1048 EXPERIMENT STATION RECORD. 



Utlo, a salad plant introduced by this Department, was badly blighted both 

 during the year covered by the report and the previous season. No spraying 

 experiments M^ere conducted with this plant. The authors note the occurrence 

 of the late blight (Phytophthora infcfitans) on Solanum commersonii, although 

 varieties of the common potato growing at a short distance showed no trace of 

 the disease. Brief notes are given on the asparagus rust, which seems to be less 

 prevalent than formerly, due in part at least to the introduction of resistant 

 varieties, the leaf blight {Glacosporiiim nervisequmn) of sycamore, and the stem 

 blight of chestnut, due to Diaporific parasitica, and general notes on other 

 diseases. 



Report of the station for plant pathology, <}. Lustner (Ber. K. LrJiranst. 

 Weill, Ohst u. Gartenhau Geisenheim, 1906, pp. 118-181, pis. 2, figs. Jf, dgms. 

 Ji). — Among the scientific investigations carried on at the station reports are 

 given on a study of an epidemic of downy mildew of grapes, host plants of 

 species of Peronosporiacetie, influence of weather conditions on the occurx-ence 

 of Peronospora riticola, means for the control of the downy mildew, effect of 

 carbolineum on trees, a Fusarium disease of young apple trees, grape chlorosis, 

 potato rots, etc. 



The relationships of the secidium-cup type of rust, E. W. Olive {Alts, in 

 Science, n. scr., 21 (1908), No: 68^, pp. 214, 215).— The author states that recent 

 investigations have to a great extent solved the problem concerning the origin 

 of the Cseoma type of rust, but the more complicated cup fructification needs 

 further explanation. 



According to the author's investigations, the a^cidium-cup type of rust is de- 

 rived from a deep-seated, more or less limited, mass of cells, the peridium aris- 

 ing as an inclosing layer, apparently in consequence of the deep-seated character 

 of the fructification as well as from its more or less centrifugal growth. The 

 Cteoma type, on the other hand, is more or less superficially placed and no 

 peridium is formed. The author calls attention to a number of differences in 

 the development and fructification of these two stages in the life history of some 

 rusts. 



The resistance of some plants to disease, G. Kock (Ztsclir. Landw. Ver- 

 snclisip. Ostcrr., 10 {1907), No. 10, pp. 7.7.9-76'/). — The autlior reports investiga- 

 tions on the resistance of certain varieties of pears to the leaf fungus (Stig- 

 matea mcspili), listing a number of si)ecies according to their iuununity or 

 susceptibility tb the fungus. 



A similar account is given of investigations on varieties of tomatoes resistant 

 to Septoria lycopersici. Among the varieties of tomatoes which were most 

 resistant, some of them appearing to be almost immune, were Wonder of the 

 Marltet, Up to Date, Mikado, and King Humbert ; those less resistant were 

 Magnum Bonum, Prelude, Ponderosa, President (iarfield, and Alice Roosevelt; 

 while Trophy and Ficarazzi were especially subject to attacks of the fungus. 



Dry rot of corn and its causes, J. T. Barrett (Abs. in Science, n. ser., 27 

 (1908), No. 68'/, pp. 212, 213). — The disease of ear corn which has been called 

 dry rot has been found, on investigation, to be caused by several species of 

 fungi. One of the most destructive is a species of Diplodia, probably D. maydis, 

 and to this species is attributed 85 to 90 per cent of the dry rot observed during 

 the past 2 seasons in Illinois. 



When an early infection takes place this fungus causes a premature ripening 

 and shriveling of the ear, which usually remains in an upright position with 

 tightly clinging and dark-colored husks. Later infections produce various de- 

 grees of rot, in many cases the disease not being detected until the husk has 

 been removed. The seasonal infections appear to be started by conidia blown 

 from the old rotten ears and the old stalks left standing in the field. 



