210 APPLIED ENTOMOLOGY 



ing scale. The insect beneath this becomes adult after a time and 

 following the laying of its eggs, dies. In the northern states the eggs are 

 laid in August or September, but in the middle states and farther south, 

 the earlier seasons permit hatching enough earlier in the season for the 

 adult condition to be reached and the eggs laid by midsummer, and these 

 eggs soon hatch and produce egg-laying adults before the following 

 winter. Thus, this insect though having but one generation each year 

 in the more northern states, has two from about the latitude of New 

 Jersey southward, except at such altitudes as to produce northern 

 conditions. 



Many of the male crawling young go to the leaves to settle and the 

 scales they form are smaller and somewhat different in shape from those 

 of the females. Beneath them they attain their growth, then pupate, 

 still under their scales, and at the end of this process emerge as very 

 small two-winged adults without any mouths or mouth parts, having un- 

 dergone a complete metamorphosis. 



Cofitrol. — These insects are least protected while crawling young, and 

 as they are sucking forms, a contact insecticide should be applied 

 while they are moving about or at least before they have had time to 

 produce scales covering themselves. The usual treatment therefore is 

 to spray with 1 part of kerosene emulsion to 9 of water, or with Nicotine 

 sulfate 40 per cent, 1 part, water 800 to 1,000 parts, as soon as the young 

 appear. They are so small, however, that it is very difficult to reach 

 them all with the spray, and as all do not hatch at the same time, a 

 second application about 10 days after the first, is desirable. Winter 

 spraying with lime-sulfur wash is also a fairly good treatment. Where 

 neither of these methods proves effective (as is sometimes the case), 

 spraying in spring, shortly before the eggs hatch, with linseed oil emulsion, 

 has worked well. This is prepared as follows: 



Raw linseed oil 1 gal. 



Hard soap ' -i lb. 



Water, to make 10 gal. 



Dissolve the soap in the water; add the oil and churn through a 

 pump as for kerosene emulsion until thoroughly mixed (it does not 

 thicken up like the latter) and spray. 



The Scurfy Scale (Chionaspis furfura Fitch). — This insect is a native 

 of America and is usually less abundant in the more northern states than 

 elsewhere, attacking the apple, pear, mountain asn, currant, gooseberry, 

 hawthorn, Japanese quince and other plants. The full-grown female 

 scale (Fig. 204) is shorter and broader than the Oyster-shell scale, 

 and when perfect in outline, rather pear-shaped, and dirty white in color. 

 Its life and habits are much the same as those of the Oyster-shell scale. 



