1921.1 Protection Against Fungi from Abroad. 655 



PROTECTION AGAINST FUNGI FROM 



ABROAD. 



Mrs. N. L. Alcock, 

 Pathological Laboratory, Ministry of Agriculture. 



* .... 



The dispersal of newly-introduced fungi is a most interesting 



and still largely unexplored subject. Certain facts stand out, 

 however, as to the extent and range of dissemination of disease. 

 It is certain that in many cases extension has been checked by 

 natural barriers when human factors have not intervened. The 

 Chestnut Blight disease in New York was for ten years confined 

 on its western boundary by a rough mountainous tract some 

 thirty-five miles broad where no chestnuts grew ; and with regard 

 to White Pine Blister Bust, American pathologists are still hoping 

 that it will not cross the Bocky Mountains. 



In many cases it is possible to trace the human agency where- 

 by the disastrous disease has entered in. In the natural course 

 disease will pass, by spores borne by wind or animals or in other 

 ways, over a distance of some ten miles. Very occasionally a jump 

 is made, and an unexplained arrival appears a hundred miles 

 from the nearest known source of infection — over continuous 

 land ; but crossing a vast expanse of sea or leaping over hundreds 

 of miles unassisted by human transport in boat, train or wagon, 

 apparently only occurs in the imaginations of early writers. 



These facts lie at the root of the attempts now being made 

 almost throughout the world to prevent the entrance of dangerous 

 new parasites into clean areas. In England we have been ex- 

 ceedingly deliberate and have given much consideration to. the 

 matter, but the time has now certainly come to try to prevent 

 further pests from entering the country. The new Destructive 

 Insects and Pests Order of 1921 gives effect to the general 

 opinion of experts and growers calling for legislative action. 



As far as new fungi are concerned, England has little to 

 fear from Europe, free intercommunication having introduced 

 most species which will thrive in the country. The greatest 

 danger is to be feared from new importations from the east or 

 from America. Japan has now a Phytopathological Service and 

 the enormous attention that the United States of America pays 

 to the science of plant pathology and to the whole subject of 

 the control of plant diseases is well known. 



A sign of the times is the co-operation w^hich is rapidly 

 strengthening between plant pathologists in all parts of the 



