Effect of biocontrol products on germination and survival of sclerotia of
Sclerotinia sclerotiorum in carrot
M.T. Tesfaendrias and M.R. McDonald
Department of Plant Agriculture, University of Guelph, ON, N1G 2W1
Sclerotinia rot of carrot caused by
Sclerotinia sclerotiorum (Lib.) de Bary is one of
the major diseases in carrot production in Ontario. In 2011 and 2012, field and controlled
environment trials were conducted to evaluate the efficacy of biocontrol products on
germination, recovery and survival of sclerotia of
S. sclerotiorum. Treatments were:
Contans (
Coniothyrium minitans 1 x 10
6 spores/ml),
Trichoderma
atroviride A (1 x 10
8 spores/ml),
Trichoderma atroviride B (1 x
10
8 spores/ml),
Microsphaeropsis ochracea (1 x 10
8) and
untreated check. Sclerotia of
S. sclerotiorum were soaked in biocontrol solutions for
24 hours and placed in grids on soil in a carrot crop. For comparison, sclerotia from each
treatment were plated onto 1% water agar at room temperature with a 12 h photoperiod under
fluorescent light. There were significant differences among the treatments for field and
invitro apothecial production, sclerotia recovery and mycelia germination of the
recovered sclerotia. In the field trial, apothecial germination of sclerotia treated with
Contans was lower than the
T. atroviride B,
M. ochracea treated sclerotia and
the untreated check. Similarly in the
in vitro trial, Contans treated sclerotia had
the lowest apothecial formation than sclerotia treated with
T. atroviride A,
M.
ochracea and the untreated check. The fewest sclerotia were recovered from grids
containing sclerotia treated with Contans (12.3%) compared to all other treatments (47-56%).
In 2011, there was no mycelial germination of the sclerotia treated with Contans,
T.
atroviride A and B. In 2012,
T. atroviride B reduced mycelial germination
by 70%, while
T.
atroviride A and Contans reduced mycelial germination of the
recovered sclerotia by 50%.
Last updated
Friday, 02-Aug-2013 11:48:09 CDT
