2 BULLETIN 686, U. S. DEPARTMENT OF AGRICULTURE. 
RfflZOPUS. 
TYPE OF ROT INDUCED. 
Among the numerous fungi which have been found growing on ripe 
strawberries, Rhizopus, as pointed out in an earlier paper (12, p. 4) 
is by far the most important. This fungus destroys strawberry 
tissue more rapidly than any other yet found and causes the affected 
fruits to collapse with the loss of much juice, producing the charac- 
teristic "leak" which so frequently discolors strawberry boxes and 
crates in the market. The spores of this fungus are apparently very 
generally present on ripe strawberry fruits. 
A list of fruits and vegetables on which Rhizopus nigricans Ehrb. 
has been reported was published by the writers (12, p. 9) . On June 1 , 
1917, this fungus was observed fruiting abundantly on red rasp- 
berries (Rubus sp.) and dewberries (Rubus sp.) in the Chicago mar- 
ket, and later (July 23) on blackberries in the Washington market. 
In all these cases the fungus seemed to be producing the leak charac- 
teristic of its action on strawberries and other fruits (12, p. 11). The 
berries had settled to about one-half their original height in the box, 
and the juice was leaking from the bottoms of the boxes or crates. 
It is of interest to note that in his studies of Rhizopus, Wormald 
(14, p. 483) proved that both the so-called plus ( + ) and minus ( — ) 
strains of this fungus are able to produce the characteristic soft rot 
of tomatoes (Ly coper sicon esculentum) . 
It is probable that Rhizopus occurs as a fruit rot of tomatoes in 
this country, although no reference to it can be found in available 
literature. In a car of tomatoes from Cuba which was examined in 
Boston in January, 1918, by Mr. C. E. Merrill, food products inspector 
of the Bureau of Markets, and one of the writers, several instances 
were found in which a species of Rhizopus was producing a soft rot 
of tomatoes. 
IMPORTANCE OF CAREFUL HANDLING. 
Early in their investigations (10, p. 364) the writers became con- 
vinced that Rhizopus rarely, if ever, enters strawberries through the 
uninjured epidermis. Continued observations and experiments have 
confirmed this conclusion. As strawberries are very easily injured, 
they should be handled as little and as carefully as possible. Sort- 
ing, or at least some examination at the packing shed, is usually neces- 
sary, but berries should be handled carefully in order to reduce to a 
minimum injury and the consequent decay. When practicable, as 
when most of the picking is done by the grower's family or by ex- 
perienced help, the berries may be sorted as picked. This is probably 
the most desirable procedure. The importance of careful handling 
as a means of reducing loss from decay in various fruits has been 
clearly shown in several investigations by Ramsey (5 and 6), Powell 
