202 AGRICULTURE FOR COMMON SCHOOLS 



Toads lay their eggs in the water just as frogs do. Every 

 one should become interested in toads and protect them. 

 There is no truth in the statement that handling toads will 

 produce warts on the hands. 



3. Cultivation. — Cultivation is one of the methods that 

 man has learned to use for combating insects. The rotation 

 of crops, as mentioned in Chapter XVI, is very effective in 

 holding in check certain.kinds of insects. When the particular 

 plant upon which an insect feeds is not planted in the same 

 field each year, it finds it difficult to travel after its food and 

 often perishes. Farmers who practice rotation of crops 

 rarely have much trouble with the corn-root louse, Hessian 

 fly, chinch-bug, and many other insects. One of the best 

 means of preventing damage from the Hessian fly is to sow a 

 narrow strip of wheat around the field several weeks before 

 the main crop is to be sowed. The fly will gather in this 

 strip and lay all its eggs on the early wheat. Just before 

 sowing the main crop the narrow strip should be plowed 

 under and the land harrowed down. The larvae in the young 

 wheat are not old enough to live over the winter without more 

 fresh food, and so all perish. 



4. Spraying. — In spraying plants to keep off insects it 

 should always be kept in mind that some insects destroy the 

 plant by chewing the foliage or stem, while others pierce the 

 skin or bark with their sharp mouth parts and suck out the 

 juices, causing the plant to wilt and die. For those insects 

 which chew their food a poison is applied to their food, but 

 for those which suck the juices of the plants such application 

 does no good, and the remedy applied must be one that will 

 kill the insect by contact. In the first class we have all the 

 beetles, caterpillars, and grasshoppers; in the second, the 



