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Use of Survival Analysis to Assess Management Options for Ray Blight in Australian Pyrethrum Fields
Citation
Pethybridge, SJ and Ngugi, N and Hay, FS, Use of Survival Analysis to Assess Management Options for Ray Blight in Australian Pyrethrum Fields, Plant Pathology: A Record of Current Work on Plant Diseases and Pests, 59, (3) pp. 480-491. ISSN 0032-0862 (2010) [Refereed Article]
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The definitive published version is available online at: http://interscience.wiley.com
DOI: doi:10.1111/j.1365-3059.2010.02256.x
Abstract
The effects of fungicide, cultivar and plant density on the time-to-death of pyrethrum flowers affected by ray blight (caused
by Phoma ligulicola var. inoxydablis) in Australia were analysed using nonparametric Kaplan–Meier (KM) estimates and
accelerated failure time (AFT) models with aWeibull probability distribution. Analyses using KMestimates and AFT models
yielded similar results. Themedian survival time (T) for all flowers in the fungicide trial was estimated at 53 days [95% confidence
interval (CI) = 43–53] in 2000 and 60 days (CI = 51–60) in 2001. In both years, all fungicides tested except copper
oxychloride significantly (P £ 0Æ0495) increased the duration of flower survival compared with nontreated plots. Significant
variation (P < 0Æ0001) was noted between years and among four cultivars in terms of flower survival, with T values for different
cultivars ranging from 41 to 81 days, and averaging 69 days (CI = 60–69) in 2005 and 64 days (CI = 56–64) in 2006 for
all cultivars. Planting at a quarter the density currently recommended increased flower survival by 41Æ8% (v2 = 29Æ19;
P < 0Æ0001), but did not increase yield. Linear regression indicated that defoliation severity accounted for at least 94% of variation
in median survival time. Improvedmanagementmay be achieved via an integrated strategy incorporating these factors.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | crop loss, disease management, failure time analysis, Phoma ligulicola var. inoxydablis, Tanacetum cinerariifolium |
| Research Division: | Agricultural, Veterinary and Food Sciences |
| Research Group: | Crop and pasture production |
| Research Field: | Crop and pasture protection (incl. pests, diseases and weeds) |
| Objective Division: | Plant Production and Plant Primary Products |
| Objective Group: | Industrial crops |
| Objective Field: | Plant extract crops |
| UTAS Author: | Pethybridge, SJ (Dr Sarah Pethybridge) |
| UTAS Author: | Hay, FS (Dr Frank Hay) |
| ID Code: | 60090 |
| Year Published: | 2010 |
| Funding Support: | Australian Research Council (LP0560562) |
| Web of Science® Times Cited: | 7 |
| Deposited By: | Agricultural Science |
| Deposited On: | 2010-01-13 |
| Last Modified: | 2011-05-03 |
| Downloads: | 0 |
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