INSECTS INJURIOUS TO ORCHARD FRUITS 475 



lively 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 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. Miscible oils are also exten- 

 sively used and have a certain advantage on hairy apple shoots 

 and on badly infested trees, as they are more penetrating and 

 spread better. Kerosene or crude oil emulsion containing 20 

 to 25 per cent of oil was the first remedy to be used and is still 

 extensively employed. Whale-oil soap, at the rate of 2 pounds 

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

 large users. 



The Fruit-tree Bark-beetle * 



If the outer bark is punctured by numerous small l> 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. 477). 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 

 breeding of the pest in them and its spread to healthy trees. 

 "Another form of injury is the destruction at the beginning of 

 spring of small twigs, together with the leaves which they bear. 

 The beetles are also reported to destroy leaves by boring into the 

 base of the buds at their axils." The holes in the bark are caused 

 by the exit of the small parent beetles and by their subsequent 

 entrance to deposit eggs. The adult beetle is about one-tenth 

 inch long, by a third as wide, and of a uniform black color, except 

 the tips of the wing-covers and parts of the legs, which are red. 



* Eccoptogaster rugidosus Ratz. Family Scolytidoe. See F. H. Chittenden 

 Circular 29, Division of Entomology, U. S. Dept. Agr., and F. E. Brooks, 

 Farmers' Bulletin 763, ibid., H. A. Gossard, Bulletin 264, Ohio Agr. Exp. 

 Station. 



