INSECTICIDES AXD REPELLENTS 83 



The following general precautions should be observed in the use of 

 insecticides: 



1. Handle all concentrates with care and avoid spillage on body or 

 clothing. Wash off immediately any that is accidentally spilled on 

 the body. If spilled on the clothing, change immediately. 



2. Avoid unnecessary and prolonged exposure to sprays, mists, or 

 dusts during application. Wear a respirator and suitable clothing to 

 reduce inhalation and contact. 



3. Avoid contaminating foods, drinking water, and food and water 

 utensils. 



4. Store insecticides and equipment used for mixing and applying 

 them where they cannot be reached by children or animals. The 

 containers should be distinctly labeled. 



5. Do not apply oil-base sprays to man or animals. Solvents com- 

 monly used to prepare insecticides may alone cause severe harm. 



6. Do not apply oil -base sprays to vegetation in quantities sufficient 

 to wet the plants. 



7.. Exercise care in discarding unused insecticide materials. Drain- 

 age into watering ponds or streams may poison animals; including 

 livestock, and fish. 



8. Do not apply flammable insecticides near flames. When 

 applying oil-base sprays inside of buildings, extinguish all fires and 

 provide as much ventilation as possible. Thoroughly air the buildings 

 after residual spraying. 



9. Remove fish, birds, and pets from houses while applying residual 

 sprays. Space spraVs may also injure fish and birds. Either remove 

 them from the rooms being treated or cover them. 



10. Do not apply more than the amount of insecticide recommended 

 for each specific use. There is particular danger in harming animals, 

 fish, and wildlife if excessive amounts are applied for controlling mos- 

 quitoes, ticks, and other arthropods. 



11. In applying even small amounts of insecticides, such as oil 

 solutions on open bodies of water for mosquito Control, keep in mind 

 that wind and wave action may cause shifting of the film on the 

 Avindward side. This may concentrate the insecticide in amounts 

 that will destroy fish or other aquatic life. 



12. Use sturdy equipment and maintain it in proper condition to 

 avoid leakage and contamination of skin and clothing. 



13. Check directions for mixing and applying insecticides. If in 

 doubt about the use of any material, consult a specialist. 



DDT 



DDT is being used for more purposes in medical entomology than 

 any other insecticide. It was the first synthetic organic compound 

 employed extensively and has been the most thoroughly investigated 

 toxicologically. 



The median lethal oral dose of DDT to laboratorv animals (such 

 as rats, rabbits, and guinea pigs) is about 250 mg. per kilogram of 

 body weight. 4 When applied to the skin in dry form it shows no 



4 Unless otherwise stated, the information on toxicity to laboratory animals was 

 obtained from a series of articles by Arnold J. Lehman, entitled "Chemicals in 

 Foods: A Report to the Association of Food and Drug Officials on Current 

 Developments, Part II. Pesticides." Assoc. Food and Drug Off. U. S. 15: 

 122-133 (1951); 16: 3-9, 47-53 (1952). 



