10 DISSEMINATION OF PARASITIC FUNGI 



in the post or on living plants but can scarcely have travelled 

 through the air, otherwise Cachar, with its similar climate to 

 Upper Assam, would certainly have become infected. Outside 

 the two areas mentioned, it is still unknown, if we except a 

 recent report from Formosa. ^ 



I'he Godavari palm disease {Pythium palmivorum) probably first 

 appeared about 1890. Where it came from is not known, 

 possibly from some of tha islands in the Indian Ocean, possibly 

 from Malabar where it occurs sporadically and sometimes causes 

 minor epidemics in the coconut forests. In Godavari it spread 

 with great intensity amongst the palmyra palms, killing from 

 50 to 75 per cent, in many parts. Extension was continuous, 

 the rate being about 1 to 3 miles per annum, and was 

 roughly centrifugal from a point on the Godavari river. 

 Over 1,000 square miles were affected in 1905. But no cases 

 have been found that could have been due to air-borne infection 

 for a distance exceeding a few miles and the immense palm 

 areas to the noith and south of Godavari have remained free, 

 except where the continuous gradual extension from palm to 

 palm was goins on. The spoies are sometimes formed in situ- 

 ations freely exposed to the air and fall ofE when ripe, but they 

 have evidently not been carried through the air for even a 

 24 hours' journey. 



The downy mildew of the vine is probably indigenous in the United 

 States, where it is common on wild native species and has 

 probably existed for a very long time. It did not reach Europe 

 until 1877, by which time American vine stocks were being 

 imported in considerable quantity to replace the vines 

 destroyed by Phylloxera. It was in France by 1878, and in 

 the next year was found in the Rhone valley, in Savoy 

 and had reached Lombarrdy. In 1880, it was found in Algeria 

 and the Tirol, and in 1881, in Greece. It subsequently spread 

 over all the rest of southern and central Europe, to north 

 Africa and parts of Asia ; it was recorded in Australia in 

 1866-67, but did not extend to Cape Colony until 1907 or 

 shortly before. It is believed to have got to Java, where it 

 was collected in 1905, on fresh grapes brought in by the mail 



1 Sawada, Lot. Mag., Tokyo, 1914. 



