28 



and the use ot a suitable contact insecticide at tlie proper time will 

 insure the destruction of the whole brood. Xot so with the San Jose 

 scale. Such a wash, to be etfective, would need to be repeated daily 

 for perhaps six weeks in order to destroy the young bom at different 

 intervals. 



The two scales most commonly met with in the orchards and nurseries 

 of the State are the scurfy bark louse and the oyster-shell bark louse, and 

 these two insects are the ones most frequently mistaken for the San Jose 

 scale The figures given so well illustrate the characteristics of these 

 scales that detailed description is unnecessary. The scurfy bark louse 

 (Fig 2) is common on trees of the apple family and on currant bushes. 

 It is compact, slightly elongate, thin, and usually of a light, dirty-gray 

 color. The oyster-shell bark louse (Fig. 3) also occurs on the apple, 

 pear, etc., and on ash, willow, and poplar as well. This insect differs 

 from the preceding species in that the scale is more elongate, and usu- 

 ally curved. The molted skin of each insect forms a protuberance at 

 its apex. In Massachusetts these two insects are seldom dangerously 

 injurious, and when over-abundant may be destroyed by the application 

 of simple remedies. 



Fig. 2. Scurfy bark louse ( G/iionaspis furfurus) : a, c, females ; b, d, males ; a, h, natural 

 size; c, <?, enlarged. From Howard, Year Book, U. S. Department of Agriculture, 189-1. 



The San Jose scale (Fig. 1) is distinguished from the preceding insects 

 by its nearly circular outline, its dark-gray color and the nipple-like 

 projection at its centre, as shown in the illustration. The male scales 

 are more numerous and are smaller and darker than the female scales, 

 bearing a distinct white dot in the centre of the protuberance. _ The 

 farmer should be able to distingui.^h between these three scales without 

 the aid of a lens. Unfortunately there are a few species of circular 

 scales closely resembling the San Jose scale, for whose separation the 

 use of a compound microscope is a necessity. The safest course for the 

 farmer who finds suspicious-appearing scales on his trees is to send a 

 piece of the infested bark or twig direct to the Experiment Station at 

 Amherst, where experts avIU gladly make a careful examination of the 

 material, and inform the sender of the nature of the insect. Sugges- 

 tions concerning remedies, where the latter are deemed necessary, will 

 also be furnished. 



