Dec. 13, 1915 
Angular Leaf-Spot of Cucumbers 
467 
Table I. —Differences between Bacterium lachrymans and Burger’s cucumber organism 
Bacterium lachrymans. 
Burger’s organism. 
1. Polar flagellate. 
2. Liquefies gelatin. 
3. Clears milk without coagulation. 
4. Strict aerobe (does not grow in closed 
end of fermentation tubes). 
5. Forms acid from saccharose in fer¬ 
mentation tubes. 
6. Forms acid from dextrose in fermen¬ 
tation tubes. 
7. Not villous along line of stab in either 
agar or gelatin. 
8. Does not become yellow with age on 
sugar agars. 
9. Moderate indol formation. 
10. Agar-plate surface colonies show 
many fine radiating lines. 
11. Does not cause soft-rot of cucumber 
fruits. 
12. Surface colonies on agar plates are 
always round. 
Peritrichiate flagellate. 
Does not liquefy gelatin. 
Coagulates milk. 
facultative anaerobe (grows in closed end 
of fermentation tubes). 
Does not form acid from saccharose in fer¬ 
mentation tubes. 
Does not form acid from dextrose in fer¬ 
mentation tubes. 
Villous along line of stab in both gelatin 
and agar. 
Becomes yellow with age on sugar agars. 
No indol formation. 
Agar-plate colonies homogeneous in struc¬ 
ture. 
Causes a soft-rot of the fruit. 
Agar colonies are round to ameboid. 
GEOGRAPHICAL DISTRIBUTION OF THE DISEASE 
Mr. Frederick V. Rand, of this laboratory, by whom these specimens 
were collected, reported the disease in 1915, from the following localities: 
Michigan: Big Rapids, Muskegon, Grand Haven, Holland, Grand Rapids, and 
Hudson ville. 
Indiana: Plymouth, Monterey, Tyner, and Donaldson. 
Wisconsin: Racine, Portage, Ripon, Princeton, and Milwaukee. 
New York: Constable, Malone, North Lawrence, and Long Island. 
Canada: Provinces of Ontario and Quebec. 
In regard to the amount of injury caused by this disease, Mr. Rand says: 
In most cases I found the angular leaf-spot causing a rather minor injury, but in an 
occasional field I found all the leaves back of the tips of the vines very badly shot- 
holed and presenting an exceedingly ragged appearance, such that serious injury 
to the crop must inevitaby result. Last year this disease had done more damage 
than any other in the vicinity of Ripon, Wis. 
This disease has also been reported recently from Maryland and several 
other Southern States. 
Earlier the senior writer received specimens from Michigan, Wisconsin 
Indiana, Connecticut, and the District of Columbia. 
INOCULATION EXPERIMENTS 
On October 26, 1914, young cucumber plants were sprayed in cages in 
the hothouse with water suspensions from young agar slants made from 
three colonies on the plates poured from diseased leaves. The plants 
were kept moist in the cages for 30 hours, then removed to the bench. 
