Public-Health Pesticide Applicator Training ManualHOUSE-FREQUENTING INSECT PESTS
| I. Bed Bugs – Developmental Stages – Bionomics – Detection and Control II. Lice – Developmental Stages – Bionomics – Detection and Control III. Fleas – Developmental Stages – Bionomics – Detection and Control IV. Cockroaches – Developmental Stages – Bionomics – Detection and Control |
Pests that reside within the home may be associated with public-health problems. But usuallythese pests are homeowner responsibility issues rather than public-agency matters, with major exceptionsbeing public housing, barracks and other similar types of government-operated institutions. A soundunderstanding of the bionomics of these arthropods is essential in order to respond correctly and provideproper advice to homeowners and public authorities. Four insect orders are included in this discussion:Hemiptera (bed bugs), Anoplura (sucking lice), Siphonaptera (fleas) and Blattaria (cockroaches). Bedbugs, lice and fleas are ectoparasites of humans. Other pests that invade homes but are less strictlyassociated with human activity (e.g., ants, spiders, flies, etc.) are treated in other chapters in this manual. The body louse is involved in epidemics of louse-borne typhus, trench fever and relapsing fever.Other human-infesting lice do not transmit disease organisms. Bed bugs have not been incriminated inthe transmission of any disease agents as a vector, but about 25 different disease organisms have beenfound in bed bugs. Some of these organisms have survived for long periods of time in these insects. Bedbugs may cause nervous disorders in sensitive people and contribute to the ill health of both children andadults. Fleas transmit the causative agents of such diseases as plague, typhus and tularemia to humansand can serve as intermediate hosts for dog, cat and rodent tapeworms, which may occasionally infesthumans, particularly young children. Cockroaches have been found to cause asthma and associatedallergies in humans. I. BED BUGS
| The wingless bed bug, Cimex lectularius, is a notable bloodsucking parasite of humans so well-adapted to humans that its bite is nearly painless. The bed bug is in the insect order Hemiptera and is a true bug. For all other orders the use of the term “bug” is incorrect scientific terminology, although it is often accepted as part of a common name when combined with another word. For example, ladybugs are not true bugs but are actually beetles. True bugs will have the term “bug” as a separate word, as in “southern green stink bug.” Bed bugs, like other hemipterans, exhibit gradual metamorphosis. |
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| Bed bug |
Insecticidal control has been so effective that bed bugs, once a major pest in the U.S., are now of minor importance. However, the increasing use of baits, which do not control bed bugs, in place ofresidual insecticidal sprays to control cockroaches and ants, combined with the ever-increasing numbersof visitors to and from other countries, is resulting in more frequent reports of bed bug infestations atmany hotels. These infestations then spread to homes and other buildings in luggage or furniture.Developmental Stages Eggs. Bed bugs lay one to five eggs a day over a period of two to 10 months, producing about200. They deposit the 1 mm white eggs intermittently each day in protected places near their hosts”sleeping quarters, cemented to bedding or in cracks. The eggs hatch in one or two weeks, depending ontemperature. Nymphs. Tiny and colorless at first, nymphs undergo five molts, each resembling the adult form and each requiring a blood meal. Each blood meal takes about three to 10 minutes, during which the nymphs inject saliva containing an anticoagulant. The nymphal period can last for several weeks underfavorable conditions to as long as a year when temperatures and host availability are low.Adults. Adults are 1/5 inch long, 1/6 inch wide and reddish-brown in color. Their flattened oval bodies are well-adapted for hiding in narrow crevices. The head bears a pair of four-segmented antennaeand piercing-sucking mouthparts that fold to lie between the first pair of legs. The wings are represented by pads. The body may become greatly enlarged and blood-red in color during a blood meal but turns adirty brown subsequently. Females can live nearly a year without food and can endure freezing temperatures for considerable time.Bionomics Bed bugs are found on the bed clothes and possessions of infested individuals. They commonlyoccur in such places as seams of mattresses, inside mattress coils, cracks in bedsteads, bedside furniture,dressers, wallboards, wood paneling, door and window frames, behind pictures, under loose wallpaperand in rooms near host sleeping areas. A heavily infested house has a distinctive odor. Some people arevery sensitive to bed bug bites while others are hardly aware of them. Immediately after feeding, bedbugs defecate the semisolid, sticky remains of the last meal, a good clue to their presence. Humans arethe preferred host, but bed bugs will feed readily on poultry, mice, rats, some song birds and otheranimals. Detection and Control Look for bed bugs by inspecting their harborage, usually in and around bedrooms or sleepingareas. Camping and sleeping equipment, outdoor animal sheds and coops are alternative sources ofinfestation. Habitat alteration to exclude alternate hosts such as rodents, birds, etc., is important in