L-1373

CONTROLLING COCKROACHES WITHOUTSYNTHETIC ORGANIC INSECTICIDES

G. L. Piper, R. R. Fleet, G. W. Frankie and R. E. Frisbie*

Cockroaches rank high on the homeowner's listof in ect problem. The mo t widespread grievanceagainst the roach is its mere presence in the home,a well as the implication of uncleanliness whichaccompanies a roach infestation. Roaches contami­nate food with excrement and salivary secretionsand lea e an unpleasant odor. They are capableof carrying disease organisms, but the role roachesplay in transmitting these organisms to man isunknown.

Many homeo\vners do not want to use syntheticorganic in ecticides to control cockroaches. Becauseof thi, eyeral method of controlling cockroachesthat do not invoh'e synthetic insecticides have beendevised.

Cockroach Description and Biology

Cockroache generally have a flattened, ovalshape, spiny legs and long, filamentous antennae.Color, depending on age and species, ranges fromdark brown to reddish-brown, and from tan toblack. Adults of some species are fully winged,while the wings of other species may be short,e peci all y on the females.

Immature forms of all cockroaches resemble theadults except that they are smaller and have unde­veloped wings. Young roaches develop rather slowlyand are found in the same places as the adults.

11 cockroaches are nocturnal; they hide in dark,damp place during the day and search for food atnight. If disturbed, they run rapidly for shelter.Roaches are omnivorous and eat practically allfoods consumed by man and domestic animals, aswell a their wa te products.

Roach eggs are deposited in groups of 12 ormore in a bean-shaped, leathery capsule or egg case.Egg case color ranges from dark brown to reddish­brown. In some species the female drops or gluesthe ca e in out-of-the-way places soon after it isformed. The female German roach carries the caseuntil the eggs are ready to hatch.

·Respectively, post-doctoral fellows, Department of Entomol­ogy, Texas A&M University; Associate professor, Departmentof Entomology, Texas Agricultural Experiment Station, TheTcxa A& r ni\'crsity ystem; and Extension entomologist,Thc Tcxas AR:M nivcr ity System.

Cockroach Species

Before starting control procedures, the home­owner should determine which cockroach speciesare present.

The most common is the large American cock.­roach (Figure I). It is reddish-brown ·to brm\'n incolor, has a tan or light yellow band around theshield behind the head, and is 1'l'2 inches longwhen mature. Outdoors it is found under the barkof trees, in leaf litter, rubbish piles, sewage systems,and in barns or other out-buildings. Inside thehome, this roach commonly is found around thfurnace and associated heating ducts. Egg cases aredeposi ted in shel tercd areas on or near the floor,usually close to a food source, and are concealedwi th debris.

The smokybrown is the other common largeroach (Figure 2). It is 1'l'2 inches long andthe color is uniformly dark brown to black. It isprimarily an outdoor species, and is most abundantin heavily wooded areas with substantial groundcover. It also can be found in firewood, lumber,trash piles and sewers. In the home this roachfreq uently is found in the attic or near fireplaces.Females prefer to attach their egg cases to cracks,depressions or corners of rough-textured surfaceslike brick, concrete or wood. Egg cases also aredeposited around window casements or behinddraperies. Cases may be concealed or exposed andcan be found anywhere from floor to ceiling.

The German cockroach is the most commonsmall roach. The adult (Figure 3) is about Y2inch long and light brown in color with two black,lengthwise stripes on the shield behind the head.This roach lives indoors and usually is brought inwith laundry, groceries or cartons. It also mayimmigrate from nearby infested dwellings. TheGerman roach is a pest in kitchens, bathrooms andother areas where there are food, warmth and mois­ture. The female carries the egg capsule protrud­ing from her abdomen for about a month, thendrops it a day or two before the eggs are ready tohatch.

The brown-banded cockroach (Figure 4) variesin color from light tan to glossy dark brown, andwhen fully grown may be % inch long. The adult's

The Texas A&M University System • Texas Agricultural Extension Service • Texas Agricultural Experiment Station

wings are marked with two light yellow, horizontalbands, one at the base of the wings and anothernear the middle of the body. This roach prefersstarchy foods, and as a resul t of a low moisturerequirement it is not restricted to the kitchen orbathroom but occurs throughout the home. Thisspecies prefers to hide in warm, elevated areas nearthe ceiling, behind wall decorations, shelving andelectrical appliances. The female glues the eggcapsule to ceilings, beneath furniture, and in closetsor other dark places.

