48 PROTECTION OF PLANTS, 1915-16 



Leaf Rollers and the Green Apple Bug on apples and pears, the first by 

 Prof. Caesar of Guelph, and the other by Prof. Brittain of Nova Scotia. 



There are two moderately common leaf rollers that attack fruit trees, 

 especially apple and pear trees in Ontario. The first is known as the Oblique- 

 banded Leaf Roller and the other the Fruit Tree Leaf Roller. These insects 

 have not been very noxious as a general rule in the past decade, with the 

 exception of the last three years. They seem to attack a single orchard in 

 a place rather than the whole area devoted to fruit-growing; and at other 

 times will attack only a certain portion of an orchard, leaving the rest in 

 a healthy condition. 



The adult of the Leaf Roller is a small moth, about half an inch long 

 when the wings are closed, but with a wing expanse of nearly an inch. The 

 upper wings are a rusty brown with several silvery-white markings ; the hind 

 wings are a light ashy brown without any markings. The larva when full 

 grown is a slender caterpillar nearly an inch long, and of a pale, yellowish 

 green color, with a black head. They are usually to be found in a rolled 

 up leaf. When disturbed, they quickly wriggle out of the leaf, and drop 

 down on a silken thread. When danger is past, they crawl up this thread 

 to the tree again. 



The larvae of the Fruit Tree Leaf Roller attack the leaves, the fruit 

 buds or blossoms and also the fruit. The attack on the leaves begins about 

 the time the buds begin to open. At this date the little larvae have just 

 hatched out of the egg. They at once work their way in among unfolding 

 leaflets, fasten them together with a few silken threads and feed upon the 

 inner tissues in this sheltered position, where it is clear one cannot reach 

 them with any contact poison. The fruit buds are often bored into and des- 

 troyed, but apparently the chief injury is done here to the fruit. Once 

 fruit begins to form, the caterpillars prefer it to anything else and they 

 eat holes in it. These holes frequently extend to the core but often do not 

 go so deeply. The worst injured apples drop; the rest remain on the tree 

 and are deformed and no better than culls. 



Arsenates will not be sufficient to control this pest, as not more than 

 50% of the larvae are thus destroyed. This application is made with 4 lbs. 

 in 40 gallons of water or Lime Sulphur Solution, applied just before the blos- 

 soms open and a second just after the petals fall. Be thorough and cover 

 every leaf if possible. 



But the best remedy is scalecide, which is a miscible oil spray made 

 by the B. C. Pratt Co., 50 Church St., New York City. It costs about 

 $30.00 a barrel, and should be diluted at the rate of about 1 gallon of scale- 



