158 Commercial Gardening 



formerly Phytoptus ribis. (See Vol. I., p. 180, for figures of this and 

 other Currant pests.) 



These acari are elongated, with four legs only in front and a ringed 

 body with a few bristles. They are scarcely perceptible to the naked eye, 

 but may be seen with a lens, especially in bright light. At their tail end 

 is a kind of sucker. They live almost entirely inside the buds of the 

 Black Currant, but now and then attack the Red and the White. Their 

 presence in the bud causes it to swell abnormally and become bloated or 

 globular in form. Large numbers of mites may be found in a single bud, 

 where they breed. The eggs are comparatively large. As the buds die the 

 acari migrate to other buds; this they do by both crawling and jumping, 

 holding on to the outside of the bud by the terminal sucker. Birds, bees, 

 &c., also carry them about. The young are much like the adults. Repro- 

 duction takes place most of the year, but less in February and the winter 

 months than at other times. Migrations are frequent, but most numerous 

 from April to June. A few mites have been found under the skin of the 

 stumps left in the ground; these probably enter the new buds or young 

 shoots. 



The mites may kill the buds, which then turn brown and remain on the 

 bushes, or the buds may burst but then seldom bear fruit. 



TREATMENT. The only satisfactory method is hand picking; this must 

 be done about three times, namely, in autumn, spring, and late spring, and 

 the buds carefully burnt. Certain varieties resist the mite more than 

 others. The "Boskoop Giant" and French Currants withstand it well 

 as a rule, whilst "Black Naples" and "Baldwins" suffer very severely. 

 No spraying has proved to be completely successful, but results of benefit 

 have been claimed by spraying six or seven times with soft soap and 

 quassia in spring and early summer, and with three dustings of lime and 

 sulphur. It is best, however, to rely on hand picking. 



Other Currant Pests. The Currant Clearwing (J2geria tipuli- 

 formis), Winter Moth (Cheimatobia brumata), Currant and Hop Pug 

 Moth (Eupithecia assimilata), Currant-fruit Moth (Spilonota roborana), 

 Currant and Gooseberry Sawfly (Nematus ribesii), the Glaucous Leaf 

 Weevil (Phyllobius calcaratus), Currant-root Louse (Schizoneura Ulmi), 

 Currant-leaf Blister Louse (Rhopalosiphon ribis), Currant-shoot Aphis 

 (Myzus ribis), Brown Currant Scale (Lecanium persicce, var. sarothamni), 

 White Woolly Currant Scale (Pulvinaria iritis, var. ribesice). [F. v. T.] 



For Fungoid diseases of Currants see p. 151, under Gooseberries. 