vermin-proofing living quarters. Keep woodpiles, shrubs and weeds away from the foundation of the dwelling.Eliminate garbage. Caulk and screen routes of entry. Store mattresses in protected areas, unfolded toprevent rodent nesting. Allow light to enter crawlspaces, cabinets, etc., to discourage use of suchharborage. To control bed bugs, caulk or otherwise repair all cracks and spaces behind baseboards and otherareas of the house. Treat infested areas with liquid or dust insecticides registered for this purpose. Treatbaseboard crevices, closets, wood paneling and other places that harbor bed bugs. Avoid spray runoff ifapplying liquid insecticides onto surfaces and into cracks. Residual applications reduce the need forrepeat applications. A single application is usually sufficient in a home, but multidwelling structures andhotels require frequent inspections and perhaps repeated applications. If the infestation is localized in anapartment building or hotel, treat all units connected to the infested area. Thoroughly treat the frame, slats and springs of beds. To treat the mattress, apply a light mist to seams, tufts and folds but not to the entire mattress. Follow label directions, or allow four hours if notspecified on the label, for the spray to dry before covering the mattress with a sheet. Ventilate the roomwhile spraying and during drying. Treat infested upholstered furniture in the same way as mattresses bylightly spraying or dusting only the edges and seams of cushions, furniture joints and the inside (hidden)framework. Avoid treating sit-on or arm-rest areas. Do not use treated furniture or bedding until it isthoroughly dry; better still, do not use it for 72 hours after treating with an insecticide. Before allowingchildren on treated furniture, vacuum it thoroughly to remove loose and excessive amounts of chemical.Space treatments and fogs are not effective. Do not treat the bedding (mattresses and frames) of infantsor the infirm, but replace with uninfested items. Two other species of bed bugs, called bat bugs, are usually found in bat colonies. They maywander into living areas just below attics. To control these pests, locate the infested bat-nesting sites,dust after the bats and detritus have been removed, then seal host entry points to prevent reinfestation. II. LICE Lice are intimately associated with humans. Louse infestations occur today in the U.S. despitegreat efforts to maintain high standards of public hygiene. Public-health agencies are often called upon ifinfestations include or expose large groups of people, particularly those in public institutions such asschools, jails, hospitals or homes for the elderly. The three sucking lice that infest humans are the headlouse, Pediculus capitis; the body louse, Pediculus humanus; and the crab louse, Phthirus pubis. The head louse and body louse are nearly indistinguishable unless observed under a dissecting microscope, and even then it might require the aid of an expert to correctly identify a specimen to species. Lice complete their entire life cycle on the human host or within the host”s clothing. Lice undergo gradualmetamorphosis. Developmental Stages Eggs. Eggs can appear white, gray, tan, brown or even black and are about 0.8 mm by 0.3 mm.They have a cap at one end to admit air during development of the embryo and to facilitate escape of theyoung insect. The eggs of the head louse and the crab louse are attached to a single humanhair with a cementlike substance. Body louse eggs are cemented to clothing fibers. Eggs areincubated by body heat and hatch in about a week to ten days. Eggs can survive and completedevelopment off-host. Although the hatching rate is far below normal, eggs can hatch in up to nine daysoff-host at room temperature. Nymphs. After emerging from eggs, louse nymphs molt three times before becoming sexuallymature adults. Crab lice and head lice will mature in seven to 12 days. The nymphal stages of the bodylouse require eight to nine days when remaining in contact with the human body but may require two tofour weeks when the clothing is removed at night. If the clothes are not worn for several days, all of thelice will usually die. All three species can survive up to 48 hours off-host without a blood meal; however, the higher the temperature, the quicker they will die. Adults. Adult body or head lice differ little from nymphs except in size and sexual maturity. Adult body and head lice range from 1.5 mm to 3 mm in length. The mouth is encircled by six pairs ofhooks that the louse uses to attach to the skin during feeding. There is also a soft, retractable, suckingmouth with piercing stylets to open the wound and provide a salivary duct. When ready to feed, the louseanchors its mouth to the skin, stabs an opening through the skin, pours saliva into the wound and pumpsblood from the injury into the digestive system by means of the pharyngeal pump. The three thoracic segments each bear a pair of strong, five-segmented legs that terminate in ahooklike claw which enables the louse to maintain its hold on hairs and fibers. Mating occurs frequentlyand at any time in the adult”s life, from the first 10 hours to senescence. Eggs are laid 24 to 48 hourslater, depending upon temperature conditions. Body lice may deposit nine or 10 eggs per day, totaling270 to 300 eggs in a lifetime. Head lice are less prolific, depositing about four eggs per day for a total ofabout 90 in a lifetime. Bionomics Head lice are confined