Thursday, February 19, 2009

Unknown bug bites and dry skin

Reports of "mysterious bug bites" increase in winter

Every winter the number of people contacting us about mysterious bug bites increases. The typical question is something like "I feel something biting me but I can't see anything", or even "I've got bites all over my ______ but I can't catch whatever it is". While there is a small number of insects and mites that actually do bite people most of these reports have a much simpler explanation.

There are many causes for mysterious or unknown bug bites. Some are caused by real insects or mites (see the Causes of Mysterious Bug Bites article below for a list of possible culprits), but others are caused by non-arthropod agents such as allergy, drugs or even environmental chemicals.

Something as simple as winter-dry skin can even be mistaken for "bug bites". Everyone has probably felt the itchy, "crawly" feeling of dry skin and wondered, at least for a moment, if some bug (probably a spider!) was getting ready to bite. For some people these feelings become overwhelming and they come to believe they are actually infested.

When confronted with a question about an unseen bug biting my first reaction is usually to suggest they consult with a dermatologist to rule out allergy and chemical sensitivity. Dermatologists are pretty good at telling the difference between these skin aliments and true bug bites.

Take a look at the article cited above for a list of the insects and mites that do bite people but also consider that what you are experiencing is actually a case of mistaken identity. In my 20+ years of taking questions about mysterious bug bites they almost always turn out to be caused by something other than an insect or mite.

Saturday, February 14, 2009

Do flea "bombs" or foggers really work?

What are flea "bombs"?
Flea bombs or foggers are pressurized cans of insecticide that totally release their contents once the trigger is pressed. In use, flea bombs are placed upright in the center of a room. When the trigger is pressed the entire contents of the can are sprayed upward as a fine aerosol spray or mist.

Flea foggers usually contain an insecticide to control adult, biting fleas plus an insect growth regulator such as methoprene, or the tradename Precor, that prevents larval fleas from developing into adults - thus "breaking the flea life cycle".

Do flea foggers really work?
Unfortunately foggers, and other total release insecticides, are not a particularly good way to apply insecticides. This is because the foggers produce spray droplets that are too large to stay suspended in air long enough to disperse to "every nook and cranny" of the room as advertised. Essentially any surface that is shielded by furniture, is not treated. Plus, surfaces that don't need to be treated, like table tops, get covered with insecticide unless they are protected

What's better?
I prefer pump sprayers for applying insecticides because you can carefully place materials exactly where they are needed, even under and behind furniture. Non-aerosol insecticides are usually cheaper than aerosols, or foggers, plus, with aerosols you are left with disposal of the spray can when you are done. Hand pump sprayers are my first choice because they combine the advantages of a sprayer and are less expensive, easier to use, and produce a large enough droplet that it stays where you put it.

Some flea control products are packaged in their own hand pump spray bottle. These are both easy to use and very economical compared to aerosols. Take a look at this article about methoprene for an example of a hand pump sprayer for treating furniture and bed bedding with flea control insecticide.

There are also small (1 quart) hand pump garden sprayers that work well indoors for everything from flea control to insecticidal soap for house plants. These sprayers are also far more economical than any of the aerosol applicators. See our 'Bugs article about the new botanical insecticides for a wide selection of materials that can be used with hand pump sprayers.

Bug infested cars and Car Talk (tm)

Cockroaches, and other "bugs", in cars

Most of you probably know that Car Talk is a popular radio talk show on NPR where two brothers, Tom and Ray, talk about cars, car repair and the like. They take calls from car owners about everything imaginable having to do with their cars. Every once in while Tom and Ray get a call concerning insects, or other critters, that have invaded someone's car. A recent show included a caller whose car was infested with cockroaches but there have been other recent callers that had cars infested with wasps, honey bees, flies, mice, snakes, and so on.

The most common insects that invade cars are of course cockroaches and ants but wasps can build nests and a number of so called "stored product" pests like carpet beetles are common as well. It is, however, very unlikely that bed bugs would infest cars unless someone is actually living and sleeping in the vehicle. The reason for this is that bed bugs become active and feed at night and hide during the day.

So, what should you do if you discover an infestation of insects in your vehicle?

Don't use insecticides or other poisons!

First, don't spray insecticide or use foggers inside your car. If you contaminate the car with insecticide you will have to "live" with the residues every time you are in the car. Depending on the insecticide these residues can be dangerous, or at the very least smelly and unpleasant.


Second, carefully clean out the car's interior of any food scraps. Check under, between and beside seats, clean carpets, and so forth. Cockroaches are world champion scavengers and will exploit any food source you leave for them. A few Cheerios (tm) can support a cockroach for weeks. Don't make it easy for them to set up shop in your car, or your home for that matter. See these articles about the life history, identification and control of cockroaches for more information.

Social insects like bees and wasps might construct their nests inside car doors and under the hood especially if the cars are not driven frequently. A relatively new, non-native, species of paper wasp in the US, the European paper wasp, is notorious for constructing nests in car door frames. Cleaning alone, of course, won't get rid of bees and wasps so one of the next steps may be necessary.

Heat and cold

One of the best and safest ways to eliminate an insect infestation is with heat or cold. Most insects will die at 20 degrees Fahrenheit (home freezer temperature) or above 140 degrees Fahrenheit (hot, but not scalding water). For example, freezing in a standard home freezer will kill all stages of most stored product insect pests like meal moths, and high temperatures will do likewise.

What about the insects that hibernate through cold winters, you say? Insects like meal moths and cockroaches are not adapted to survive low winter temperatures like some species that are native in cold climates. Virtually any freezing temperature will kill stored product type insect pests, most of which originated in the tropics.

So, the trick is to find a way to safely heat or cool the car to these temperatures for at least several hours. If you live in a hot climate your problem is solved. Park the car in the sun on a summer day, close the windows (leave them cracked slightly otherwise expanding hot air might pop them off the frame!), and come back in a few hours to a completely sanitized interior. Don't leave anything in the car that you value such as pets, kids, etc.

Short of this your options are more limited. Finding a place to heat a car to 140 degrees is probably easier than cooling something this large (drive-in freezer perhaps?). One idea I had is an auto body shop that paints cars. I've not yet checked with our local car repair shop but I think these paint drying rooms are capable of heating to at least 140 degrees.

Carbon dioxide fumigation

Another option is carbon dioxide. Carbon dioxide gas (the stuff the makes cola fizzy and contributes to global warming) is lethal to most insects. Carbon dioxide fumigation is routinely used, for example, to dis-infest horticultural plants like fresh flowers prior to shipment. I'm not really sure how well the following might work because as far as I know it has not been tested. But, carbon dioxide is easy to get in the form of dry ice. Many ice cream stores have dry ice for sale that they use to keep ice cream frozen. It is cheap and easy to transport in an ordinary cooler. If one placed a plastic tarp over the car with the edges weighted down and put a block of dry ice (a pound or two would be a good starting point) inside the car you might be able to safely fumigate the interior in a few hours as the dry ice "melted" to carbon dioxide gas. Be sure to completely air out the interior before you get in to driving away!

Ideas? Someone must have other good ideas for applying the principal of insect control with heat, cold or carbon dioxide to a car. Leave a comment.

RIP Tommy.