Apr. 15, 1921 
Bacterial Spot of Tomato 
129 
yellow prematurely. Cotyledon lesions resulting from seed inoculation 
are larger, black or leaden gray, shiny, depressed areas, irregular in 
outline, and often cause distortion (PI. 25, 15 , C). These are likely to 
occur near the tip where the seed coat adhered and was carried up 
after germination. 
Stem, petiole, and racliis infection is of common occurrence. Such 
lesions are circular to linear, blackened, at first slightly elevated spots 
with a very irregular margin, and are 3 to 5 mm. long, often consider¬ 
ably longer (PI. 25, D). 
Petiolule and rachis lesions may cause the death of leaflets, and sec¬ 
ondary infection of seedlings is particularly destructive. Stem lesions 
are not in themselves a serious injury to the plant except near the grow¬ 
ing points. Peduncle and hypoeotyl lesions have been produced. 
Inoculation of pepper foliage has yielded circular water-soaked lesions 
similar to those described by SherbakolT. Fruit and leaf lesions of, the 
disease on peppers are well described and illustrated by SherbakolT. 
Inoculation of potato foliage has resulted in small, sunken, black 
dots on the lower surfaces of the leaves. 
ECONOMIC IMPORTANCE 
Under held conditions, as observed in 1919, bacterial spot is appar¬ 
ently a minor disease of the foliage of mature plants, but its attack 
upon the fruit is very objectionable from both the market and the can¬ 
ning standpoints. The lesions are unsightly and if numerous and of the 
larger type destroy much of the edible pericarp, thus rendering a fruit 
unsalable (Pi. 24, C, D). In addition, these lesions afford entry to rot- 
producing organisms. 
Canners object to this disease because even the rather superficial lesions 
are not removed with the skin but remain on the peeled fruit. Affected 
fruits must therefore be culled out of the first-grade canning stock and 
either discarded or used for catsup. As the result of a chance observa¬ 
tion made at the sorting aprons in a canning factory, September 25, 
while tomatoes grown near Indianapolis were passing over the belt car¬ 
rier, it was estimated that about 5 per cent of the fruits were affected 
with bacterial spot. In fact, growers and canners in general are coming 
to recognize this disease as a real source of loss. Huelsen reports that 
in 1918 a great many tomatoes were thrown out at this factory because 
of bacterial spot, and as a result of his field work in the canning crop 
during that season, he considers bacterial spot, as it occurs on the fruit, 
a serious disease. Nelson found the disease of serious importance in 
Tennessee and southern Illinois in 1917. He found it in all Illinois fields 
examined. 
In one out of eight fields examined in southern Georgia where seed¬ 
ling transplants were being raised for the use of northern growers, bacterial 
