April 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
of adult mosquitoes. The cost was calculated to average less than 16 cents per acre. Where there is a forest cover, however, or a dense cover of other vegetation, such m marsh elder (Zvaoraria), or the introduced fox tail, reed, or plume grass (Phragmites communis),so many of the coarser, mechanically produced spray droplets are screened out by the dense plant cover, that insects concealed beneath it are not reached effectively by the insecticide. By contrast, because the smaller fog droplets tend to follow the flow lines of transporting air currents, an aerosol fog of appropriate droplet diameter applied from the air with the usual downthrust should pass through a forest crown with little loss and with effective concentration as a long suspended space spray, or persistent fog beneath.
679
LITERATURE CITED
(1) Gibbs, W. E.,“Clouds and Smokes,” London, J. & A. Churchill, 1924. (2) Glasgow, R. D., Mosquito News, 7,No. 1,22-7 (March 1947). (3) Lodeman, E. G., “The Spraying of Plants,” New York, MacmilIan Co., 191% (4) Riley, C. V., “Entomological Publications of C. V. Riley,” Jefferson City, Mo., Regan and Carter, 1873. ( 5 ) Riley, C. V., Fourth Report of the U. S. Entomological Commission, Washington, D. C., U. S. Govt. Printing Office, 1885. (6) Sempers, F, W., “Injurious Insects and the Use of Insecticides,” 1894. (7) Weed, C. M., “Insects and Insecticides,” published by the author, 1891. RECEIVED November 22, 1947.
Insecticide Industry’s Contribution to Food Production I
L. S. Hitchner
Agricultural Insecticide & Fungicide Association, New York,N . Y .
A
MERICAN farm history is a series pf cases in which a new quality and cleanliness by making it possible to keep dairy barns pest appeared, spread and devastated, and finally was and processing plants free from insect infestation and contaminabrought under control, more or less, by some chemical. tian. The National Livestock Loss Prevention Board has started The Bureau of Entomology and Plant Quarantine estimates that there are 80,000 kinds of insects in North America. At work in several midwestern states on the protection of cattle by least 5000 of these are known to have economic importance. the use of chemicals. Board representatives have traveled No accurate dataexist to show just how extensively through the cattle states many of these are being systematically conpointing out the proved and tangible dollars and cents benefits-a 50-pound trolled with chemicals, but in the last Statistics prove that chemical annual report of that bureau there is mengain in weight per head, in a single season, tion of research and test work on less than is an inexpensive form on beef animals and comparable gains in of crop insurance. The United 200 insect species. Annual losses from inmilk yields from dairy herds. I n Kansas States has taken the lead in the and Oklahoma alone more than 2,000,000 sect pests in the United States are estiapplication of chemistry to the mated to average 2 billion dollars. cattle were treated last year with an esti- farm, but the relation of pestiIn the field of plant disease pests, the mated gain of 75,500,000 pounds of beef. cides to the food supply has now American Phytopathological Society estiChemists today are vigorously conbecome important to the world. mates that there are in the United States tinuing their search for new pesticides. 25,000 infectious plant diseases including One company tested more than 12,000 10,000 of known economic importance and chemical compounds in a ten-year period; many others potentially dangerous. The 500 leading diseases on of these, 10 were found to be promising for agricultural use. If the entomologist and pathologist would tell the chemist what major crops cost 2 billion dollars a year and the remaining diseases an equal amount-a total plant disease cost to the nation pests need to be controlled, and their characteristics and of 4 billion dollars. economic importance, specific chemicals could be developed to A survey made during the war showed that of 360,000,000 control specific pests. acres farmed in the United States about 45,000,000, or one The Food and Agriculture Organization of the United Nations eighth, are in crops which have been protected by chemicals. is now making world surveys on problems involving the use of Of the total crop value in 1943 (about 13 billion dollars) it was pesticides. Entomologists from 47 governments gathered in found that the value of the chemically protected crops was London recently to consider the loss of stored foodstuffs caused approximately 4.5 billion dollars, a little more than one third. by insects and other types of pests which can be controlled by Industry estimates indicate that when not only insecticides, but insecticides and fungicides. It was emphasized that the loss of fungicides, herbicides, rodenticides, soil and seed treatment stored food through infestation, in many cases, is higher than materials, defoliants, and plant hormones are included, the annual 10%. Even in countries with well-developed technical services value of agricultural chemicals consumed in the United States is the average is 5%. A later conference will be held by world scientists on another approximately $175,000,000 on a wholesale basis. Thus it is evident that chemical control is a very cheap form of crop insurance. phase of the food problem-the control of pests on growing crops. For years the importance of pest control has been pointed out However, a preliminary report has already been issued by the by citing crop losses. The importance of dollar savings should Food and Agriculture Organization on insecticides, fungicides, also be stressed. and allied products; this contains a survey of postwar conditions I n the years from 1936 to 1945, grasshoppers destroyed crops in nine specific areas of the world, and the present supply posivalued a t $400,000,000. During the same period control meastion and prospects for pesticides during 1948. ures saved crops worth $600,000,000, a t a cost of less than This organisation has also created a plant industry branch to $25,000,000. The story is the same on many other pests and on act as a world clearinghouse of information on plant industry many other products. problems and to encourage the use of insecticides and fungicides In addition to the actual savings in the production of food and in the lesser-developed countries of the world. fibers, chemicals have contributed tremendously to improved R E C ~ I V ~November D 22, 1947.
