Page:The Scientific Monthly vol. 3.djvu/437

 MALARIA AND CROP PRODUCTION 431

��THE BELATION OF MALABIA TO CHOP PRODUCTION

By D. L. van dine bubmau op entomology, united states dbfabtment of aobicultubb

THE principal effects of malaria upon farming are a reduction in the net profits on the crops grown and reduced values from the non- development of farm lands. Herrick (1903) mentions these losses, as applied to southern agriculture, ,and Howard (1909) emphasizes the economic loss from malaria by figures which are startling. He esti- mates that there is an annual loss in the United States through this dis- ease of not less than $100,000,000.

The rural nature of malaria places the larger portion of the loss from the disease upon the farming class. The disease is more prevalent in the south than in other regions of the United States. The higher prev- alence in the south is due to the larger areas of swamp and vndrained lands, and lands subject to overflow which offer favorable breeding- places for the mosquitoes that convey the disease, to the longer season of high temperatures which favors mosquito development and which in- creases the length of the active season of the disease, and to the presence in larger numbers of an indifferent race which is tolerant of the disease. Although the losses from malaria have been appreciated for many years, the exact manner in which the disease operates against farm profits is not generally understood.

In 1913 the Bureau of Entomology undertook a detailed study of the relation of malaria to agriculture in the south. The ultimate object of the study is the prevention of malaria on the farm. The investigation is based on the idea that the prevention involves measures for the con- trol of malaria mosquitoes which are practicable under the usual farming conditions. In the absence of definite information on the relation of the disease to farming, the primary work dealt mainly with the exact man- ner in which malaria operates against the net profits from farm crops. The study is an intensive one and its scope extends no further than the strictly agricultural and biological phases of the problem. The effort is to obtain concrete and fundamental information as a basis for an extensive application of measures for prevention. It is believed that the first step is to secure definite data on the manner in which malaria affects agriculture.

During the course of the investigation it has been determined that the important losses from malaria on a plantation are sustained through the loss in time and the reduced efficiency of the labor at the season of the year when the labor is most needed to work and to harvest the crops.

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