394 PATHOLOGY [Bot. Absts. 



2706. Ministere de l'Agriculture. Rapports sommaires sur les travaux accomplis 

 dans les laboratoires et comptes rendus des missions d'etudes. [Summaries of the entomo- 

 logical and pathological work accomplished and a list of projects.] — -Ann. Serv. Epiph. 5: 253- 

 272. 1918.— Pathological reports by Arnaud (Paris) and Capus (Cadillac). The latter 

 contains notes on downy mildew and black rot of grapes, experiments with lime-sulfur solu- 

 tion for the control of powdery mildew (Oidium) of grapes, and notes on a disease of walnut 

 caused by Armillaria mellea. — D. Reddick. 



2707. Molz, E. IJber die Ziichtung widerstandsfahiger Rebsorten. [Breeding disease 

 resistant grapes.] Jahrb. Deut. Landw.-Ges. 33: 166-199. 1918. 



2708. Munn, M. T. Seed-borne plant diseases. Seed World, 5 10 : 20-21. 1919— An 

 outline is given of the methods pursued in studying the fungous infection of seeds. The bi- 

 nocular microscope and the centrifuge were utilized, also, the centrifuge washing water and 

 sediment were examined under the compound microscope for the spores or remains of fungi. 

 Observations and tests which are cited demonstrate that many points concerning the health 

 of the seeds can be determined in the seed laboratory. While it is not an easy matter to 

 determine whether or not a lot of seed is free from fungous infection, the methods described 

 were of considerable value in making the determinations. — M. T . Mann. 



2709. Murrill, W. A. Collecting fungi in Virginia. Mycologia 11: 277-279. 1919. 



2710. MtlLLER, H. C, and E. Molz. Versuche mit Saatschutzmitteln. [Investigations 

 with seed protectives.] Landw. Jahrb. 52:67-130. 1918.— Investigations, covering 5 years, 

 of the protective value of various materials for seed treatment against rodents and other 

 animals and against smut of wheat and leaf stripe of barley and of the effect of the treat- 

 ments on vitality of the seed. A large number of standard and proprietary materials were 

 tested. — D. Reddick. 



2711. Nash, G. V. Injury to evergreens. Jour. New York Bot. Gard. 19: 48-50; 159-164. 

 1918. — Winter injur}'. 



2712. Neger, F. W. Die Blattrollkrankheit der Kartoffel. [The leafroll disease of the 

 potato.] Zeitschr. Pflanzenkrankh. 29:27-48. 7 fig. 1919. — Contribution to the etiology 

 of the disease and to the physiology of the potato plant in general, following a preliminary 

 note in Deutsche Landw. Presse No. 76: 1918. Author discusses the translocation of starch 

 in sound and leafroll diseased potatoes, and is of opinion that the starch accumulation in 

 leafroll diseased leaves stands in closest relation to the degree of leafrolling. There cannot 

 exist any doubt that starch accumulations and rolling of leaves are coincident, yet this does 

 not prove these phenomena to be causally related; both indeed may constitute symptoms 

 caused by a third factor, as yet unknown. Nevertheless, excess of starch may be the pri- 

 mary, and the rolling of the leaf the secondary factor, yet it is not clear how the former would 

 cause the leaf to curl. The investigations continue with an inquiry into the causes of starch 

 accumulations. It is suggested that, coincident with the excess of starch in diseased leaves, 

 there occurs an accumulation of diastase; both factors would indicate the serious disturbance 

 of the enzymatic processes within the plant, but as to cause and origin of which no clear 

 vision has yet been reached. The investigations are summarized as follows: As a ride trans- 

 location of starch does nor occur readily in leafroll diseased leaves, only under optimum 

 growth conditions a translocation occurs of the excess of starch, provided, however, that the 

 discoloration present in the unsound leaves has not progressed too far. The ability to dis- 

 charge the normal starch contents (Bildungsstarke) at comparatively low temperature (10° C.) 

 differs in varieties, indeed often in individuals. Generally speaking, even the sound leaves 

 of leafroll susceptible varieties discharge sluggishly these starch accumulations at a tem- 

 perature of 10° C. (Important in relation to seed approval.) Translocation occurs the more 

 readily the more vigorously the leaf is aerated. Leafroll diseased leaves contain much more 

 diastase than sound leaves. That starch is not dissolved is apparently due to the accumu- 