to the head hair and scalp where the adult and immature lice, particularlythe eggs, are found fastened to the hairs. Body lice are found on hairy parts of the body below the neck,with adult and immature lice and eggs frequently on clothing, especially along the seams of the innersurfaces. Crab lice are found in the pubic and anal regions and occasionally in the armpits, on hairy areasof the chest, and on eyebrows and eyelashes. Head lice affect an estimated 12 million people annually in the U.S. The vast majority of theseare school-aged children, particularly children ages 5 to 10. Head lice infect children of all backgroundsregardless of care given to personal hygiene. Head lice are primarily transmitted through direct head-to-head contact, but objects such as combs and hats also may contribute to transmission. Recent researchhas suggested head lice have become resistant to some of the more popular treatments available over-the-counter. This condition may be contributing to the increased number of head lice cases. Adult and immature head lice are seen less frequently than the eggs, commonly called nits, whichare fastened to the hairs, particularly those behind the ears. Public-health workers should be aware thatforeign material in the hair and hair casts (inner hair root sheaths that have slid along the hair shaft) havebeen mistaken for eggs. A number of infestations have been reported in which solidified globules of hairspray were confused with eggs. In other instances, students have been sent home because of smallwhitish objects attached to their hair. An amorphous cellular mass was found in some cases and hairfollicle mites (Demodex spp.) in others. Seen through a microscope, a nit is easily distinguished fromother objects by distinct characteristics: the ring at the base of the egg by which it is fastened securely tothe hair; the egg itself, frequently with an embryo visible inside; and the cap (operculum), which hasdefinite pores. The female louse oviposits eggs on the hair shafts very near the scalp. As the hair grows, the egg moves further away from the scalp. Eggs that are more than 2.5 cm from the scalp are probablyold eggs that did not complete development or empty egg shells.
| Infestations of body lice are generally associated with people living crowded together and having limited facilities for regular bathing and laundering. They are most common during times of stress, suchas in evacuation centers, labor camps and institutions, and are commonly associated with tramps andmigrants as “hobo”s disease.” Severe infestations lead to scratching, secondary infections and the classicsigns of pediculosis — scarred, hardened or pigmented skin. After the widespread use of DDT followingWorld War II, there were relatively few reports of body lice in the U.S. Body lice are still uncommonexcept among populations of homeless people or those in similar situations. |
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| Body lice |
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Crab lice are approximately 1 mm to 2 mm in length as adults and are relatively uncommon in the human population. The last two pairs of legs have hooked mitts that resemble claws. They usually are transmitted during sexual intercourse.
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| Crab louse |
Most sucking lice spend their entire life as ectoparasites on mammals. The body louse is a conspicuous and important exception because it rests on clothing except when feeding. Sucking liceoccur only on mammals, not on birds, reptiles or amphibians. Each species of louse generally feeds upononly one species of host animal, one genus or, more rarely, one group of mammals. In general, closely related groups of mammals appear to be infested by closely related species of lice. The three species oflice that infest humans are host specific. They exist only on humans. Lice of other animals normally donot infest humans. Human lice depend upon human blood for sustenance. They suck blood for long periods of timebut do not ordinarily become fully engorged. During feeding, dark red feces may be deposited on theskin. Head louse adults and nymphs are most prevalent on the back of the neck and behind the ears. Theyare not known to infest eyebrows or eyelashes, as does the crab louse. The typical head louse infestationconsists of fewer than a dozen adult lice. While as many as 1,000 body lice have been removed from theundergarments of one person, infestation of fewer than 10 lice per person is more typical. Most of thelice are on the inner surface of the clothing, next to the skin. Detection and Control Public institutions, such as hospitals, jails and nursing homes, sometimes find incoming peopleinfested with lice. When the incidence is high, it may be necessary to use experienced inspectors orpublic-health nurses to inspect all people entering such institutions and to treat infested people.Infestation should be handled as a medical problem, and considerable effort must be made to avoidexposure of patients to ridicule. When outbreaks occur in schools, children must be examined daily uponreturning home, otherwise they are likely to become reinfested and the condition may spread toclassmates. In many instances other family members and close associates may require treatment. Liceinfestations are a medical problem. Pesticide applicators, even those in public health, should not makerecommendations concerning medications for