266 TOBACCO 



ably certain that to neglect these diseases might lead to 

 far greater injury than the loss which is now known. It 

 is not impossible that the great susceptibility to these 

 diseases has some connection with the intensive cultivation 

 and with the selected and, in other respects, so valuable 

 strains. Should this be the cas<e, it may, of course, be 

 hoped that other strains may be discovered which are 

 better abk to withstand these diseases; but it should not 

 be overlooked that nothing is gained thereby if the new 

 strains should produce a tobacco inferior to the present 

 one. It is preferable to have a pure strain producing a 

 fine leaf and susceptible to disease than a strain free from 

 disease but giving a bad leaf. Provisionally, we shall have 

 to regard the susceptibility to both these diseases as a 

 necessary evil, to be fought with every means at our 

 disposal. 



On most of the estates a great deal of labour and 

 money is being devoted to this struggle, and this prin- 

 cipally against the Phytophthora, as they are really quite 

 helpless against the mosaic disease. None of the many 

 remedies sug'gested against the latter has met with any 

 success. It seems that only by the exclusive use of 

 healthy and strong seedlings, and by giving careful atten- 

 tion to the selection of seed plants to prevent any mosaic 

 diseased trees being used for this purpose, the disease 

 may be kept to some extent within bounds. Against the 

 Phytophthora very many remedies exist, but none of 

 them is efficient. Yet each of these methods has its special 

 object. By means of various chemicals (lime and 

 sulphate of ammonia, permanganate of potash, carbon 

 disulphide, paraformaldehyde) efforts are made to dis- 

 infect the ground where the diseased plants stood, <so 

 as to preserve the life of the young plants which are to 

 grow on the same spot, and to prevent traces of the 

 disease finding their way to neighbouring plants. In 

 the nurseries the disease, locally called " bibit disease," 

 can with absolute certainty be kept within limits by water- 

 ing' with bouillie bordelaise. If only certain plants in 

 the gardens are affected, the neighbouring plants may be 

 protected from infection by applying caterpillar glue to 

 the necks of the roots and by syringing with bouillie 

 bordelaise. Of great importance, finally, is the destruc- 



