456 
Journal of Agricultural Research 
Vol. XXVI, No. io 
Table I. Results of infection experiments on wood of boxelder with pure cultures of th e 
fungus , Fusarium negundi 
Ex- 
pert¬ 
inent 
No. 
Date. 
Source of 
inoculum. 
Medium 
and 
dimensions 
(inches). 
Method of 
sterilization. 
Num¬ 
ber 
of 
tubes. 
Results. 
Date of 
results. 
1 
Apr. 
7,1921 
Culture No. 
91. 
Blocks of 
heartwood, 
1X1X5. 
Autoclaved 
at 15 lbs. 
for 45 min. 
3 
Slight red stain in 
wood surround¬ 
ing inoculum. 
Penetration of 
stain, slight. 
May 9,1921. 
2 
Apr. 
7 . 1921 
Culture No. 
45 . 
Blocks of 
heartwood, 
1X1X5. 
Autoclaved 
at 15 lbs. 
for 45 min. 
3 
Considerable sur¬ 
face staining of 
wood where hy- 
phae developed. 
Penetration of 
stain, slight. 
May 9,1921. 
3 
Apr. 
8, 1921 
Culture No. 
45 - 
Blocks of 
heartwood, 
1X1X5. 
Autoclaved 
at 15 lbs. 
for 45 min. 
2 
No staining. Hy- 
phal growth 
scanty. Myxo¬ 
mycete strands 
developed from 
inoculum. Sele- 
rotia-like 
growths on 
wood. 
Apr. 26,1921. 
4 
Apr. 
7 , 1921 
None. Con¬ 
trol. 
Block of 
heartwood. 
Autoclaved 
at 15 lbs. 
for 45 min. 
I 
No growth. No 
staining. 
. May 9,1921. 
5 
Dec. 
1,1922 
Culture No. 
182. 
Blocks of 
fresh sap- 
wood, 1 
X1MX2. 
Surfaces 
washed 
with HgCls 
and with 
distilled 
water. 
3 
Considerable sur¬ 
face staining in 
vicinity of inoc¬ 
ulum. Penetra¬ 
tion of stain into 
wood for a dis¬ 
tance of ) 4 . inch.® 
Dec. 14,1922. 
6 
Dec. 
i, 1922 
Culture No. 
182. 
Blocks of 
fresh sap- 
wood, iM 
X1HX2. 
Surfaces 
washed 
with HgCh 
and with 
distilled 
water. 
2 
Considerable stain¬ 
ing of surface 
and slightly be¬ 
low. Surface of 
block gives acid 
reaction. 
Dec. 14,1922. 
7 
Dec. 
1, 1922 
None. Con¬ 
trol. 
Block of 
fresh sap- 
wood, i % 
X1HX4. 
Surfaces 
w a shed 
with HgCh 
and with 
distilled 
water. 
I 
No staining. No 
hyphae of Fu¬ 
sarium devel¬ 
oped. 
Dec. 14,1922. 
a On Dec. 28 a Myxomycete developed and fruited on the surface of one of the blocks. 
If it is found desirable to attempt the control of the disease on box- 
elder trees in the forest and wood lot intensive methods of control will 
be impracticable. Such sanitary measures as the burning of affected 
slash and rapid handling of the logs are steps which can be taken to 
reduce the number of inoculum sources. Rapid removal of the logs to 
the mill may reduce the production and dispersal of spores and rapid 
seasoning may check the development of the fungus in the wood. 
[SUMMARY 
A disease of the boxelder characterized by a bright red stain in the 
wood has been under observation by the writer since 1920. The stain 
is very frequently met with and, therefore, popularly believed to be a 
fairly reliable character for the identification of this wood. 
