CONTROLLING INSECT PESTS 413 



the wire-worms and the eggs of grasshoppers and other pests 

 are thus destroyed. Late plowing of fallow lands is especially 

 important, as there are usually many insects in such fields. 



Trap Crops. It is sometimes profitable to plant a crop that 

 is attractive to the insects that are to be combated and after 

 the insects have gathered there, to destroy the whole crop by 

 burning or plowing it under or spraying it with some insecti- 

 cide that will kill the insects. In this way the main planting 

 of the same or other crops may be left comparatively free from 

 the pests. 



ACTIVE METHODS OF CONTROL 



In spite of all our care and precautionary measures, however, 

 many pests \vill certainly become established in the orchard or 

 garden or field, and then the fight must be waged against the 

 insects themselves. 



Hand-picking. This is often the simplest way of getting rid 

 of many of the larger insect pests. Large caterpillars, like the 

 tomato-worm and the larvae of other moths, are easily seen 

 and destroyed. Tent-caterpillars are also best fought by 

 gathering them after they have collected in their "tents" and 

 crushing or burning them. In the fall or winter the eggs 

 of such moths as the tussuck-moth are easily gathered and 

 destroyed. 



Trapping, etc. Insects may often be found collected in con- 

 siderable numbers under loose boards or boxes scattered over 

 the field. If such places be examined occasionally many injuri- 

 ous insects can be destroyed. The larvae of certain moths, as 

 the codling-moth, pupate in any sheltered place they find on 

 the trunk of the tree. Advantage may be taken of this habit 

 by placing a band of burlap around the tree. Under this the 

 larvae collect and they may easily be destroyed. The use of 

 lights in the field to attract moths is more or less successful in 

 some places. Numbers of cut-worm moths may thus be 

 destroyed. Codling-moths are not attracted to these lights. 



Insecticides. The most widely used and perhaps the most 

 effective method of fighting insect pests after they have obtained 

 a foothold in the orchard, is the use of insecticides, or insect 



