THE DISEASES OF THE SUGAR-CANE. 467 



1863, hy Phylloxera vastatrix,^ coccid which was known to 

 be present on the roots of American vines. In Europe, 

 however, its attacks on the roots of the vine were much 

 more virulent. It is estimated to have cost France alone 

 many times as much as the war indemnity paid to Germany. 

 In 1S77, the continued importation of American vines 

 brought over Pcronospora viticola, a parasite even more 

 deadly than the Phylloxera. In each of these cases a 

 parasite was thrust into the midst of a cultivation utterly 

 unprepared by natural selection to withstand its attacks — 

 a result which would certainly have been avoided with care- 

 ful legislation on the free distribution of cultivated vines. 



The Mallow disease, Piiccinia Malvacearuin, introduced 

 into Europe from Chili, affords another example of the 

 amazing damage which a mild parasite may cause if intro- 

 duced into a new country.^ For some years there did not 

 probably exist an exposed Malvaceous plant in Europe 

 which was not severely attacked. In certain localities, it 

 will be remembered, hollyhocks could not be grown because 

 they were destroyed by Pucchiia before reaching the flower- 

 ing stage. 



It is quite certain that many cane diseases have been 

 propagated in this way. As will be seen later, it is an 

 established custom in many parts of the world to send cane 

 plants from one district to another, since by this means a 

 better growth is obtained. Cane plants thus introduced 

 from Ceylon into Mauritius are supposed to have caused 

 the severe epidemic of borer grubs already noted. ^ These 

 facts, and others of a similar nature, have led to a carefully 

 marked out system of plant distribution in Java. It was 

 found that plants brought from the mountains and planted 

 in the plains were much less liable to sereh. It was further 

 noted that certain districts were comparatively free from 

 sereh. These parts of the island were marked off and 

 placed under strict protection. No cane plants whatsoever 

 were allowed to be introduced into the free regions, whereas 

 plants were freely supplied from them to the plains. Thus 

 we read successively of three more or less sereh-free regions, 

 1 Cooke. '■^ Bojer. 



