New Zealand Journal of Crop and Horticultural Science abstracts
Application strategies for control of onion white rot by fungal
antagonists
K. L. MCLEAN
A. STEWART
Soil, Plant and Ecological Sciences Division
P. O. Box 84, Lincoln University
Canterbury, New Zealand
email: StewartA@lincoln.ac.nz
Abstract The fungal species
Chaetomium globosum,
Coniothyrium minitans,
Trichoderma harzianum,
T. koningii,
and
T. virens were confirmed as antagonists of
Sclerotium
cepivorum, the causal agent of onion white rot in two glasshouse trials. In
Trial 1, all fungal treatments afforded disease control equivalent to the
fungicide procymidone (1 g a.i./100 g seed) when applied to the soil
as a soil additive (sand:bran:fungal mix, 1:1:2) at the time of planting.
Applications of
T. harzianum (C52) and
T. koningii (C62)
significantly reduced disease incidence from 39.8% in the control to 7.7 and
5.4%, respectively. When treatments were applied 2 weeks before planting, only
T. harzianum (C52) gave disease control equivalent to the fungicide. In
Trial 2, disease incidence was significantly less when
T. harzianum
(C52, D73) and
T. virens (GV4) were applied as soil additives at
planting (34, 40, and 43.1%, respectively) compared with that in the control
treatment (66.5%) 8 weeks after planting. However, disease control declined as
Trial 2 progressed with over 95% of the plants infected in all treatments at
trial completion. Strategies for field application of the best biological
control agents for control of onion white rot are discussed.
Keywords Chaetomium globosum; Coniothyrium
minitans; Trichoderma harzianum; T. koningii; T.
virens; Sclerotium cepivorum; biological control; sand:bran:fungal
mix; onion white rot; glasshouse trials
H99034
Received 22 September 1999; accepted 6 March 2000
PDF file of entire paper: medium quality (644K); (scanned from paper original: notes about this process)
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