Fungi associated with root rot of subterranean clover in Western Australia

1985 ◽  
Vol 25 (3) ◽  
pp. 574 ◽  
Author(s):  
DH Wong ◽  
MJ Barbetti ◽  
K Sivasithamparam
Keyword(s):  
Fusarium Oxysporum ◽  
Western Australia ◽  
Root Rot ◽  
Seedling Emergence ◽  
Subterranean Clover ◽  
First Record ◽  
Field Trials ◽  
Pythium Irregulare ◽  
Highly Pathogenic ◽  
South West

Field trials were conducted during 1982-84 to determine the severity of root rot, and the identity and pathogenicity of the fungi associated with root rot of subterranean clover at five locations in the south-west of Western Australia. At all sites, there was moderate to severe root rot and seedling emergence was greatly reduced. Pythium irregulare and Fusarium oxysporum were the fungi most frequently isolated from diseased roots. F. avenaceum, P. irregulare, P. spinosum and R. solani were highly pathogenic to subterranean clover seedlings. F. oxysporum and P. medicaginis were less pathogenic and F. acuminatum, F. culmorum, F. equiseti, one isolate of M. phaseoli, and W. circinata were only weakly pathogenic. Ceratobasidium sp. (AG K), F. sulphureum, one isolate of M. phaseoli, P. coloratum, and R. cereale were non-pathogenic. This is the first record of pathogenicity of F. acuminatum, F. culmorum, F. equiseti, M. phaseoli and P. spinosum on subterranean clover in Western Australia. P. clandestina was detected at all sites.

Root rot of subterranean clover in the irrigation areas of south-western Western Australia

1978 ◽  
Vol 18 (92) ◽  
pp. 426 ◽  
Author(s):  
MJ Barbetti ◽  
GC MacNish
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
Lateral Root ◽  
Disease Incidence ◽  
Seedling Emergence ◽  
Soil Water Potential ◽  
Subterranean Clover ◽  
Pythium Irregulare ◽  
Plant Emergence ◽  
Apparently Healthy

Investigations in 1974 identified the fungi associated with the roots of subterranean clover at four irrigated sites at Wagerup, Western Australia. Two of these sites had previously had a disease problem, two were apparently healthy. A range of fungi were isolated, including Pythium irregulare, P. debaryanum, P. acanthicum, P. middletonii, Fusarium oxysporum, and Rhizoctonia spp. There was a more rapid buildup of Pythium spp. population following the initial irrigation, and an overall lower incidence of Fusarium spp., at the diseased sites. The incidence of Rhizoctonia spp. was usually low and variable at all sites. Disease index ratings rose more rapidly for diseased sites. No association was proven between disease incidence and soil water potential. The three most frequently isolated fungi; viz. P. irregulare, P. acanthicum, and F. oxysporum, were all shown to be capable, under the conditions of this investigation, of producing high levels of tap and lateral root rot, and of causing reductions in seedling emergence. In some cases the levels of both tap and lateral root rot were increased, and the plant emergence decreased, by the application of two or more fungi in combination in comparison with application of a single fungus. Overall P. irregulare was the most pathogenic of the fungi tested.

Effects of soil temperature and moisture on the pathogenicity of fungi associated with root rot of subterranean clover

1984 ◽  
Vol 35 (5) ◽  
pp. 675 ◽  
Author(s):  
DH Wong ◽  
MJ Barbetti ◽  
K Sivasithamparam
Keyword(s):  
Soil Temperature ◽  
Root Rot ◽  
Marked Effect ◽  
Subterranean Clover ◽  
Pythium Irregulare ◽  
Highly Pathogenic ◽  
Soil Temperatures ◽  
Moisture Conditions ◽  
Water Holding ◽  
Soil Temperature And Moisture

