62 EXPERIMENTAL FARMS 



9-10 EDWARD VII., A. 1910 



Cankerworms. — In 1908, Cankerworms did serious damage in many of the or- 

 chards in the Maritime Provinces. From Nova Scotia, particularly, many complaints 

 were received of the prevalence of these insects, correspondents claiming that the 

 injury had been very severe in many districts. 



There are two kinds of caterpillars which attack apple trees, which are known as 

 Cankerworms, viz., the Spring Cankerworm and the Autumn Cankerworm. The 

 female moths of both kinds are wingless and have a very spider-like appearance. 

 Those of the Spring Cankerworm appear chiefly in spring and lay oval, pearly-white 

 eggs, in irregular masses, beneath flakes of bark, &c. The moths of the Autumn 

 Cankerworm, on the other hand, appear late in the season (October and November), 

 and the females lay eggs which are brown, flattened at the top, like miniature tumblers 

 with caps on them, and stand close together in clusters of about 100 or more on the 

 outside of the bark. The males are delicate moths, with gauzy wings. The cater- 

 pillars of both species are slender brown, blackish, or green loopers, or ' measuring 

 worms,' about an inch in length when full grown, and with only six pairs of legs, 

 three pairs of which are on the front part of the body, the other three pairs at the rear. 



The young caterpillars appear about the time that the leafbuds open, and at that 

 time the trees should be carefully examined, and, if any are found, the trees should 

 at once be sprayed with an arsenical poison. When the caterpillars are small they are 

 very easily killed by the ordinary poisoned Bordeaux mixture, or by Paris green 

 1 pound in 150 gallons of water, or arsenate of lead 3 pounds in 40 gallons of water. 

 When they are more than half an inch long, however, they are very difficult to kill with 

 any such poisons. At such times, Dr. Fletcher recommended as much as one pound 

 of Paris green in 100 gallons of Bordeaux mixture, and that this latter should be made 

 with five pounds of lime to the four pounds of copper sulphate in the 40 gallons 

 of water. 



As the female moths crawl up from the ground to deposit their eggs on the trees, 

 all trees in orchards where the Cankerworms have been destructive should be banded 

 in autumn and spring with one of the mechanical tree protectors, or the moths may 

 be prevented from climbing by being caught on bands of thick paper which have been 

 painted with an adhesive mixture, and tacked closely and firmly around the tree. A 

 mixture of castor oil two pounds and resin three pounds has been found satisfactory 

 for cold weather, but in hot weather it is necessary to add one more pound of resin. 

 These ingredients are heated slowly until the resin is all melted and the mixture is 

 then applied to the bands while it is warm. Another formula is five pounds of resin 

 and three pounds of castor oil for warm weather and equal parte by weight for cold 

 weather. As mentioned above, the most convenient way to apply these mixtures is 

 to paint them on bands of thick paper, but they may be applied to the tree without 

 injury to the latter. If this is done it is sometimes necessary to put on a second 

 coating if too much of the oil is absorbed by the bark. Printers' ink five pounds, 

 mixed with one gallon of fish oil, is akio much used in Nova Scotia, and the amount 

 mentioned will treat an acre of orchard. 



The Chemical Division of the Dominion Experimental Farms recently carried on 

 some experiments in the hope of finding a more economical adhesive material which 

 could be used for such insects. Considerable progress was made, but the Chemist, 

 Mr. Shutt, has informed us that this work is not yet far enough advanced to make a 

 report upon. It is hoped, however, that when further experiments have been con- 

 ducted, some useful deductions may be made. 



The Pear Leaf Blister Mite, Eriophyes pyri Nalepa. — This old enemy of the 

 pear is steadily spreading in the apple-growing districts of the southern portions of 

 Ontario. It occurs in every part of Canada where the pear is grown, but it is only of 

 late years that it has turned its attention to the apple, although in Europe it is well 

 known to attack that tree. During 1908, it was much complained of, and information 

 asked as to the best known remedy for its destruction. 



