24 



BULLETIN 1118, U. S. DEPARTMENT OF AGRICULTURE. 



Table 6 gives the results of artifical inoculations of fruits of grape- 

 fruit, Satsuma orange, and Dancy tangerine with the citrus-scab 

 fungus, and Table 7 gives similar results on leaves of a number of 

 susceptible species. Numerous inoculations were attempted on 

 sweet oranges, but without exception they gave negative results. 

 Because of space limitation these tests are not here reported in 

 detail. 



Table 6. — Results of inoculations with the scab fungus on grapefruit, Satsuma orange, 



and Dancy tangerine fruits. 





Size of 

















Date. 



fruit 

 (in six- 

 teenths 



of an 



Total 

 inocu- 



Drop- 

 ped or 



Fruits 

 remain- 



Total 

 posi- 



Total 

 nega- 



Per- 

 centage 



Degrees of infection. 





lations. 



lost. 



ing. 



tive. 



tive. 



posi- 

 tive. 







inch). 

















Grapefruit: 



















Apr. 17, 1917-.. 



4 



6 







6 



6 







100 



Very severe. 



Apr. 10,1920.... 



4 



58 



9 



49 



48 



1 



98 



Do. 



Do. 



4 to 5 

 4 to 8 



31 

 230 



6 

 65 



25 

 165 



23 



129 



2 

 36 



92 



78 



Do. 



Apr. 19, 1920.... 



Do. 



Do. 



4 to 8 



46 



9 



37 



4 



33 



10.8 



33 Royal, no scab; 4 Fos- 



















ter, badly scabbed. 



Apr. 20, 1917.... 



4 to 12 



16 



6 



10 



5 



5 



50 



Very severe on small 



fruits. 

 Infection mostly on small- 



May 2, 1917 



2 to 20 



20 



1 



19 



11 



8 



58 



7 

















est fruits. 



May 9, 1917 



4 to 20 



16 



2 



14 



11 



3 



79 



Do. 



Apr. 23, 1920.... 



5 



50 



20 



30 



29 



1 



97 



Moderate. 



May 27, 1920.... 



6 to 8 



36 



22 



14 



13 



1 



93 



Severe. 



Apr. 3, 1919 



6 



102 



49 



53 



53 







100 



Do. 



Apr. 20, 1918.... 



6 to 8 



38 



9 



29 



23 



6 



79 



Severe on smallest; mod- 

 erate on larger fruits. 



Apr.10,1919.... 



6 to 8 



100 



33 



67 



67 







100 



Moderate. 



May 27,1920.... 



6 to 8 



36 



22 



14 



13 



1 



93 



Do. 



Apr. 27, 1920.... 



6 to 8 



36 



22 



14 



13 



1 



93 



Do. 



June 4, 1920 



6 to 12 



40 



1 



39 



9 



30 



23 



Lesions on smaller fruit 



only. 

 Yellow, poor specimens. 



June 11, 1920... 



4 to 12 



25 



6 



19 



2 



17 



10.5 



May 1,1917 



8 



25 



2 



23 



17 



6 



74 



Only a few lesions on 

 each fruit. 



May 13,1920.... 



8 



24 



5 



19 



19 







100 



Very severe; Hall {Sil- 

 ver Cluster). 



Apr. 17, 1919. . . . 



8 to 10 



108 



32 



76 



34 



42 



45 



Infection on smallest 

 fruits only. 



Apr. 15, 1918.... 



8 



30 



10 



20 



15 



5 



75 



Moderate. 



June 17, 1920... 



14 to 16 



15 



5 



10 







10 









Do. . . . 



10 to 24 



11 to 14 



50 

 100 



20 

 29 



30 

 71 





 



30 

 71 





 





Apr. 24, 1919.... 





May 1,1919 



11 to 17 



99 



41 



58 







58 









Apr. 29, 1920.... 



12 



48 



19 



29 



6 



23 



21 



One or two small spots 

 on each fruit; Hall 

 variety. 



June 11,1920... 



12 



21 



5 



16 







16 









May 13,1920.... 



12 



14 



6 



8 



1 



7 



12.5 



Lesions very small; only 

 one or two per fruit. 



May 8, 1920 



15 to 18 



50 



15 



35 







35 









May 13,1920.... 



16 



12 



6 



6 







6 









May 8, 9, 1919... 



lto22 



100 



32 



68 







68 









May 13,1920.... 



ItolS 



7 



1 



6 







6 









May 15,1919.... 



lto24 



100 



9 



91 







91 









Satsuma orange: 



















May 24, 1917.... 



4 to 8 



328 



157 



171 



147 



24 



86 



Very severe. 



May 8, 1920 



5 



17 



3 



14 



14 







100 



Severe. 



May 31, 1917.... 



10 to 20 



100 



50 



SO 



3 



47 



6 



Moderate on smallest 

 fruits. 



June 4, 1920 



6 to 8 



18 



10 



8 



7 



1 



88 



Severe. 



May 27, 1920. . . . 



8 



5 



1 



4 



4 







100 



Do. 



.Tune 11, 1920... 



8 



5 



2 



3 







3 









Do 



8 



4 



3 



1 







1 



0' 





June 25, 1920 . . . 



12 



10 



2 



8 







8 









June 17, 1920... 



14 



10 



6 



4 







4 









June 25, 1920... 



16 



10 



1 



9 







9 









Dancy tangerine: 



















June 4, 1920 



4 



24 



7 



17 



13 



4 



76 



Very severe. 



June 11, 1920... 



6 



20 



15 



5 



5 







100 



June 17,1920... 



6 



25 



14 



11 



n 







100 



Do! 



Jiuie25, 1920... 



6 



10 



2 



8 



8 







100 



Do. 



Do 



6 to 8 



10 







10 



9 



1 



90 



Do. 







