140 THE HOP. 



foliage by what appears to be the common red spider 

 of our American greenhouses (Tctranychus tclarius), 

 although English writers have found sufficient differ- 

 ence between the spinning mite found in the hop fields 

 and the ordinary form to establish a new variety which 

 they call T. tclarius var. huniuli. In 1868, and again 

 in 1893, this little mite did much mischief in many hop 

 yards. The leaves fell off, the burr or blossom was 

 damaged, and in some instances the plants were com- 

 pletely shrivelled up. In 1897, again serious injury 

 was threatened, but a succession of showers and a fall 

 of temperature fortunately checked multiplication. The 

 first indication of the presence of these mites is the 



o 



FIG. 72. "RED SPIDER," OR SPINNING MITE. 



Female, male and ears? greatly enlarged. (Redrawn from Journal of the Board 

 of Agriculture of England for December, 1897.) 



yellowing of the lower leaves of the plant, and when 

 examined carefully upon the under surface, thick, 

 silken webs will be seen spreading from rib to rib, 

 under which the mites live, actively sucking the juices 

 of the leaf. The remedies adopted in England are very 

 sensible, and consist, principally, of a heavy spray of 

 soap and water and sulphide of potassium. Sulphur 

 in any form is a specific against mites, and a spray of 

 kerosene soap emulsion, to which a small quantity of 

 flowers of sulphur has been added, is generally 

 effective. 