The oriental cockroach (Figure 5) is glossyblack, 1 to I Y2 inches long when mature and flight­Ie s. It feeds on a wide range of decaying organicmatter and is considered the filthiest of domesticroaches. ear the home, this insect lives in cool,moist areas such as beneath. leaves and yard debris,in plant composting materials, or beneath porcheswithout foundations. This roach readily invadeshouseholds through sewer and drain pipes, crackedfoundations, ventilators and under doors. Once in­side, oriental roaches are found most often underrefrigerator, washing machines and sinks. Thefemale u ually deposits the egg capsule in debrisor food in a sheltered place.

The brown cockroach (Figure 6) is 1 to I Y4inche long and glossy reddish-brown. It resemblesthe American roach somewhat. This roach is foundoutdoors in trees, piles of firewood or beneath gar­bage cans. It commonly invades homes near woodyareas, and inside is most often found in the kitchen.Egg cases are attached to walls and ceilings.

Cockroach Control Measures

Sanitation. Sanitary measures are very impor­tant in cockroach control. Proper sanitation, bothindoors and outdoors, effectively limits roachpopulations.

Roache can be discouraged from entering thehome by sealing cracks in foundations and outsidewalls. The eal or caulking around air condition­ing units, windows, doors and other openings intothe home should be checked to insure there areno cracks through which roaches might enter.

Garbage should be stored in tightly coveredcontainers kept on easily cleaned racks, platformsor slab, and should be disposed of frequently.Excess refuse should be stored in roach-proof boxesor bag and disposed of as soon as possible.

Paper, cardboard, lumber, stacks of firewoodand other debris near the home provide excellentrefuges for several roach species. Elimination ofyard trash and storage of firewood in areas notadjacent to the home or garage will minimize thechance of roach invasion from these potential hid- .ing places.

Indoor, all possible hiding and breeding areasshould be eliminated. Cracks and holes in floors,

walls and ceilings should be repaired, and openingsaround plumbing fixtures, furnace flue, electricaloutlets, between window sills and walls and alongbaseboards or ceiling molding should be sealed withappropriate materials. Areas where egg cases mightbe deposited should be inspected regularly. Anycases found should be removed and crushed orburned.

Good housekeeping and thorough cleaning areessential in controlling cockroache. Unwasheddishes and ki tchen utensils and uncovered foodshould not be left overnight. All spilled liquidsshould be mopped up. Cupboards, shelves and binswhere small amounts of food can accumulate houldbe cleaned periodically. Dry pet food should bekept in roach-proof containers and never stored illor near the kitchen. The pet's feeding di handarea should be washed daily.

TmJ)ping. Cockroaches can be trapped both in­side and outside the home. Outdoor trapping nearareas where roaches are found can reduce roachpopulations and limit the number of roaches enter­ing the home. Indoor trapping can hold in checkindoor-breeding species such as the German andbrown-banded cockroaches, and may practicallyeliminate outdoor species such a the Americanand smokybrown from the home.

A properly prepared and positioned trap maycatch up to 50 adult or nymphal roaches per day,although the number trapped will vary accordingto the total roach population and the eason. Forexample, primarily outdoor specie are much Ie sactive during winter, and the number trapped dur­ing this time will be reduced.

Experiments show that trapping can be aneffective method of roach control. In one case, 20smokybrown and about 50 German roaches wereremoved from the ki tchen of a home in a weekusing only'three traps. During the sub equent yearno other smokybrown roaches were een, and whileGerman roaches were seen, their numbers werekept low by continued trapping.

