Evaluation of fungicidal action of plant extracts on damping-off fungi in sugarbeet.
The effect of extracts from 6 species of Polygonaceae, viz. Polygonum persicaria, P. convolvulus [Fallopia convolvulus], P. aviculare, P. hydropiper, P. bistorta and P. sachalinense [Reynoutria sachalinensis], against Aphanomyces cochlioides, Pythium debaryanum, Phoma betae [Pleospora betae], Fusarium oxysporum, F. culmorum and Rhizoctonia solani, the main fungi associated with damping-off in sugarbeet seedlings, was studied in in vitro experiments. Plant preparations were obtained as cold (macerate), hot (brewed) or alcohol + acetone extracts. Extracts from the different species affected the growth of damping-off fungi colonies differently. The extracts from P. bistorta were the most effective against almost all the fungal species tested. Alcohol + acetone extraction was the best method of preparation.