Insecticides arsenical

Basic copper ethanoate arsenates(iii) prepared from verdigris (or other basic copper salt), sodium arsenate(m) and ethanoic acid. Used in insecticides for spraying fruit trees. Readily decomposed to soluble arsenic compounds so use is very restricted. 

Lead oxide is used in producing fine "crystal glass" and "flint glass" of a high index of refraction for achromatic lenses. The nitrate and the acetate are soluble salts. Lead salts such as lead arsenate have been used as insecticides, but their use in recent years has been practically eliminated in favor of less harmful organic compounds. 

Rotenoids. The use of rotenone-bearing roots as insecticides in the United States was developed as a result of federal laws against residues of lead, arsenic, and fluorine upon edible produce. Rotenone [83-79-4] (5) is harmless to plants, highly toxic to many insects, and relatively innocuous to... 

The refined arsenic trioxide is analysed for purity and also tested for solubihty, a term referring to its rate of reactivity with nitric acid this test is important if the arsenic is used in the manufacture of insecticides and herbicides. The product is graded for marketing as white soluble having 99% min AS2O2, white insoluble, or cmde having 95% min AS2O2. 

Arsenates are oxidizing agents and are reduced by concentrated hydrochloric acid or sulfur dioxide. Treatment of a solution of orthoarsenate with silver nitrate in neutral solution results in the formation of a chocolate-brown precipitate of silver orthoarsenate, Ag AsO, which may be used as a test to distinguish arsenates from phosphates. With hydrofluoric acid, orthoarsenate solutions yield hexafluoroarsenates, eg, potassium hexafluoroarsenate [17029-22-0] (KAsFg)2 H2O. Arsenates of calcium or lead are used as insecticides sodium arsenate is used in printing inks and as a mordant. 

In 1916, calcium arsenate [7778-44-1] dusted by airplane was used to control the boU weevil however, throughout many developments in effective insecticides, such as organophosphates, the boU weevils became resistant to poisons that were formerly effective (see Insectcontroltechnology). 

Heavy metals on or in vegetation and water have been and continue to be toxic to animals and fish. Arsenic and lead from smelters, molybdenum from steel plants, and mercury from chlorine-caustic plants are major offenders. Poisoning of aquatic life by mercury is relatively new, whereas the toxic effects of the other metals have been largely eliminated by proper control of industrial emissions. Gaseous (and particulate) fluorides have caused injury and damage to a wide variety of animals—domestic and wild—as well as to fish. Accidental effects resulting from insecticides and nerve gas have been reported. 

Non-arsenical insecticides (occupational exposures in spraying and application of) (Vol. 53 1991) Polychlorinated biphenyls [1336-36-3] (Vol. 18, Suppl. 7 1987)... 

Arsenic trichloride 7784-34-1 Organic synthesis Pharmaceuticals Insecticides Ceramics... 

The purpose of this work was to determine the toxicity to mosquito larvae of insecticide spray residues. That certain insecticides are translocated in plants (4, 5) adds impetus to this study. Fresh orchard fruit sprayed or dusted with preparations containing parathion (0,0-diethyl O-p-nitrophenyl thiophosphate), tetraethyl pyrophosphate (TEPP, HEPP), DDD [2,2-bis(p-chlorophenyl)-l,l-dichloroethane], DDT [2,2-bis(p-chlorophenyl)-l,l,l-trichloroethane], chlorinated camphene, and basic lead arsenate were shipped from California to Yonkers, N. Y., by air express for bioassay. 

In addition to the tests made on peaches and apricots, samples of prunes from trees that had been sprayed with parathion, DDT, DDD, basic lead arsenate, and toxaphene at the rate of from 1 to 2 pounds of these insecticides per 100 gallons of water were tested on larvae of Aedes aegypti. The trees had been sprayed on April 20 and June 16, 1948. The fruit was harvested on or about September 10. Prunes from trees that had been treated with 1 quart of tetraethyl pyrophosphate and 12 pounds of sulfur dust per acre on June 15, and harvested about July 6, were tested on larvae of the above named species. None of the prune samples tested in this study exhibited any significant toxicity to mosquito larvae as compared with the unsprayed check. 

The use of plant extracts for insect control dates into antiquity the use of Paris green as an insecticide for control of the Colorado potato beetle in 1867 probably marks the beginning of the modern era of chemical control of injurious insects. The development of lead arsenate followed later in the nineteenth century for gypsy moth control. The commercial production of nicotine insecticides, the production of calcium arsenate at the time of the first world war, and the use of fluorine, arsenical, and cyanide compounds, as well as other inorganic chemicals for insect control, were important steps in pest control. These chemicals were applied largely by dilute high pressure sprays or dusts. 

After mothproofing wool, the next logical step for Geigy was to invent an insecticide that killed more kinds of pests. Imported natural insecticides made from plants, including pyrethrum from tropical chrysanthemums, rotenone from a tropical vine, and nicotine from tobacco, could be quite expensive they were also not persistent and were easily destroyed by light and heat. American and European attempts to synthesize their active ingredients had failed. Arsenic compounds remained the only cheap and effective insecticides. 

To Muller, just starting out on his search for an effective insecticide, the situation looked desperate indeed. A flood of patents had already been issued, and he realized that the chances were worse than poor only a particularly cheap or remarkably effective insecticide had any prospects of being used in agriculture. Yet there was hope. After experimenting with products described in the patent literature, he realized that practically none of the new compounds was being sold the existing arsenates, pyrethrum, and rotenone insecticides were more effective. Reassured about the competition, Muller had the courage to press on. 

James Whorton. Before Silent Spring Pesticides and Public Health in Pre-DDT America. Princeton, NJ Princeton University Press, 1974. Source for lead arsenate insecticide and Terres article. 

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