Man's physical universe

xanabras

CHEMICAL WARFARE USED TO COMBAT INSECTS 755

is a mixture of diethylene glycol monobutyl ether acetate, diethylene

glycol monoethyl ether, alcohol, and corn oil. This mixture is also

very repellent against mosquitoes.

Mosquitoes are also repelled by a mixture of thyme oil and pyrethrum

extract in castor oil.

In the treatment of insect pests, it would often be desirable to attract

insects.

When insects such as the Japanese beetle or grasshoppers are

to be killed in quantities of hundreds of tons, it would help a great deal

if substances could be used to attract the insects into containers where

they could be killed on a large scale. It has been found that male June

beetles are attracted by isoamylamine and that Japanese beetles are

attracted by geraniol or a mixture of geraniol and eugenol.

STUDY QUESTIONS

1. Discuss the methods by which man combats his insect enemies.

2. What are man's chief competitors for food?

3. What is the objection to the use of arsenic and lead poisons for spraying

plants?

4. What is the active ingredient in many fly sprays?

5. List two methods other than the use of poisons for killing insects.

6. In what respects are insects superior to man?

7. What would be the advantages of substances which would attract or repel

insects?

8. Why is rotenone such a valuable insecticide? Where is it obtained?

9. Prepare a list of diseases and their insect carriers.

10. Why is the promiscuous destruction of insects undesirable?

IL Would you say that insects are winning in their warfare against man?

12. Compare international wars with man's war against insect pests.

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