Fusarium avenaceum, a seed-borne pathogen of subterranean clover roots

1974 ◽  
Vol 25 (4) ◽  
pp. 549 ◽  
Author(s):  
DC McGee ◽  
AW Kellock
Keyword(s):  
Root Rot ◽  
Laboratory Tests ◽  
Subterranean Clover ◽  
Fusarium Avenaceum ◽  
Seed Infection ◽  
Highly Pathogenic ◽  
Infected Seed ◽  
Clover Root ◽  
First Time

Fusarium avenaceum (Corda ex Fr.) Sacc. has been shown for the first time to be a seed-borne pathogen of subterranean clover (T. subterraneum L.). In laboratory tests symptoms of subterranean clover root rot occurred on plants grown from infected seed. F. oxysporum (Schlecht.) also was seed-borne. It was only weakly pathogenic, although isolated more frequently from diseased roots than F. avenaceum. Pythium sp. was not detected on seed and rarely isolated from roots of diseased field plants, but it was highly pathogenic to subterranean clover roots in laboratory tests. F. avenaceum was detected in 81 out of 85 seed lines tested, which comprised 11 cultivars, from four Australian States. Infection with F. avenaceum occurred on up to 27% of the seed in a sample. An application of benomyl (0.63 g/kg seed) controlled seed infection.

Infection of seed of subterranean clover and allied species by species of Fusarium

1980 ◽  
Vol 31 (2) ◽  
pp. 297 ◽  
Author(s):  
AW Kellock ◽  
LL Stubbs ◽  
DG Parbery
Keyword(s):  
Root Rot ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Scar Tissue ◽  
Seed Infection ◽  
Fusarium Spp ◽  
Blotting Paper ◽  
Optical Brighteners ◽  
First Time ◽  
Healthy Seed

Fusarium avenaceurn (Corda ex Fr.) Sacc. was shown for the first time to be carried in the hilum of subterranean clover (Trifolium Subterraneum L.) seed. Scanning electron microscopy and thin-section techniques showed that the fungus occurred only as dormant mycelium in parenchyma cells of funicle scar tissue. It emerged from these tissues after a 12 h incubation at 24�C and in 48 h penetrated internal parts of the seed through the hilum fissure. After 21 days on moist blotting paper, seedlings grown from infected seed developed lesions on their roots similar to those of root-rot of subterranean clover in the field. Fusarium spp. were also detected in the hilum of seeds of white (T. repens L.) and strawberry (T. fragiferum L.) clover and barrel medic (M. truncatula L.). It was demonstrated experimentally that all parts of the burr, incl~tding the funicle, became infected with F. avenaceuni when subterranean clover plants grown from healthy seed in pasteurized soil buried their burrs in soil inoculated with the fungus. Use of optical brighteners failed to trace seed infection because the compounds, although absorbed by the pathogen in culture, were not translocated.

Nodulation of subterranean clover growing in permanent pastures on acid soils in North-Central Victoria

1986 ◽  
Vol 26 (1) ◽  
pp. 31 ◽  
Author(s):  
HR Jones ◽  
BC Curnow
Keyword(s):  
Root Rot ◽  
Acid Soils ◽  
Subterranean Clover ◽  
Rhizobium Trifolii ◽  
Soil Factors ◽  
North Central ◽  
Exchangeable Calcium ◽  
Central Victoria ◽  
Clover Root

A survey ofclover at 44 sites in permanent dryland pastures in North-Central Victoria, highlighted poor nodulation of subterranean clover.In 1982 and 1983 respectively only 40 and 62% of plants were effectively nodulated 8-10 weeks after germination of the clover. Clover root rot was also present in both years, 64% of plants being affected in 1982 and 14% in 1983. Nodulation was negatively correlated with the incidence of root rot and with the percentage of exchangeable aluminium in the soil and positively correlated with the percentage of exchangeable calcium in the soil. The number of Rhizobium trifolii in the soil was not correlated with any of the soil factors measured.

The pathogenicity of Fusarium avenaceum to wheat and legumes and its association with crop rotations

1974 ◽  
Vol 14 (69) ◽  
pp. 572 ◽  
Author(s):  
JF Kollmorgen
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Crop Rotations ◽  
Fusarium Avenaceum ◽  
Wheat Roots ◽  
Barrel Medic ◽  
Wheat Pasture ◽  
Wheat Stubble ◽  
First Time

Studies were made of the pathogenicity of Fusarium avenaceum (Fr.) Sacc. to wheat (Triticum aestivum), subterranean clover (Trifolium subterraneum) and barrel medic (Medicago truncatula var. truncatula), and of the effects of crop rotation on field populations of the fungus. F. avenaceum reduced emergence and dry weight of wheat, subterranean clover, and barrel medic seedlings. Infection reduced the height of both legumes but not the height or yield of wheat. The fungus caused a greater reduction in dry weight and height in barrel medic than in subterranean clover. Barrel medic is recorded as a host of F. avenaceum for the first time. The fungus was isolated from the roots of seedlings and from 0.3 per cent of a commercial seed sample. When this infected seed was sown in wheat stubble in crop rotations of fallow-wheat (stubble burnt), fallow-wheat and fallow-wheat-pasture-pasture its incidence in seed increased to 5.2, 6.0 and 10 per cent, respectively Studies on the effects of rotations on the incidence of F. avenaceum in wheat roots and wheat soil demonstrated a relation between crop sequence and population levels of the fungus. F. avenaceum was more prevalent in fallow-wheat-pasture than fallow-wheat.

scholarly journals Influence of selected Rhizoctonia solani isolates on sugar beet seedlings

