Control of Arthropods of Medical and Veterinary Importance

Abstract

This chapter deals with current and developing methods and materials for the control of arthropods of medical and veterinary importance. Some of these are parasites in their own right, while others act chiefly as vectors of one or several diseases. The control measures considered concern mainly the use of insecticides, but it cannot be stressed too strongly that good hygiene (or good animal husbandry) is a pre-requisite. The use of pesticidal chemicals is an integral part of good hygiene, but is not a substitute. Indiscriminate use of insecticides may actually unmask formerly unrecognized pests, themselves tolerant to the chemicals, but previously held in check by predatory insects. The control of anophelines and culicines is considered separately. The control of anopheline mosquitoes is inextricably bound up with programs for the control of malaria so that it is convenient to begin with a brief consideration of the present status of eradication of this disease. Chemical control of Aedes and Cirlex is by larviciding or by treating resting places of the adults with residual insecticides. Suitable larvicides include suspensions, solutions and granules of DDT, dieldrin, malathion, fenthion, tetrachlorvinphos (Gardona), difenphos or Dursban. Insecticides are screened in accordance with a seven-stage evaluation scheme organized by the World Health Organization. Control measures directed against adult flies include residual and space spraying inside farm buildings and the use of baits and impregnated cords. Tests for the investigation of suspected insecticide resistance is described. The chapter discusses the development of modern insecticides with notes of some quite controversial moves, such as the withdrawal of dieldrin from most of its former veterinary uses. Mechanisms of insecticide action are being examined with increasing interest and with vastly improved physical and chemical micro-techniques.