. Damping-off in forest nurseries. Plant diseases; Trees. DAMPlXti-Ol F IX FOREST NURSERIES. 13 of seedlings which succumbed to damping-off after emergence were reduced to a percentage based on the indicated number of viable 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 1 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- ul
. Damping-off in forest nurseries. Plant diseases; Trees. DAMPlXti-Ol F IX FOREST NURSERIES. 13 of seedlings which succumbed to damping-off after emergence were reduced to a percentage based on the indicated number of viable 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 1 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. ti.—Root sickness in Pinus nigra poiretiana. The two seedlings at the right are healthy. The three at the lefl have had their taproots decayed to within li 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 Please note that these images are extracted from scanned
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