control. Head lice. Several over-the-counter and prescription preparations are used to eliminate head louse infestations. Newer over-the-counter products available do not contain traditional pesticides butpossess botanical ingredients or enzyme derivatives. The prescription preparations are usually effectivewith a single application, whereas the others may need to be used twice — first to kill live lice, and then six to 10 days later to kill those that emerge from nits. Both types are applied to wet hair and thenshampooed out after a sufficient exposure period. Infested family members should be treated at the sametime, and bedding, hairbrushes, knit caps, etc., should be washed. Rugs and carpets should be vacuumedand cleaned or simply quarantined for 10 days after vacuuming. Body lice. Hatch is greatly reduced or completely prevented by exposure to temperatures above 100°F or below 75°F. Thus, the body louse is readily suppressed when the same garments are wornintermittently. When the same clothing is worn for several weeks or months, it may become heavilyinfested with body lice. Conversely, if clothing is stored for a month, even without treatment, all eggswill hatch or die, and any young that hatch will die. Body louse epidemics on humans are controlled byemergency applications of pesticides (usually in the form of shampoos), but control is maintained bycleaning and washing clothes. Some pesticides are labeled for spraying but are of little use. Infestedindividuals should bathe to detach and kill moving lice on the body. Clothing and bedding should bewashed with hot water and detergent and then dried in a clothes dryer set on “high” to kill the lice.Disinfectants and detergents can be used on bed frames, furniture, ambulances and hospital equipment. Crab lice. Commercial preparations are available for crab louse treatment, many of which are the same as for head or body lice. Bedding and underwear should be washed, toilets disinfected andcarpets vacuumed; there is no need to make insecticidal applications to surrounding areas. III. FLEAS
| Fleas are members of the order Siphonaptera, named for their mouthparts and wingless condition. Worldwide, more than 2,200 species of fleas parasitize mammals and birds. Fortunately, humans encounter only a few of these species, the most common being the cat flea (Ctenocephalides felis), dog flea (C. canis), human flea (Pulex irritans) and oriental rat flea (Xenopsylla cheopis). Fleas are medically important because of their irritating bites, abundance and ability to transmit diseases. The oriental rat flea is the primary vector of bubonic plague and murine typhus. Dog and cat fleas areintermediate hosts of tapeworms that can infest humans if accidentally ingested. |
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| Adult cat flea |
People have differing reactions to flea bites, in which three stylets are used to penetrate the skin and suck blood. Some are oblivious to the bites, unattractive to fleas or both. Others seem to be highly attractive to fleas. In a flea-infested household, one or two individuals may show severe irritation from the bites, whereas others may not even realize fleas are present. Household fleas prefer the blood of pets. Thus, people may coexist with the pet and the pet”s flea population while being bitten only occasionally. When the pet is removed from the environment, such as during a family vacation, a large population of hungry adult fleas may accumulate. When hungry, adult fleas tend to lose their one-track desire for thepet”s blood and will then attack any warm-blooded animal, humans included. Fleas most often bite people on the legs and ankles; characteristically, two or three bites in a row. A small, red spot with a light-colored center appears where the mouthparts entered the skin. Irritation,itching and rash are caused by salivary secretions that the flea injects during feeding. The typical humanreaction to a flea bite is a small, hard, red, slightly raised, itching spot. Usually there is no swelling. Somebleeding can occur, particularly if the bite is scratched. Cats and dogs scratch and bite themselvesconstantly when heavily infested. Their coats become soiled and roughened, and their skin is irritated asa result of a flea infestation.Developmental Stages Under normal conditions, the entire life cycle of cat fleas may be completed in as few as 20 to 35days. The cycle is influenced by temperature and moisture conditions, with 85°F and 85 percent relativehumidity being near ideal. Under less favorable conditions, complete development may require months oreven a year. Flea production may take place indoors year-round, while outdoor production is limited towarm weather months. Sustained temperatures below 55°F inhibit larval development. There are fourstages in the life cycle of fleas: egg, larva, pupa and adult. Eggs. Flea eggs are smooth, oval, whitish, about 1/50 inch long and visible to the naked eye. The eggs hatch in two to 14 days, depending on environmental conditions. Larvae. Newly hatched larvae are wormlike and whitish; when mature, they can be up to inch long. Larvae lack legs and eyes and have chewing mouthparts. Fleas pass through three larval stages andare fully developed within eight to 24 days. The larval stage, however, can be prolonged to more than sixmonths under adverse conditions. Pupae. Before entering the inactive pupal stage, the fully grown larvae spin silk cocoons. They incorporate debris