Ready, Set, Grow! August 2021

mosquitojpgThe other night I went out in my yard and was overwhelmed by mosquitoes. Two of them were trying to carry me off when I heard one say, “Let’s hurry up and get him before the BIG guy shows up!” …Okay, slight exaggeration.

Mosquitoes are serious pests, though. Besides the annoying buzzing, biting, and itching, they are disease vectors. They are known to spread malaria, Zika, and other illnesses to humans. They also spread fowl pox to chickens and equine encephalitis to horses. Countless products are available for you to fight them – sprays, traps, and repellents of all descriptions. (And let’s not forget the ineffective but entertaining bug zapper!)

But what really works? Of course there is no single chemical or physical solution or we’d be rid of the pests by now. The best approach is “integrated mosquito management” (IMM), a combination of applied control methods. In other words, use every tool at your disposal.

City and parish health departments use the IMM approach. While evening spray trucks are the most visible part, they use a variety of methods. The acronym “SSLAP” is often used – Surveillance, Source Reduction, Larval Mosquito Control, Adult Control, and Public Education.

Surveillance of populations tells pest control professionals when and where to send the mosquito truck spraying, for instance. Source reduction targets standing water, where mosquitos spend most of their lives as larvae. The time from egg to adult can take just a week, so we homeowners need to stay vigilant. Especially during periods of frequent rain, check the yard for anything that holds water – buckets, wheel barrows, tire swings, rain barrels… Even a soft drink can will serve as a nursery for the pests.

Some things like birdbaths and rain barrels are impractical to empty. We can treat these with mosquito dunks or granules, readily available at nurseries and hardware stores. The dunks (little round wafers) contain bacteria and the granules have an insecticidal chemical. Both are effective in killing the larvae before they have a chance to develop.

Adult mosquitoes are harder to target. They spend most of their day resting on foliage, then come out in the evening to prey on us. Professional pest controllers and do-it-yourself-ers can apply insecticides like permethrin with hand-held foggers. The effect is short-lived, so this is mostly handy if you’re planning an outdoor event in the near future.

Unfortunately the bug zappers have little effect on mosquitoes and kill more beneficial insects. Electric or propane “suction traps” can have some effect but “Actual results may vary.” Citronella candles and torches do work in the immediate area the smoke pervades. But it’s limited in area and any air movement negates the protective zone.

For repellents, it’s hard to beat DEET. It’s widely available and can last up to six hours. But it’s also oily and has an odor. Some “natural” repellents like lemon oil of eucalyptus can work for a short time and smell better. Picaridin is becoming more widely used. It’s odorless and does not feel greasy. The longevity is comparable to DEET and it can be applied to outdoor equipment like tents and umbrellas.

The same permethrin chemical mentioned earlier can be applied to equipment and outerwear. (Some clothing is sold infused with it.) The repellent effect can last as much as a couple of weeks or several rounds through the laundry cycle.

If you want to know more about gardening, landscaping, or anything else horticultural, contact the St. John & St. James Parishes County Agent André Brock at Also, the LSU Ag Center’s website can be accessed at with lots of user-friendly information, including this article. Visit our parish Facebook page at

8/17/2021 3:17:58 PM
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