DISEASES OF CULTIVATED PLANTS 599 



pies in the tropics, but it did not get its name from this. The odor is 

 supposed to be due to acetic ether, the same as in the pineapple. 

 However, in all the canes which I have had, the odor could be read- 

 ily told from that of pineapples. The odor is an ethereal one, some- 

 times quite strong and penetrating, and is, in fact, very pleasant 

 to the smell. 



As the fungus grows in the soil, and is more or less at home 

 there, it is a disease quite difficult to control. In tropical coun- 

 tries, where the fungus is everywhere present in the soil, the only 

 thing that can be done is to treat the seed cane with some fungicide 

 as Bordeaux Mixture, thus prohibiting the entrance of the fungus 

 into the stalk. The disease may be spread into new regions in a 

 number of ways, a few of which are as follows: 



There has been considerable exchange of cane by planters dur- 

 ing the last few years. This has especially been the case since the 

 introduction of some of the newer and better varieties as D-74. The 

 planters have been desirous of trying the new varieties and have ob- 

 tained them wherever they could. In the future, the planter should 

 be on his guard in regard to this. He should not obtain cane from 

 other regions unless he is positive that the pineapple disease is not 

 present in the region from which he is obtaining it. If he gets some 

 seed cane from some planter that has the pineapple disease, he can 

 expect nothing else than to plant the pineapple disease on his plan- 

 tation. 



The disease may be carried to the mills in the cane and obtain 

 a foothold in the region adjacent to the mills. If the owner of a mill 

 is in a region where there is no pineapple disease, it would probably 

 be better for him to refuse to take cane that comes from an infected 

 region. Cane grown in an infected region should be ground as near 

 to the place where it was grown as possible. 



Insects, doubtless, are important in spreading and increasing 

 the severity of the disease. All means possible should be taken to 

 prevent the insect work. Active measures should be taken against 

 the borers and the poo-a-pouche. Furthermore, all sugar cane ma- 

 terial in the field should be cleaned up as far as possible, thus re- 

 ducing the amount of infectious material which a large number of 

 insects might work on. The insects working on this material are 

 liable to carry the spores of the fungi to other plantations and in 

 that way spread the disease. The cleaning up of the fields has al- 

 ready been touched on in the discussion of the rind disease. 



After the soil is thoroughly infected with the disease, perhaps 

 the only thing that will insure a good stand of cane is the treatment 

 of the cane with some fungicide. Both the pineapple disease and the 

 rind disease enter the seed through wounds and the cut ends of the 

 stalks. The rind is impervious to the attack of these fungi. The 

 object desired in treating cane cuttings is to thoroughly cover thorn 

 with some compound that is poisonous to the fungi causing the dis- 

 eases. For instance, if the cut ends of the stalks are dipped in tar 

 and carbolic acid and then planted, the fungi not being able to grow 

 where these substances are present, will not be able to get to the 



