WILT-DISEASES OF TOBACCO. 235 



August 2Q. Yesterday I saw slight wilt on another Datura stramonium standing in the bed 

 where the North Carolina tobacco was buried. It is a large plant and has been healthy hitherto. 

 This morning I brought it in and had a photograph made (pi. 43). It is badly wilted. Stem sound 

 externally; vessels filled with Bacterium solanacearum. Fusarium not present. Infections took 

 place through broken roots. The bacteria are most abundant in the lower part of the stem and 

 ooze out copiously on cross-section (fig. 125). 



August 31. To-day, removed an additional wilted tomato plant from bed in the old rose house. 

 The surface is sound except some small roots. The vessels in the lower half of the plant are filled with 

 gray slime which under the microscope has the characteristic morphology of Bacterium solanacearum. 

 Short rods ; many in pairs (dividing) . The plant is 3 feet long. The vessels are browned only in the 

 lower part. Not many bacteria present in the upper part and no stain there. As one goes toward 

 the root-system bacterial occupation increases. Infection took place unquestionably through the 

 root system. This is the twentieth tomato plant to wilt. 



October 28. Old rose house. Removed the remainder of the Daturas this morning. Some were 

 in fruit. They have lost many of their leaves and others are brown spotted, but the cause of the dis- 

 ease is uncertain. None of them except the 4 already mentioned appear to be attacked by the tobacco 

 disease. Also pulled out the remainder of the tomatoes, none of which were wilted. Out of this bed 

 I have removed 21 wilted tomato plants attacked by Bacterium solanacearum, and now these 9 which 

 are not wilted. These 9 plants have sprawled over the ground, covering it with foliage, and have 

 made a growth of 8 or 10 feet altogether, but have borne very little fruit. Only one or two green 

 tomatoes were present, and the gardener says he has not seen fruit on them. It is not certain from 

 this that the plants are resistant to the disease. It may be that they got such a good root start that 

 the disease could not attack them successfully, or it may be they are resistant individuals. With a 

 view of testing this I made cuttings from soft wood at the tops of 8 of these plants and removed all 

 the leaves. I then planted them in the same bed after spading it up. There are 27 of these cuttings. 

 If the plants are not resistant some of the cuttings ought to contract the disease, provided the organ- 

 ism is still living in the soil. I also pulled out all the remaining Daturas and set in place egg-plants, 

 two varieties of peppers, and some Connecticut tobacco. There are three rows of the egg-plants, 

 1 2 plants, var. Black Beauty. They were growing vigorously with leaves as large as my hand or 

 larger, and perhaps a dozen such leaves. I pulled off all the leaves and root-pruned each one severely 

 before setting it out. The peppers are Cayenne and Ruby King, 1 2 plants of each sort. Six of each 

 sort were set out very carefully without disturbing the roots in the least, and 6 of each sort were 

 thoroughly root-pruned and had all the leaves pulled off. Of the tobaccos, I set 6 in one part of 

 the bed and 6 in another part of the bed. Three of each lot were transplanted without injury to 

 the roots; the other 3 had all the leaves pulled off and most of the roots. In addition, I made 3 

 cuttings from a vigorous growing Datura, and set these out in the bed. 



Some tomatoes which were set out in a portion of this soil by Mr. Bisset, the gardener, about 2 

 months ago have made a very uneven growth. As a control I had a similar bed on the other side 

 of the partition planted at the same time with a number of tomato plants, but in soil which had not 

 received the diseased tobacco. These check-plants are very leafy, 3 feet or more in height and 

 healthy-looking. Of the 24 in the diseased soil only 10 plants are good-looking ones; the others are 

 dwarfed and have the terminal leaflets dead or dying. Nine of the 1 4 dwarfed ones are very badly 

 dwarfed. These are only about a foot high, and have only about one-fourth as much foliage as the 

 check-plants. I have seen no wilt on them, and I am not yet certain as to the cause of the dying of the 

 terminal leaves and general dwarfing of the plants. 



November 16. The rooted tomatoes, now about 3 months old,showno distinct indications of wilt, 

 but they are dwarfed and sickly. They have made not nearly so good a growth as the check plants 

 in similar soil but which had not received diseased tobacco. I am at aloss to know whether this disease 

 is due to the slow action of the tobacco organism on the roots of the tomato or whether it is a distinct 

 disease. The checks are free, although the two beds are separated only by a glass partition and 16 

 inches of space. The three cuttings from young Datura stramonium, have died, i. e., they did not root. 

 The 12 transplanted tobacco plants show no indications of disease. The 12 pepper plants with un- 

 pruned roots are continuing to grow normally. Of those with heavily pruned tops and roots, 10 appear 

 to be recovering, one is dead, and another is dying. I have just pulled up the latter and find the base 

 of the stem rotten. These plants are not recovering easily from the heavy top and root pruning. The 

 1 2 egg-plants, which were transplanted after being very heavily root and top pruned, are beginning to 

 recover and are making a little growth. Of the 29 tomato shoots which we attempted to root in this 

 bed, only 5 appear to be living ; the others have gradually rotted away. More mature cuttings should 

 have been used. The stems hitherto examined have not shown any definite indications of bacterial 

 infection in the vascular bundles. 



