382 SUMMARY OF CURRENT RESEARCHES RELATING TO 



great care in the selection of scion- wood, which should not be taken 

 from a rose-house in which the disease is known to exist. Much damage 

 was done by the fungus at Council Bluffs, Iowa. A. L. S. 



Is the Common Potato Scab Controllable by a mere Rotation of 

 Crops ?— M. Shapovalov {Pkytopathologij, 1919, 9, 422-4, 1 fig.). The 

 author has found that ih^ Scab fungus, Actinomyces Scabies, can exist 

 on a comparatively moderate amount of cellulose, so that there will 

 always be enough of material in any soil to enable Actinomyces to propa- 

 gate from year to year. Control is thus almost impossible. A. L. S. 



Publications of George Francis Atkinson. — H. M. Fitzpatrick 

 {Am,er. Journ. Bot., 1919, 6, 303-8), G. F. Atkinson, one of the fore- 

 most mycologists in America, died last Spring while on a collecting trip 

 in the Far "West. He had made his mark in other botanical subjects, 

 but in late years he had devoted himself especially to the study of 

 mycology. The author of this list has given a short account of 

 Atkinson's career {Science, 1919, 49, 371-2), and in this published list 

 of papers evidence is given as to the many branches of botany that 

 claimed his interest, though the greater proportion deal with mycology, 

 more especially from the side of plant pathology. A. L. S. 



Banana Wilt.— E. W. Brandes {Phytopathology, 1919, 8, 339-89, 

 14 pis.). The examination of this disease has been undertaken in Porto 

 Kico. The author gives, however, a general account of the importance 

 of the banana as a food ; many varieties of the banana-plant are culti- 

 vated, and a number of them are liable to the disease, which is wide- 

 spread in the American tropics. It has been found that the causal 

 organism is Fusarium cuiense, of which a full account is given as it 

 occurs on the tree and as it grows in artificial cultures. Sporodochia of 

 the fungus occur on the surface of the leaf -stalks and blades or of leaf- 

 bases, emerging through the stomatal openings. Within the host the 

 mycelium is mainly intracellular, though there is evidence that it is also 

 intercellular. The germinating conidium pierces the epidermis by 

 means of a germinating tube, and passes from cell to cell. The vessels 

 of the xylem are usually filled with the mycelium. The plant shows 

 yellowing or wilt of the leaves, which soon droop and die ; finally the 

 tree itself falls to the ground and quickly rots. Remedies are suggested 

 and experiments to cope with the disease are described. A. L. S. 



Destructive Disease of Seedling Trees of Thuja gigantea. — 

 G. H. Pethybridge {Quart. Journ. Forestry, 1919, April, 4 pp.). 

 Specimens of diseased larch and Thuja seedlings were found at Baun- 

 reagh. Queen's County, and were examined by the author. The larches 

 were infected by Botrytis ; the Thuja trees were about three years old, 

 and many hundreds had been killed by a fungus which on examination 

 proved to be an Ascomycete, Keithia Thujina. It was fii'st found on 

 leaves of Thuja occidental is, near Lake Superior, in Wisconsin, in 1908. 

 Hitherto it has not been reported outside America, and there seems to 

 be no satisfactory explanation as to how the fungus may have been 

 imported. -^- L. S. 



