PROCEEDINGS, 1915. 91 



THE CANKER WORM IN NOVA SCOTIA. 



By G. E. Sanders, Field Officer in Charge 

 Dominion Entomological Laboratory, Annapolis Royal, N. S. 



r "yPHE Canker Worm like the Tussock Moth is one of our perio- 

 -*- dical insects which is controlled after serious outbreaks by para- 

 sites, and which is now on the increase throughout the Annapolis Valley. 

 During 1915 a great many orchards throughout the valley were partially 

 or wholly defoliated. The reports of the Browntail Moth Inspectors for 

 November 1915 give the Canker Worm as being more or less common in 

 every section of the Valley, so we may look for a great deal more damage 

 in 1916 than we had in 1915, unless measures for its control are made 

 more effective. 



The most common species in Nova Scotia is the Fall Canker Worm, 

 Alsophila pometaria Har, the adults of which emerge and deposit their 

 eggs in the fall. In 1915 the maximum emergence took place between 

 Nov. 12 and 30; during this period the wingless females or slugs were 

 crawling up the trunks of the apple trees while the winged male moths 

 could be seen fluttering about the trunks of the apple trees. Those who 

 applied tanglefoot to their trees before Nov. 12, have therefore safe- 

 guarded their orchards from damage by Canker Worm next spring. 



In the great majority of orchards in the valley that are lightly, mod- 

 erately or even heavily infested, no tanglefoot was applied, and the own- 

 ers will have to rely on spraying to protect their orchards in the spring of 

 1916. 



Time to Spray. 



In 1915 the Canker Worm eggs in Nova Scotia hatched on May 25, 

 or just half way between the time when the leaf is the size of a ten cent 

 piece and when the buds are showing pink. The Canker Worm is a no- 

 toriously hard insect to poison after it is one-third grown, and the only 

 way to control it by spraying in bad infestations, is to use an excess of 

 poison say 8 to 10 pounds of Arsenate of Lead to 100 gallons and have 

 the leaves thoroughly coated with the spray when the young Canker 

 Worms are beginning to feed. 



For very light infestations, such as might occur in poorly sprayed or- 

 chards or where the infestation is just beginning, the two regular sprays 

 before the blossoms, one when the leaves are the size of a ten cent piece 

 and the other immediately before the blossoms with 5 lbs. of Lead Ar- 

 senate or 2 lbs. of Arsenate of Lime to 100 gallons, should control it. 



In case of a bad infestation it would be advantageous to hold the 

 first spray until the leaves are the size of a twenty-five C3nt piece, or else 



