542 EXPERIMENT STATION EECOED 



Comparative studies of certain disease producing species of Fusarium, 

 C. E. Lewis (Maine Sta. Bui. 219 (1913), pp. 203-258, pis. 15).— In a study of 

 apple decays the author found in 1908 two species of Fusarium in decaying 

 fruits. Since that time a considerable number of apples have been found in 

 which a Fusarium was causing decay. This led to a study of various species 

 of Fusarium, forms from 24 sources being investigated at considerable length, 

 and an equal number of additional forms being studied but not reported upon 

 in detail. The growth and cultural characters of the organisms are described 

 and accounts given of the results of inoculation experiments to test the patho- 

 genicity of the various strains on different host plants. 



The two species mentioned above as occurring on the apple were found ca- 

 pable of causing the decay. One is considered very similar to, if not identical 

 with, F. putrefaciens, a cause of apple decay in Europe. The other species is 

 said to resemble vei*y closely the fungus which causes a rot of carnations, de- 

 scribed by Stewart as Sporotrichiim pow (E. S. R., 20, p. 647), differing, how- 

 ever, from that species by having a larger proportion of septate spores in the 

 apple fungus. 



In an appendix to the bulletin, W. J. Morse gives a list of species studied 

 as determined by Wollenweber, and also a host index that shows a wide range 

 of hosts for the different species. With the possible exception of F. conglu- 

 tinans, all of the strains produced some decay on some varieties of apples. 



Is apple scab on young shoots a source of spring infection? W. J. Morse 

 and W. H. Darrow (Phytopathologij, S (1913), No. 5, pp. 265-269) .—There is 

 said to be little unanimity of opinion among investigators as to the part played 

 by young branches and water shoots in the spring occurrence of apple scab. 

 The authors have made a study of this matter, examining a large number of 

 trees, and while they do not wish to be understood as denying that the asco- 

 spores formed on the leaves of the previous year are the source of a great pro- 

 portion of the spring infection of apple scab, it is thought that under certain 

 conditions and with certain varieties of apple trees, diseased twigs and water 

 sprouts are an important factor in the propagation and spread of the disease 

 at the beginning of the following year. Attention is called to the fact that the 

 application of some strong fungicide before the opening of the leaf buds would 

 doubtless greatly reduce infection from this source. 



Apple rust found on fruit, A. de Jaczewski (Bui. Trimest. Soc. Mn/col. 

 France, 29 (1913), No. 1, pp. 165-169, fig. 1; ahs, in Bot. CentU., 123 (1913), 

 No. 5, p. 115). — The author reports finding in September, 1912, on the surface 

 of diseased apples, secidia characteristic of Roestelia, heretofore supposed to 

 be confined to leaves and branches. 



Biologic forms of black knot, E. M. Gilbert (Phytopathology, 3 (1913), 

 No. J^, pp. 246, 24^)' — The author notes the common occurrence of black knot 

 (Plowrightia morhosa) on some species of Prunus, while it is almost entirely 

 absent from others. 



Inoculation experiments with black knots from cultivated varieties of plums 

 were made, using w^ild plum, choke cherry, and pin cherry. The results of the 

 experiments show that in no instance was there the formation of any structure 

 that could be compared to the typical black knot. It would appear that the 

 black knot of the wild plum and the choke cherry are biological forms and 

 that this may also be true of the form found upon cultivated varieties. 



Vine chlorosis and its treatment, L. Ravaz (Prog. Agr. et Vit. (Ed. VEst- 

 Centre), 34 (1913), No. 47, pp. 641-652). — Discussing the results of experi- 

 ments by Maz§ with maize (E. S. R., 28, p. 429), and those of the same author 

 in connection with Ruot and Lemoigne (E. S. R., 29, p. 826) on legumes, in 

 which the chlorosis following use of calcium carbonate was relieved on addi- 