The effects of soil temperature (10, 15, 20 and 25�C) and moisture (45% water holding capacity (WHC), 65% WHC, and flooding) on the pathogenicity of five fungi, both alone and in combinations, were investigated to determine the involvement of these fungi in a severe root rot disorder of subterranean clover in Western Australia. Fusarium avenaceum, Pythium irregulare, and Rhizoctonia solani were highly pathogenic while Fusarium oxysporum and Phoma medicaginis, particularly when used singly, were only weakly pathogenic. Compared with individual fungi, fungal combinations increased the severity of root disease and decreased plant survival and plant fresh weight. While the fungi investigated caused root rot over the range of soil temperatures and moisture conditions of this investigation, the most severe root rot occurred at 10�C, with less at 15 and 25�C, and least at 20�C. Temperature had a marked effect on the disease severity and its effect varied with individual fungi and their combinations, in particular, combinations involving P. irregulare (severest root rot at 10 and 15�C). The most severe root rotting, compared with the control, occurred at 65% WHC, with less at 45% WHC, and least under flooding conditions. There was often a significant interaction between temperature and moisture for the various fungi and fungal combinations tested.

Fungi associated with root and hypocotyl diseases of seedling lupins in Western Australia

1989 ◽  
Vol 40 (4) ◽  
pp. 781 ◽  
Author(s):  
MW Sweetingham
Keyword(s):  
Field Experiment ◽  
Western Australia ◽  
Root Rot ◽  
Fusarium Spp ◽  
Pythium Irregulare ◽  
Root Pathogen ◽  
Isolation Frequency ◽  
South West ◽  
Pot Experiments ◽  
Pathogenicity Tests

Pleiochaeta setosa, Pythium irregulare, Fusarium spp. and Rhizoctonia spp. were frequently isolated from root lesions on lupin seedlings growing at 18 locations in the temperate south-west of Western Australia. P. setosa was isolated from all 13 sites where lupins had previously been grown (average isolation frequency 90%) but from none of the 5 sites with no lupin history. P. setosa was pathogenic in pot experiments using colonized millet or conidia as inoculum. Certain isolates of P. irregulare and Rhizoctonia spp. were pathogenic, but all Fusarium isolates appeared very weak or non-pathogenic. In a fungicide drench field experiment Rovral� reduced the isolation of P, setosa from roots by 97% and reduced root rot by 42%, providing complementary evidence for the importance of P. setosa as a root pathogen in Western Australia.Rhizoctonia solani was isolated from characteristic reddish-brown hypocotyl lesions and reproduced these symptoms in pathogenicity tests.

Efficacy of Clonostachys rosea strain ACM941 and fungicide seed treatments for controlling the root rot complex of field pea

2003 ◽  
Vol 83 (3) ◽  
pp. 519-524 ◽  
Author(s):  
A. G. Xue
Keyword(s):  
Root Rot ◽  
Untreated Control ◽  
Seedling Emergence ◽  
Field Trials ◽  
Field Pea ◽  
Seed Treatments ◽  
Clonostachys Rosea ◽  
Pea Root ◽  
Pea Root Rot ◽  
Better Than

The efficacy of seed treatments with bioagent ACM941 (a strain of Clonostachys rosea), its formulated products GB116 and ACM941-Pro, and common fungicides for the control of pea root rot complex were examined in six field trials in western Canada from 1996 to 2000. The effects on seedling emergence, root rot severity, and yield varied among years. In trials 1 and 2 (1996–1997), none of the treatments significantly reduced root rot severity or increased yield. ACM941 + Thiram 75WP was the most effective treatment, increasing emergence by 17.4% and was significantly better than that of the untreated controls. In trials 3 and 4 (1997–1998), Apron FL alone and ACM941 + Apron FL were significantly better than the untreated control, increasing emergence by 6.2 and 7.7%, and yield by 10.8 and 11.5%, respectively. In trials 5 and 6 (1999–2000), AC M 941 and GB116 were equally the most effective treatments, increasing emergence by 11.5 and 12.2%, and yield by 8.2 and 6.3%, respectively. These effects were significantly greater than that of the untreated control, but not significantly different from those of Apron FL or Vitaflo-280. ACM941-Pro was developed and tested in 2000 only, and it increased emergence by 17.1% and reduced root rot severity by 29.6%. Key words: Bioagent, Clonostachys rosea, field pea, Pisum sativum, pea root rot complex (PRRC), seed treatment, fungicide

