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A CONSIDERATION OF THE PHYSIOLOGY AND 
LIFE HISTORY OF A PARASITIC 
BOTRYTIS ON PEPPER 
AND LETTUCE.! 
BY GEORGE L. PELTIER. 
INTRODUCTION. 
During the autumn of 1911, while gathering the peppers 
(Capsicum) in the vegetable plat of the Missouri Botanical 
Garden, the writer observed a fungus which was appearing as 
a parasite on the fruits. The peduncles were covered with a 
dark brown mass of conidia and mycelium, which so weakened 
the tissues that the fruit soon fell to the ground. On opening 
the peppers a number of large, flat, crust-like sclerotia, 1 cm. 
long and .5 em. wide, were found to fill the interior. In most 
cases the seeds were also covered with the crust-like masses. 
The conidial stage was identified as Botrytis cinerea Pers. 
(Botrytis vulgaris Fr.). Although Botrytis cinerea has been 
observed parasitic on a large number of hosts, this is the first 
time it has been reported as a parasite on the peppers. 
Later, while carrying on infection experiments, it was in- 
troduced into one of the vegetable greenhouses, where it 
became quite a serious disease of the lettuce, causing the 
characteristic “drop” and a ‘“‘damping-off” of the seedlings. 
Thus a very good opportunity was afforded for the study of 
the development of the parasite and its action on several hosts. 
HISTORICAL. 
By using a part of the artificial classification suggested by 
Duggar (17), the genus Sclerotinia may be divided into four 
distinct groups :— 
1 Abstracted from a thesis presented to the Faculty of Washington 
University, in candidacy for the degree of Master of Arts, June, 1912. 
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