EXPERIMENT STATION BULLETINS. 



583 



The importance of applying remedial measures against this pest where- 

 ever it is found cannot be too strongly urged, for although it may re- 

 main for a long time without multiplying injuriously, it is liable, like 

 the pear psylla, to become very troublesome when the conditions for its 

 rapid increase become favorable. The fact that it is a conspicuous, sta- 

 tionary insect that has no power of flying away just when we want to 

 treat it, is greatly in favor of the plum grower. 



REMEDIES. 



In New York state, where the pest has been most destructive, it is 

 found that a spray of strong kerosene-emulsion will kill them. Prof. 

 Slingerland says:* 



"Spray infested trees once after the leaves fall in the autumn, and at 

 least twice in the spring before the buds open. Use kerosene-emulsion 

 diluted four times (Hubbard formula), and the application cannot be done 

 too thoroughly; each little scale must be hit." 



CURRANT SCALE. 



Lecanium ribesii Fitch? 



On April 12 a branch of currant covered with soft, fleshy scales was 

 sent us from near Fort Huron. The specimens seem to agree very well 

 with the meager description of Lecanium ribessi Fitch. f 



They are yellowish-brown in color, mottled with brownish-black, and 

 the entire surface is covered with dirty-white pustules. A prominent 

 longitudinal ridge, amounting almost to a carina, runs down the center 

 for half the length of the scale. The adult female measures from one- 

 eighth to three-sixteenths of an inch in length and the breadth is usually 

 about two-thirds of the length. Fig. 12 shows a group of the scales, 

 greatly magnified, on a twig. 



rf^sHsigSSiib 



Fig. 12. Curranit Scale {Lecanium ribeni Fitch) enlarged. (Original.) 



While this scale has not done any great damage during the past season, 

 the fact that it feeds on the currant and that it has been known to be- 

 come destructive by reason of its rapid increase under favorable con- 

 ditions, makes it of enough importance to bear careful watching. ^ A 

 thorough spraying with strong kerosene-emulsion during the early spring 

 months will undoubtedly prove effective. 



*Bull. 108, Cornell Exp. Sta. 



t "Third Rep. on Injurious Insects of New York. p. 109 " 



