Feb., 1907.] 
Phytophthora and Plasmopora. 
79 
favorable conditions. It is strongly, positively phototactic, 
not only to white light, but to red, green, violet, orange, blue and 
yellow, showing a probable preference for red. 
Ohio Wesleyan University, 
Delaware, Ohio, November, ’06. 
Literature Cited. 
Forbes, S. A., ’70—List of Illinois Crustacea. Bull. Ill. State 
Lab. N. H., No. 1, 5. 
Hay, O. P., '82—Notes on Fresh-water Crustacea. Amer. Nat¬ 
uralist. XVI-(144) 1882. 
Smith, Sidney I., ’72--Report of U. S. Fish Com. Fresh-water 
Fisheries of the U. S. Report of 1872-73-A, Synopsis of 
the Higher Fresh-water Crustacea of the Northern U. S., 
pp. 641-42. 
Stimpson, William, ’71, Ann. N. Y. Lyceum N. H., x 130 (Not 
seen). 
ON THE OCCURRENCE OF PHYTOPHTHORA INFESTANS 
MONT. AND PLASMOPORA CUBENSIS (B. & C.) HUMPH. 
IN OHIO.* 
A. D. Selby. 
The first named fungus, parasitic upon potato, Phytophthora 
infestans Mont., is a species of large economic importance, whose 
periodic epidemic outbreaks have become historic and have had 
far reaching economic and political effects. Most of you will 
recall the statements, that the potato rot resulting from this 
fungus, occurred in a virulent form in Eastern North America 
in 1842 and again in 1843 also in 1874. In 1845, and at later 
dates the disease spread to Great Britain, Ireland, Belgium and 
parts of Germany and France. In one earlier year, 1845, the 
greatest injury was done in Nova Scotia, New Brunswick and 
in Ireland. 
This restatement of old facts is made to ask you to bear in 
mind the climate of the areas of greatest disease. 
Doubtless most have heard of potato late blight and rot from 
this fungus and may be surprised to learn that it is of such rare 
occurrence in our state that not a single Ohio specimen of 
Phytophthora infestans is to be found in any of the herbaria of 
the country, save only a few collected at the Ohio Experiment 
Station within the last three years. However, I know that 
specimens were taken by the late Dr. E. W. Clavpole, near Ak¬ 
ron, O., in the early 80’s, since 1 saw him once exhibit such ma¬ 
terial. This material was unfortunately destroyed in the fire 
* Read at the meeting of the Ohio Academy of Sci. 