particles that camonhatroso.comage the cocoons in natural surroundings. Each larva then pupates within its cocoon. The pupa, initially creamy white, gradually darkens to a brownish color. The pupalstate typically lasts five to seven days but may be prolonged up to a year by unfavorable conditions. Adults. Adult fleas are small, wingless insects, approximately 1/16 to 1/8 inch long. They are dark reddish-brown to black, with the mouthparts of both males and females adapted for puncturinganimal skin and sucking blood. The third pair of legs is modified for jumping. Some species breedcontinuously, needing only a month or so to complete a generation, whereas others have but onegeneration per year. Bionomics Most flea species infest smaller animals, such as rats, mice, rabbits, moles and bats, but some areparasites of larger animals and birds. Most are specific in host preference. They are very sensitive to temperature and humidity. The adult flea, even while still in the cocoon, recognizes the presence of a potential host by the host”s body heat and odor and by vibrations. This is one reason fleas often attackpeople returning home after vacation or when new occupants move into quarters formerly occupied bypeople with pets. Eggs are usually deposited onto the skin or hair of the host pet, from which they droponto the pet”s bedding, carpet, rugs, mats, etc. Thus, the greatest concentration of eggs is where the petspends the most time. The fertilized adult female flea lays two to 14 eggs after each blood meal,producing as many as 800 eggs in her lifetime. The slender, whitish, sparsely bristled, legless larvae are often found in floor cracks, rugs,carpets and animal bedding. They can move quite readily using their body bristles for traction. They arescavengers, feeding on a wide variety of organic debris including pet dander, but their main food is thedried blood defecated by the adult fleas. Flea larvae prefer a dark, moist environment. Adults may remain in the cocoons for up to five months, depending on the availability of a hostand environmental conditions. Their bodies are well-adapted to their particular way of life. That is, thebody is thin (laterally compressed) and covered with a series of backwardly directed spines so that adultscan move rapidly through the hair or feathers on the host. Their powerful legs permit them to jump as faras 7 to 8 inches vertically and 14 to 16 inches horizontally. This ability may give the false impression thatfleas can fly. Cat fleas and dog fleas. These pests exhibit similar behavior, habitat preferences and life cycle characteristics. The cat flea is the most prevalent species in the U.S. and is commonly associated with cats, dogs and humans. The dog flea is a major pest throughout Europe, preferring dogs and other canids,but is infrequently encountered in the U.S. These fleas prefer places where dust and organic matteraccumulate and are commonly found inside and outside, under buildings and in yards. They remain onthe body of the host, feeding frequently, whereas rodent fleas stay in the host”s bedding, feeding onlywhen the host is present in the daytime. The digested host blood is excreted as a corkscrew-shaped stringof black, nearly dried blood that breaks up into pepperlike specks. They inject irritating saliva thatprevents the host blood from coagulating and often initiates an allergic reaction in the form of dermatitis,hair loss, etc. Oriental rat flea. This important vector is found as far north as New Hampshire, Minnesota and Washington, where it is abundant in the summer but less so in colder months. Xenopsylla vexabilis, the Hawaiian rat flea, is a close relative with similar bionomics. Fleas become infected after feeding on a plague-infected animal. The bacteria, Yersinia pestis, multiply in the flea”s crop and stomach, where they might cause an obstruction. Such fleas are said to be “blocked.” When the flea attempts to feed again, blood cannot pass beyond the blockage and becomes contaminated with plague bacilli. The contaminatedblood is then regurgitated back into the host. This flea is the most important vector of plague because ofthis tendency to regurgitate plague organisms, its ability to feed on both humans and rodents, and itsgreat abundance near human habitation. Human flea. This flea is important because of its ability to cause dermatitis and allergic reactions by its bites. It attacks many other hosts, including dogs, ground squirrels and prairie dogs.Among these hosts it is responsible for transmission of tapeworms. In Hawaii the false human flea, Pulexsimulans, co-exists with the human flea and feeds primarily on dogs. Sticktight flea. The sticktight flea (Echidnophaga gallinacea) attaches firmly to its host, often causing ulcers on the head and neck. The female flea remains attached for the rest of her life, sucking blood and laying eggs that fall off the host and collect in the environment. Larvae hatch and go through a life cycle similar to that of the cat flea. Although the main host is poultry, this flea attacks cats, dogs and many other animals, including humans. Detection and Control In addition to families and pets, several species of urban and rural wildlife support fleainfestations, including chipmunks, ground squirrels, opossums, raccoons, coyotes and prairie dogs. Thesesources might need to be considered when control efforts seem to be only partially successful. Pets arealways aware of the location of wildlife