SOIL TREATMENTS AND SEED GERMINATION 



19 



Table 8. — Effect of Pyroligneous Acid on Damping-off and on 

 Final Stands 



Damping-off was usually well controlled and germination much improved by 

 undistilled pyroligneous acid 5:100. Its effects on germination and on damping-off 

 are shown in Figure 2. The severity of damping-off was also lessened in most 

 cases by a dilution of 4:100, although neither this nor 5:100 was always so effective 

 as acetic acid, and different samples of this pyroligneous acid were not all equally 

 effective. Effects of these treatments on several species are here summarized. 



Pyroligneous Acid Species Species 



LIndistilled Not Injured Sometimes Injured 



5:100 Sweet pea English daisy 



Petunia Beet 



Mignonette Cucumber 



Nicotiana 

 Sweet Alyssum 



4:100 English daisy 



Marigold 

 Ageratum 

 Sweet William 

 Viola cornuta 

 Beet 

 Cucumber 



In later experiments, a pyroligneous acid made from pine wood was applied to 

 soil, without dilution, immediately before seeding. In amounts up to 125 cc, 

 it did not injure beet, cress, and lettuce, and 125 cc. controlled damping-off 

 very satisfactorily. There was considerable benefit also from 100 cc. per square 

 foot when it was diluted to 1 liter and applied after seeding. Its use, both before 

 and after seeding, deserves to be investigated further. 



