking some of these steps to prevent mosquitoes from setting up shop in your yard can help you enjoy your gardening tasks, backyard barbeques, and summer outings without the constant barrage of itchy bites.

For more information about preventing mosquito bites, contact Kelly Allsup, Extension educator, horticulture, at or contact your local Extension office at 309-663-8306. Univer