Seedling diseases of sugar beets and their relation to root-rot and crown-rot,

SEED TREATMENTSugar-beet seed is quite universally infected with parasitic fungi.It was therefore necessary to devise some method of freeing the seed from infection before inoculation experiments could be successfully conducted.Among the substances tried were hydrogen peroxid, hydrochloric acid, sulphuric acid, formalin solution, formaldehyde vapor, and hot water.Peroxid solution (6 per cent) was used for varying periods up to one hour.The seed was then sown in sterilized soil and watered with distilled water.The pots were protected from infection, but damping-off was in no degree checked, and Phoma betae was invariably isolated from the diseased seedlings (Pl.XVII).Hydrochloric acid was employed in various concentrations up to a specific gravity of 20° B. for 15 minutes.The seed was then rinsed in sterile water, followed by lime water, which in turn was followed by sterile water.This treatment was without effect upon the vitality either of the seed or of the fungi.Sulphuric acid was used in various strengths up to full concentration for one hour.'The treated seed germinated strongly and from 24 to 48 hours earlier than the untreated control, but there was no decrease in the amount of damping-off.Formalin solution was employed up to concentrations of 2 per cent of formaldehyde for various intervals up to one hour.This seriously injured