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Visual and Radiometric Assessments for Yield Losses Caused by Ray Blight in Pyrethrum


Pethybridge, SJ and Hay, FS and Esker, PD and Groom, T and Wilson, CR and Nutter, FW, Visual and Radiometric Assessments for Yield Losses Caused by Ray Blight in Pyrethrum, Crop Science, 48, (1) pp. 343-352. ISSN 0011-183X (2008) [Refereed Article]

DOI: doi:10.2135/cropsci2006.11.0709


The potential of remote sensing to nondestructive measure relationships between ray blight disease (caused by Phoma ligulicola), plant measurements and components of pyrethrum [Tanacetum cinerariifolium (Trevir.) Sch. Bip.] biomass and yield using a hand-held multispectral radiometer was examined. A range of disease intensities were generated using fungicides in three fields over two years. Nondestructive assessments were obtained by measuring the percentage of sunlight reflected from canopies with a radiometer equipped with five wavelength bands. Combinations of wavelength ratios and four vegetation indices were calculated. Relationships between reflectance and biomass were investigated by removing foliage from the canopy and periodically measuring reflectance. Measurements such as stem height and the number of flowers in October consistently had significant linear relationships with relative pyrethrin and flower yield. The best predictors of relative flower and pyrethrin yield were found using either percentage reflectance in the near infrared (830 nm) and the difference vegetative index (DVI). Sev eral measures had significant linear relationships with fresh weight of foliage, including the near infrared bandwidth and the DVI, which explained 95 to 97% of the biomass variation. This study demonstrated that plant measurements and disease intensity are strongly related to pyrethrin yield, and that remote sensing has great potential to nondestructively obtain preharvest yield and biomass estimates. © Crop Science Society of America.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant pathology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Horticultural crops
Objective Field:Horticultural crops not elsewhere classified
UTAS Author:Pethybridge, SJ (Dr Sarah Pethybridge)
UTAS Author:Hay, FS (Dr Frank Hay)
UTAS Author:Wilson, CR (Professor Calum Wilson)
ID Code:40819
Year Published:2008
Funding Support:Australian Research Council (LP0560562)
Web of Science® Times Cited:18
Deposited By:Agricultural Science
Deposited On:2008-04-08
Last Modified:2011-09-30

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