154 EXPERIMENT STATION RECOED. 



The disease is said to be common throughout the Northwest, being known as 

 apple tree anthracnose or black spot canker. The fungus develops in the bark, 

 cambium, and to some extent in the sapwood, infection occurring in the fall 

 and early winter. The fungus matures slowly during the summer in the dead 

 bark of the cankers thus formed, finally producing the perfect form mentioned 

 above. 



Both the conidial and ascosporic stages have been found on pear trees, and 

 cankers have been produced by inoculation with the conidial stage of the fungus 

 isolated from the apple. Cankers have also been produced by inoculation 

 with the fungus from the apple transferred to peach, prune, and cherry 

 branches, but no spores have been observed to be matured in these cankers. 



No evidence has been secured that new cankers are formed by the spread of 

 the fiuigus from the tissues of old ones. The fungus has, however, been isolated 

 from the heartwood, and the extent and imporance of the fungus as a heart 

 rot is to be investigated. 



Control measures have been described elsewhere (E. S. R., 27, p. 249). 



The " roug'h-bark " disease of the Yellow Newtown apple, J. W. Roberts 

 (C7. S. Dept. Agr., Bur. Plant Indus. Bui. 280, pp. 16, pis. 3, figs. 2).— In the 

 summer of 1909 the author's attention was called to a disease, locally known as 

 rough bark, which is said to be prevalent In certain sections of Virginia. 



The first appearance of the disease is found in the sinking of definite areas 

 of the bark, which later enlarge, turn black, and finally crack or break open 

 about their margins, resulting in a roughened bark effect. The disease may 

 continue to develop, sometimes involving an entire branch, but the chief de- 

 struction seems to be to the smaller branches, as the larger limbs and the 

 trunk, though injured and badly roughened, are seldom deeply girdled. The 

 disease, so far as known, is confined to the variety Yellow Newtown. It is 

 due to a species of fungus to which the author has given the name Phomopsis 

 mali n. sp. 



Trees which are in good growing condition are said to be usually exempt 

 from attacks of the fungus, and fertilization and cultivation, together with 

 proper pruning, are believed to be effective means in keeping the disease in 

 check. 



The fungus was found to grow on leaves previously diseased, often following 

 Sphceropsis malorum, but is not a serious leaf disease. It also produced a rot 

 of the fruit, but this is believed to be of rare occurrence in nature. 



Sooty blotch on apples, J. A. McClintock {Mich. Farmer, UfO (1913), No. 

 14, p. 425, fig. 1). — ^A popular account is given of the sooty blotch of apples, 

 due to the fungus Leptothyrium pomi, with suggestions for its control. This 

 disease is said to have been especially troublesome in Michigan, being very com- 

 mon on Northern Spy, Baldwin, Greening, Red Canada, Pewaukee, and Mann 

 tipples in various parts of the State. 



Cherry 'g'ummosis, H. P. Barss {Oregon 8ta. Bien. Crop Pest and Hort. Rpt. 

 1911-12, pp. lDS-217, figs. 10). — A preliminary report is given of an investigation 

 of cherry gummosis, the study of which was begun by F. L. Griffin and attrib- 

 uted by him to Pseudomonas cerasus (E. S. R., 26, p. 144). 



The author began his study in February, 1912, and has confirmed many of 

 the previous observations and conclusions. The experiments seem to indicate 

 that the blighting and gumming of buds and spurs on some varieties of the 

 sweet cherry is due to the bacterium mentioned above. It is also able to pro- 

 duce gumming when inoculated, into the body and branches of these varieties. 

 Other bacteria similar to P. cerasus have been found during the spring in 

 nearly all splitting cankers on the trunks and limbs as well as in diseased spurs. 