habitats in their own backyard. As soon as they are released theyrun to these places to investigate. This behavior facilitates flea reinfestation of clean pets. Close inspection of indoor and outdoor pet areas may be required to detect even high fleapopulations. Typically, fleas need warm and relatively humid conditions to thrive outdoors. Favored petfeeding, sleeping or resting areas, such as pet beds or blankets, kennels, doghouses, under bushes, incrawlspaces, etc., are natural flea harborages. Formal surveys are essential in managing flea-borne disease, usually focusing on sampling rodentand other small animal populations to determine the relative abundance of fleas in an area. To do this,rodents are trapped with snap traps, and the captured animals are placed in plastic bags (within eighthours) to contain the ectoparasites. Larger animals are trapped with live traps from which the animalsare removed, anesthetized and then combed with a fine-toothed comb over an enamel pan to collectspecimens. Protective clothing is worn during this process to prevent escaping fleas from bitingpersonnel. The surveys, made before and after control operations, can be used to measure effectivenessand duration of management techniques. It is essential to manage fleas before controlling their host. If the hosts are killed first, the fleas abandon them and seek other hosts, complicating the operation and potentially exposing alternate hosts to disease organisms. Habitat alteration. Exclusion procedures to prevent access of pets and infested animals to crawlspaces and areas under porches and buildings, as well as trapping and relocating wildlife, may berequired to eliminate difficult infestations. Wall voids, subfloors and spaces, and under product shelvesserve as rodent entryways and lead to contact with humans. Burrow treatments. Insecticidal dusts can be applied in a manner that leaves a light filmcovering the entire treated surface. Apply the dusts with a duster wherever target rodent burrows arefound, such as in prairie dog colonies, holes in floors and walls, and other enclosed areas that may serveas harborages. Urban pesticide application. To successfully control fleas, treat inside infested structures, outside at sites of flea concentrations and the infested animal(s). Treating only one or two of the three almost always leads to a reinfestation because fleas that remain will find the animal and then are furtherdistributed to other areas. Before applying insecticide indoors for flea control, vacuum the premises thoroughly, especiallypet resting areas, to remove as many developing fleas as possible. Vacuuming carpets will not completelydestroy larval populations because the spiny larvae wrap themselves tightly around carpet fibers.However, vacuum-cleaner vibrations will cause adult fleas in cocoons to emerge immediately, allowingthem to be sucked into the vacuum. Vigorously vacuum the entire structure, especially those areas mostfrequented by the infested animals. Vacuum carpets, particularly around legs of furniture that pets rubagainst. Also vacuum cracks and crevices along baseboards, upholstered furniture if the pets are allowedon such furniture pieces and even under beds if the pets are allowed on the beds. As soon as thevacuuming is completed, place the vacuum bag in the trash in a sealed plastic bag. Otherwise, thevacuum bag may become a source of reinfestation of the house. A fine insecticide mist can be sprayed on floors, furniture, cracks and crevices using insecticides approved for adult fleas. An insect growth regulator (IGR, usually with fairly long residual activity) will help prevent flea larvae from maturing and can be incorporated into the spray mixture. These products are odorless, nonstaining and relatively nontoxic. It is usually necessary to make a second applicationafter about 10 to 14 days because flea pupae not affected by the first spray will then be adults. Whiletotal release aerosols are available for quick knockdown of adult fleas, this type of application alone israrely successful because it does not affect the other stages of the flea. During warm weather thoroughly treat infested outdoor premises such as dog houses, garages,porches, dog runs, fence lines and the loafing areas of the yard. Prevent pets and all other animals fromgetting under the house. Treat all areas frequented by pets. As with indoor situations, a secondapplication may be necessary outdoors. In cold weather, fleas may remain in the pupal stage for longperiods and thus escape the effects of a treatment that eliminates larvae and adults. Treatment of pets at the same time as the structure is important because the pet may be theprimary source of flea infestation. Veterinarians can supply on-animal flea-control products that provideseveral weeks of suppression either by a few drops on the back of the animal”s neck or as a spray withlong-term residual activity that also kills all the fleas on the animal within a few hours. Also availablethrough a veterinarian are IGR formulations that can be administered to a pet once a month in the form ofa tablet (dogs) or liquid formulation in food (cats). When initiated early in the season this can prevent aflea problem from developing because the IGR is incorporated into the pet”s blood and prevents femalefleas from producing viable young. Specific formulations can be applied topically once a month to dogsand cats over six weeks of age that kill adult fleas and prevent