Do It Yourself Pest Control: How to Choose Bug Spray

Bug sprays are either repellents designed to keep bugs away or insecticides designed to kill them. Each of these insect control products is a type of pesticide. While pesticides are often considered to be insecticides only, pesticide products include any substance that's designed to kill or deter a pest. Weed killers or herbicides, rodenticides, fungicides and germicides are also pesticides. Our Pesticide Buying Guide will give you an overall view of the family of products referred to as pesticides, and Herbicide and Pesticide Safety will help you use them properly.

For the purposes of this article, bug spray applies to liquids designed to control both insects and spiders. Application methods for bug sprays include:

• Aerosol sprays
• Trigger sprays
• Pump and battery pump sprays
• Foggers
• Hose-end sprays
• Tank sprays

Insect repellents are designed to keep some types of bugs away. They typically work against mosquitoes and ticks, but some are also effective against flies and pests such as biting gnats. Bug spray repellents are formulated for application to skin or clothing. Diethyltoluamide (DEET) is one of the most common active ingredients in insect repellent. DEET bug spray doesn't kill mosquitoes. The chemical makes it difficult for mosquitoes to detect you as prey. You can apply DEET to skin and to some types of clothing. While you can use DEET on some fabrics, such as wool, nylon and cotton, you should avoid using it on or near other materials, like leather and most synthetic fabrics as well as plastics and painted items. Check the product instructions for more details on proper application.

Different insect repellents have different concentrations of DEET, expressed in percentages. Typically, these range from 15% to 40%. Choose the concentration based on the amount of time you plan to spend outdoors. Higher percentages mean a longer period of protection rather than a more effective product.

You may see DEET-free bug spray with the chemical active ingredient picaridin, which is also effective against mosquitoes, ticks and files. Like DEET, rather than killing insects, picaridin discourages the insects from landing on your skin. Lemon eucalyptus oil is another DEET-free bug spray, which can be effective as a mosquito repellent.

How frequently you need to reapply insect repellent depends on factors like the type and concentration of active ingredient in the repellent and how much you're sweating. Since lower percentages of active ingredients provide protection for shorter periods of time, consider these for use when you'll be outdoors for a limited time or can easily reapply. Repellents with higher concentrations of active ingredients work well for longer-term outdoor activities such as hiking. The type of pest may have an impact on how long protection is effective as well. For example, a product may provide longer-lasting protection against mosquitoes than against flies.

While insect repellents keep bugs away from you, other types of bug spray are insecticides, designed to kill insects that come into contact with them, and in some cases, to interrupt the life cycle of the insect to prevent it from reproducing.

These insect killers typically work on contact. Some can be used for spot treatment and last for one application only. Some, like those that provide perimeter or barrier protection, are designed to continue killing the insects for weeks or even months before needing to be reapplied. Synthetic chemicals often include chemicals called pyrethroids as active ingredients. There are different types of pyrethroids, but all of these bug killers interfere with an insects' nervous systems and kill the insects quickly. They're also typically effective against a variety of insects.

Different types of insecticides target different pests and use different types of applications. You'll find products for bugs in the house and in the lawn and garden:
 

• Bug sprays for indoor spot treatment are effective against pests such as ants, roaches, fleas, bedbugs and flies.
• Area bug sprays for indoor use against flying insects kill on contact and settle onto surfaces to provide ongoing protection.
• Indoor foggers create a fine mist that allows the insecticide to reach into crevices and under baseboards to kill hidden bugs like ants, bedbugs and roaches.
• Products designed to kill spiders, scorpions, wasps and hornets on contact often allow application at a distance.
• Different formulations of bug spray for plants can protect flowers, ornamentals, edibles and other plants from insect damage.
• Yard bug sprays are often designed to be rainproof after several hours. In addition to killing on contact, many continue to protect the lawn from listed insects for several weeks.

There are alternatives to synthetic pesticides. For example, natural bug sprays for plants use natural oils — such as neem oil, lemon grass oil and sand sesame oil — or active ingredients — like potassium salts of fatty acids — to kill and control insects. Keep in mind that natural bug spray will need more frequent application than synthetic products.

As with any pesticide products, read the instructions to learn how to apply bug killers properly and safely, safety measures you need to take, first aid instructions in the event of swallowing, inhaling or contact with skin and eyes, and more. Read the label before you buy the insecticide and before each use. Here are some factors to think about:
 

• Signal words on the label indicate the short-term toxicity of a product. Pesticides will be labeled with the signal word CAUTION, WARNING and DANGER. Products that use the word CAUTION have lower short-term toxicity; those labeled with WARNING have a higher level and products labeled with DANGER have the highest.
• Identify the problem pest or pests. While many insecticides kill a range of insects, match the treatment to the pest and the problem location. Learn which insects the pesticide kills, and use only products designed to combat the insect you're dealing with. Insecticides may have different application instructions for different insects and different locations. Follow the instructions for the target pest and location.
• Perform the necessary prep work before application. For example, make sure pets and children are clear of the application area. When spraying for bugs in the house, also cover aquariums and remove food or utensils from the area when using insecticides.
• Pesticides can harm nontarget insects and aquatic life in streams, rivers, etc. Identify nontarget species the chemicals can harm and take steps to prevent contact. Remember that some insects are beneficial — like ground beetles or ladybugs — because they help kill and control pest insects or — like bees and butterflies — because they pollinate plants.
• Avoid applying insecticides where they could enter storm drains or where runoff from the pesticide could reach a storm drain and enter waterways.
• Avoid applying insecticides outdoors on windy days or on days where rain is expected within 24 hours. Wind can carry the chemical outside of the target area and expose bees and other beneficial insects to the chemical, and rain can wash newly applied insecticide into storm drains.

Many types of bug spray expire after several years, but the actual shelf life for bug spray varies by product. For example, insect repellents that contain DEET have a different shelf life than products with picaridin. You may be able to find an expiration date for bug spray and other types of pesticide on the product packaging, or you can contact the manufacturer. Keep in mind, the shelf life may be shorter than indicated if the product hasn’t been stored properly.