1913.] PUBLIC DOCUMENT — No. 31. 41 



A NEW RUST. 



G. E. STONE. 



CUKKANT EUST, WhITE PiNE BlISTEE RuST. 



In previous reports we have mentioned an epidemic of rusts 

 whieli have been unusually severe the past few years on the 

 apple, bean, quince and ash, and last year we noted a new rust 

 on Vinca. A new form has lately made its appearance on the 

 black currant. The white pine blister rust has also been with us 

 for several years, affecting most largely young nursery stock, 

 although it is occasionally found on white pines of fairly good 

 size. On September 28 some specimens of currant rust were 

 sent in from a large estate in Essex County, this being the first 

 outbreak recorded in Massachusetts to our knowledge. At prac- 

 tically the same time Dr. G. P. Clinton observed a similar out- 

 break in Connecticut, and Prof. F. C. Stewart, of the Geneva 

 Experiment Station, noted an outbreak in I^ew York. 



The rust in this State is confined, so far as we know at the 

 present time, to one block of 200 currant plants of the Black 

 Champion variety. The plants were two-year-olds, purchased 

 last spring from a N^ew York nursery, and practically all in this 

 block were infested except about twenty-five or thirty in the 

 southwestern corner of the block. About a quarter of a mile 

 south of the diseased currants was a small block of old black 

 currants, but they showed no signs of Cronartium. About the 

 same distance east was a magnificent stand of eight-year-old 

 pines, but rigid examination failed to reveal any signs of blister 

 rust infection ; neither was any infection found on the near-by 

 block of red currants. 



The following description of the currant rust and white pine 

 blister rust, which are different stages of the same rust, was 

 prepared at my request by Mr. E. A. Larrabee, from various 

 literature. 



