Insects, Man, and Homes

Household Insects

L. S. Henderson.

The many kinds of pests that invade households cause trouble in numerous ways.

Termites, carpenter ants, powder-post beetles, and other wood borers attack buildings and the wood in furniture.

Clothes moths, carpet beetles, silverfish, roaches, and crickets damage clothing, rugs, and upholstery.

Various kinds of weevils, beetles, moths, mites, psocids, flies, roaches, and ants infest food. Flies, mosquitoes, fleas, lice, mites, and roaches may carry diseases.

Scorpions, wasps, and some kinds of ants may sting us. Bed bugs, lice, fleas, mites, mosquitoes, punkies, sand flies, ticks, and black widow spiders may bite or suck blood from us or our household pets.

Some pests may cause no particular damage but are a nuisance just by their presence in homes house spiders, millipedes, centipedes, drain flies, some kinds of ants, springtails, and psocids.

Some, such as bed bugs, silverfish, clothes moths, brown dog ticks, and some kinds of roaches, and ants, spend their entire lives in homes or other buildings.

Others normally live out of doors and invade homes only in search of food. Boxelder bugs, cluster flies, clovermites, elm leaf beetles, lady beetles, and wasps often enter homes in the fall to find a protected place in which they can spend the winter. They do not multiply in houses and do no feeding during the winter. On warm days some may become active and find their way into rooms. All of them will go outside if they can when warm weather arrives in the spring.

A number of kinds of insects are not usually household pests but may enter homes occasionally, sometimes in tremendous numbers. When conditions happen to be favorable for them to live there, or under some unusual circumstances, pillbugs, black widow spiders, scorpions, earwigs, psocids, thrips, springtails, millipedes, or ground beetles may become a serious problem. In addition there are myriads of kinds of beetles, moths, flies, wasps, leafhoppers, and other outdoor insects which may accidentally get into homes or be attracted there by lights.

Commercial establishments often encounter serious problems from the same insects that are household pests. Offices, stores, restaurants, warehouses, factories, and food processing or packaging plants all suffer losses caused by insects. Personnel are annoyed or disturbed, records are destroyed, food is contaminated, or raw materials and finished products are damaged.

AS THE NUMBER of homes in the United States becomes greater and greater, as our population becomes increasingly urban, and as industry and production continue to expand, the household-insect problems become more prevalent and more acute. Heavy concentrations of population and industry create conditions favorable to the easy spread and development of household insects and insects that infest stored products. They find an abundance of food and numerous suitable places to live and multiply.

Evidence of the growing importance of the problem is the development of the commercial pest-control industry since about 1935. People within the industry state that 50 million dollars is a conservative estimate of the annual volume of pest-control services rendered. More than 700 firms are organized in the National Pest Control Association, whose major aims are to improve service and business practices. Several universities conduct instructional conferences and short courses, which many pest-control operators attend year after year. "Pest Control," a periodical containing technical information, is published primarily for the industry. The association and some of the firms employ entomologists as technical directors and advisors. Pest-control service is now available in many communities from experienced and reliable firms.

Early recommendations for controlling household insects leaned heavily on the use of kerosene, turpentine, bichloride of mercury, white arsenic, and gum camphor. Poison baits were used commonly. Ants were attracted to bits of sweetened sponge and dropped into boiling water. The value of heat was early discovered for killing insects in some commodities and buildings. The "curious effect" of Persian insect powder (dried and powdered pyrethrum flowers) on roaches was referred to in a publication as early as 1864 about 50 years later the value of pyrethrum extracts in insect sprays was fully realized.

Shortly after the turn of the century, fumigants began to receive attention. New and more effective fumigants were discovered. Techniques were developed for fumigating warehouses, mills, factories, and homes. Commodities were fumigated in atmospheric vaults and vacuum chambers. Since 1946 the use of DDT, chlordane, and lindane residual sprays has reduced the amount of fumigation done.

Since 1920 much has been learned about the biology and habits of clothes moths and carpet beetles. Mothproofing solutions were studied for several years. Thorough treatment of fabrics with common silicofluoride solutions now available in stores was found to give a worth-while degree of protection. Commercial treatments applied at the factory in the hot dye bath gave more complete and longer lasting protection and withstood more laundering and dry cleaning.

German cockroach.

An investigation of cedar chests and other cedar products was ended in 1922. It was found that storing woolens in chests made of the heartwood lumber of eastern red cedar seven-eighths inch thick gave good protection against clothes moths if no large larvae were put in with the woolens. They could be removed by sunning and brushing or by dry cleaning. Small larvae and adults were killed quickly in the cedar chests. Thin cedar veneers and cedar oil were found to be relatively ineffective against clothes moths. These facts, and other results of the research, were then made available to the public in bulletins.

Between 1920 and 1940, great emphasis was placed on the development of more effective space sprays and contact sprays. These insecticides had to be used repeatedly and frequently against insects as hard to control as roaches, bed bugs, carpet beetles, and brown dog ticks.

DDT, first brought to this country in 1942, was rapidly developed for the control of bed bugs, mosquitoes, flies, and roaches, which are of importance to the Armed Forces. By 1946 DDT was available to the general public and immediately received extensive use in homes.

THEN A WHOLE new trend began in the field of insect control a parade of synthetic chlorinated organic insecticides with residual properties toxaphene, chlordane, methoxychlor, TDE, benzene hexachloride, lindane, aldrin, and dieldrin. Some had undesirable physical, chemical, or toxicological properties that made them unsuitable for use in homes. Some turned out to be less effective than DDT against household insects, others were more effective than DDT against some species or for specific uses. Confusion existed for a time when the products were new, and answers were sought to questions as to which should be used for which purpose. A more orderly condition now exists as the various insecticides find their proper places.

Aerosol bombs were bought eagerly when they became available to civilians and were often ineffectively or wastefully used. Many people did not understand their proper uses and limitations; they thought all one had to do was open the valve and release the entire contents in a closet or kitchen to kill all the clothes moths or roaches. In time they learned that the aerosol spray is not a fumigant but a highly effective form of space spray made up of extremely small particles. There was also a mistaken belief that since many aerosols contained DDT an effective residual deposit should remain after their use. A more recent development is a sprayer resembling an aerosol container, which produces a mist spray with particles larger than the aerosol particles. This type of sprayer is designed to apply a surface spray of a residual insecticide. Mothproofing solutions for application to fabrics are also available in this kind of sprayer.

Another development is the finding of more effective synergists for pyrethrum. Sesame oil previously was used to increase the killing effect of pyrethrum; now materials like piperonyl butoxide or n-propyl isome are available and are more effective.

THE CONTROL of household insects cannot be reduced to such simple terms that a single insecticide or method of application will suffice for all purposes or under all conditions. The developments since 1942, however, make the job much easier than it used to be.

A few basic principles of control should be understood.

Good housekeeping and thorough sanitation are of paramount importance in controlling or preventing infestations of many kinds of household insects. These practices remove insects, disturb them, or make conditions unfavorable for them. The removal of garbage, bits of food, lint, scraps of waste fabrics or other materials, and other accumulated matter reduces the available food supply of insects and deprives them of some possible hiding places. If such things are allowed to remain, a few or many insects may develop there and spread to places where they will cause damage or annoyance.