The Effect of the Fungicides Metalaxyl and Fosetyl-Al on Root Rot (Phytophthora cactorum) of American Ginseng (Panax quinquefolium) in the Greenhouse

• Published in: HortScience Vol. 30; no. 4; p. 830
• Main Authors: Medina, M.V, Gray, A.B, Ju, H.Y
• Format: Journal Article
• Language: English
• Published: 01.07.1995
• ISSN: 0018-5345; 2327-9834
• DOI: 10.21273/HORTSCI.30.4.830B

Ginseng seedlings were inoculated with Phytopthora cactorum by dipping their roots for 5 min in a suspension of 10 5 zoospores/ml. Inoculated plants were repotted and grown under shade in the greenhouse. In various experiments, fungicides were applied 1 week before inoculation, at the time of inoculation, 2 days after inoculation, or a combination of the first two of these. Treatments included fosetyl-Al applied as a foliar spray until run-off at a concentration of 2.5, 5.0, or 10 g a.i./liter of water or as a soil drench containing 0.25, 0.5, or 1.0 g a.i./100 ml water per plant and metalaxyl applied as a soil drench containing 5 or 10 mg a.i./100 ml of water per plant. The treatments with fosetyl-Al as a spray did not reduce root rot ratings, but fosetyl-Al applied as a drench significantly reduced root rot ratings at all three concentrations when applied at inoculation. The best control was achieved using metalaxyl at either 5 or 10 mg a.i./plant applied either at inoculation or both 1 week before inoculation and at inoculation.