|
Frequently Asked Questions
What kinds of cockroaches are there?
How long do smokybrown cockroaches live?
What do they eat?
Where do they hide?
When are these cockroaches active?
Are there any natural enemies of the smokybrown cockroach?
Are there non-insecticidal methods?
What's the best insecticide?
Are there other types of insecticides?
Where can I get insecticides to control cockroaches?
Have these insecticides been tested?
What can I do about cockroaches inside my house?
What kinds of cockroaches are there?
This web site is about the smokybrown cockroach, Periplaneta fuliginosa (Serville). Many of you know the adults - black, large, and they can fly! This is the most common type of cockroach that lives outdoors, around homes in Alabama, and much of the southeastern US. Another common cockroach often seen in apartments is the German cockroach, Blattella germanica (L.). These are small light brown cockroaches. There are large reddish brown cockroaches, the American cockroach, Periplaneta americana (L.). These cockroaches are most often associated with sewers and large buildings like warehouses. There are large black cockroaches seen rarely in Alabama urban areas that have reduced or no wings as adults, the oriental cockroach, Blatta orientalis (L.). In Mobile, occasionally other places there is the Nicaraguan cockroach, Ischnoptera bilunata (Griffin). It looks very similar to the German cockroach, but flies and lives outdoors. Another strange cockroach in Mobile is the Surinam cockroach, Pyncnocelus surinamensis, (L.) a large black cockroach found in lawns and digging in flower beds. It is not a pest, but its appearance may frighten homeowners. All of these cockroaches were imported to the US from foreign lands. Because cockroaches are so well adapted to the human environment, it wasn't difficult for them to sneak aboard ships. The smokybrown cockroach was first noticed in New Orleans a century ago (1850's). It began its spread throughout the southeastern US early this century, when it was known as the "traveling roach". As a matter of fact it displaced the American cockroach which had invaded the US probably before 1700. The smokybrown cockroach is not liked by American cockroaches. Apparently the American cockroaches don't like the way the smokybrowns smell. The stronghold of Americans in sewer systems is safe, because that is not a preferred habitat of the smokybrown cockroaches. The cockroaches native to Alabama are the woods roaches. These cockroaches are generally small, and live under rocks and logs. They rarely enter homes and so are rarely seen. In most of our native cockroaches, females are wingless and only the males fly. In the spring when males fly, they may be attracted to lights to the consternation of homeowners. But never fear, they cannot invade your home and set up household.
How long do smokybrown cockroaches live?
The smokybrown cockroach is long lived requiring 2 or more years to reach adulthood under outdoor conditions. It takes 50-80 days for the egg case, which usually contains 20-26 eggs, to hatch under warm conditions (greater than 70°F). The young, or nymphs, require about 250 days to reach adulthood at an optimum temperature of 85°F. Because the temperature at night and during the winter may be substantially below this, the nymphs require 2 or 3 years to reach adulthood outdoors. Like most other insects, the growth rate of smokybrown cockroaches depends on the temperature. When it's cool, insects barely grow at all, but when it's hot, they grow like crazy. Once they become adults, they probably live until the subsequent winter kills them. During this time females can potentially deposit 20-30 egg cases. However, inadequate food, low temperatures, and other problems may mean the average female cannot produce near the maximum number of egg cases. When the nymphs hatch they are black with white stripes. As they grow older they become brownish with yellow spots, and as the nymphs approach full size, they become a uniform reddish brown. The adults are dark reddish-brown to black and are they only stage with wings.
What do they eat?
Smokybrown cockroaches are omnivorous. They love dog and cat food. They will eat animal poop, wild mushrooms, fallen fruits and flowers, rotting vegetation, and food scraps in or near trash bins. They don't need to eat every day or even every week. A cockroach fattened on fallen fruits or pet food, could easily last more than 50 days before dying of starvation. In cold weather they may last much longer. Because they are not active in cold weather, they stay in their hiding places and burn very few calories. However, these cockroaches do require a great deal of water. They sweat a lot compared to other cockroaches. They can get moisture from standing water, food, moist soil under leaf litter, etc.
Where do they hide?
