Dilophospora alopecuri and decline in annual ryegrass toxicity in Western Australia

1994 ◽  
Vol 45 (4) ◽  
pp. 841 ◽  
Author(s):  
IT Riley
Keyword(s):  
Western Australia ◽  
Soil Samples ◽  
Annual Ryegrass ◽  
Biological Factors ◽  
The South ◽  
Population Densities ◽  
Important Contributor ◽  
Annual Ryegrass Toxicity

Biological factors contributing to the decline in the incidence of annual ryegrass toxicity (ARGT) in Western Australia were investigated. Annual ryegrass and soil samples were collected in the area where ARGT outbreaks first occurred in Western Australia, an area where the incidence of ARGT has markedly declined. The nematode vector, Anguina funesta, was found in 68% of samples, whereas the toxigenic bacterium, Clavibacter toxicus, was detected in fewer than 2% of samples. The population densities of the nematode were low, but other attributes assayed were normal. The fungus, Dilophospora alopecuri, also associated with A. funesta, was found at 58% of the sampling sites. The abundance of D. alopecuri suggests that it is an important contributor to decline in ARGT. Therefore, the distribution of D. alopecuri in Western Australia was determined in the following season. D. alopecuri was common in the southerly range of A. funesta, but absent in the northerly range where ARGT outbreaks are still common. In the south, D. alopecuri appears to have displaced C. toxicus and reduced A. funesta populations. The findings suggest that there is potential to use D. alopecuri to control ARGT

Reliability of paddock sampling for the organisms (Anguina funesta and Clavibacter toxicus) responsible for annual ryegrass toxicity

1993 ◽  
Vol 33 (7) ◽  
pp. 861 ◽  
Author(s):  
IT Riley ◽  
JM Stanton ◽  
AGP Brown
Keyword(s):  
Western Australia ◽  
Recent History ◽  
Annual Ryegrass ◽  
Population Densities ◽  
Testing Service ◽  
Reliable Tool ◽  
History Of ◽  
Annual Ryegrass Toxicity

An examination of within-paddock distribution of the nematode (Anguina funesta) and bacterium (Clavibacter toxicus) responsible for annual ryegrass toxicity (ARGT) was undertaken to determine the reliability of farmer-collected samples in determining the risk of ARGT. Areas in Western Australia with a recent history of ARGT outbreaks were selected for study. The results indicate that the distribution of ARGT organisms is patchy in paddocks with low population densities, but as the populations grow they spread throughout the paddock. Populations are not likely to reach toxic levels before they become widespread in the paddock. Farmer-collected samples processed by the ARGT Testing Service procedure were found to be a reliable tool for the management of ARGT in Western Australia.

Development of annual ryegrass toxicity

1983 ◽  
Vol 34 (6) ◽  
pp. 653 ◽  
Author(s):  
BA Stynes ◽  
AF Bird
Keyword(s):  
Electron Microscope ◽  
Plant Growth ◽  
Western Australia ◽  
Growth Stage ◽  
Maximum Level ◽  
Annual Ryegrass ◽  
Physiological Aging ◽  
Bacterial Inhibition ◽  
Annual Ryegrass Toxicity ◽  
Experimental Plots

Ryegrass pasture, containing seed galls induced by Anguina agrostis and colonized by Corynebacterium rathayi, was harvested from experimental plots near Katanning in Western Australia. Plant growth stage, numbers of emerged inflorescences and numbers of galls present were estimated for 10 harvests collected at weekly intervals, commencing 22 September when the first inflorescences had emerged. The concentration of toxin (corynetoxins) at each harvest was estimated using a bacterial inhibition bioassay. Levels of toxin were up to 459 �g per m2 pasture prior to and during anthesis, but the concentration increased rapidly during the final four harvests (corresponding to ripening) and reached a maximum level of 6292 �g m-2. A possible relationship between toxicity and the presence of ultramicroscopic particles observed in the galls was investigated. Galls from each harvest were sectioned and examined under the electron microscope. Particles were not found in galls sampled prior to anthesis, but were found in galls from the last four harvests. From these results, the production of toxin appears to be related to physiological aging of the plant and may also be related to the accumulation of particles.

