FRIENDS AND ENEMIES OF PLANTS 183 



taken to destroy all rubbish in which the bugs hide away to pass 

 the winter, much will be accomplished towards getting rid of them. 

 Frequent change of crops will also be .helpful. 



The cankerworm is a common measuring worm. It is usually 

 green or brown and is the larva of a moth., Cankerworms eat 

 ravenously, and in a short time can clean up the foliage of every 

 tree in the orchard. The tree may be protected against the female 

 moth by wrapping a piece of gummy or sticky paper or cloth 

 closely around its trunk. 



The army worm is the larva of a common moth and is 

 one of our most destructive pests. These worms are called army 

 worms because they move about in vast numbers like* a destroying 

 army, devouring all vegetation that lies in their path. They are 

 hard to combat successfully when they make their appearance in a 

 field. Farmers frequently plow an extra deep furrow around the 

 field in order to trap them in their onward march. This ditch 

 is then partially filled with straw and a torch is applied. As the 

 straw burns a great many of the army worms that are imprisoned 

 in the ditch are burned and destroyed. 



The Tent Caterpillar. The apple-tree tent caterpillar is a 

 destructive pest with which every farmer is more or less familiar. 

 The parent moth lays her eggs in the form of a girdle around a 

 twig in the summer, and in the following spring these hatch into 

 greedy caterpillars which strip the leaves of the tree as they move 

 from twig to twig. They spin a web or tent, generally in the forks 

 of some branch, and this affords them a shelter at night. 



They may be held in check by our destroying their eggs in the 

 winter, by burning their nests, by spraying the foliage with ar- 

 senate of lead or Paris green, and by encouraging the residence of 

 cuckoos, blue jays, crows, orioles, and other birds that feed upon 

 these caterpillars. 



The tobacco worm is the larva of the sphinx moth, and is very 

 destructive in its ravages on the tobacco plant. The worms are 

 usually picked by hand from the plants and destroyed. The moth 

 is very fond of the blossoms of the Jimson weed, and if a little 

 cobalt mixed with sirup is placed in such blossoms the moth is 

 easily poisoned. 



The currant worm is the larva of the sawfly. The larvae hatch 