egg hatch. These products provide rapidknockdown of fleas on pets, have long-term residual activity and are relatively convenient to use. Whileroaming pets may still encounter fleas, the fleas will be unable to survive and infest the home. Flea-control products containing rapidly degraded insecticides, although effective, do not provide residual effect. Other formulations labeled for use on pets include shampoos, aerosols, dips, dusts andsprays that usually provide short-term control. Treatment of puppies and kittens may be hazardous. Some products provide long-lasting control,but can be lethal to cats and puppies. Read the label carefully. Attention should be directed to theirmothers and infested areas after they have been moved to clean bedding. IV. COCKROACHES Cockroaches have plagued mankind since the beginning of recorded history. Not only cancockroaches live with us, they live around us in both urban and rural areas. Even cockroaches that do notnecessarily thrive under the same living conditions as house-dwelling species will wander in from theoutdoors through convenient openings in walls, windows and doors. Small populations of house-dwelling cockroaches may not be obvious, as they prefer to hide incracks and crevices during the day and forage for food and water at night. Cockroach numbers can easilygrow, however, creating large populations in relatively short periods of time. Even small cockroachpopulations can create problems for humans. The problems that cockroaches cause may be classified aseither aesthetic or health-related. Aesthetically, cockroaches produce objectionable odors, leave behindtheir cast skins and feces, and result in disgust and/or embarrassment for homeowners. Health-related problems caused by cockroaches include asthma and allergies, especially forchildren living in inner cities where high cockroach populations are endemic and up to 35,000cockroaches might infest a single apartment. At such density, cockroach feces and body parts areabundantly present as allergens. Cockroaches are also potential mechanical vectors of disease and havebeen shown to be capable of mechanically harboring the pathogens that cause leprosy, urinary tractinfections, conjunctivitis, pneumonia, wound infections and food poisoning. Pathogens may be spread byoral or fecal contact, or by cockroaches walking across surfaces or through foodstuffs. Given theopportunity, cockroaches will also feed on human tissue, secretions and hair, resulting in direct contactwith humans and possible direct transmission of pathogens. Developmental Stages Eggs. Female cockroaches of all species produce egg capsules (oothecae) that may be carried within her body or extrude from the tip of the abdomen. Depending on the species of cockroach, eggcapsules may be glued to surfaces such as walls, or inside furniture, or they may be held untilimmediately before hatch. Egg capsules are usually 1 mm to 1.5 mm long and may contain 12 to 48 eggs.Depending on species, the egg case may take several days or weeks to hatch. Nymphs. Cockroach nymphs undergo gradual metamorphosis and may go through eight to 13 molts before they become adults. Nymphs are usually very similar in appearance to adults, except thatthey do not have fully formed wings. The time required from hatch until the final adult molt may rangefrom just under two months to as long as two years, depending on environmental conditions andcockroach species. Adults. Adults of many species of cockroaches possess wings, although not all of these are actually able to fly. The longevity of adult cockroaches depends on both the species of cockroach andvarious environmental conditions. As a general rule, the larger the cockroach species, the more long-lived it is. For example, adults of the American cockroach, a large peridomestic species, may live up to a year or more, whereas smaller species such as German or Asian cockroaches have an average adult lifespan of approximately six months. Bionomics Most cockroach species display negative phototaxis, moving away from light sources. Theyprefer to forage for food, water and mates during the hours that begin a few minutes after sunset and endshortly before dawn. Generally, female cockroaches with egg cases and small nymphs tend to stay withinhidden harborage areas. Males and large nymphs are usually the most active cockroaches and aretherefore seen more often by humans. Their ability to adapt to a variety of conditions and to thrive incommerce leads to infestation by being transported in grocery sacks, boxes and a wide variety of carriers. Cockroaches have evolved into a laterally compressed body shape that allows them to fit intorelatively small cracks and crevices, and they have legs that are well-adapted for running. Cockroacheswill react to slight puffs of air by darting forward, running away from the air source. This defensivemechanism aids in protecting cockroaches from predators. Cockroaches are omnivorous and can subsist on a wide variety of possibly unlikely food sources.It has been documented that cockroaches eat garbage, fresh or decaying food and food scraps, hair,leather, skin, dead animals, dry plant materials and some paper products. However, cockroaches can gofor long periods of time without either food or water. Their ability to subsist on a minimum amount ofresources, combined with their great mobility and tremendous fecundity, greatly enhances their survivalability in both urban and rural environments.
