GRAPE INSECTS 421 



In the garden they may be destroyed by hand-picking, or in 

 larger vineyards they may be killed by spraying with arsenicals 

 while the caterpillars are small. 



References 



Riley, 6th Rept. Ins. Mo., pp. 88-90. 1874. 



Lintner, 5th Rept. State Ent. N. Y., pp. 179-183. 1889. 



The Erinose of the Vine 



Eriophyes vitis Landois 



In central Europe, Italy and in CaUfornia the leaves of the 

 vine are often deformed by attacks of a minute mite. In in- 

 fested leaves the portions between the larger veins puff up, leav- 

 ing a cavity on the under side which is clothed with a dense 

 felt-hke covering. As a rule, thin-leaved varieties of grape are 

 more subject to attack, or at least show greater evidence of the 

 presence of the mite. In CaUfornia erinose rarely causes seri- 

 ous injury to the vine or to the crop ; it has often been confused 

 with a fungous disease, the powdery mildew. 



The mite, as usually found on the leaf, is a minute, nearly color- 

 less, elongate, four-legged creature, about .13 mm. in length. The 

 mites hibernate under loose strips of bark on the larger branches 

 of the vine and in the spring migrate to the under side of the 

 opening leaves where they puncture the epidermal cells with 

 their sharp mandibles, thus producing abnormal thread-Uke 

 outgrowths from the underlying layers of cells, known as erinea. 

 These erinea when abundant have the appearance of dense felt, 

 and it is in the shelter thus afforded that the mites Uve, lay their 

 eggs and the young find suitable food. From time to time 

 individuals leave the older leaves and start new colonies on the 

 young leaves at the ends of the branches. In the fall some of 

 the mites desert the leaves and go into hibernation on the bark 

 of the older canes. 



