ORCHARD INSECTS 309 



the smaller sprouts near the crotch before spreading to the 

 rest of the tree, and in the disgusting black masses of curled 

 foliage, dripping with honey dew and swarming with ants, 

 which they soon cause. 



Control. Most of these aphides may be controlled by 

 much the same treatment. Spraying the trees in the winter 

 with lime-sulphur wash as for the San Jose scale (page 289), 

 will kill a large percentage of the eggs and thus materially 

 reduce the numbers, though it cannot be depended upon for 

 complete eradication. With all of these aphides it is impor- 

 tant to spray them in the spring just as the buds are bursting 

 and before they become secreted in the foliage which soon 

 curls around them, and thus protects them from being hit by 

 the spray. Early and thorough spraying is essential; spray- 

 ing after the foliage is curled is of but little value. Kerosene 

 emulsion, diluted to contain 7 per cent of kerosene, dilute 

 miscible oils, whale-oil soap 1 pound to 5 or 6 gallons of water, 

 or tobacco extracts, will destroy the aphides, though the 

 exact strength must be varied with the species. The most 

 successful spray for aphides of all sorts seems to be a to- 

 bacco extract known as Black-leaf 40 or Nicotine Sulphate. 

 The spray used against aphides should be applied with some 

 force so as to penetrate the expanding buds. Where Bor- 

 deaux mixture is being applied for plant diseases, either 

 whale-oil soap or tobacco extracts may be added to it for 

 the control of aphides. Lime-sulphur solution has not 

 proven satisfactory for the destruction of aphides on foliage. 



160. Orchard Caterpillars. Several hundred species of 

 caterpillars have been listed as attacking the foliage of our 

 common fruit trees, but a few are so common as to require 

 attention almost every year. 



The Fall Webworm * is so-called because its webs usually 

 * Hyphantria cunea Drury. Family Arctiidce, see page 81. 



