No. 2, Septembek, 1921 J PATHOLOGY 143 



age that will be done to seed wheat by copper-sulphate treatment and by saprophytic fungi 

 can be predicted by examination of the phj'sical condition of the seed for mechanical injury 

 and the locationof the injuries. Machine thrashing usually breaks seed coats of wheat directly 

 over the radicle. Turkestan barley and varieties of similar structural type are broken at 

 the hilum either in machine or hand thrashing and barley seed is more easily injured than 

 wheat seed. — Perfect wheat seed is injured by exposure to saturated copper sulphate solution 

 for G hours or more, indicating that the seed coat is not completely semipermeable. — 

 D. Reddich. 



909. KoRSTiAN, Clarence F., Carl Hartley, Lyle F. Watts, and Glenn G. Hahn. A 

 chlorosis of conifers corrected by spraying with ferrous sulphate. Jour. Agric. Res. 2P: 153- 

 171. ^ fig. 1921. — All coniferous species groAvnin a nursery in Idaho are affected with chlorosis. 

 With chlvirosis is as-^ooiatcd poor growth of roots, stems and leaves, failure to form terminal 

 buds, and susceptibility to winter injury. Excessive soil moisture does not seem to 

 be a factor in producing a chlorotic condition. The soils on which chlorosis of conifers oc- 

 curs all contain considerable amounts of carbonate and have been formed in part from lime- 

 stone. The water supply at one nursery contains much calcium bicarbonate. No correla- 

 tion could be found between occurrences of chlorosis and the amount of calcium or of carbonate 

 present. Chlorosis in western yellow pine, Pinus ponderosa, and jack pine, P. banksiana, 

 has been definitely corrected by spraying the plants at 10-day intervals with 1 per cent ferrous 

 sulphate. Douglas fir, Pseudotsuga taxifoHa, gave similar but less decisive results. Sul- 

 phate of iron of 2 per cent strength is injurious. — The literature on chlorosis is reviewed and 

 a bibliography of 24 titles appended. — D. Reddich. 



910. Lee, H. Atherton. The increase in resistance to citrus canker with the advance in 

 maturity of citrus trees. Phytopathology 11 : 70-73. 1921 . — On the evidence obtained through 

 extensive field observations, the hypothesis is advanced that as citrus trees advance in ma- 

 turity there is a gradual increase in their resistance to citrus canker. Citrus trees of the more 

 resistance species. Citrus nobilis, C. mitis, etc., often show great susceptibility to canker 

 when^oung while more mature trees are practically free from injury. This is apparently 

 true also, to a less noticeable extent, of the more susceptible species. — B. B. Higgins. 



911 . ScH affnit, E. Untersuchungen iiber die Brennfieckenkrankheit der Bohnen. [Inves- 

 tigations on anthracnose of beans.] Mitteil. Deutsch. Landw. Ges. 36: 199-201. 1921. — Bean 

 varieties resistant and susceptible to anthracnose were grown with various fertilizers, especial- 

 ly those supplying an excess of nitrogen. The plants as well as controls were inoculated with 

 the anthracnose organism, but no appreciable change in relative resistance was found as a 

 result of the fertilizer applications. Greater diastase and protease content was found in the 

 susceptible than in the resistant varieties. — Wilber Brotherton, Jr. 



THE PATHOGENE (BIOLOGY; INFECTION PHENOMENA; DISPERSAL) 



912. BuRKHOLDER, WALTER H. The bacterial blight of bean: a systemic disease. Phyto- 

 pathology 11: 61-69. 1921. — The bean blight organism {Bacterium phaseoli) may infest the 

 vascular system of the bean {Phaseohis vulgaris) plant, with or without the production of 

 surface lesions and symptoms of bean blight as generally noted. The bacteria in the cotyle- 

 dons of plants from infected seed may enter the vessels and pass down into the stem of the 

 young plants. The symptoms produced by this vascular invasion appear to depend, in some 

 way, on environmental conditions. The plants may wilt at once, lesions may appear on the 

 stems and leaves, or the plants may show incipient wilting or dwarfing without the appear- 

 ance of definite lesions. The seeds are often invaded through the vessels without the pro- 

 duction of lesions on either the seed coat or the pod. — This systemic infection does not produce 

 the greatest amount of damage, but it is of importance in seed selection. It also acts as an 

 important source of infection for the peculiar epidemics of blight which appear in late summer. 

 — B, B. Higgins. 



