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1948-49 Theatre Catalog, 7th Edition, Page 250 (239)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 250
Page 250

1948-49 Theatre Catalog, 7th Edition, Page 250

ing not more than 7 milligrams of DDT per kilogram (about 2% pounds) of fruit."

As for DDTis continued effectiveness as a high-powered insecticide there is now some doubt. Only recently, the Bureau of Entomology and Plant Quarantine confirmed the suspicion that house fiies in many parts of the country are developing resistance to DDT. This is an untoward achievement in the insect world that may very well be mastered by mosquitoes. If and when that time comes, DDT will have lost much of its value for the driveein operator.


"Krenite" is an effective wateresoluble, dinitro spray containing as its active ingredient sodium dinitro-orthocresylate. Since it is not entirely in solution in concentrated form, it must be well mixed before using.

This material is especially effective as a dormant spray used to control insects and diseases on fruit trees, small fruits, and hardy deciduous trees and shrubs. ff1(renite,f is unique in that it will control both insects and diseases susceptible to treatment at the time of its recommended application. ffKrenite" has its greatest application as a ground floor spray in areas where extreme disease infections are likely to occur and where present foliage fungicides alone have proved inadequate.


"Loroi, is a thiocyanate contact insecticide especially edective for the hard* to-kill insects of ornamentals and fruit. Unlike volatile contact insectekilling materials, "Loro" is effective early in the season when temperatures are low, yet its effectiveness is not impaired by high er temperatures. With the exception of lime-sulfur, "Loro" is compatible with practically every type of fungicide and insecticide in common use. Small quantities-as little as one part to 800 parts of wateregive excellent results when directions are observed.


fthothane" (DDD) is an insecticde of the same general order of effectiveness as DDT, yet it is said to be ten times safer than DDT to man and warmblooded animals.

Lead Arsenate

Although not as strong as some other insecticides especially other arsenicals, lead arsenate is stable, remains well in suspension, minimizes clogging of screens and nozzles and provides an even spread over plant foliage. Once the spray has dried upon foliage it adheres, like paint, for a long time. It is compatible with such insecticides as: cryolite, fluosilicates, certain oil emulsions, selfboiled lime and sulfur, wettable sulfurs, bordeaux mixture, nicotine sulfate, and nicotine. Lead arsenate can be applied as a dust or a spray. It has been very extensively used to protect deciduous fruits, ornamental plants, and forest and Shade trees from injury by chewing insects. Its great advantages are: its high degree of safety to plants, its stability in storage, and its spreading and adhesive qualities after it has been applied.


Lead arsenate sprays should not be used near white painted surfaces since they tend to spot or discolor the White.

"Alcoa" Cryolite

"Alcoaii Cryolite is a fluffy, white, free-fiowing insecticide. Chemically it is sodium nuoaluminate, an important member of the fluorine compound family. It contains 49% fiuorine which is equivalent to 90% cryolite. Its uniform particle size and excellent adhesive quality combine to give maximum deposit and uniform coverage of plants.

In general, the fluorine compounds kill more rapidly than the arsenicals and in many instances they are more econome ical. They are less toxic to animals and human beings and tests have proved that they are safer to use on plants. Frequently they exercise a valuable repellent effect upon pests.

Cryolite is compatible with lime-sulfur, wettable sulfur, neutral fish-oil soap, summer spray oils, gypsum, lead arsenate and nicotine sulfate. Of all the Huorine insecticides available, sodium fluoaluminate (ffAlcoai, Cryolite) is said to be the safest to use on plants. In addition, under proper conditions of use it does not injure plant foliage and it has no abrasive action on dusting equipment.


Pyrethrum is a very useful insecticide and is applied in dusts or sprays to control both sap-sucking and chewing insects which attack vegetables, ornamentals and fruits. Other uses include: the protection of valuable turf, such as golf greens; the destruction of sod webworms without injury to plants; the destruction of mosquito larval 1n pools, marshes and swamps without injury to fish, vegetation, or waterfowl.

The big advantage of pyrethrum is its high toxicity to insects, coupled with a very slight toxicity to plants and animals. However, it does not possess the stability of some of the other insecticides, and for this reason it is difficult to keep the stored concentrate for more than one season.

Other Control Methods

Some investigations have indicated the

possibility of utilizing light to lure and.

destroy insects. This line of attack consists of precisely fixing the candle power or the exact color or portion of the spectrum which is attractive to the bugs. It has been noticed that many insects are much more strongly attracted by the blue portion of the spectrum and by ultraviolet than by the red rays. Once attracted to a specific spot, the insects can be quickly dispatched with a modified version of the electric chairean automatic electronic grill shooting enough juice into contacting insect bodies to electrocute them.

Plant growth regulators (hormones) have been widely used in horticultural work, including the control of pre-harvest drop of apples, the stimulation of root growth of plants and trees, the prevention of blossom and pod drop of beans, and recently the control and destruction of weeds. These same plant hormones now appear to play an added roleethe suppression of insect damage

to plants. Conversely, recent evmence reveals that certain insecticides may also act as a plant growth promoting sub stance. A stimulation and suppression effect in some plants has been found following treatments with DDT. Vegetables grown in the absence of insects showed that certain concentrations of DDT produced increased growth rates of the entire plants. The plants tested varied as to susceptibility to DDT. Excessive applications of DDT caused adventitious buds and the development of witchesi broom symptoms quite identical to those frequently caused by conventional growth substances.

Finally, in closing this section, at least brief mention should be made of the repellents which are not necessarily toxic to the insect world but which act to keep insects away from a treated area. The repellents are usually included in a formulation with killer insecticides so that both repelling and killing result from the same spray. Outstanding repellents include dimethyl phthalate; and lauronitrile. Both of these chemicals are inoffensive to human beings but violate some insect sense of olfactory propriety.


Almost as important as a death-dealing chemical is the method for getting it into intindate contact with the insects who fostered the clean-up project in the first place. In most locations, application will be by spray and the insecticide will be released into the air as a fog, not long before the first automobiles drive into the parking arena. It is claimed that some of the more recent insecticides will linger in the air in microscopic particles to provide lasting protection throughout the show.

Airplane spraying, which has come into vogue especially in weed control projects, will undoubtedly prove its value in those locations where multiple contracts enable the custom sprayer to quote minimum rates; or where it is deemed advisable to spray neighboring swampy areas not reachable by ground. It is no secret that single spraying jobs would confront the drive-in theatre operator with a prohibitive expenditure. Some recently introduced techniques in spraying indicate that the way is now opened to a low-cost and effective job. In fact, so simple are the new methods that it is even possible that, lacking a local service company the drive-in opera ator might appoint one or two members of his own staff to be applicators and thus include insecticide-spraying in his normal operating expenses. Or he might set up in business as a custom sprayer some ambitious local citizen with the obvious advantages of (1) free servicing for his own theatre area, (2) extra profits derived from maintaining a sound business in insect extermination, or (3) an added source of advertising and publicity. There are probably others but these will indicate the primary benefits. In the sections that follow, two examples of the new simplified techniques are described with the objective of showing how the job can be done with a maximum of efficiency but with a minimum of cost and labor.
1948-49 Theatre Catalog, 7th Edition, Page 250