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^06 NEW YORK STATE MUSEUM 



to look for now, and the pest is usually discovered earlier. Trees which 

 have been badly infested for some time have a rough bark covered with 

 dark gray, scurfy patches, and, if this be scratched with a knife or finger 

 nail, an oily, yellowish substance will be crushed from the living insects 

 under the scales. This insect breeds so rapidly that it is not uncommon 

 to find large numbers on a tree previously comparatively free. In that 

 event the bark may be literally covered with recently established scales 

 and not appear very rough. There is, however, a pecuHar, granular 

 look, and those familiar with the bark of a rapidly growing tree are 

 aware that some change has taken place. There is nothing like a good 

 magnifier in these cases, and, if this shows hundreds of circular, black or 

 dark gray objects, with dot and ring, or lighter gray, yellowish marked 

 scales, send a sample of the bark to somebody competent to identify the 

 trouble. Cutting into the bark under a San Jose scale is almost sure to 

 reveal a reddish discoloration of the green tissues beneath. Lenticels 

 occasionally deceive people, and I have seen fungous growths which at 

 a little distance looked much like masses of young pernicious or San 

 Jose scale. An infestation of any extent on fruiting trees is almost sure 

 to show itself on the leaves and fruit, the reddish blotches being more 

 conspicuous than the insects (fig. 3). The reddening of the fruit is not 

 absolute proof that San Jose scale is present, because I have seen nearly 

 the same effects produced by Chionaspis furfura Fitch. The 

 pear illustrated shows a condition which obtains in badly infested 

 orchards in July. Late in August the blossom end and sometimes the 

 other may be literally incrusted with patches of young and old scales like 

 the one represented in figure 7. A close examination of a slightly 

 infested tree may result in finding a very few scales somewhere on the 

 bark, most frequently near a bud or some protecting elevation, and, in 

 these cases, the piece of infested bark should be cut away and sent to an 

 entomologist for identification. 



Description. This scale insect is so minute that a superficial descrip- 

 tion must be drawn in most general terms. The twig, fruit and leaf shown 

 in figures 3, 4 and 5 of plate 3 represent a very characteristic appearance in 

 July in a pear orchard badly infested by this pest. A dark grayish or yel- 

 lowish area on the bark may be caused by a mass of these scales. An enlarge- 

 ment of the darker patches will show a condition much like that repre- 

 sented in figure 7. Adult, yellowish gray scales may be found surrounded by 

 hundreds of tiny black ones. The form of the larger scales is modified 

 somewhat by the degree of crowding, and it is common to find a num- 

 ber of them adhering in a patch ; but a close examination of the w,ell 



