DISEASES OF PLANTS. 47 



sidered probable that nematodes are responsible for the Injury, but the investi- 

 gations are still in progress. 



Contributions on the biology of the Fusaria of cereals, B. Schaffnit 

 (Jahresber. Ver. Angew. Bot., 9 {1911), pp. 39-51).— This is a study of snow 

 mold wintering over in cereals, attributed by Sorauer (E. S. R., 14, p. 263) 

 to Fusarium nivale, which is claimed by Ihssen (E. S. R., 23, p. 545) to be 

 identical with Nectria graminicola. The author considers F. nivale to be only 

 one of several fungi comprehended under the term snow mold. Detailed com- 

 parisons with closely related species of Fusarium are given. 



Apparatus for control of smut, E. Riehm {De-ut. Landw. Preftse, 40 {191S), 

 No. 10. pp. 107, 108, figs. 3). — The author gives brief discussions of several 

 forms of apparatus for the employment of heat in combating grain smuts. 

 See also a previous note (E. S. R.. 26, p. 546). 



Leaf cut, or tomosis, a disorder of cotton seedling-s, O. F. Cook (U. S. Dept. 

 Agr., Bur. Plant Indus. Girc. 120, pp. 29-31,, fig. i).— Leaf cut is a name sug- 

 gested for a disease of the leaves of cotton to distinguish it from leaf curl, 

 which is induced by plant. lice. Leaf cut is said to be widely distributed and 

 familiar to planters, although generally confused with leaf curl. It is in the 

 nature of an environmental injury and is not due to parasitic organisms or to 

 constitutional weakness, but is sometimes connected with exposure to heat and 

 dryness. All varieties of cotton seem to be susceptible to this trouble during 

 the early stages of growth. 



Though leaf cut is not fatal, it is believed to be responsible for much damage 

 by retarding the growth of the young plants. Often the terminal buds are 

 destroyed, and this interferes with the normal branching and the plants are 

 permanently deformed. Damage from this cause can be avoided or reduced by 

 improved cultural methods, and the deformed plants may be removed in late 

 thinning. 



A dry rot of the Irish potato tuber, E. M. Wilcox {Ahs. in Science, n. ser., 

 37 {1913), No. 949, p. 386). — The author gives a preliminary report on a 

 disease of potatoes observed in 1908 in western Nebraska which has been in- 

 vestigated and determined as due to Fusarium tuberivorum. For a further 

 account of this disease see below. 



A dry rot of the Irish potato tuber, E. M. Wilcox, G. K. K. Link, and 

 Venus W. Pool {Nebraska 8ta. Research Bui. 1, pp. 88, pis. 28, figs. 23). — The 

 authors give a detailed report of investigations of a di^y rot of the Irish potato 

 tuber which appears to affect the mature tubers only. The rotting is rather 

 slow, but within 4 to 6 weeks from one-third to three-fourths of the tuber is 

 destroyed. The disease may make its appearance at any point on the surface 

 of the tuber, though most commonly it appears at the bud end. There is no 

 watei*y degeneration of the tuber unless other organisms gain entrance, so 

 that it is a true dry rot. 



The trouble is caused by the attack of a species of Fusarium, to which the 

 authors give the name Fusarium tuherivorum n. sp. The morphology of the 

 causal organism and the etiology of the disease are described at considerable 

 length. 



Marked differences in susceptibility were noted for different varieties of 

 potatoes. Inoculation experiments failed where the epidermis was uninjured. 



In experiments for the control of the disease, tubers were treated with 

 different fungicides prior to storage, lime sulphur, formalin solution, and 

 formalin vapor giving the best results. 



Summarizing their report, the authors state that the dry rot of the Irish 

 potato tuber is primarily confined to the mature tubers, and that the disease Is 

 of great economic importance through the serious destruction of the tubers 



