Ecological field studies on Anguina funesta, the vector in annual ryegrass toxicity

1981 ◽  
Vol 32 (6) ◽  
pp. 917 ◽  
Author(s):  
AC McKay ◽  
JM Fisher ◽  
AJ Dube
Keyword(s):  
Environmental Conditions ◽  
Field Studies ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Second Stage ◽  
Stage Of Development ◽  
Annual Ryegrass Toxicity

Entry of second-stage juveniles (J2) of Anguina funesta into the apex of Lolium rigidum was dependent on environmental conditions and so varied in 1978 and 1979. Penetration and initiation of galls dependent on stage of development of the plant, was more consistent and occurred in late August-early September. Two to three nematodes initiated each gall. The first egg was deposited at the end of September and the first J2 hatched in mid-October. The implications of these observations for control are discussed. Mowing and grazing, the fungus Dilophospora alopecuri, and good clover growth all showed promise in reducing numbers of the nematode.

Control of the nematode associated with annual ryegrass toxicity

1983 ◽  
Vol 34 (4) ◽  
pp. 403 ◽  
Author(s):  
AC McKay ◽  
JM Fisher ◽  
AJ Dube
Keyword(s):  
Subterranean Clover ◽  
Good Control ◽  
Parasitic Fungus ◽  
Annual Ryegrass ◽  
Pasture Management ◽  
Pasture Production ◽  
Second Stage ◽  
Before And After ◽  
Legume Growth ◽  
Annual Ryegrass Toxicity

To control the nematode Anguina funesta (considered by some to be A. agrostis), the vector in annual ryegrass toxicity, pasture management treatments were applied before and after gall initiation. Before gall initiation, the herbicides paraquat and diclofop methyl were used to remove ryegrass. These treatments gave good control of the nematode, but reduced pasture production in winter when feed is generally scarce. Diclofop methyl had no detrimental effect on legume growth, and was more effective on actively growing ryegrass than was paraquat, which severely retarded subterranean clover. Desiccating the ryegrass heads, with mechanical topping or the desiccant herbicide paraquat, after gall initiation, but before hatching of the second-stage juveniles ( J2s ) , gave good control of the nematode population. The main limitations with mechanical topping are that the ryegrass heads must be tall enough to cut before the J2s hatch and not all paddocks are suitable for topping. With paraquat, the main limitations are that treated material was susceptible to weathering and there was less regrowth to set seed. Oxamyl, a systemic nematicide applied after gall initiation, had no effect on the nematode, nor had spraying pasture with the nematode parasitic fungus Verticillium sp.

Development and application of polymerase chain reaction-based assays for Rathayibacter toxicus and a bacteriophage associated with annual ryegrass (Lolium rigidum) toxicity

2007 ◽  
Vol 47 (2) ◽  
pp. 177 ◽  
Author(s):  
M. C. Kowalski ◽  
D. Cahill ◽  
T. J. Doran ◽  
S. M. Colegate
Keyword(s):  
Polymerase Chain Reaction ◽  
Immunosorbent Assay ◽  
Potential Application ◽  
South Australia ◽  
Enzyme Linked Immunosorbent Assay ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Chain Reaction ◽  
Polymerase Chain ◽  
Annual Ryegrass Toxicity

Annual ryegrass toxicity (ARGT) is responsible for significant stock losses in South Australia and Western Australia. The toxicity is caused by corynetoxins produced by the bacterium Rathayibacter toxicus (with the possible involvement of a bacteriophage), which infects annual ryegrass (Lolium rigidum). Polymerase chain reaction (PCR)-based assays, compatible with an existing enzyme-linked immunosorbent assay for the corynetoxins, have been developed and used to screen L. rigidum for both the presence of R. toxicus and for the bacteriophage isolate NCPPB 3778. The results from analysing bacterially infected galls from toxic grain screenings showed a positive correlation between the presence of the bacterium and corynetoxins but not with the bacteriophage. Analysis of pasture-derived samples of annual ryegrass showed about a 50% correlation of corynetoxins with bacterial presence and about a 5% correlation of phage with the presence of the bacterium. These observations support the potential application of the PCR-based assays in providing a useful, complementary tool in the assessment of the likelihood of pasture and feed to cause ARGT and to enable a better understanding of the complex aetiology of ARGT.

Rapid estimation of corynetoxins in bacterial galls from annual ryegrass (Lolium rigidum Gaudin) by high-performance liquid chromatography

1985 ◽  
Vol 36 (1) ◽  
pp. 35 ◽  
Author(s):  
PA Cockrum ◽  
JA Edgar
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
South Australia ◽  
Reversed Phase ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Aqueous Methanol ◽  
The Individual ◽  
Annual Ryegrass Toxicity

A rapid and sensitive method is described for the extraction, detection and measurement of corynetoxins in ryegrass seed galls colonized by Corynebucterium rathayi. Excised galls are extracted with aqueous methanol and the extract analysed, without further purification, by reversed-phase high-performance liquid chromatography with detection by uItraviolet absorption. The method is applicable down to the level of a single gall or part of a gall with a minimum level of detection of about 0.25 �g using the equipment described. The corynetoxin content of the individual galls examined varied from below the detection limit to 10.6 �g. The highest level of corynetoxin in a single gall was 1.15% of gall weight. The corynetoxin composition of galls collected during outbreaks of annual ryegrass toxicity in South Australia, Western Australia and South Africa during a 19-year period were found to be similar.

