INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



11 



scales of the buds. The3 r appear in the spring as soon as the buds 

 open and begin to work upon the undersides of the young leaves. The 

 blisters are gradually enlarged until they often cover the entire 

 under surface. 



Fig. 11. — Erinose produced on grape leaf by Eriophyes 

 vitis Landois. The discolored areas are dark brown or black. 

 Natural size. (Original) 



Nature of Work.— The felt-like swellings have already been de- 

 scribed. They are well illustrated in Fig. 11. Severe infestations 

 sometimes result in the killing of the leaves and a corresponding 

 weakening of the vines. 



Distribution.— The erinose mite occurs throughout the grape-grow- 

 ing districts of the State. It was probably imported from Europe. 



Food Plants. — The foliage of many varieties of grapes is attacked, 

 but a few are apparently immune and quite a number are only slightly 

 infested. 



Control.— Sulphuring the vines early in the spring, soon after the 

 buds open, or as ordinarily applied for mildew, is usually sufficient to 

 hold this mite in complete subjection. 



THE PEAR-LEAF RUST MITE 



Epitrimerus pyri Nalepa (Family Eriophyidae) 

 (Figs. 12, 13) 



Description. — The mites are so small that they cannot be seen singly 

 without the aid of a hand lens. When fully matured they are pale 

 yellowish and, according to Nalepa, the females are about - X | T inch 

 and the males -^ i$ inch long. The body is nearly triangular in shape, 

 being broadest near the head, tapering nearly to a point at the tail, 

 which supports two rather long caudal seta?. The entire body is 

 encircled with numerous transverse bands, as shown in Fig. 13. 

 There are two pairs of legs near the head. 



