Dec. 8,1933 
The Red Stain in the Wood of Boxelder 
455 
life history 
Not a great deal has been learned of the life history of this fungus. 
The presence of chlamydospores and conidia in hollow knots, in holes 
produced by sapsuckers, on the surface of broken branches showing 
red stain, and on dead wood exposed by wounding, indicates that these 
spores are produced upon the surface of the host wherever wounding 
and other factors have afforded suitable conditions. Undoubtedly many 
of the spores are wind or water borne, but judging from the activities of 
sapsuckers in connection with this host it is reasonable to suppose that 
these birds play an important part in disseminating the spores. A 
glance at Plate 3 will show a number of small red, stained areas in the 
sapwood between the bark and the continuous red area (dark band) sur¬ 
rounding the decayed heartwood. These areas are seen to be directly 
associated with “bird peck/' a type of injury caused by the sapsucker in 
search of food. The evidence in Plate 3 shows that the same cavity is 
used at intervals to tap the cambial layer; in this case three annual rings 
intervene between two red areas which are directly in line with the hole 
drilled in the bark by the bird. The most recent injury, apparently 
produced in the spring of 1922, was not healed at the time the tree was 
cut in November of the same year. If these deductions are correct, then 
it is quite possible for the bird to transmit the fungus from one portion 
of the tree to another or from tree to tree. 
The years of greater activity of this bird for a particular area on the 
tree can be measured by the larger number of bird-peck stain spots 
occurring along the same annual ring. The smaller spots represent the 
stained areas above or below the original injury and nidus of infection. 
The three blocks in Plate 3 show the “bird pecks” in longitudinal section 
of the wood. 
In pure cultures the spores of Fusarium negundi Sherb. are produced 
within a period of three days. Under natural conditions sporulation 
could easily take place within the hole drilled in the bark by the sap- 
sucker before the callus developed sufficiently to isolate tie fungus 
within the sapwood. The next visit of the bird to the spot would result 
in a contamination of its bill with these spores. 
Wounds caused by wind breakage, by pruning, by fire and by sap- 
sucker attack, appear to be the most common infection courts for the 
entrance of this fungus. The part which insects may play in the life 
history of this stain organism has not been investigated. 
The organism in the form of hyphae overwinters within the host tissue, 
renewing its activity upon the return of favorable temperature and 
moisture conditions. 
CONTROL MEASURES 
Sanitary measures are probably the only practicable means in control¬ 
ling this disease on shade trees, providing the fungus is found to cause 
sufficient damage. Proper care of the trees in respect to the various 
injuries it suffers will aid greatly in reducing the chances of infection, 
not only of this disease but of the more serious heartrot and parasitic 
types. Wounds of all kinds should be given particular attention. 
Detailed information regarding the proper methods of caring for wounds 
on shade trees may be found in United States Department of Agriculture 
Bulletin No. 1178. 11 
11 Collins, J. Franklin, tree surgery. U. S. Dept. Agr., Farmers’ Bui. 1x78, 33 p., 24 fig. 1923. 