The effects of different cultivars of subterranean clover (T. subterraneum L.) on sheep reproduction in the South-west of Western Australia

1970 ◽  
Vol 21 (2) ◽  
pp. 359 ◽  
Author(s):  
HL Davies ◽  
RC Rossiter ◽  
R Maller
Keyword(s):  
Western Australia ◽  
Uterine Prolapse ◽  
Subterranean Clover ◽  
Conception Rate ◽  
The South ◽  
Progressive Decline ◽  
South West ◽  
Conception Rates

The cultivars Dwalganup, Geraldton, Yarloop, Woogenellup, and Mt. Barker were each grazed continuously by Merino and Merino x Border Leicester ewes from April 1963 to November 1967. There was a progressive decline in the proportion of Merino ewes conceiving on the three high oestrogen cultivars Dwalganup, Geraldton, and Yarloop; crossbred ewes showed a decline on Dwalganup and Yarloop. For neither breed of sheep was the decline in conception rate significant on the two low oestrogen cultivars Woogenellup and Mt. Barker. The incidence of uterine prolapse was higher on the high oestrogen cultivars. The percentage lambs marked in 1967 was only 50% for the high oestrogen cultivars (excluding the crossbred ewes on Geraldton), compared with 93% for the low group. Conception rates were significantly related to the concentration of the isoflavone formononetin in the clover leaves.

Severity of root rot in mature subterranean clover and associated fungal pathogens in the wheatbelt of Western Australia

2009 ◽  
Vol 60 (1) ◽  
pp. 43 ◽  
Author(s):  
Tiernan A. O'Rourke ◽  
Tim T. Scanlon ◽  
Megan H. Ryan ◽  
Len J. Wade ◽  
Alan C. McKay ◽  
...  
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
Fungal Pathogens ◽  
Lateral Roots ◽  
Subterranean Clover ◽  
Growing Season ◽  
Root Diameter ◽  
Root Disease ◽  
Soil Dna ◽  
Tap Root

Pasture decline is considered to be a serious challenge to agricultural productivity of subterranean clover across southern Australia. Root disease is a significant contributing factor to pasture decline. However, root disease assessments are generally carried out in the early part of the growing season and in areas predominantly sown to permanent pastures. For this reason, in spring 2004, a survey was undertaken to determine the severity of root disease in mature subterranean clover plants in pastures located in the wheatbelt of Western Australia. DNA-based soil assays were used to estimate population density in the soil of a variety of soil-borne pathogens known to commonly occur in the Mediterranean-type environments of southern Australia. The relationships between severity of disease on tap and lateral roots and root diameter, root length, nodulation, and total rainfall were determined. The survey showed, for the first time, that severe root disease is widespread in spring across the wheatbelt of Western Australia. There was a positive correlation between rainfall and tap root disease, and between tap root disease and average root diameter of the entire root system. Despite the high levels of root disease present across the sites, the DNA of most root disease pathogens assayed was detected in trace concentrations. Only Pythium Clade F showed high DNA concentrations in the soil. DNA concentrations in the soil, in particular for Phytophthora clandestina and Rhizoctonia solani AG 2.1 and AG 2.2, were higher in the smaller autumn sampling in 2006. This study suggests that the productivity of subterranean clover-based pastures is severely compromised by root rot diseases throughout the growing season in the wheatbelt of Western Australia.

Occurrence of Phytophthora clandestina in Trifolium subterraneum paddocks in Australia

2001 ◽  
Vol 41 (2) ◽  
pp. 187 ◽  
Author(s):  
R. Aldaoud ◽  
W. Guppy ◽  
L. Callinan ◽  
S. F. Flett ◽  
K. A. Wratten ◽  
...  
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
New South ◽  
New South Wales ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Soil Samples ◽  
South Wales ◽  
Differential Cultivars

