18 BULLETIN 44, U. S. DEPARTMENT OF AGRICULTURE. 
but at length gradually become yellow and die. Scotch pine, Rocky 
Mountain yellow pine, white fir (Abies concolor (Gord.) Parry), 
Douglas fir, and Norway spruce have been found affected, the latter 
most seriously. A very similar trouble is known in Germany under 
the name ‘“ Einschniirungskrankheit.” It is figured by Tubeuf.t 
Various coniferous and broad-leaved species are affected, beech, fir, 
and spruce being most prominently mentioned. In Germany Pesta- 
lozzia hartigi Tub. is found on the constrictions and is considered to 
be the cause of the disease. The causal relation has not been proved 
by inoculation, despite extensive experiments by Fischer.2 Of the 
few cases of disease observed by the writer the fungus has been found 
fruiting on the lesions in a single case on Rocky Mountain yellow 
pine from New Mexico. In this case the bark had been dead so long 
that it had become loose. While the stem girdle in this country may 
be due to Pestalozzia hartigii, proof is lacking. 
The important practical facts are that the disease does not often 
do serious damage, and that the only method of combating it which 
can be suggested is to destroy all diseased material. All girdled 
trees with bark killed entirely around the stem are certain to die 
and should be pulled out and burned at once without waiting for 
them to turn yellow. 
MULCH INJURY. 
In nurseries where beds are covered with a mulch during the winter 
to prevent heaving or winterkilling, heavy losses sometimes occur 
while the mulch is on the beds or just after it is taken off. While 
mulch injury usually occurs during the winter it is an entirely differ- 
ent thing from the winterkilling in unmulched beds. The general 
experience of nurserymen has been that the disease was worst where 
the mulch was heaviest, or where it was composed of fine material 
which packed down into a close covering. While the injury is the 
result of the use of mulch, the immediate cause of death is unknown. 
Winle physical factors may be entirely responsible, it is quite likely 
that death is due to some needle parasite whose work is favored by the 
conditions which prevail in mulched beds. What is very likely the 
same trouble occurs occasionally under a light mulch, or even under 
no mulch at all, when there is heavy or very late snow. 
In two cases the writer has had opportunity to examine injured 
white-pine and Douglas-fir seedlings shortly after the mulch was re- 
moved. In both bases the roots were still healthy despite the death 
of the needles and in many plants of the upper parts of the stems. 
1Tubeuf, Karl von. Diseases of Plants Induced by Cryptogamic Parasites. English 
edition by W. G. Smith. London, New York, and Bombay, 1897, p. 492. 
2 Fischer, C. E. C. Note on the biology of Pestalozzia hartigii, Tubeuf. Journal of 
Economic Biology, v. 4, No. 3, p. 72-77, pl. 7, 1909. 
