92 
Pilzkrankheiten der Pflanzen 
graminicola Sacc., Septoria gracilis Pass.. Ophiobolus graminis Sacc. 
und verschiedene Pleospora- und Helminthosporium-kxtew. 
Leere (Neubabelsberg). 
HARTLEY, C., The blights of Coniferous nursery stock (U. S. 
Dept. Agric. Bull. 44 [12. Dec. 1913] 21 pp.). 
A discussion of non-parasitic nursery diseases occupies the 
larger part of the publication. Damping-off diseases are characterized as 
parasitic diseases of seedlings less than two months old, and are only 
briefly mentioned. 
„Blight“ is a serious thing in American nurseries; sometimes almost 
the entire stock of one or more species of conifers is lost from this source. 
The different types of blight are given as follows: 
Sun scorch, which is the commonest and most serious in most 
nurseries, and is due to leaf transpiration in excess of root absorption. 
In one instance 70 °/ 0 of all 2-yr. seedlings of Pinus divaricata and 
P. sylvestris were lost at Halsey, Nebraska. In serious cases seedlings 
of all ages are killed outright; where less serious the tips of plants, or 
the lower needles, may be first affected. Attacks may be sudden in dry 
hot weather, when dead needles usually fall within a month. The ab¬ 
sorbing portions of the roots die at the same time, or before, the tops. 
Hot dry winds, sandy soil and crowded stands favor the disease, 
and species like Picea excelsa and Pseudotsuga taxifolia , which normally 
inhabit moist soil, suffer most, while such species as Pinus ponderosa 
from Rocky Mt. seed are more resistant. Frequent and heavy watering, 
coupled with partial shading (about one-half), entirely prevents the trouble. 
Soil samples taken at a depth of 2 to 11 inches from blighted areas 
showed about 30 % less water than in unaffected areas, the average wil¬ 
ting coefficient at Halsey, Nebraska, according to the Briggs-Shantz 
method, being 3,6 %. ' 
Winter-killing. This is understood to mean death due to exces¬ 
sive transpiration while the soil is frozen. The sudden warm winter and 
spring winds of the west, known as „chinook 4 winds, are a frequent cause. 
The effect in the nursery is similar to sun-scorch, except that the trouble 
is worse in open stands. The remedy is protection by windbreaks and 
the judicious application of straw mulches. 
Frost injury. This is due to the formation of ice crystals in 
unripenend tissue, also possibly to the injury of growing roots by early 
freezing of the soil. Careful mulching should prevent the latter, while 
danger from late spring frosts may be met by shading, sowing susceptible 
species, like Pseudotsuga taxifolia and Pinus divaricata , on high ground, 
and possibly by the use of heaters or temporary night mulches. 
Ebermayer’s blight. In Germany this is said to occur on heavy 
soils which are not frozen but are too cold for normal root absorption. 
It is not common in the United States. 
Needle-cast (Schüttekrankheit), due to Lophodermium 
pinastri is stated not to occur in American nurseries, but is to be guarded 
against in the future, especially in moist localities. Lophodermium 
brachysporum has already been reported from White Pine in the 
United States. 
Needle blight. Pestalozzia finerea is very common on dead 
eonifer needles in the United States, but attempts to artificially infect 
