10 BULLETIN 531, U. S. DEPARTMENT OF AGRICULTURE. 
found it to be the most important cause of decay of quince (Cydonia) 
fruit, Orton (11) reports it as causing a soft rot of white potatoes 
(Solanum), and Hawkins (9) corroborates the observations of Orton. 
The writers have also found this species on red raspberries in the 
Washington market. 
This fungus may at times cause a serious rot of pears, and to 
some extent of peaches, as shown by the following manuscript note 
furnished by Mr. M. B. Waite : 
In September, 1902, shipments of Kieffer pears from Patuxent (Woodward- 
ville P. O.), Md., to the Washington, D. C, market suffered very severely from 
decay induced by Rhizopus nigricans. Pears of this variety had been shipped with 
success from 4-year-old trees in 1900 and from 5-year-old trees in 1901 by pick- 
ing them hard and green, beginning about September 10 and continuing through 
the month. After picking they were stored in bins, usually for about a week, 
partly covered with canvas cloth. The layer of pears, about 2 to 2| feet thick, 
colored up nicely without shriveling and brought a good price on the market. 
Shipments started in this way in 1902, picked about September 10 and shipped 
a week later, began to arrive in good condition. Daily shipments were made, 
and a few days after the first arrived trouble was experienced with a soft rot. 
found on examination to be due to Rhizopus nigricans. The individual fruits 
attacked were completely disintegrated, those not attacked remaining sound. 
About September 20, a carload of fruit was shipped in barrels and baskets. 
The barrels were of the open-head truck type, with cloth covers. The baskets 
were of the ordinary slatted, 4/8, 25-pound Delaware type. About half the 
fruit in baskets was salable at a reduced price, some of the baskets being one- 
third or one-half rotted. 
The fruit in barrels, however, was almost a total loss. About 50 or 60 of these 
barrels were placed on arrival in the second story of a commission house, to 
allow them a few days to ripen, and the juice leaked freely out of the more open 
barrels through the floor and dropped down to the lower story. The tighter 
barrels became slightly swelled, so that they were water-tight, and on exami- 
nation they were found to be partly filled with the liquefied contents, with a 
few perfectly sound pears floating or immersed in the liquid. The fruit was 
packed on one day, delivered to the city by rail on the afternoon of the follow- 
ing day, and hauled to the commission house. On the following morning the 
rot was found starting in strongly, and in another 24 hours the results already 
described appeared. 
The fruit was thought to be fairly well handled by methods that had given 
good results in previous years, but the Kieffer pear is very hard and brittle, and 
the epidermis is easily ruptured by rubbing or scratching. The inability of the 
fungus to penetrate certain fruits is accounted for by their complete freedom 
from the slightest injury to the cuticle. Later pickings from the same orchard, 
with cooler weather and perhaps somewhat better handling, gave good results. 
Fruit picked and shipped green the first week in October stood the trip to 
Washington and was immediately placed in cold storage without any trace's of 
Rhizopus rot. Shipments were made for 10 years following this without on- 
countering this difficulty to any appreciable extent. 
Occasionally trouble somewhat similar has been experienced to a minor de- 
gree in shipments of peaches. Last summer (1915). about August 15. a refrig- 
erator carload of Belle peaches, shipped to the Washington market from Clarks 
Gap, Va., showed this type of rot before it was completely sold. The car 
opened up in good condition, and part of the fruit was sold the morning after 
