EXPERIMENT STATION BULLETINS. 471 



insert their slender beaks into the bark and develop scale-like coverings. 

 During the winter the partially developed scales are black in color, nearly 

 round, flattened; and in most cases, as can be seen with a magnifying 

 glass, have a small nipple at the center, surrounded by a well-marked 

 sunken ring. The size is such that a single scale to the unaided eye looks 

 like a small black spot. The full-grown scales are of a grayish-brown 

 and reach one sixteenth of an inch in diameter. The scales are but loosely 

 attached to the tree and can be readily scraped off. Beneath the shell- 

 like covering the true insect can be found. These are yellow in color and 

 on being crushed will be found to contain a yellow oily substance. 



When the scales are scattered upon the young twigs a purplish color of 

 the bark will be noticed and on cutting into the bark it will be found 

 much discolored. This discoloration of the inner bark is caused by no 

 other scale, and if this is present and the ring-like depression can be made, 

 out, it indicates that it is the San Jose" scale. This insect will ruin, if it 

 does not kill young fruit trees, and will render large trees unfruitful, and 

 is to be dreaded particularly on account of its rapid reproduction and 

 small size, which render it possible for it to obtain a foothold, and even 

 spread to adjoining trees before it is discovered, as well as because it is 

 difficult to reach and destroy every specimen upon a tree with a spraying 

 solution, while the cost of the materials will make it an expensive under- 

 taking. 



In case one has but a few infested trees it will be cheapest and saresr 

 to uproot and burn them, especially if they are small and incrusted witn 

 the scale. 



In attempting to destroy the scale by spraying, some material must bo- 

 used that has considerable penetrating power. The leading remedies are 

 whale-oil soap and kerosene, either alone, mechanically mingled with 

 water, or as an emulsion. 



As a winter treatment use either a solution of whale-oil soap (one 

 pound to one gallon of water), or kerosene emulsion (one part kerosene, 

 one part soft soap, or whale-oil soap, and three parts of water). A pump 

 should be used to make the emulsion, and the agitation should be kept 

 up until a cream-like mass is produced. In either case the soap should 

 be dissolved in boiling water and applied while still hot. If kerosene is to 

 be added to form an emulsion, the soap should be removed from near the 

 fire before adding the oil. 



Before spraying the trees it will be well to cut them back severely 

 and remove as many as possible of the small shoots; thus the surface to be 

 sprayed will be reduced, and what remains will be near the ground. The 

 application should be very thorough, so as to reach every part of the 

 tree and soak all of the scales. The insects are often under bits of bark, 

 in the crevices of the buds and even beneath the surface of the soil, and 

 pains should be taken that none escape. This application will kill most 

 of the scales, but, as some may survive, another application should be 

 made shortly before the buds open in the spring. At that time the bark 

 will be full of sap, and, if a warm bright day is selected for the spraying, 

 it will be safe to use undiluted kerosene, (except, perhaps, upon the 

 peach) provided it is carefully applied. Care should be taken to use a very 

 fine mist-like spray, and to use only as much as will hold to the bark 

 without running down the trunks. If it is allowed to saturate the ground 

 about the roots it mav be fatal to the trees. 