| German cockroach (Blattella germanica). Approximately 80 percent of a German cockroach population consists of nymphs. The remaining 20 percent is approximately evenly divided into adult males and females. Of the females, a large proportion of them will be gravid and will be secluded inharborage areas. Nymphs of all stages are black in color with a light brown band around the outer edge, as well as down the middle of the back. The length and breadth of the band will vary in size, depending on the age of the nymph. Adults are approximately 1.6 cm in length. Both males and females range in color from light to dark brown, with the female somewhat darker than the male. Both males and females possess wings and have two black lines extending down the pronotum, or upper back area. |
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| German cockroach |
German cockroaches, with rare exception, are found within human structures. They prefer tofrequent kitchens and bathrooms where a constant source of water is usually available. The cockroacheswill remain hidden during the day in areas behind appliances, under sinks, in cabinets and behindbaseboards. However, German cockroaches are not limited to occupying specific areas. In hospitals, theyhave been found in the hollow metal legs of food service carts and within bed railings. They can becomea problem in food service and equipment areas in commercial establishments such as restaurants andsupermarkets. At night they will leave the safety of their harborage areas to seek food and water. Asian cockroach (Blattella asahinai). Both adults and nymphs of the Asian cockroach appear nearly identical to German cockroaches. Distinguishing Asian cockroaches from German cockroaches is accomplished through their differing behavioral characteristics. While the German cockroach is anindoor species that does not fly, the Asian cockroach is an outdoor species that flies readily and well. TheAsian cockroach breeds in mulch, leaf litter and grassy areas outdoors. During heavy infestations of thiscockroach, grass will shimmer and appear to move as the cockroaches move about. Additionally, Asiancockroaches swarm to lights and lighted areas during dusk. During the evening when lights are turned onindoors, Asian cockroaches will fly into homes and create a nuisance for homeowners. It has beenreported that Asian cockroaches can become established within homes, but their primary pest status isderived from the fact that they are flying insects that invade porches and the interior of homes. It may bedifficult to pinpoint the source of an Asian cockroach problem because they may be breeding in areasother than where they create problems. Therefore, attempts at control should take into consideration thefact that they are proficient flyers and may be invading from neighboring areas.
| Brownbanded cockroach (Supella longipalpa). Brownbanded cockroaches may be mistaken for German cockroaches because of their similar size. However, brownbanded cockroaches may be easily distinguished by their markings. Nymphs have distinct, light-colored bands extending latitudinally across the back of the body region. They also possess lighter markings around the edges of the pronotum. Both adult male and female brownbanded cockroaches possess wings. |
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| Brownbanded cockroach |
Brownbanded cockroaches are found primarily in homes and prefer harborage in high areas such as in closets and behind picture frames and moldings. They prefer drier areas than do German cockroaches and are not associated with kitchens and bathrooms. It has been reported that brownbanded cockroaches will fly within homes and may be seen flying around light structures. Female brownbanded cockroaches will deposit egg cases in a variety of areas, including furniture and linens. Egg capsules are approximately 5 mm long and carryapproximately 10 to 20 nymphs.
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American cockroach (Periplaneta americana). This cockroach is a large species, measuring approximately 3.8 cm in length as an adult. The nymphs are patterned dark reddish-brown and yellowish-brown and do not possess wings. Adult males and females are very similar in appearance, with the femalehaving a somewhat wider and more rounded abdomen than the male. Additionally, an egg capsule isoften seen protruding at least partially from the abdomen of the female, further aiding in identification.Males have two sets of thin, pointed appendages (cerci and stylets) at the tip of the abdomen, whereas females have only one set of cerci. Both male and female American cockroaches are a uniform darkbrown to reddish-brown, with a dark yellow band encircling and dividing the pronotum.Adults of both sexes possess fully developed wings and are capable of flight. |
| American cockroach |
American cockroaches tend to breed in cool, damp, dark locations such as sewers, basements and gutters, and they readily infest commercial establishments where food preparation occurs. They can become established in homes by entering through conduits such as plumbing or sewer lines, or migrating from basement areas. Once established within a home, American cockroaches will thrive, given access to food, water and preferred temperatures. Females produce approximately one egg capsule per week and will glue thecapsule to any available substrate. Egg cases have been found on ceilings, in furniture, along baseboards and in cabinets. After the nymphs hatch, the split egg case will remain glued in place, providing evidence that cockroaches were present. Close relatives include the brown cockroach, smokybrown cockroach and Australian cockroach, all associated with harborage in plants but capable of building sizeable populations in dwellings.
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