MITES 



545 



to the roots of the vine. This mite has been distributed all 

 over the world in its food plants. 



The indications of its presence are : arrest of growth ; the 

 leaves becoming yellow : failure to produce flowers ; reddish- 

 brown spots on the bulb-scales, indicating places where the 

 mites have been feeding. 



There was at one time some difference of opinion as to 

 whether the mite was the primary cause of injury to the bulbs 

 infested with it. It was thought that the injury might be due 





Fig. 165. "Left-hand fig., gooseberry red spider {Bryobia ribis, 

 Thomas). Right-hand fig., eucharis mite, bulb mite, etc. [rhizo- 

 glyphus echinopus). 



in the first instance to some error of treatment, and that the 

 mites were simply feeding on the more or less decayed 

 portions. It has, however, been definitely proved by Michael 

 that the mites are the primary cause of injury, and that indeed 

 they prefer sound bulbs. The base of the bulb and the roots 

 are most frequently attacked, and the mites can often be seen 

 in large numbers in the injured ' cushion ' of the bulb when a 

 magnifying-glass is used. The mites are very minute, some- 

 times not more than one-twentieth of an inch in length ; they 

 are yellowish-white in colour, with just a suffusion of pink, 

 the legs and rostrum are red. 



The following remedial measures are given in Leaflet 

 No. 136, Board of Agriculture and Fisheries: 



1. This pest is very difficult to combat because the extremely 



2 M 



