154 EXPERIMENT STATION RECORD. 



the aggregate are very large. The most common form of dry rot disease is 

 that caused by the fungus Diplodia may (lis. 



Ears infected with this fungus shrivel, darken in color, and become light in 

 weight. The kernels are also shriveled, very brittle, and loosely attached to 

 the cob. The fungus penetrates all portions of the ear, producing many dark 

 brown spores, which servo to propagate it. 



There are several other forms of dry rot which are more or less important, 

 some of which at least are due to species of Fusarium. 



In the case of the Diplodia disease, and probably the others, the fungus per- 

 petuates itself over winter on old diseased ears and old stalks. It is recom- 

 mended that all diseased ears be collected and burned, and that where fields 

 are infected to any considerable extent the stalks be deeply plowed under or 

 burned. If tlie first suggestion is adopted and the second followed wherever 

 necessity demands it, according to the authors, serious losses will ))e practically 

 prevented. 



Diseases of the peach, E. Foex {Prog. Agr. et Vit. (Ed. VEst-Centre), 20 

 {1008), Nos. 5, pp. IS.ff-l.'tl, pi. 1; 0, pp. 167-170). — Descriptions are given of 

 some of the diseases to which the peach and allied plants are subject, with sug- 

 gestions for their control. Among those described are gummosis, peach leaf 

 curl, a disease caused by Asterula beyerinclcii, peach powdery mildew, and 

 peach rust. 



A spot disease of potatoes, N. H. Swellengkebel (Arch. N^erland. Sci. Exact, 

 vt Xdt., 2. scr., 13 (1008), No. 1-2, pp. 151-108, pis. 8).— A disease of potatoes 

 is described in which the tubers when cut exhibit brownish spots arranged in 

 a circle, corresponding to the distribution of the fibrovascular bundles. About 

 the discolored areas a layer of cork cells is formed. Later the tissues break 

 down, and often cavities are formed within the tubers. When the tubers are 

 fully developed there is no further spread of the cork areas if the potatoes are 

 kept in dry, well-aired places. 



No fungi were found associated with the diseased spots when subjected to 

 microscopical examination, but on cultures 3 bacteria were obtained from the 

 diseased tissues: BueUJiis incgathci'mm. B. vulgatns, and B. mescntericus. In 

 addition Bacterium pwitctatum was isolated from the cavities. These bacteria 

 are common soil organisms that appear under certain conditions to be able to 

 attack the tissues of the potato. Inoculations with them produced pronounced 

 cork formations, and in some instances there developed a dry form of rot, in 

 others a wet rot. 



The different manifestations exhibited by this disease have led to its being 

 confused with other diseases, and the author claims that this accounts for its 

 infrequent mention. lie states that the cavities in the tubers are caused either 

 by Acrostalagiiiiis cinnaharinus or Bacterium pmictatum. In the latter case it 

 often results in a wet rot of the tubers. 



As precautionary measures for preventing this disease it is recommended 

 that the soil should be well limed, that planting should not be done on infested 

 soils, and that the tubers should not be cut before planting. In order to pre- 

 vent the destruction of the tubers in the storehouse, they should be kept in cool, 

 dry places and not in pits. 



A Fusarium disease of potatoes, O. Appel {K. Biol. Anst. Land. u. Forstw. 

 Flughl. 42, pp. 4> Mill. Bl. K. Prenss. Verwalt. Landw. Domdnen u. Forsten, Jf 

 (1908), No. 2, pp. 51-55, figs. 2). — A description is given of a Fusarium disease 

 of potatoes, the most striking characteristic of which is the rolling of the leaf- 

 lets. These roll in toward their midribs and assume a yellowish color. When 

 the attack is late in the season or not very severe but little loss in the crop 

 will be found, but at other times the tubers are so reduced in size that the 