Cockroaches are nocturnal and need to have a place to hide during the day. They can easily hide under pine straw, fallen magnolia leaves, leaf litter, bricks, and in wood piles. Of course it is almost impossible to find them far from human habitation. Out in the woods, there are probably too many enemies (opossum, lizards, snakes), and too few places to hide from their potential enemies. Great numbers of cockroaches cannot fit in small cavities under pine straw or leaves. Large protected cavities are the kind of high-rises that can support massive densities of cockroaches, for example tree holes. Man-made cavities include cinder block walls (which often hide unobstrusively behind apparently tight brick facing), voids under concrete stoops and porches, blocked rainspouts and culverts, small aluminum and wooden sheds, and of course wall voids in your house. Some cavities can easily accommodate thousands of cockroaches. You may occasionally see them inside your house, but only rarely. Most houses today have air-conditioning and year-round humidity less than 60%. That's way too dry for smokybrown cockroaches to thrive, since they sweat so much. The cockroaches you do see inside wandered in during random exploration and they couldn't find their way back out again. Many people often see them turned over on their backs after they have died of thirst and dried up. In the rare cases where there are large number of these cockroaches inside your house sharing the living space with you, there must be some structural flaw in the building. For example, standing water in the crawl space promotes large populations which creep into your house more often. Alternatively, cracks or crevices leading to the outdoors or to hiding places in wall voids, allow easy access of cockroaches to the inside of your home.
When are these cockroaches active?
Being nocturnal, they are active mainly at night. When temperatures dip below 60°F for more than a few hours, smokybrown cockroaches tend to stay in their hiding places trying to keep warm. They are very sensitive to temperatures, and will freeze to death very easily. Such homeowners claim to see more cockroaches in the spring and fall. This is not because they are more active at this time of year, but rather reflects the influence of cold temperatures. In the spring, cockroaches awakening from their cold-induced lethargy may have forgotten the route leading to the outdoors, and end up mistakenly indoors. In the fall, the cold temperatures are driving the cockroaches to find warm hiding places, causing a greater number than usual to find their way inside. In general the cockroaches are most active on warm nights with new moons. Seemingly punctuated periods of cockroach activity in the summer as observed by homeowners may be due to the lunar cycle. Rain does reduce activities outdoors and may increase the chances of the ever-exploring roach of finding its way indoors.
Are there any natural enemies of the smokybrown cockroach?
When confined to closed spaces, skinks, fire ants, and argentine ants (often called black sugar ants) have been observed to eat cockroaches. However, when cockroaches have an easy escape route, these potential predators probably don't have a chance trying to catch them. Lizards and ants are more likely to chase the cockroaches from their normal hiding places. There is strange little wasp that lays its eggs inside the egg cases. The larvae that hatch from these eggs devour the developing cockroach eggs. Unfortunately, this little wasp, known as an ensign wasp, is not very common and does not seem to provide a limit to the development of cockroach populations.
Are there non-insecticidal methods?
If cockroaches leak into your house, sealing cockroach entrance ways is a good method of preventing their entry. Weather stripping around doors, caulking around kitchen pipes and cabinets, and screening attic crawlspace vents are all good preventive measures. Inspect your house carefully and try to determine how the cockroaches may be getting inside. Many homeowners are very familiar with the cockroaches entryways, however, residents may prefer greater air-exchange with the outside, more than they prefer preventing cockroaches from entering their home.
If preventing entry is not enough, there are other approaches. Basically if you deny the cockroach appropriate hiding places, food and water, the cockroaches will be decimated at your house. Storing pet food in sealed containers and not leaving uneaten food in pet dishes overnight will deny the cockroaches a rich source of food. Removing fresh pet poop, fallen fruit, food scraps around trash bins will also play a role. Many hiding places near homes like sheds, wood piles, and other storage piles (bricks, lumber, etc.) should be moved as far away from the house as possible. If they are not very important to you and they harbor lots of cockroaches, you may wish to dispose of them completely. Alternatively, wood could be stacked on frame, keeping the wood off the ground and making the wood pile drier and less suitable to smokybrown cockroaches. Some harborages like tree holes and voids in retaining walls cannot be easily moved or disposed off. In these cases, the voids must be identified and cockroaches denied access to them. By sealing entry ways with cement, plastic fiber, or other material, the cockroaches will be forced to go elsewhere for a place to live. In general drier environments are not preferred by smokybrown cockroaches. Cutting down trees, where desired, cutting shrubs back from the sides of your house will allow more sun and air movement to penetrate and dry the environment. Conversely if you love the forest, let it grow up to your door step without a lawn or decorative shrubbery (a very long term solution, unless you build a new house in the middle of the woods). Snakes and opossums among others will help control your cockroaches. However, you must also have a dry crawl space under your house, not have piles of thing stacked against the house, etc.
What's the best insecticide?
