FURTHER STUDIES OF THE ROTS OF STRAWBERRY FRUITS. 11 



Botrytis sp. or some other fungus." Continued study (12, p. 9) 

 convinced the writers that the most common method of entrance of 

 Rhizopus was thi'ough wounds. 



Later investigations (8 and 9) led Stevens to modif}" his earUer 

 views, and in a paper pubhshed jointly with Peterson he states 

 (9, p. 264) that " Rhizopus nigricans is the fungus which, at the desti- 

 nation of the berry, is most in evidence and the fungus wliich, in 

 reality, does most of the damage to shipped berries. * * * It is 

 evident that this fungus does not attack sound berries, but is second- 

 ary in its nature, following one or another of the fungi mentioned 

 above or gaining entrance through some mechanical wound." So 

 far as concerns the importance of Rhizopus and the possibility of its 

 entering through womids, this is in substantial agreement mth the 

 observations of _the writers. 



Until the spring of 1917 no good opportunity was afforded for 

 studying the effect on Rhizopus infection of previous infection by 

 Botrytis. It seemed entirely probable, however, that Botrytis was 

 of no particular advantage in the entrance of Rhizopus, since Rliizopus 

 is very abundant in strawberries in which there is no Botrytis 

 infection. 



During the epidemic of Botrytis on strawberries of the RusseU 

 variety in the field at Hammond, La., already described, and in 

 connection with the experiments on shipping washed and unwashed 

 strawberries, advantage was taken of the opportunity to test the 

 shipping quahty of berries from a field badly infected with Botrytis 

 as compared with that of berries from a field in which httle Botrytis 

 appeared. A single crate was filled, haK with berries from the field 

 of Klondikes in which there was little Botrytis and hah with berries 

 from the field of Russells in which Botrytis was so common. These 

 boxes were chosen at random from lots which had been sorted and 

 packed in the ordinary commercial manner. Half of each variety 

 were dipped and half left as checks. All were then shipped to Chicago 

 under refrigeration. The results are presented in Table III, tests 1 

 and 2. 



While this observation is^ of course, complicated by the fact that 

 different varieties were used in the two cases, it at least shows that 

 there was no marked increase in the amount of Rhizopus present 

 in the berries which came from a field badly infected by Botrytis. 



Further evidence as to the relation between these fxmgi was ob- 

 tained by actual inoculation of infected fruit from the same field. 

 Berries naturally infected with Botrytis were inoculated vnth spores 

 and mycefium of Rhizopus from pure culture. Berries which had 

 only small areas infected with Botrytis were readily inoculated with 

 Rhizopus in the remaining sound tissue. In no case was infection 