In 1995–96, a survey of soil samples from subterranean clover (Trifolium subterraneum L.) paddocks was conducted across Victoria, South Australia, New South Wales and Western Australia, to determine the distribution and the prevalence of races of Phytophthora clandestina (as determined by the development of root rot on differential cultivars), and the association of its occurrence with paddock variables. In all states, there was a weak but significant association between P. clandestina detected in soil samples and subsequent root rot susceptibility of differential cultivars grown in these soil samples. Phytophthora clandestina was found in 38% of the sampled sites, with a significantly lower prevalence in South Australia (27%). There were significant positive associations between P. clandestina detection and increased soil salinity (Western Australia), early growth stages of subterranean clover (Victoria), mature subterranean clover (South Australia), recently sown subterranean clover (South Australia), paddocks with higher subterranean clover content (Victoria), where herbicides were not applied (South Australia), irrigation (New South Wales and Victoria), cattle grazing (South Australia and Victoria), early sampling dates (Victoria and New South Wales), sampling shortly after the autumn break or first irrigation (Victoria), shorter soil storage time (Victoria) and farmer’s perception of root rot being present (Victoria and New South Wales). Only 29% of P. clandestina isolates could be classified under the 5 known races. Some of the unknown races were virulent on cv. Seaton Park LF (most resistant) and others were avirulent on cv. Woogenellup (most susceptible). Race 1 was significantly less prevalent in South Australia than Victoria and race 0 was significantly less prevalent in New South Wales than in South Australia and Western Australia. This study revealed extremely wide variation in the virulence of P. clandestina. The potential importance of the results on programs to breed for resistance to root rot are discussed. in South Australia.

scholarly journals Characterization and Pathogenicity of Rhizoctonia Species on Canola

Plant Disease ◽  
1999 ◽  
Vol 83 (8) ◽  
pp. 714-721 ◽  
Author(s):  
Ravjit K. Khangura ◽  
Martin J. Barbetti ◽  
Mark W. Sweetingham
Keyword(s):  
Root Rot ◽  
Seedling Emergence ◽  
Subterranean Clover ◽  
Enzyme Electrophoresis ◽  
Nuclear Staining ◽  
Damping Off ◽  
Weed Species ◽  
Bare Patch ◽  
Hyphal Morphology ◽  
Leguminous Crops

A total of 112 Rhizoctonia isolates were collected from various canola (Brassica napus) growing areas of Western Australia. Pectic enzyme electrophoresis differentiated these isolates into six distinct zymogram groups: R. solani, 54% ZG5 (AG2-1), 8% ZG6 (AG2-1), and 1% ZG9 (AG10); binucleate Rhizoctonia, 12% CZG1 (CAG1), 4% CZG4, and 6% CZG5 (AGK); and the remainder unidentified binucleate groups (15%). Binucleate groups were also confirmed by fluorescent nuclear staining and hyphal morphology. One or more isolates from each of the above zymogram groups (including four unidentified binucleate groups) and an isolate of ZG1-1 (AG8) that causes bare patch in cereals and legumes were tested for their pathogenicity on canola. Isolates of ZG5 and ZG1-1 were highly pathogenic on canola, delayed seedling emergence, and caused severe hypocotyl and root rot, respectively. ZG5 also induced postemergence damping-off. Increasing the depth of sowing from 1 to 3 cm significantly delayed seedling emergence and increased disease severity. Four unidentified binucleate isolates (WAC9316, WAC9297, WAC9307, and WAC9290) were moderately pathogenic to canola, while two isolates (WAC9307 and WAC9316) caused significant preemergence damping-off. Two CZG5 isolates were weakly pathogenic. Isolates of ZG5 and ZG1-1 were also tested for their pathogenicity on other rotational crops (narrow-leafed lupin, subterranean clover, wheat, oats, barley, and mustard) and two weed species (wild radish and annual ryegrass). ZG5 caused a severe hypocotyl rot on mustard and mild symptoms of hypocotyl rot on narrow-leafed lupin and clover, but failed to infect any of the cereal hosts, such as wheat, oats, barley, and ryegrass. In contrast, all crops tested were highly susceptible to ZG1-1 except mustard, which was only moderately susceptible. Results indicate that ZG5 is most pathogenic to crucifers and is a mildly virulent pathogen of the leguminous crops but not of cereal crops tested. ZG1-1, known to cause bare patch in legumes and cereals, also can cause severe root rot in canola. This is the first report of hypocotyl rot and pathogenicity of ZG5 on canola in Australia.

