HORTICULTURAL DIVISION 



703 



PLATE No. 261 

 APHIDS AND HONEYDEW ON TULIP-POPLAR LEAVES 



Photograph by Uuited States Bureau of Entomology. 



mined by the examination of the smooth bark of branches from various 



parts of the trees. The scales are usually recognizable as small to large 



bodies, hard shelled or soft, 



which adhere close to the 



bark but which may be 



readily crushed or scraped 



off. The scales on conifers 



are usually whitish or gray 



in color and occur on the 



leaves. 



In combating scale in- 

 sects, the removal and de- 

 struction of dead and heavily 

 infested material that can be 

 spared is advised. Fertiliza- 

 tion and an adequate supply 

 of water are of great help, 

 and spraying, where practi- 

 cable, is very valuable. Dor- 

 mant spraying in the early spring, before new growth starts, with miscible 

 oils or oil emulsions, is usually quite effective. The oils should be used 



according to the manufacturers' directions. 

 The spraying apparatus should be care- 

 fully cleaned, and in the application care 

 should be taken to cover the tree well but 

 not to allow the oil to accumulate in pud- 

 dles about the base of the tree. 



DEFOLIATORS 



The most common type of insect in- 

 jury to trees is that of foliage eating. In 

 the case of deciduous trees defoliation is 

 not a very serious injury unless it occurs 

 year after year and is complete. Further- 

 more, late summer or fall defoliation of 

 hardwoods is seldom followed by severe 

 effects, as can be observed in the case of 

 the locust, which is often to be recognized 

 year after year by its brown leaves in late 

 PLATE No. 262. THE PINE LEAF SCALE surnme r due to the work of the locust leaf 



Photograph by United States Bureau of . ITT- i u J r 1* 



Entomology. miner. With evergreens, however, delolia- 



