DAMPING-OFF IN FOREST NURSERIES. 
13 
of seedlings which succumbed to damping-off after emergence were 
reduced to a percentage based on the indicated number of viable seeds, 
and they are directly compared in columns 6 and 7 of Table I. At 
three of the nurseries the data of the same species of pine and with 
the same treatment were averaged. 
The data in Table I do not indicate any regularity either in the 
extent of loss before emergence, the loss after emergence, or in the 
ratio between these 
two values. For ob- 
vious reasons, no reg- 
ularity is to be ex- 
pected in any of these 
items. The table is 
of some interest, 
however, in confirm- 
ing the evidence of 
the inoculation ex- 
periments, of obser- 
vation of sprouting 
seed dug up in the 
beds, and of the par- 
tial or complete fail- 
ure of emergence at 
the centers of large 
damping-off foci 
(figs. 4, 7, and 8) that 
the work of parasites 
before the seedlings 
appear may in some 
cases be of consider- 
able importance. It 
is obviously impos- 
sible to make any 
general quantitative 
statement of the se- 
riousness of such loss, 
in view of the varia- 
tion in its extent at 
different times and 
places and of the in- 
accuracy of any computations based on the relative emergence 
of hosts as irregular in their germination as the conifers are 
known to be. The case is complicated in addition by the fact 
that, despite careful avoidance of treated plats known to have 
suffered chemical injury, it is probable that a few seedlings were 
killed before emergence by the disinfectants used in some of the 
Fig. 6. — Root sickness in Pinus nigra poiretiana. The two 
seedlings at the right are healthy. The three at the left 
have had their taproots decayed to within 1J inches 
of the soil surface. All are putting out lateral roots from 
the lowermost sound point. Similarly injured seedlings 
when transplanted lived and made satisfactory growth. 
