348 EXPEEIMENT STATION EECORD. 



tions for their control as far as definite means are liuown. In addition to frost 

 cankers and sunscald, the forms of canlier and their causal agents talien up are 

 apple tree canker (Physalospora cydoniw), fire blight canker {Bacillus amy- 

 lovorus), European apple tree canker (Nectria ditissima), Illinois blister 

 canker {Niimnmlaria discreta), bitter rot canker (GlomcreUa cingulata), and 

 a superficial bark canker caused by Myxosporium corticolum. 



Field studies of apple rust, N. J. Giddings and A. Berg (A6s. in Phyto- 

 pathology, 4 {1914), ^0. 6, p. 401). — In continuation of previous studies (E. S. 

 R., 28, p. 748), the authors give the results of experiments undertaken for the 

 control of the apple rust. 



The results indicate that it is impracticable to control this disease in com- 

 mercial orchards by use of liquid sprays, as spray material applied a week 

 previous to infection did not appreciably reduce the amount of disease. Of the 

 fungicides tested, commercial lime sulphur gave the best results, with Bordeaux 

 mixture second and atomic sulphur third. 



Orchards were found infected to a considerable extent three-fourths of a 

 mile from any cedar trees, and the effects of a severe rust infection, it is 

 claimed, may be noted on trees for at least two years following it. There is 

 believed to be some evidence that heavy infection of a cedar tree is followed 

 either the first or second season afterwards by a loss of vitality and inhibition 

 of growth, which renders that tree practically immune for one or two seasons. 



Apple rots, C Brooks, D. F. Fisiiek, and J. S. Cooley {Ahs. in Phytopathol- 

 ogy, 4 {1914), ^0. 6, p. 403). — The authors report having isolated from market 

 and storage apples the following fungi which are capable of producing a rot of 

 the same: Sphceropsis malorum, Glomerella cingulata, Monilia sp., Botrytis 

 cinerea, Phomopsis mail, PenicilUum expansuM, P. commune, P. pinophilum, 

 Mucor stolonifer, Cephalotheciiim roseum-, Aspergillus niger, Trichoderma sp., 

 Pestalozsia guepini, P. hrevipes, Verticillium' sp., Ramularia macrospora, Fu- 

 sarium radicieola, F. putrefaciens, and several species or sti*ains of Alternaria. 



Of the above species, P. expansum is the most common on the storage fruit. 

 Sphseropsis and the Alternarias cause most of the blossom rot in eastern States, 

 and the Alternarias and the Fusariums the core rots in the Northwest. The 

 Alternarias are also of common occurrence following Jonathan spot and scald. 



York spot and York skin-crack, H. S. Reed {Ahs. in Phytopathology, 4 

 {1914), No. 6, p. 405). — The author reports some new, or at least undescribed, 

 troubles observed in Virginia in 1914 on the York Imperial apple. 



The spot appears somewhat different from the Jonathan spot and is charac- 

 terized by much larger sunken areas on the fruit, which bear some resemblance 

 to moderate hail injury. The tissue beneath the spots is dry and corky. Where 

 the trouble is severe the supei*ficial tissues are water-soaked. 



York skin-crack was first noticed by the author in 1911, but did not become 

 serious until 1914. The skin of the fruit is at first pitted and then cracks open, 

 giving entrance to various decay fungi. There is a rather constant association 

 of a species of Alternaria with this trouble, and this fungus has been isdlated 

 and is now under further study. 



Orchard experiment with Jonathan spot rot in 1914; G. W. Martin {Al)s. 

 in Phytopathology, 4 {1914), No. 6, p. 4O6).— In continuation of a previous report 

 (E. S. R., 29, p. 847) the author bagged apples, as in the previous investigation, 

 and compared the protected with the unbagged apples. The results obtained are 

 in harmony with those of 1913, which indicate that Jonathan spot rot is caused 

 by a species of Alternaria and that infection occurred later than June 9. 



Jonathan spot, bitter pit, and stigmonose, C. Brooks and D. F. Fisher 

 {At)S. in Phytopathology, 4 {191Jf), No. 6, pp. 402, 403). — Experiments of the 

 authors have shown that both Jonathan spot and bitter pit are usually worse 



