Related Experiment Video
Updated: Jan 29, 2026
14:58
Quantifying X-Ray Fluorescence Data Using MAPS
Published on: February 17, 2018
11.3K
Quantifying Loss Caused by Ray Blight Disease in Tasmanian Pyrethrum Fields.
Sarah J Pethybridge1, Paul Esker2, Phillip Dixon3
1Tasmanian Institute of Agricultural Research (TIAR), University of Tasmania, P.O. Box 3523, Burnie, Tasmania, 7320, Australia.
Plant Disease
|February 21, 2019
Summary
Fungicide application significantly reduced ray blight disease in Tasmanian pyrethrum fields, increasing flower yield by up to 81%. Disease thresholds were identified to guide effective management strategies for pyrethrum growers.
Area of Science:
- Agricultural Science
- Plant Pathology
- Horticulture
Background:
- Ray blight, caused by Phoma ligulicola, significantly impacts pyrethrum yield and quality.
- Effective disease management is crucial for maximizing pyrethrum production in Tasmania.
Purpose of the Study:
- To quantify the efficacy of commercial fungicide recommendations in reducing ray blight intensity.
- To assess the impact of fungicide application on pyrethrum yield and pyrethrin content.
- To determine disease intensity thresholds for effective management decisions.
Main Methods:
- Field trials conducted over two seasons (2003-2004) in Tasmanian pyrethrum fields.
- Comparison of fungicide-treated plots with untreated control plots.
- Assessment of disease severity (defoliation, stem, flower incidence) and yield parameters.
- Tobit regression analysis to identify disease thresholds.
Main Results:
- Fungicide treatment significantly decreased defoliation and ray blight incidence.
- Flower dry weight increased by 68-76% and pyrethrin yield by 78-81% in treated plots.
- Identified critical thresholds for defoliation severity (35.3%, 38.2%) and stem severity (13.7%) impacting disease progression.
Conclusions:
- Commercial fungicide protocols are highly effective in controlling ray blight in pyrethrum.
- Established disease thresholds provide valuable guidance for growers to optimize fungicide application and minimize yield loss.
- Implementing these thresholds can lead to significant improvements in pyrethrum flower and pyrethrin yields.
Related Concept Videos
02:18X-ray Crystallography
26.1K
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
26.1K
01:10Line Loss
541
The different configurations of source-load connections include wye (star) and delta connections. The relationship between line and phase voltages and currents varies depending on the configuration. When the source is supplying power, it is transmitted through the wires to the load, and during this transmission, some power is absorbed by the wires, leading to line loss.
Line loss impacts power delivery efficiency in a balanced three-phase circuit. The symmetry in such a circuit simplifies the...
Line loss impacts power delivery efficiency in a balanced three-phase circuit. The symmetry in such a circuit simplifies the...
541
01:18Reducing Line Loss
385
In a three-phase circuit, line loss is an indicator of energy dissipated as heat due to the resistance of transmission lines. To address this, incorporating transformers into the system—a step-up transformer at the source and a step-down transformer at the load—is a strategic solution. Two three-phase transformers are introduced to improve this.
With a step-up transformer at the source, the voltage is increased, thereby reducing the current in the transmission lines since power loss in...
With a step-up transformer at the source, the voltage is increased, thereby reducing the current in the transmission lines since power loss in...
385
02:30Quantifying Work
24.3K
As a system undergoes a change, its internal energy can change, and energy can be transferred from the system to the surroundings, or from the surroundings to the system.
24.3K
01:24X-ray Imaging
10.1K
German physicist Wilhelm Röntgen (1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible "ray" would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound. In 1895, Röntgen made the first durable record of the internal parts of a living human: an "X-ray" image (as it came to be called) of his wife’s hand. Scientists worldwide quickly began their own experiments with...
10.1K
01:21Energy Losses in Transformers
1.3K
In an ideal transformer, it is assumed that there are no energy losses, and, hence, all the power at the primary winding is transferred to the secondary winding. However, in reality, the transformers always have some energy losses, and, hence, the output power obtained at the secondary winding is less than the input power at the primary winding due to energy losses.
There are four main reasons for energy losses in transformers.
The first cause can be the high resistance of the...
There are four main reasons for energy losses in transformers.
The first cause can be the high resistance of the...
1.3K