PLANT DISEASES OF CONNECTICUT. 347 



As the germs of this disease can be carried on the seed, as 

 determined by Harding and Stewart, it is wise to see that the 

 seed used does not come from a diseased crop. If doubt exists, 

 it is well to treat the seed with formalin, 1-240, or corrosive 

 sublimate, i-iooo, for fifteen minutes, as recommended by the 

 investigators just mentioned. Likewise, if the disease shows 

 up in a seedbed, this should be changed the next year. If bad 

 in the field, this land should not be used for cruciferous crops 

 for several seasons, and even if the disease is not present, yearly 

 rotation is desirable where it can 'be carried on without especial 

 difficulty. Refuse from diseased cabbages should never find its 

 way to the manure pile. 



CURRANT, BLACK, Ribes nigrwn. 



PINE-CURRANT RUST, Cronartium ribicola Waldh. Plate 

 XVII b-c. In our last report, 1909-10, p. 730, we noted the 

 finding of a few specimens of the peridial stage of this fungus, 

 known as Peridermium Strobi Kleb., on recently imported white 

 pine seedlings in several plantations in the state. These pines 

 all came from one firm in Germany. In April, 1912, Mr. 

 Walden, while inspecting imported nursery stock in one of the 

 nurseries of the state, found in a shipment of three-year-old 

 white pine seedlings, purchased from Schaum and Van Tol of 

 Oudenbosch, Holland, at least 185 that showed the character- 

 istic swellings or fruiting stage of this blister rust (see illustra- 

 tions). The whole shipment was destroyed in consequence of 

 this finding. Since then the United States Government has 

 placed a quarantine on the importation of white pines into this 

 country from any of the European countries where this disease 

 is known to exist. Since our inspection of the plantations previ- 

 ously mentioned, no other examples of this rust have come to 

 our attention, and, so far as we know, it does not exist to-day 

 in this state. 



The II and III stages of this rust occur on species of the 

 genus Ribes, which includes our currants and gooseberries. 

 Although occasional outbreaks of the rust on currant had been 

 reported at Geneva, N. Y., we had never found it in this state. 

 In 1912 Stewart, of the Geneva, N. Y., Station, reported another 

 of these outbreaks, and later Stone, of the Amherst Station, found 



