4 BULLETIN 531, U. S. DEPARTMENT OF AGRICULTURE. 
refrigeration can not be transported to distant markets without loss. 
Although berries may be in the best of condition when picked, they 
often decay before reaching the consumer, owing largely to the ac- 
tivity of rot-producing organisms. 
FUNGI. 
Bacterial rots are rare in strawberries. This may be due to the 
high acid content of the fruit. On the other hand, ripe strawberries, 
especially if injured, furnish a favorable substratum for the growth 
of many fungi. Among the less important fungi found were species 
of Alternaria, Botrytis, Cladosporium, Dematium, Fusarium, Mucor, 
Patellina, and Penicillium. All these fungi will grow on strawberry 
tissue, and under unusually favorable conditions some of them may 
cause appreciable damage. 
Botrytis,, long known to occur commonly on strawberries and fre- 
quently found in fruit from some sections, is not of first importance 
as a cause of decay in transit. Berries affected by Botrytis in the 
field are recognized readily and should be thrown out as culls. The 
growth of Botrytis in the ripe strawberry is so slow that but little 
damage occurs in the short time between picking and marketing. 
Penicillium, which occurs frequently in small quantity, has been 
abundant in only one case which has come under the observation of 
the writers. In a shipment from Florida in the spring of 1916 in 
which the berries were very soft, owing apparently to the effect of 
the severe sand storm previously mentioned, Penicillium was very 
common. It is uncertain whether this was due to the condition of 
the berries or to some unusual opportunit}^ for infection. 
By far the most important cause of rot of strawberries in transit 
is a species of Rhizopus. Not only is this fungus the most common 
one on strawberries from every section studied by the writers, but in 
some instances it is almost the only fungus present. During the 
spring of 1916 the writers examined more than 14,000 decayed straw- 
berries shipped on various dates from three localities in Florida. 
Most of these were kept until quite rotten, and more than 90 per cent 
of them developed only Rhizopus. 
In addition, several hundred inoculations on strawberries of various 
varieties have been made, and in no case has Rhizopus failed to pro- 
duce typical rot when introduced into a wound (fig. 1). No similar 
results could be obtained with any of the other fungi found. 
RHIZOPUS NIGRICANS. 
In his recent monograph of the genus Rhizopus, Hanzawa (8) used 
physiological as well as morphological characters in distinguishing 
the species. The writers have not investigated the physiology of this 
fungus sufficiently to compare with Hanzawa's results, but so far as 