Production of corynetoxins in vitro by Corynebacterium sp. isolated from annual ryegrass seedheads

1988 ◽  
Vol 39 (1) ◽  
pp. 63 ◽  
Author(s):  
AL Payne ◽  
PA Cockrum
Keyword(s):  
Incubation Temperature ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
In Vitro Production ◽  
The Family ◽  
Agar Surface ◽  
Vitro Production ◽  
Corynebacterium Sp ◽  
Annual Ryegrass Toxicity

Corynetoxin complex is the family of tunicamycin-like antibiotics isolated from annual ryegrass (Lolium rigidum) seedheads infected with a plant pathogenic Corynebacterium and identified as the causative toxins for annual ryegrass toxicity (ARGT) in Australia. Only trace amounts of corynetoxins have been reported to be produced in vitro. Enhanced in vitro production of corynetoxins by Corynebacterium sp. has now been demonstrated. The important conditions required were growth on an agar surface, absence of light, low incubation temperature and strain of the organism. Strains of the Corynebaterium sp. grown under conditions not supporting corynetoxin production failed to produce corynetoxins when subsequently grown under more favourable conditions. Even when maintained under the most favourable conditions, toxigenicity of strains declined on repeated subculturing. While levels of toxin typically produced in vitro were only about 5% of those found in infected ryegrass seedheads, they were high enough to be a useful source of corynetoxins for experimental purposes.

Relationship between herbicide resistance in Lolium rigidum and populations of Anguina funesta, the nematode vector in annual ryegrass toxicity

1994 ◽  
Vol 34 (5) ◽  
pp. 633 ◽  
Author(s):  
IT Riley ◽  
GS Gill
Keyword(s):  
Herbicide Resistance ◽  
Rapid Development ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Annual Ryegrass Toxicity ◽  
Causal Bacterium

Samples of annual ryegrass (Lolium rigidum Gaudin) seed tested for herbicide resistance were examined for seed-galls of Anguina funesta, the nematode vector of Clavihacter toxicus the causal bacterium in annual ryegrass toxicity (ARGT). Of the 246 samples examined, 63% contained galls, with concentrations up to 1400 galls per 10 g of seed. Higher herbicide resistance was associated with increased concentrations of A. funesta. We conclude that use of selective herbicides for ARGT control may have contributed to the rapid development of herbicide resistance.

Corynetoxins are not detoxicated by in vitro fermentation in ovine rumen fluid

1986 ◽  
Vol 37 (5) ◽  
pp. 523 ◽  
Author(s):  
P Vogel ◽  
MG McGrath
Keyword(s):  
Rumen Fluid ◽  
Annual Ryegrass ◽  
Inhibition Assay ◽  
Lolium Rigidum ◽  
In Vitro Fermentation ◽  
Bacterial Inhibition ◽  
Annual Ryegrass Toxicity

Tunicamycin and seed galls of annual ryegrass (Lolium rigidum) containing corynetoxins, the causal agents of annual ryegrass toxicity, were incubated in ovine rumen fluid-buffer mixtures. A bacterial inhibition assay of extracted incubation mixtures revealed that no detoxication occurred under these in vitro conditions.

scholarly journals Annual ryegrass toxicity – an animal disease caused by toxins produced by a bacterial plant pathogen

2012 ◽  
Vol 33 (1) ◽  
pp. 18 ◽  
Author(s):  
Jeremy Allen
Keyword(s):  
Plant Pathogen ◽  
Neurological Disease ◽  
Animal Disease ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Grain Crop ◽  
Bacterial Plant Pathogen ◽  
Annual Ryegrass Toxicity

Annual ryegrass toxicity (ARGT) is an acute and often fatal neurological disease of livestock caused by consumption of annual ryegrass (Lolium rigidum) seed heads infected with the bacterium Rathayibacter toxicus (formerly Clavibacter toxicus and Corynebacterium rathayi). These toxic seed heads may be present in pasture, crop stubbles or provided feed (hay, grain, crop fines or pellets).

Variation in colonisation of Lolium rigidum by isolates of Dilophospora alopecuri, an antagonist of the causal organisms of annual ryegrass toxicity

2005 ◽  
Vol 45 (9) ◽  
pp. 1157 ◽  
Author(s):  
G. Yan ◽  
I. T. Riley
Keyword(s):  
Avena Sativa ◽  
The Other ◽  
Marked Variation ◽  
Annual Ryegrass ◽  
Holcus Lanatus ◽  
Lolium Rigidum ◽  
Grass Hosts ◽  
Annual Ryegrass Toxicity ◽  
Selection Of

The ability of 31 isolates of Dilophospora alopecuri to colonise Lolium rigidum co-inoculated with Anguina funesta and grown in pots outdoors was tested over 2 years. The isolates were collected from 3 grass hosts from sites across the southern mainland states of Australia. Marked variation among isolates of different host and regional origins was found. Isolates from L. rigidum showed the greatest colonisation with a mean of 16 infected inflorescences per 240 mm pot containing 32 plants. Isolates from the other hosts, Avena sativa, Holcus lanatus and Polypogon monspeliensis, only resulted in means of 1.9, 7.7 and 1.3 infected inflorescences per pot, respectively. The data allow selection of an aggressive isolate for dissemination for antagonism of A. funesta, one of the causal agents for annual ryegrass toxicity.

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