Pflanzenkrankheiten. 339 



the movement for international concerted action for the controi of 

 plant diseases and insect pests and the Coming Meeting in Rome 

 on Febr. 24, 1914 of the International Commission on Phytopathology. 

 The suggestions embodied in this paper are made to contribute 

 toward the establishment of those fundamental principles on which 

 succesful international action must be based. 



First the writer discusses the biological basis of disease controi, 

 giving a great many examples of parasites which have assumed a 

 more destructive röle when carried to another continent; this factor 

 should be considered in all plans for international action. Legislation 

 relating to inspection Services and Conventions between nations 

 should recognize that a given parasite does not threaten all nations 

 equally, and that each country must guard itself more carefully 

 against invaders from overseas than from those of neighbouring 

 lands. Legislation cannot safely proceed in advance of knowledge 

 except in the direction of greater precaution. Scientific investigation 

 needs far greater support than it receives at present, and is indeed 

 an mdispensable part of the international program of action. 



Secondly the study of environmental influences is of considerable 

 importance: it should be the aim of international phytopathology to 

 ascertain the factors limiting the spread of parasites with greater 

 precision than is the case at present. 



Third: there are many problems which can be carried farther 

 by international Cooperation than by a Single country. Exchange of 

 specialists between the various countries of the world is to be brought 

 about. An understanding of international ph3^topathology can be 

 attained only by travel and study in foreign countries. Through 

 this means the best methods of controi of other lands will be brought 

 to each country, more effectively than by publications. 



International phytopathology has relation to commerce especially 

 in View of the introduction of new plants, because serious pests have 

 been usually brought with small experimental importations of foreign 

 plants. This importation must be allow^ed only under certain restric- 

 tions. M. J. Sirks (Haarlem). 



Pool, V. W. and M. B. Mc Kay. Puccinia siihnitens on the 

 sugar beet. (Phytopathology. IV. p. 204—206. 1914.) 



A Short report about the ocurrence of the aecidial stage oi Pucci- 

 nia siihnitens Diet. on the sugar beet in the Arkansas Vallej", 

 thusfar not mentioned in litterature, but also observed by Arthur 

 in Colorado. The teleuto form was found to occur abundantly on 

 Salt grass, Distichiis stricta (Torr.) Rydb. The aecidial stage, also 

 occurring in masses on Choiopodiinn alhiim L., was more commonly 

 found on the cotyledons of the small beet plants; usually one or 

 two rust Spots appeared on the cot57-ledons (middle of May), but no 

 great damage seemed to result from this infection. New infections 

 appeared on the older leaves (June and July), after which the inten- 

 sity of infection quickly diminished and uredinia and telia were 

 observed on Distichiis. Artificial inoculations with the telia from 

 Distichiis upon beets resulted in the leaves of year-old beets in 

 developing aecidia. Also cotyledon-inoculations yielded success; in 

 one case the crown of the whole plant was infected, The observa- 

 tions in 1913 showed that under favorable conditions an infection 

 might occur that would greatly injure the young beet plants. Two 

 different methods were employed in the care of the road sides and 



