. Bacteria in relation to plant diseases. Bacteria; Plant diseases. 22; BACTERIA IN RELATION TO PLANT DISEASES. he has seen. Whether the Fusarium alone is sufficient to cause a wilt disease of tobacco remains to be determined by experiment. Delacroix has recently described a Fusarium disease of tobacco, and it is not improbable that two diseases may have been confused. With these facts in mind, the writer suggested to Dr. McKenney in the summer of 1912 that he visit the tobacco fields of North Caro- lina. This he did, but could then find only the bacterial disease. I still think, however, that
. Bacteria in relation to plant diseases. Bacteria; Plant diseases. 22; BACTERIA IN RELATION TO PLANT DISEASES. he has seen. Whether the Fusarium alone is sufficient to cause a wilt disease of tobacco remains to be determined by experiment. Delacroix has recently described a Fusarium disease of tobacco, and it is not improbable that two diseases may have been confused. With these facts in mind, the writer suggested to Dr. McKenney in the summer of 1912 that he visit the tobacco fields of North Caro- lina. This he did, but could then find only the bacterial disease. I still think, however, that a Fusarium disease of tobacco will be found, for, as I pointed out in 1899, this widely disseminated form-genus contains active parasites destruct- ive to a great variety of cultivated plants, a fact now generally recog- nized, but then unknown to science (Scientific American Supplement, No. 1246, page 19981). The preceding statements rep- resent the writer's knowledge of this subject up to the summer of 1905, if we exclude Uyeda's first paper, to be treated a little later. That sum- mer diseased tobacco plants were sent to him from Ouincy, Florida, and from Creedmoor, North Caro- lina. In both cases the cause of the disease appeared to be bacterial, and the signs of the disease corre- sponded quite closely to descriptions of the slime disease as it occurs in Sumatra, and also to the signs men- tioned by Stevens and Sackett. From the North Carolina ma- terial agar poured plates were made a number of times, and always large numbers of one organism were ob- tained from the inner tissues (pi. 37). This was a short, motile bacterium, the small roundish surface colonies being gray-white at first on agar, but afterwards brownish (pi. 23, fig. 2). Usually the plates showed no other organism present, but occa- sionally scattering colonies of other bacteria appeared. They were made, of course, from clean parts. Fig. *Fig. 116.—Cross-section of petiole of a tobacco leaf, showing
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