328* STATE BOARD OF AGRICULTURE. 



Fig. 50. — San Jose Scale from Howard and Marlatt, Bui. No. 3, new series, Div. of Entomology, 



U. S. Dept. of Agr. 



thin, papery covering or scale, free from the body. The female scale being grey 

 in color, usually with a yellow or orange central spot where the exuviae or cast- 

 skins are placed. The male scale is circular at first, with a central raised nipple 

 and an elevated ring about it. When fully developed, the male scale becomes 

 elongated by a growth at one side. Fig. 51 gives a good idea of the appearance 

 of the scales of both sexes. 



If the bark under a colony of such scales be scraped off. the deeper layers often 

 show a purple staining. Fruit also is often stained in this manner. This stain- 

 ing, however, must not be taken as positive evidence, for several other scale- 

 insects sometimes produce the same coloring. The females always remain 

 attached to the twig, but the males are winged when adult. 



The young of this species are born alive and several broods are produced each 

 year, so that under favorable circumstances, the rate of increase may be very 

 rapid indeed. As the insects become fixed very early in their lives, the spread 

 of a colony and the foundation of new colonies must take place during the first 

 stage, or just after birth. At that time they are very minute appearing as small 

 as grains of sand. They are active for a few hours, however, and during that 

 time, they run about from one part of the tree to another. They also probably 

 crawl upon the feet of birds and upon other insects, and are by them transported 

 to new quarters. 



BEMEDIES. 



Many sprays have been tried for the extermination of this pest. In the West, 

 fumigation under tents is also used. We find at least three sprays effective and 

 practical here. Perhaps, in view of the cheapness and the ease with which it is cor- 

 rectly made, we may place lime-salt and sulphur as first in the list. Directions 

 for making and applying all of them will be found in the chapter on insecticides. 

 All of these sprays must be applied during the winter season, while the trees are 

 dormant, or else they are almost sure to injure the trees. Next comes kerosene 

 emulsion, diluted so that one part of oil is used with four parts of water, or so 

 that the oil forms 20 per cent of the spray when ready to apply; and last, because 

 it is the most expensive, is whale-oil soap, a very effective spray when used at the 

 rate of two pounds to a gallon of water. Other sprays are useful, but these three 

 seem to give the best satisfaction. Strong polash kills a goodly proportion of the 

 insects and it cleans the bark, giving it a fresh, healthy appearance, but it is 

 quite expensive and does not seem to kill quite so large a proportion of the 

 insects as the others. Kerosene and water, applied with a mixing pump (a special 

 pump that takes the water from one tank and the oil from another, mixing them 



