DAMPING-OFF IN FOREST NURSERIES. 
11 
Something is already known about the seed fungi of herbaceous 
plants (76, 91), broad-leaved trees (79, 92), and juniper (95). 
RELATIVE IMPORTANCE OF THE DIFFERENT TYPES. 
Of the types of damping-off described in the foregoing pages the 
first two are ordinarily the most important. Late damping-off is 
rarely as serious as the normal type of damping-off. Top damping is 
only of importance in cases of excessive and unusual atmospheric 
moisture, so far as the writer's experience indicates. In the Middle 
West it has proved relatively insignificant. The three types which 
Fig. 5. — Nearly complete destruction of the seedlings of Pinus banksiana at an unusually 
early age, at Garden City, Kans. (Photographed by Dr. J. V. Hofmann.) 
occur after the seedlings appear above the soil surface can, of course, 
be evaluated by frequent counts during the damping-off season. This 
has apparently not yet been done by anyone. However, in experi- 
ments on damping-off control by soil disinfection, data have been 
obtained on comparative emergence (number of seedlings appearing 
above the soil surface) in treated and untreated plats and on the total 
parasitic losses after the seedlings appear which permit a certain 
amount of analysis of the losses due to damping-off parasites. The 
data from five nurseries bearing on this point are presented in 
Table I. 
