September, 1955 FORSBERG: 
the brown rot isolates were, in general, less 
sensitive to copper sulfate than were the 
vascular and basal dry rot isolates. 
Copper chloride was used in a way sim- 
ilar to that in which copper sulfate was 
used. The 47/100 concentration was pre- 
pared from 1.7 grams of copper chloride 
dissolved in a liter of Coons’s agar and the 
other concentrations were prepared from 
this stock diluted with Coons’s agar. Only 
four concentrations, 47/100, 1/300, 
M/500, and 7/1000, were used, table 7. 
Further dilutions of copper chloride were 
not used because the reactions of the iso- 
FUSARIUM DISEASE OF GLADIOLUS 
467 
lates of Fusarium appeared to be follow- 
ing the same pattern with copper chloride 
as they did with copper sulfate. 
Reactions to Mercurie Chloride 
The preplanting treatment of gladiolus 
corms in a solution of mercuric chloride 
has been one of the methods used by grow- 
ers to control the Fusarium disease. Be- 
cause seemingly erratic results have some- 
times been obtained from chemical treat- 
ment of corms, it was decided to test the 
+0 isolates of gladiolus Fusarium for sen- 
Table 8.—Reactions* of isolates of the gladiolus Fusarium to six concentrations of mer- 
curic chloride in Coons’s agar.+ 
CoNCENTRATION OF MErcuRIC CHLORIDE 
IsoLATE ; 
1:10,000 1:12,500 1:14,285 1:16,666 1:20,000 1:25,000 
STEM ee eee 0 0 0 0 13.001 14.001 
ASSO Ae Seale ge 0) 0 0) 0 15.001 15.000 
EUS OPN RL es Senos 0 0 15.001 15.001 15.001 15.001 
AN Ae Oe Semen 0 0) 0 0 15.001 15.001 
GEA re ee 0 0 0 0 14.001 15.001 
Ef pe Ae Rien 9 0 0 0 0 15.001 15.001 
LAO Dies eee 0 0 0 0 15.001 15.001 
TELNAES (ae Perea 0 0 0 0 15.001 15.001 
CNG A VS Os Sea ra 0 0) 13.001 15.001 15.001 15.001 
OSS ae eae 0 0 0 0) 14.001 15.001 
eae eS ae ee 0 0) | 0 0) 15.001 | 15.001 
LAUR eae eee 0 0) 0 0 14.001 15.001 
cee ak 0 0 0 15.000 15.000 | 15.000 
50-6. 0 | 0 0 0 0 | 14.001 
50-24 0 12.005 15.005 15.000 15.000 15.000 
50-27 0 13.001 15.001 15.001 15.001 15.001 
50-28 0 0 0 0 14.001 15.001 
SPASM Simei acd: 0 0 0) 0 0) 15.001 
45-74... 0) 0 15.001 15.001 15.000 15.001 
55] See Beer 2 0) 0 15.001 15.001 15.000 15.001 
45-78 0) 0 0 15.001 15.000 15.000 
46-4. 0 13.001 15.001 15.001 15.001 15.001 
46-12 0 0 0 0) 13.001 14.001 
47-1. 0 0 15.001 15.001 15.001 15.001 
47-8. 0) 0 0 15.001 15.001 15.000 
47-12 0 13.001 14.001 14.001 15.001 15.001 
47-19 0 15.001 15.001 15.001 15.001 15.001 
47-32 0 0 0 0) 13.001 15.001 
49-1. 0 0) 0 15.000 15.000 15.000 
49-17 0 0) 15.001 15.001 15.000 15.000 
49-19 0 0 tr tr 15.001 15.001 
50-7. 0 0 0 0) 13.001 15.001 
50-22 0 0 15.001 15.001 15.001 15.001 
50-25 0 0 0 12.001 14.001 15.001 
47-2 0 0 15.001 15.001 15.001 15.000 
47-3 0 13.001 14.001 14.001 15.001 15.000 
49-8. 0 0 0 15.001 15.000 15.000 
49-20 0 0 0) 0 13.001 15.000 
50-23 0 0) 0) 0 14.001 15.001 
50-26 0 0 0 12.001 14.001 15.001 
*Reactions are expressed in the numbering scheme of Coons & Strong (1931), as explained in the text, 
+See table 3 for control readings. 
