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Spatiotemporal Analysis of Epiphytotics of Downy Mildew of Oilseed Poppy in Tasmania, Australia
journal contribution
posted on 2023-05-16, 13:26 authored by Jason ScottJason Scott, Hay, FS, Calum WilsonCalum Wilson, Cotterill, PJ, Fist, AJDowny mildew, caused by Peronospora arborescens, has become the major disease affecting oilseed poppy (Papaver somniferum) since its first record in Tasmania in 1996. Two field trials conducted in 2000 and 2001 studied the progression and spatial distribution of downy mildew epiphytotics. The logistic and exponential models best described the progression of disease incidence and severity, respectively. Incidence and severity increased rapidly following canopy closure. In 2001, incidence increased from 0.16%, prior to canopy closure, to 100% at late flowering (40 days). Spatial analyses of epiphytotics were conducted by fitting the beta-binomial and binomial distributions, median runs analysis, and the spatial analysis by distance indices. All analyses demonstrated that the distribution of incidence and severity was strongly spatially aggregated from canopy closure until at least late flowering. These results suggest that secondary spread from a few primary infections is the major factor in epiphytotics.
History
Publication title
PhytopathologyVolume
93Issue
6Pagination
752-757ISSN
0031-949XDepartment/School
Tasmanian Institute of Agriculture (TIA)Publisher
American Phytopathological SocietyPlace of publication
St Paul, Mn 55121 USARepository Status
- Restricted