544 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



treatment has never come into favor in the East, principally, 

 perhaps, because of the larger trees and the more scattered nature 

 of the fruit 'ndustry. 



Practically the only methods now used in the East consist in 

 spraying the dormant trees with washes which penetrate the 

 scales and destroy the insects. This may be done more effec- 

 tively if the trees are pruned and headed in so as to reduce the 

 wood to be covered. Rough bark should be scraped off so that 

 the scales beneath may be reached. Badly infested trees should 

 be sprayed in the the early winter as soon as they have hardened 

 up and again in the spring just as the buds commence to swell. The 

 spring spraying will suffice for trees slightly infested. Every bit of 

 bark on the tree must be thoroughly wet, so none will escape. 

 Lime-sulfur mixture seems to be the favorite wash for winter 

 spraying at present, as it not only kills the scale, but aids in the 

 control of many fungous diseases (see p. 50). Miscible oils are 

 also extensively used and have a certain advantage on hairy 

 apple shoots and on badly infested trees, as they are more pene- 

 trating and spread better. Kerosene or crude oil emulsion con- 

 taining 20 to 25 per cent of oil was the first remedy to be used and 

 is still extensively employed. Wha'e-oil soap, at the rate of 2 

 pounds to the gallon, applied hot, is effective, but is too expensive 

 for large users. (See p. 50) . 



The Fruit- tree Bark-beetle * 



If the outer bark is punctured by numerous small " worm- 

 holes " so that it looks as if it had been struck with a charge 

 of bird-shot, it indicates the presence of the fruit-tree bark-beetle 

 or some nearly related species (see p. 653). Usually more or 

 less gum exudes from the holes, particularly on stone fruits. 

 Diseased or weak-growing trees are most subject to attack, but 

 occasionally serious damage is done to perfectly healthy trees, 

 especially when young. Injury is largely due to allowing dead 

 and dying trees to stand in the orchard, thus encouraging the 



* Scolytus rugulosus Ratz. Family Scolytidoe. See F. H. Chittenden, 

 Circular 29, Division of Entomology, U. S. Dept. Agr. 