Almost anything will kill these smokybrown cockroaches. Pesticide resistance has not been detected among these cockroaches for several reasons. Pesticide resistance is a problem among German cockroaches because this species multiplies very fast - egg to adult in less than 90 days. This along with frequent application of insecticide quickly selects for cockroaches that are no longer affected by the insecticide. This is very similar to the selection process used by plant breeders to create super-yielding crop varieties. Fortunately, the smokybrown cockroach is slow growing, and people do not apply pesticide as often. This reduces the selective pressure for super bugs. Therefore, pesticide resistance is not likely to be seen among smokybrown cockroaches. Any spray formulation will be effective when applied outdoors to cracks, crevices, and other holes and objects where cockroaches may be hiding. One gallon of water, and the prescribed amount of insecticide will be enough to treat any house for cockroaches. This is the most efficient approach. Professional pest control operators also sometimes use banded perimeter sprays for the control of these cockroaches. This generally requires 20 to 50 times the amount of mixed insecticides for complete coverage. However, this application is not very efficient, because a banded perimeter spray using 25 gal. of pesticide is not any more effective than 1 gal. targeted spray. Clearly more is not better. Besides higher price, more insecticide is spread in the environment, with greater opportunity for human contact, and greater opportunity for effects on other insects and animals. The most common insecticide sold in places like Wal-Mart and K-Mart is a solution of DURSBAN. A common example is SPECTRACIDE. Do not use aerosols like RAID or BLACK FLAG to treat outdoors. Each can contains very little material and it would be very expensive to spray the equivalent of a gallon. Sometimes it is very satisfying to spray the cockroach that runs in front of you, but why waste the insect and poison the environment, when the bottom of your shoe is just as effective? Indoor treatments will almost always be ineffective. One, insecticides inside the house will not reduce the pool of cockroaches outside your house trying to get in. Two, since the cockroaches will typically die once they get inside your house anyway, the insecticide, if the cockroaches encounter, will only marginally quicken their death.
Are there other types of insecticides?
The main alternative to spray applications are bait applications with products like COMBAT paste in a plastic syringe. The bait can be placed in secluded cracks and crevices where cockroaches may be hiding. It takes about two ounces of bait to treat a property. Little dabs of bait, about 30-50 from a tube, are all that is needed at each bait placement. Use the syringe to apply bait rather than use prepackaged bait-stations (the round black holders, often mistaken for cockroach traps). The syringe will allow the bait to be placed in cracks and crevices where the bait stations do not fit, and also the paste can be spread among more cracks and crevices than the usual 12 bait stations in a package allow.
This method of control is much more selective than spray treatments. The bait is spread over a much smaller area than a targeted spray. In addition, the bait will only affect those insects that eat the bait. This method of application has negligible effects on common natural enemies of insects like ground beetles and spiders. Spray applications affect many more species of arthropods, and may cause increases in pests like fire ants, Argentine ants, crickets, and snails, even though the number of cockroaches have been reduced. The active ingredient in COMBAT paste bait is also less toxic to vertebrates like birds and squirrels, than is DURSBAN. Besides being less toxic, baits in secluded crevices also remains effective longer (as long as it is not eaten), than spray treatments.
Where can I get insecticides to control cockroaches?
Currently the only two products marketed to consumers are DURSBAN spray, marketed under many different names in stores like K-Mart and Wal-mart, and COMBAT paste bait. There are other baits and sprays, but these are generally only available to professional pest control operators. Many of these compounds require specialized knowledge in their application, but are not more effective than those products available retail. Of course it is always important safety point to follow label directions. In addition, sprays or baits must be targeted at cockroach hiding places to get the greatest effectiveness from a treatment.
Have these insecticides been tested?
In Alabama, baits and sprays have been tested over several years in 3 different urban areas: Mobile, Birmingham, and Auburn-Opelika. These methods are equally effective in all three cities and by extension to smokybrown cockroach problems throughout the southeastern US.
What can I do about cockroaches inside my house?
The best method for reducing the number of smokybrown cockroaches inside your house is the removal or treatment of cockroach hiding places outside your house. If you reduce the number of cockroaches outside, you will reduce the number of cockroaches inside the house. Sealing up cracks and crevices through which cockroaches enter your house is also important. Many people employ boric acid dust. Applied in backs of cabinets and other places where you frequently see cockroaches, it may kill cockroaches faster than the dry air in most houses. However, you will probably still see a few cockroaches scurrying around (they just happened to find their way into your house and are doomed anyway, whether you use poison or not). Boric acid must remain dry to be effective. If the powder becomes moist it will cake and the dust, which the cockroaches eat when they clean themselves, will not stick to the cockroaches. This quality of boric acid also makes it very poor for outdoor use. Boric acid in contact with moist soil will dissolve and if in high enough concentration could even poison nearby plants. Boric acid in corners of garages, again, must remain dry and powdery to remain effective. Thus outdoor use is very near impossible in Alabama, where summer humidities often exceed 85%, especially at night. Personally, a few cockroaches can be tolerated, especially since they come inside by mistake and can't find their way back out. Putting out poison to control the occassional doomed transient cockroach may be hazardous, especially with children and pets around. Avoid using insecticides indoors. The rare occassions where smokybrown cockroaches have taken up residence in your house, may be controlled with insecticides as a first step, but as mentioned above, these situations also indicate the need for repairs or modifications to your home.
HOME
|