The distribution and importance of annual ryegrass toxicity in Western Australia and its occurrence in relation to cropping rotations and cultural practices

1980 ◽  
Vol 31 (3) ◽  
pp. 557 ◽  
Author(s):  
BA Stynes ◽  
JL Wise
Keyword(s):  
Western Australia ◽  
Cultural Practices ◽  
Annual Ryegrass ◽  
Four Seasons ◽  
Annual Ryegrass Toxicity

Surveys in Western Australia showed annual ryegrass toxicity to occur on 152 farms in an area around Gnowangerup measuring c. 100 km by 150 km and on 18 farms in four other isolated areas. The disease has spread rapidly during the last 10 years, and has been favoured by practices aimed at pasture improvement in alternating crop-pasture rotations. In the last four seasons, between 76 and 95 % of all stock mortalities due to ryegrass toxicity occurred on fields grazed in the season following a cropping year. Under these conditions, ryegrass is dominant in the pasture, and infection levels are highest. Burning these fields in autumn reduces the level of infection and makes the pasture relatively safe to graze in this season.

Survey of feral honey bee (Apis mellifera) colonies for Nosema apis in Western Australia

2007 ◽  
Vol 47 (7) ◽  
pp. 883 ◽  
Author(s):  
Rob Manning ◽  
Kate Lancaster ◽  
April Rutkay ◽  
Linda Eaton
Keyword(s):  
Apis Mellifera ◽  
Honey Bee ◽  
Western Australia ◽  
Honey Bees ◽  
Nosema Apis ◽  
The South ◽  
South West ◽  
Feral Populations ◽  
Significant Difference

The parasite, Nosema apis, was found to be widespread among feral populations of honey bees (Apis mellifera) in the south-west of Western Australia. The location, month of collection and whether the feral colony was enclosed in an object or exposed to the environment, all affected the presence and severity of infection. There was no significant difference in the probability of infection between managed and feral bees. However, when infected by N. apis, managed bees appeared to have a greater severity of the infection.

scholarly journals Our New Cathedrals: Spirituality and Old-Growth Forests in Western Australia

2006 ◽  
Vol 3 (1) ◽  
Author(s):  
David Worth
Keyword(s):  
Social Movements ◽  
Western Australia ◽  
The State ◽  
The South ◽  
Old Growth ◽  
The Past ◽  
South West ◽  
Old Growth Forests ◽  
Heated Debate ◽  
Policy Proposals

Over the past 30 years in Western Australia (WA), there has been heated debate about the future use of the remaining karri and jarrah forests in the south-west of the State. This debate revolves around policy proposals from two social movements: one wants to preserve as much of the remaining old-growth forests as possible, and an opposing movement supports a continued

scholarly journals Least limiting water range of Udox soil under degraded pastures on different sun-exposed faces

2017 ◽  
Vol 31 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Renato Ribeiro Passos ◽  
Liovando Marciano da Costa ◽  
Igor Rodrigues de Assis ◽  
Danilo Andrade Santos ◽  
Hugo Alberto Ruiz ◽  
...  
Keyword(s):  
Soil Management ◽  
Sun Exposure ◽  
Soil Samples ◽  
The South ◽  
Undisturbed Soil ◽  
North West ◽  
The North ◽  
Pasture Degradation ◽  
Least Limiting Water Range ◽  
Degraded Pastures

AbstractThe efficient use of water is increasingly important and proper soil management, within the specificities of each region of the country, allows achieving greater efficiency. The South and Caparaó regions of Espírito Santo, Brazil are characterized by relief of ‘hill seas’ with differences in the degree of pasture degradation due to sun exposure. The objective of this study was to evaluate the least limiting water range in Udox soil under degraded pastures with two faces of exposure to the sun and three pedoenvironments. In each pedoenvironment, namely Alegre, Celina, and Café, two areas were selected, one with exposure on the North/West face and the other on the South/East face. In each of these areas, undisturbed soil samples were collected at 0-10 cm depth to determine the least limiting water range. The exposed face of the pasture that received the highest solar incidence (North/West) presented the lowest values in least limiting water range. The least limiting water range proved to be a physical quality indicator for Udox soil under degraded pastures.

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