INSECTS INJURIOUS TO THE APPLE AND PEAR 597 



other insecticides tested. These emulsions are prepared the same 

 as kerosene emulsion (p. 48), using one gallon of the oil, and 

 i to 1 pound of soap to 10 or 12 gallons of water. When the eggs 

 are hatching and the young are crawling the trees may be sprayed 

 with the above or 15 per cent kerosene emulsion, or whale-oil 

 soap. 1 pound to 4 or 5 gallons of water. The effectiveness of 

 the last two insecticides seems to vaty according to local conditions, 

 as they have proven satisfactory in certain experiments and of 

 less value in others. As for the San Jose scale, the trees or shrubs 

 to be treated should first be pruned of the dead and worst-infested 

 wood, and loose bark scraped off, so that the bark may be thor- 

 oughly covered. 



; > 



Apple Plant-lice * 



Several species of aphides or plant-lice commonly infest the 

 foliage of the apple, and less commonly that of the pear, arid 

 though they differ somewhat in appearance and habits they are 

 sufficiently alike to be discussed together, as the same methods 

 of control apply to all. 



The Apple-aphis f 



This is the common apple-aphis of Europe, and was first 

 noticed in this country late in the last century, when it spread to 

 all parts of the country within a few years, probably being dis- 

 tributed on nursery trees. Only young trees are usually much 

 injured by this and the following species of aphides, old trees 

 rarely being injured, except that where the aphides are excess- 

 ively abundant they sometimes injure the young fruit, causing 

 it to become stunted and misshapen. The foliage of young trees 

 soon becomes covered with the vermin, which feed on the under 

 surfaces of the leaves, causing them to curl up and then drop. 



*See Sanderson, 13th Report, Del. Agr. Exp. Sta.; A. L. Quaintance, 

 Circular 81, Bureau of Entomology, U. S. Dept. Agr.; Gillette and Taylor, 

 Bulletin 133, Colo. Agr. Exp. Sta. 



f Aphis pomi DeG. Family Aphididce. See above references, and J. B. 

 Smith, Bulletin 143, N. J. Agr. Exp. Sta.; C. P. Gillette, Journal of Economic 

 Entomology, Vol. I, p. 303. 