Root rot of irrigated lentils in Iran

1980 ◽  
Vol 58 (24) ◽  
pp. 2549-2556 ◽  
Author(s):  
Walter J. Kaiser ◽  
Glenn M. Horner
Keyword(s):  
Root Rot ◽  
Lens Culinaris ◽  
Pythium Ultimum ◽  
Macrophomina Phaseolina ◽  
Field Trials ◽  
Fusarium Spp ◽  
Sources Of Resistance ◽  
Highly Pathogenic ◽  
P Fertilizer ◽  
Greenhouse Tests

In some areas of Iran, root rot of irrigated lentils (Lens culinaris) was a serious problem resulting in high plant mortality and decreased yields. Pythium ultimum was the predominant soil-borne pathogen isolated from discolored, necrotic roots of diseased plants in furrow-irrigated fields at Karaj, and appeared to be the primary incitant of root rot of irrigated lentils at several other locations in the country. Pythium aphanidermatum was the primary pathogen isolated from roots of diseased lentils at two irrigated sites in southern Iran. Isolates of P. ultimum and P. aphanidermatum were highly pathogenic on roots of lentil in greenhouse inoculation studies. Other fungi isolated from diseased lentil roots less frequently were Rhizoctonia solani, Phytophthora sp., Macrophomina phaseolina, Fusarium oxysporum, F. roseum, and F. solani. Cultures of R. solani, Phytophthora sp., and M. phaseolina were less pathogenic on lentil roots than either Pythium sp., whereas the three Fusarium spp. were nonpathogens. Incidence and severity of root rot increased in Karaj field trials in treatments receiving N and P fertilizer and irrigation every 6 days. In greenhouse tests, incidence of root rot increased when naturally infested Karaj soils were amended with 1 or 10% cow manure before planting. Sources of resistance to the lentil root rot complex were found in germplasm screened in naturally infested soils at Karaj.

Effect of short chemical fallow on Rhizoctonia bare patch and root rot of wheat at Esperance, Western Australia

1987 ◽  
Vol 27 (5) ◽  
pp. 671 ◽  
Author(s):  
GC MacNish ◽  
CS Fang
Keyword(s):  
Grain Yield ◽  
Western Australia ◽  
Root Rot ◽  
Subterranean Clover ◽  
Research Station ◽  
Annual Ryegrass ◽  
Bare Patch ◽  
Rhizoctonia Root Rot ◽  
Mixture Prior ◽  
Chemical Fallow

The effects of short chemical fallows after ryegrass pasture on rhizoctonia bare patch and root rot ofwheat were studied in 2 experiments at the Esperance Downs Research Station, 35 km north of Esperance, W.A. In 1 experiment the subterranean-clover dominant pasture was sprayed with a paraquat-diquat mixture prior to resowing with annual ryegrass at densities ranging from 3 to about 400 plants m-2. The ryegrass was allowed to grow for either 42 or 63 days prior to treatment with a desiccant herbicide (paraquat-diquat) followed by a short chemical fallow of 26 or 5 days, respectively, before sowing with wheat using minimum tillage. Some treatments were cultivated twice to 10 cm. Neither the ryegrass density nor the length of chemical fallow had any effect (P=0.05) on rhizoctonia bare patch score or incidence or severity of root rot. However, cultivation caused 76% reduction in mean patch score and a 38 and 68% reduction in mean rhizoctonia incidence and severity respectively. Yield was negatively correlated with rhizoctonia incidence and severity: each 1% increase in incidence percentage resulted in 17 kg ha-1 reduction in grain yield of wheat. In another experiment, chemical fallow periods of 66, 52, 24 or 1 day prior to sowing wheat had no effect (P= 0.05) on rhizoctonia root rot incidence.

Sign in / Sign up

Export Citation Format

Share Document