206 BACTERIA IN RELATION TO PLANT DISEASES. 



from this disease varies from a few plants to at times every plant in small areas ofttimes amounting 

 to as much as 80 per cent to 90 per cent of the whole field. There seems to be no special preference 

 for either high or low land. 



The same year, in Proceedings Florida Horticultural Society, Rolfs made some observa- 

 tions on the distribution of the disease in Florida and again reported successful inoculations. 



Last summer at the Experiment Station [Lake City] several plots were set aside for studying the 

 effects of this disease. A plot of egg-plants, another plot of tomatoes and a plot of peppers, each one- 

 hundredth of an acre, were planted contiguously and the disease [was] started in the corner of the egg- 

 plant field, this corner being the most remote from the tomatoes and the peppers. The disease mani- 

 ested itself in less than a week on the plants inoculated. For a time it was confined to this corner but 

 before long sporadic cases occurred throughout the plots of egg-plants and tomatoes, until within the 

 course of about three weeks the entire plots of egg-plants and tomatoes were destroyed. In no case 

 was a pepper plant hurt. * * * Soon after the egg-plants and tomatoes had all been destroyed 

 the field was cleared of all these plants and of all the debris left from the plots. The plots were then 

 kept free from vegetation for two weeks, when they were again planted to egg-plants and tomatoes 

 just as before. The disease now appeared in various spots over the entire field. We then took out 

 the plants as soon as they showed signs of the blight and the place occupied by the plant was filled by 

 another one, so that it gave us a full field, all of it being in plants that showed no blight, but neverthe- 

 less the blight continued to appear until cold weather cut short the growth of both egg-plants and 

 tomatoes. * * * 



During last winter these plots were planted first to radishes, and next to lettuce. None of these 

 plants showed any indications of the disease. As soon as the weather permitted, egg-plants and 

 tomatoes were planted in the same plots as last year. These have now begun to show signs of blight- 

 ing which makes it seem quite probable that the disease can remain over winter in the field. 



In 1900, F. S. Earle, then of the Experiment Station at Auburn, Alabama, also wrote 

 upon the disease as follows: 



This serious disease of the tomato has so far only been observed in the southern part of the State. 

 It is very destructive in Mobile and Washington counties. * * * Each succeeding crop suffers 

 worse than the last. * * * As the result of rather wide experience with it in Mississippi I am of 

 the opinion that direct underground infections do take place as suggested by Dr. Smith. * * * 



Contagion carried by winged insects may well be the means by which the disease first becomes 

 introduced to new fields, but this method of infection can hardly account for the spread of the disease 

 from year to year in somewhat regular concentric circles from such new centers, especially as it usually 

 takes almost every plant in its path. Insect infection would not either account for the facts reported 

 by me in the 6th Annual Report of the Mississippi Station, pp. 53-61, where, in a large tomato field 

 that was under observation, the disease was very largely confined to a narrow strip of wet, seepy land, 

 running diagonally through it, while the drier land on either side was nearly exempt. 



As the disease is thus so markedly a soil disease, the possibility of soil treatment as a remedy at 

 once suggests itself. Very few experiments are recorded in this direction. In the Mississippi experi- 

 ments mentioned above in one case heavy applications of kainit seemed beneficial and in another case 

 there was apparent benefit from the use of lime. Marked benefit also seemed to follow the use of 

 lime in an experiment at Deer Park, Ala. (see Ala. Bull., 92 : 109). These experiments, however, 

 need confirmation. Sulphuring the soil does not seem to have been tried. Spraying the plants and 

 the surface of the ground with Bordeaux mixture gives no result. 



In his report for 1907-8 Stevens, of the North Carolina Experiment Station, stated that 

 the wilt disease of tomatoes due to Bad. solanacearum was widely prevalent in North Caro- 

 lina and constantly spreading into new territory. 



The newer Dutch East Indian studies are reported under Wilt-Diseases of Tobacco 

 (pp. 224, 244). 



