348 Report op the Horticulturist of the 



Canker Worm. — After the codling moth, the canker worm is 

 perhaps the next worst insect enemy of the apple grower. There 

 are two forms of this insect, known as the Sjjring Cankerworm and 

 the Fall Cankerworm. They resemble each other in general ap- 

 pearance, and in the injury that they do. When an orchard is badly 

 infested nearly every leaf may be stri]3ped from the trees. When 

 left undisturbed the insects increase rapidly from year to year and 

 do serious damage. The eggs of both species hatch when the buds 

 are unfolding and the little worms at once begin feeding on the 

 tender leaves. They are commonly known as loop worms, or 

 measuring worms. When first hatched the worms are very small 

 and of a light green color, so that tliey are not readily seen. They 

 grow rapidly, and when mature are about an inch long, varying in 

 color from light green to brown. They now drop from the trees by 

 a thread and go into the ground, where they enter what is termed a 

 resting stage. Most of the Spring Cankerworms remain in the 

 ground in this form over winter and in the spring the mature insect 

 emerges as a moth. The female is wingless and is slow and awk- 

 ward in her movements, so that it is difficult to believe that she is 

 related to the graceful flying male. The moths come out of the 

 ground in greatest numbers after the ground begins to get warm in 

 the spring, but some of them appear before the snow has gone. 

 After emerging from the ground, the females at once crawl up the 

 trees to lay their eggs. 



In the case of the Fall Cankerworm the moths issue from the 

 ground in the fall, when the female lays its eggs on the twigs. As 

 mentioned above, the eggs hatch at the same time that those of the 

 other species do, and the worms mature at the same time. 



Remedies. — The most practical way to combat this insect is to 

 poison the worms. The infested trees should be sprayed with 

 Paris green when the first leaves are expanding, as the little worms 

 begin feeding at this time. It often happens that rainy weather in 

 the spring of the year greatly interferes with spraying, by preventing 

 the applications from being made when necessary, or if applied, a 

 good share of the poison may be washed off the trees. In such cases 

 the previous use of traps will be a valuable aid. If rain interferes 

 seriously with the Paris green treatment it is suggested that kero- 

 sene emulsion be tried, being careful to hit as many as possible with 

 the spray. The number of treatments that will be necessary to con- 

 trol this insect must be determined by the circumstances. When 



