June. 1920] PATHOLOGY 397 



of dead tissue. These appear externally a& ' • ' pits from 0.3 to 2.5 cm. in diameter .'tn<l with 

 a lenticel or eye in the center. As they become* <li •«■• an I hard it they change from brown to 

 blackish pray. Further description is given together w ! > results indicating thai a toxic gas 

 or liquid is the cause. Donald Folsom. 



2728. Petri, L. Studi sulla malattia del castagno detta "dell'inchiostro." Morfologia e 

 biologia del micelio parassita. [Morphology and biology of the organisms causing the ink dis- 

 ease of chestnut.] Ann. R. 1st. Hup. For. Naz, Firenze 3: 151-185. 4 pi-, t6 fig. 1018. — 

 The causal organism | Blepkar08pora cambivora) is classified in the order Saprolegniae. The 

 production of spores occurs in nature only in the water moistening the humus around the 

 roots of the trees, while cultures were found to fruit in dilute solutions of nutritive mineral 

 salts. Formation of oospores has been observed only in infected tissues of germinating seed- 

 lings. The disease is carried from one tree to another in the same grove by means of rains 

 and streams washing the soil, but may be disseminated to a great distance through oospores 

 carried by the wind. Artificial inoculation clearly demonstrates the parasitic nature of the 

 disease, showing that the organism can attack the roots and the basal portion of the trunk 

 of trees in all stages of growth. The relative ease with which the mycelium of the fungus 

 attacks the living tissues of chestnut indicates that conditions predisposing the tree toward 

 infection may be regarded as negligible. Humidity and mild temperature in winter and 

 spring are the principal conditions favorable to the appearance of the disease. — E. K. Cash. 



2729. Pole Evans, I. B. [Report of the] Division of botany. Rept. Dept. Agric. Union 

 South Africa 1917-18: 61-68. 1918.— Pathological report (p. 65-68) deals with the organiza- 

 tion work for the eradication of citrus canker.— Brief statement of the problems under inves- 

 tigation by members of the staff. — D. Reddick. 



2730. Prunet, A. Le black-rot et son traitement. [Black rot of grape and its control.] 

 Prog. Agric. et Vitic. 69:533-545. 1918. 



2731. Ramirez, Roman. Enfermedad grave de la cafia. [Serious disease of sugar cane.] 

 Revista Agric. [Mexico] 4: 348-349. 2 fig. 1919.— Thielaviopsis paradoxa (black rot or pine- 

 apple disease) reported as causing loss in Yellow Caledonia cane in Mexico. — John A. 

 Stevenson. 



2732. Rands, R. D. De bruine binnenbastziekte van Hevea brasiliensis. (Voorloopige 

 mededeeling.) [The brown bast disease of Hevea brasiliensis. j Arch. Rubbercult. Ned.-Ind. 

 3: 156-159. 1919. — In this disease a brownish gum is found in the diseased tissue in the 

 intercellular spaces between the parenchyma, sieve tubes, or latex vessels of the bark. In 

 severe cases it is also found in latex vessels near the cambium. By its behavior toward oxi- 

 dizing agents and its staining reactions it is shown to be one of those gums that serve the 

 purpose of "wound stoppage." No causative organism present but experiments show that 

 the Hevea tree responds to most wounds extending to or near the cambium by the secretion 

 of the brown gum. It appears therefore that brown bast is an accentuated condition of 

 gum secretion probably resulting from the response on the part of the tree to the present 

 methods of tapping. — W. E. Cake. 



2733. Ravaz, L. Nouveau essais de traitement contre le mildiou. [Recent studies on 

 grape downy mildew control.] Prog. Agric. et Vitic. 69: 313-315, 361-363. 191S. 



2734. Ravaz, L. Ce qu'il faut connaitre du mildiou. Regies a suivre pour le combattre. 

 [Downy mildew of grapes and its control.] Prog. Agric. et Vitic. 69: 457-468. 1918. 



2735. Reddick, Donald, and Stewart, V. B. Additional varieties of beans susceptible 

 to mosaic. Phytopath. 9: 149-152. 1919. — In addition to tests mentioned in Phytopath. 

 8: 530-534, 1918 the following varieties have been tested in the field and found susceptible: 

 Phaseolus vulgaris, black-eyed wax. and 25 other varieties; Phaseolus lunatus macrocarpus, 

 long pod; Phaseolus acutifolius latifolius, Tepary; Vicia faba, horse bean, and winter horse 



