2 1 2 Canker - 1 Vonns. 



over, is a partial preventive ; and if used in connection with the tar, and 

 placed above it, would shelter it from rain. When removed, it sliould 

 be scalded, to destroy the eggs laid on the under side ; and those laid on 

 the bark of the tree below the tar or protector should be scraped off, or 

 destroyed by washing with potash. A belt of cotton-wool, or straw with 

 the ends downward, which has been recommended, forms no obstacle 

 whatever to their ascent. 



While the worms are eating, they can be attacked by jarring the trees, so 

 as to shake them down, or by throwing coarse sand into the tree, when they 

 will begin spinning down, and may be brought to the ground by breaking 

 their threads with a pole. They will immediately make for the foot of the 

 tree, where they can be crushed, or a brood of chickens will devour an 

 enormous number. One cultivator told me that he had some young ducks, 

 which, after gorging themselves with the worms, would lie down and digest 

 them, and in about a quarter of an hour would be ready to begin again. 

 Sometim.es the belt or trough of tar is used to keep them from re-ascend- 

 ing ; but care must be taken that it be not bridged over with their bodies. 

 The worms, when they spin down after they have finished eating, are them- 

 selves eaten by robins and the common crow-blackbird; and they are also 

 eaten while on the tree by the Canada robin or cedar-bird : but I have 

 never known of the perfect insect being eaten by any bird. The worms, 

 as before mentioned, are sometimes destroyed by frost ; but the perfect insect 

 will endure a considerable degree of cold. 



It has been advised to examine trees, and remove and destroy the eggs 

 before they are hatched. This would do very well on young trees, but 

 would be impossible on large ones. Where the grubs are very abundant, 

 they will climb on fences and buildings, and lay their eggs ; and these should 

 be taken off, and destroyed. Swine turned into an orchard will root up 

 and kill many of the chrysalids ; and it is probable, that, by ploughing to 

 the depth of sixth inches in the autunm, many would be crushed, and 

 others destroyed by the cold. 



Among the greatest aids to the cultivator in destroying the canker-worm 

 are other insects which prey upon them. They are also attacked by para- 

 sites, one of which deposits its egg in the body of the worm, while another 

 lays its own egg in the egg of the canker-worm. It is probable that the 



