130 
Journal of Agricultural Research 
Vol. XXI, No. t 
spot was found to be epidemic and serious. Not only were the leaves 
badly spotted and the plants rendered somewhat objectionable to the 
more observant consignees, but among the plantings badly stunted 
by other unfavorable growing conditions, the severe attack of this dis¬ 
ease on the foliage was particularly destructive. Later, H. D. Brown 
found bacterial spot of considerable importance in tomato plant beds at 
Campbellsburg, Ind. Definite centers of infection were noted. It is 
evident, therefore, that this disease may be classed among the major 
diseases of seedling tomatoes. Severe foliage infection causing the death 
of many leaflets was noted on southern-grown plants in a field near 
Kokomo, Ind., in the middle of July. In a warm, wet season, bacterial 
spot may therefore be destructive as a foliage disease in the field crop. 
Link and Ramsay report that bacterial spot equaled nailhead in sever¬ 
ity and prevalence on tomatoes from Dania, Fla., in 1920. 
Sherbakoff found the disease of peppers to be of considerable impor¬ 
tance as a blemish of the fruits. Observations in the Chicago market 
bear out this opinion. 
CAUSAL ORGANISM 
ISOLATION 
The first series of isolations from tomato fruit lesions were made in the 
following manner: The surface of the fruit was carefully wiped off with 
mercuric chlorid 1 to 1,000, and the epidermis over a lesion was sliced 
off with a flamed scalpel. Portions of the underlying blackened tissue 
were cut out with a flamed scalpel and planted in a poured plate of 
potato agar. Black lesions in various s'ages of development were used. 
Out of 80 tissue plantings made, only 4 developed fungi, while 73 yielded 
bacterial growth of a more or less uniform type. By plating out from 
these colonies about the tissue transfers, the organism which later proved 
pathogenic was isolated. 
When it thus became apparent that no fungus was associated with 
the black fruit lesions, isolations were made by slicing off the epidermis, 
macerating some of the underlying infected tissue in a drop of sterile 
water on a flamed slide, and plating out from this water in potato agar 
by the loop dilution method. 
Stem and petiole lesions were rinsed in mercuric chlorid 1 to 1,000, 
excised with a flamed scalpel, rinsed in sterile water, and then macer¬ 
ated in drops of sterile water on a flamed slide. A loopful from each of 
these was transferred to a second drop of sterile water, which was then 
plated out in potato agar by the loop dilution method. 
Leaf lesions were cut out with a flamed scissors, immersed in mer¬ 
curic chlorid 1 to 1,000 a few minutes, rinsed in sterile water, and mac¬ 
erated in drops of sterile water, from which plates were poured as 
described above. 