In a second home, more than 250 smokybrownroaches were captured in IS traps over a 4-weekperiod. Trap catches were high during the first]0 days, and then steadily declined as the roacheswere trapped out. Prior to the trapping roaches,,'ere seen every day, but the homeowner reportedeeing only two roache within 4 month after

trapping ended.Cockroach trap construction is a simple matter,

and the materials are readily available in the home.Smear a thin layer of petroleum jelly around theinside lip of a pint jar to a width of about 2 inches.Place the trap upright, with appropriate bait in­side, in an area frequented by roache. Apple andpotato are excellent bait for American, moky­brown and brown-banded roaches, while German

Fig. 1. American Cockroach, Periplanetaamericana

Fig. 3. German Cockroach, Blattella g~rmanica

Fig. 5. Oriental Cockroach, Blatta orientalis

Fig. 2. Smokybrown Cockroach, Periplanetafuliginosa

Fig. 4. Brown-banded Cockroach, Supellalongipalpa

Fig. 6, Brown Cockroach, Periplaneta brunnea

roaches prefer banana peel. The number of trapsused will depend on the severity of the infestation.

Roaches will enter the jar to eat the bait butwill be unable to climb out over the petroleumjelly barrier. Once trapped, the roaches may bedestroyed by dropping them into a pail of hot,soapy water.

InoTganic Insecticides. Boric acid powder andsilica aerogel dust are inorganic insecticides whichcan be used to control roach infestations in thehome. Both are relatively inexpensive, low in tox­icity to humans and pets, and retain their killingpower long after the initial application. In addi­tion, roaches have not developed resistance to thesechemicals. Their only disadvantage is that theyare rather slow-acting, and often require a weekor more to reduce roach numbers. For best results,the insecticides should be applied to cockroachhiding places and runways. These areas may belocated by entering darkened rooms with a flash­light and observing where the roaches flee. Ifdesired, professional pest control operators canapply these materials.

Boric acid powder acts primarily as a stomachpoison. It is picked up on the roach's body andswallowed when the insect cleans itself. Unlikeother insecticidal dusts, boric acid is not recognizedas a poison by the roaches, and thus they don'tavoid it. Boric acid powder can be purchased atmost drug stores and used in several ways. Thepowder alone can be applied liberally to infestedareas. In exposed areas, avoid leaving heavy trailsof powder, or more than half a teaspoon in anyoneplace. Boric acid powder may be mixed withpowdered sugar or milk and placed in con tainersfor direct consumption by roaches. The powderalso may be dissolved in water and mopped on thefloor, using 1 cup of boric acid for each gallon ofwater. A teaspoon of baking soda should be added

to the water if the powder does not dissolve readily.The water should be warm enough to completelydissolve the boric acid, but boiling water will de­crease the chemical's effectiveness. When the solu­tion dries, an invisible film of boric acid crystals isleft on the floor. Roaches crawling on a treatedfloor pick up a lethal dose of boric acid within aweek. For heavily infested areas both mopping anddusting methods should be used.

CAUTION: Gloves should be worn whenhandIi ng the powder, and care should be taken toprevent inhaling it during application. Boric acidshould be kept in airtight, properly labeled con­tainers out of the reach of children and pets. Thepowder should not be applied to plants, soil II '1.

contains plants or any place where air currenl~

may carry it to plantings, as they will be severelyburned or killed. Boric acid, either dry or in solu­tion, should not be used outdoors or where itmight be carried outdoors.

Silica aerogel dust absorbs the waterproof layerof wax on the roach's body and causes death bydehydration. A visible film of dust should beapplied with a squeeze bulb or plunger duster tosuspected roach hiding places, since body contactwith the chemical is necessary for control. Silicaaerogel is particularly effective in controllingroaches in attics, wall voids or any closed space. Adisadvantage of this chemical is that roaches learnto avoid treated areas. Also, the dust cannot beused in damp areas since its effectiveness is de­creased if it becomes wet.

Cockroach control need not be equated withtotal eradication by chemicals. Instead, controlefforts should be directed toward reducing roachpopulations to unobjectionable levels. Proper androutine use of the methods described in this bro­chure will help to accomplish this goal safely andinexpensively.

This summary of cockroach control methods resulted from research investigationsby the Texas Agricultural Experiment Station and was supported by EnvironmentalProtection Agency Grant R803068-01.

Educational programs conducted by the Texas Agricultural Extension Semice serve people of all ages regardless of socio-economiclevels, race, color, sex, religion or national origin.

Cooperative Extension Work in Agriculture and Home Economics, The Texas A&M University System and the United StatesDepartment of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, 1914, as amended, andJune 30, 1914.18M-6-75 ENT