No. 1, July, 1920] pathology 199 



1312. LflAGH, JULIAN <',. The parasitism of Puccinia gramlnis tritici Ericks. and Henn. 

 and Puccinia graminis tritici-compacti Stak. and Piem. Phytopatfa 9'. 58 38. PI. 

 1919. — Extensive experiments with these strain on eventy-two hosts indicate a oarrowei 

 host range for tritici-compacti. The explanation leemt to be thai bard spring wheati are gen- 

 ally resistant while soft winter wheats are quite susceptible Sard winter wheal . a 

 varying resistance to tritici-compacti] bu1 aone of these wheats is r< a 

 number of wheats arc listed w hieii show a dist met difference ni behavior i'» the two rusts and 

 may be classed as differential hosts. The experiment lm« tritici-compacti to tx 

 distinct and constani biologic form not changed by the use of bridging hosts, and tfa ' 

 biologic forms have specific food requirements, conforming to the molecular configuration 

 of the protoplasm ; and resistance can be explained on this basis. m E. If. Gilbert. 



1313. LeheNBAUBB, 1'. A. The control of carnation stem rot. Florists' Exchange 49: 2 

 31t>, 3is. 1920. — In the greenhouses of Illinois, the stem rot produces an average annual i 

 of 2.3 per cent of the carnation (Dianthua coryopkylliu) crop. In the field the di • 



still more destructive. The causal organism (Rhizoctonia) is widely disseminated as a soil 

 fungus. Under field conditions no control is known. Treatment of greenhouse soils with 

 sulphuric acid, lime, Bordeaux mixture, copper sulphate, and formalin has been ineffective. 

 Soil sterilization has not produced satisfactory control due to the frequency <>f introduction 

 of the fungus from outside sources, particularly in the soil carried on the roots of plants. 

 Since a relatively high temperature is necessary for infection, and since wet soil seems to favor 

 the disease, it is believed that the lowering of the temperature of the greenhouse and the 

 limiting of the water supply will prove to be the most effective control measures. — C. W. 

 Bennett. 



1314. Leone, G. Ancora del marciume radicale degli agrumi in Tripolitania. [Further 

 remarks on the root rot of orange in Tripoli.] Agrie. Colon. Firenzc 13:354-355. 1919. — An 

 unidentified nematode resembling Tylenchus semipenetraris has been found in roots of orange 

 t rees suffering from root rot. The presence of the disease in a young orchard planted on loose, 

 deep soil and receiving only a small water supply tends to invalidate the author's previous 

 theory that the disease is caused by excessive irrigation. — E. K. Cash. 



1315. Levine, Michael. Studies on plant cancer. — I. The mechanism of the formation 

 of the leafy crown gall. Bull. Torrey Bot. Club 46: 447-452. * pi. 1919.— Testing the hy- 

 pothesis of E. F. Smith that inoculation of Bacterium tumefaciens into regions of totipotent 

 cells gives rise to leaf} - shoots which were comparable to a typical teratoid embryomata, the 

 author inoculated Bryophyllum calycinum with B. tumefaciens, (1) into the leaf notches which 

 normally produce leafy shoots readily, (2) into the leaf near the notches, (3) into the mid- 

 ribs of the leaf, (4) into the growing regions of the stems of young plants. — In all cases it 

 was found that B. tumefaciens does not cause the formation of leafy shoots but rather inhibits 

 and retards their normal development and that the pathological condition which does develop 

 is the ordinary crown gall. — G. H. Coons. 



1316. Mackik, W. W. Seed treatment for the prevention of cereal smuts. California 

 Agric. Exp. Sta. Circ. 214. 8 p. 1919. The details of the methods of seed treatment with 

 copper sulphate and with formaldehyde solutions are given, with a brief discussion of their 

 relative merits under different conditions. — //. S. Fawcett. 



1317. Marshall, Roy E., and F. D. Fromme. Red cedar trees and cedar rust: a report 

 of a cedar rust survey of Augusta county, Virginia. Virginia Polytechnic Inst. Ext. Bull. 39. 

 8 p. 1 text fig. 1920. — The report contains details of a survey of apple orchards planned 

 to determine the relation between severity of cedar rust infection and relative numbers of 

 red cedars within a mile radius, all data on infection being based on the York Imperial va- 

 riety. Field data are drawn from 113 orchards and harvest records from 44 orchards. The 

 severity of infection was found to be proportional to the numbers of cedars. Forpurposes of 

 comparison the orchards are grouped in four classes very few cedars, few cedars, many 



