564 abstracts: phytopathology 



PHYTOPATHOLOGY.— i7os^ relationships of the North American 

 rusts, other than Gymnosporangiwns, which attack conifers. Arthur 

 S. Rhoads, George G. Hedgcock, Ellsworth Bethel, and 

 Carl Hartley. Phytopathology 8 : 309-352. July, 1918. 

 This paper, which is of special interest to forest pathologists and 

 mycologists, treats of fifty-two species of rusts attacking species of 

 Abies, Ephedra, Larix, Picea, Pinus, Pseudotsuga, and Tsuga. With 

 each species of rust is an abbreviated synonomy; citations of publica- 

 tions containing treatment of the species; a liiBt of the coniferous host 

 species; the names of genera bearing alternating stages, when present, 

 of each rust; the distribution; remarks relative to important char- 

 acters; and data of inoculating proof of the connection between the 

 aecial and telial stages. 



At the close of the paper is a host index in two parts, one of aecial 

 hosts, the other of uredinial and telial hosts; and 148 citations of 

 literature bearing upon the subject. , G. G. H. 



PH YTOPATHOLOG Y.— .So/??e bacterial diseases of lettuce. Nellie A . 

 Brown. Journ. Agr. Res. 13: 367-388, pis. 29-41. May 13, 

 1918. 



The paper describes two new bacterial diseases of lettuce, one occur- 

 ring in South Carolina and Virginia on lettuce grown out of doors, the 

 other on greenhouse plants in Kansas. The organism producing the 

 disease in South Carolina and Virginia has been named Bacterium 

 vitians. In South Carolina, Bacterium vitians causes the lettuce stems 

 to turn ])lue, then brown when seen in cross or longitudinal sections. 

 Leaves are spotted occasionally but the stem affection is the prevalent 

 condition. The organism isolated from diseased stems of South Caro- 

 lina plants produces spots on leaves as well as brown stems when inocu- 

 lated into healthy lettuce plants. 



In Virginia the leaf spotting only was noted, but the isolated organ- 

 ism from these leaf spots will produce stem-rot readily when inoculated 

 into the stem of healthy lettuce plants, as well as spots on leaves when 

 it is sprayed on the leaves of healthy lettuce. The diseased Virginia 

 lettuce had a second organism present producing spots on it, and this 

 organism was isolated along with Bacterium vitians. It is one already 

 known and described {Bacterium viridiliviclum) and the colonies isolated 

 proved to be infectious. 



It appears that Bacterium vitians and Bacterium viridilividum may 

 be present and active in soil which is heavily fertilized with green 



