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Baseline sensitivity of Australian Phoma ligulicola isolates from pyrethrum to azoxystrobin and difenoconazole
journal contribution
posted on 2023-05-16, 18:10 authored by Suzanne JonesSuzanne Jones, Pethybridge, SJ, Hay, FS, Groom, T, Calum WilsonCalum WilsonRay blight caused by Phoma ligulicola is an important disease of pyrethrum in Australia, and successful management relies upon the fungicides, azoxystrobin and difenoconazole. Azoxystrobin and difenoconazole were introduced into pyrethrum production in 2001. The sensitivity of P. ligulicola isolates collected in 2003 to azoxystrobin (n = 56) and difenoconazole (n = 61) was tested. Testing for sensitivity to azoxystrobin and difenoconazole used a conidial germination and mycelial growth assay respectively. For each fungicide, the effective dose required to reduce mycelial growth or conidial germination by 50% (EC50) was determined by probit analysis. The EC50 values ranged from 0.007 to 0.193 μg/ml for azoxystrobin and 0.04 to 13.8 μg/ml for difenoconazole. No evidence was found for cross-resistance between azoxystrobin and difenoconazole in this baseline population. This information serves as important baseline data for tracking future changes in sensitivities of P. ligulicola to these fungicides. © 2007 The Authors.
Funding
Australian Research Council
Botanical Resources Australia Pty Ltd
History
Publication title
Journal of PhytopathologyVolume
155Issue
6Pagination
377-380ISSN
0931-1785Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Blackwell Verlag GmbHPlace of publication
GermanyRepository Status
- Restricted