22 



BULLETIN 1029, U. S. DEPARTMENT OF AGRICULTURE, 



general, however, the disease was not very prevalent in Eacine fields 

 at the end of the season. Where the mercuric-chlorid and dry-heat 

 treatments were combined, very little disease developed, but since 

 mercuric chlorid alone controlled the disease as well in this locality, 

 the superiority of the double treatment was not demonstrated. 



Table IX. — Development of cabbage black-leg in commercial fields grown from 

 treated seeds in Wisconsin in 1919. 





Treatment. 



Field 

 No. 



Diseased plants. 



Date 



Locality and seed lot. 



Affected. 



Prevent- 

 ed from 

 heading. 



of 

 observa- 

 tion. 



Racine: 



15-18 a 



1 to 1,000 EfeCl2 30 minutes, rinsed 



do 



1 

 2 

 3 

 3 



4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 



12 



13 



Per cent. 

 31.0 

 97.0 



Per cent. 



4 

 60 

 11 



3 

 25 



2 

 11 



4 



1 



2 



1 



1.2 



.25 



Sept. 19 

 Do 



15-18 o 



13-18 a 



1 to 500 HgCl2 30 minutes, rinsed 



do 



Oct 12 



2-18 a 





Do 



2-180 



..do 



25 



2 



u 



4 



Oct 13 



2-18 » 



do 



Do 



2-181 



do 



Do 



2-18 a 



. do 



Oct 11 



3-18 » 



do 



Sept. 19 

 Oct. 13 



3-18 o 



do 



2 

 1 

 1.2 



.25 



3-18 a 



do 



Do. 



3-18 



1 to 1,000 HgCl2 20 minutes, rinsed, 

 plus dry heat 85° C. for 72 hours. 



1 to 1,000 HgCl2 20 minutes, rinsed, 

 plus dry heat 90° C. for 36 hours. 



1 to 1,000 HgCl2 20 minutes, rinsed, 

 plus dry heat 95° C. for 12 hours. 



1 to 500 HgCl2 30 minutes, rinsed 



Do. 



3-18 



Do 



3-18 



Do 







Average, 5 fields, 



10.5 

 1.0 



9.0 

 1.3 





lot No. 2-18. 

 Average, 3 fields. 



do 







lot No. 3-18. 



1 to 1,000 HgCl2 30 minutes, rinsed 



do 



14 

 15 

 15 





Appleton: 



2-18 



100 

 100 

 92 



90 

 68 

 63 



Oct. 10 



2-18 



Do. 



2-18 



1 to 500 HgCl2 30 minutes, rinsed 



1 to 1,000 HgCl2 30 minutes, rinsed 



Do. 







Average, 3 fields, 









lot No. 2-18. 



1 to 500 HgCl" 30 minutes, rinsed 





97.3 



73.6 







do 



16 

 17 

 18 

 19 





Shiocton: 



3-180 



50 to 90 

 50 to 90 

 60 to 90 



50 to 90 



50 to 90 



50 to 90 



90 



Oct. 11 



3-180 



. do 



Do. 



3-18a 



do 



Do. 



14-18a 



1 to 256 HCHO 30 minutes, rinsed 



1 to 500 HgCh 30 minutes, rinsed 



Do. 









Average, 3 fields, 

 lot No. 3-18. 



50 to 90 



50 to 90 











a Disinfected by seed grower. 



b One diseased plant found in a 3-acre field. 



Conditions were decidedly different in the Appleton and Shiocton 

 districts. A survey showed that the disease had dcA^eloped into a 

 uniformly severe epiphytotic in fields of both localities grown from 

 Nos. 2-18 and 3-18 seed (Table IX). Unfortunately the seed beds 

 were not examined, but the even distribution and advanced stage of 

 the disease left no doubt that the fungus had become widespread be- 

 fore transplanting. In one field at Shiocton where the formalde- 

 hyde treatment was used the disease was not controlled. A com- 

 parison of precipitation records (fig. 1) taken at Menasha (near 



