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

in HortScience
Authors:
M.V. MedinaNova Scotia Agricultural College, P.O. Box 550, Truro, NS B2N 5E3, Canada.

Search for other papers by M.V. Medina in
ASHS
Google Scholar
PubMed
Close
,
A.B. GrayNova Scotia Agricultural College, P.O. Box 550, Truro, NS B2N 5E3, Canada.

Search for other papers by A.B. Gray in
ASHS
Google Scholar
PubMed
Close
, and
H.Y JuNova Scotia Agricultural College, P.O. Box 550, Truro, NS B2N 5E3, Canada.

Search for other papers by H.Y Ju in
ASHS
Google Scholar
PubMed
Close

Ginseng seedlings were inoculated with Phytopthora cactorum by dipping their roots for 5 min in a suspension of 105 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.

  • Collapse
  • Expand