2016 ◽  
Vol 56 (2) ◽  
pp. 116-121
Author(s):  
Paweł Skonieczek ◽  
Mirosław Nowakowski ◽  
Jacek Piszczek ◽  
Marcin Żurek ◽  
Łukasz Matyka
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
Laboratory Tests ◽  
Anastomosis Group ◽  
Damping Off ◽  
Highly Pathogenic ◽  
Breeding Lines ◽  
Brown Root Rot

Abstract From 2008 to 2010 the levels of sugar beet seedlings infection caused by Rhizoctonia solani were compared in laboratory tests. Seven sugar beet lines were tested: H56, H66, S2, S3, S4, S5 and S6 as well as three control cultivars: Carlos, Esperanza and Janosik. Sugar beet lines with tolerance to rhizoctoniosis and cultivars without tolerance were infected artificially by R. solani isolates: R1, R28a and R28b. These isolates belong to the second anastomosis group (AG), which is usually highly pathogenic to beet roots. The aim of the experiment was to test whether the tolerance of sugar beet genotypes to R. solani AG 2 prevents both root rot, and damping-off of seedlings, induced by the pathogen. Sugar beet lines tolerant to brown root rot in laboratory tests were significantly less sensitive to infection of the seedlings by R. solani AG 2 isolates in comparison to control cultivars. Rhizoctonia solani AG 2 isolates demonstrated considerable differences in pathogenicity against seedlings of sugar beet lines and cultivars. The strongest infection of sugar beet seedlings occurred with the isolate R28b. The greatest tolerance to infection by AG 2 isolates was found for the S5 and S3 breeding lines.

Seed-borne Fusarium species on subterranean clover and other pasture legumes

1978 ◽  
Vol 29 (5) ◽  
pp. 975 ◽  
Author(s):  
AW Kellock ◽  
LL Stubbs ◽  
DG Parbery
Keyword(s):  
White Clover ◽  
Root Rot ◽  
Fusarium Species ◽  
Subterranean Clover ◽  
Fusarium Spp ◽  
Root Rot Disease ◽  
Pasture Legumes ◽  
Rot Disease ◽  
Clover Seed ◽  
First Time

Fusarium avenaceum (Corda ex. Fr.) Sacc. was detected for the first time on seed of strand medic (M. littoralis Rhode), lucerne (M. sativa L.), white clover (T. repens L.) and strawberry clover (T. fragiferum L.). The percentage of seed infected was 24% on medic seed, 2–3% on strawberry clover, 2–6% on white clover, and 10–14% on lucerne, compared with 1–42% on subterranean clover seed. The majority of infected seed lines were grown in the main seed-producing areas of Victoria. F. arthrosporioides Sherb., F. equiseti (Corda) Sacc., F, acuminatum Ellis & Everhart and F. culmorum (W. G. Sm.) Sacc. were isolated from subterranean clover seed for the first time, comprising between 1 and 8% of Fusarium spp. isolates, while F. oxysporum (Schlecht) and F. avenaceum comprised the remaining 55% and 35% of isolates respectively. In laboratory tests, isolates of F. avenaceum from each seed host were all strongly pathogenic on roots of subterranean clover, but there was no evidence of pathogenicity by other Fusarium spp. F. oxysporum had no effect on the severity of root rot disease either alone or in combination with F. avenaceum.

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.

Effects of soil pasteurization on root rot, seedling survival and plant dry weight of subterranean clover inoculated with six fungal root pathogens

1987 ◽  
Vol 38 (2) ◽  
pp. 317 ◽  
Author(s):  
MJ Barbetti ◽  
K Sivasithamparam
Keyword(s):  
Root Rot ◽  
Seedling Survival ◽  
Lateral Roots ◽  
Subterranean Clover ◽  
Dry Weight ◽  
Plant Size ◽  
Natural Soil ◽  
Virgin Soil ◽  
Pythium Irregulare ◽  
Clover Root

Subterranean clover was exposed to two levels of inoculum of millet seed colonized by Fusarium avenaceum, Fusarium oxysporum, Phoma medicaginis, Phytophthora clandestina, Pythium irregulare, or Rhizoctonia solani within pasteurized and unpasteurized field soil from sites with (root rot site) and without (virgin site) a history of subterranean clover root rot at Augusta, W.A., with the aim of establishing their pathogenicity in the presence of other soil organisms including resident pathogens. Introduction of F. avenaceum (2.5% w/w), P. clandestina (0.5 and 2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) increased damage to tap and lateral roots of subterranean clover in pasteurized and unpasteurized root rot and virgin soils. All fungi tested, with the exception of P. medicaginis (2.0 and 10.0%) or P. medicaginis (2.0 and 10.0%) and F. oxysporum (0.5 and 2.50%), caused reduction of seedling survival in pasteurized root rot and virgin soils respectively. When the soil was unpasteurized, all fungi except F. oxysporum (2.5%) and P. medicaginis (2.0 and 10*0%) in virgin soil, but only P. irregulare (2.5%) or R. solani (0.2 and 1.0%) in root rot soil, reduced seedling survival. In unpasteurized soils plant dry weight was reduced by P. clandestina (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) in root rot and virgin soils, but F. oxysporum (0.5%) reduced plant size only in the root rot soil. Within pasteurized soil all fungi, with the exception of P. medicaginis (2.0 and 10.0%) in virgin soil and F. avenaceum (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2%) in root rot soil, caused reduction in plant size. P. clandestina, P. irregulare or R. solani, in particular, and to a lesser extent, P. avenaceum, are capable of causing serious damage to subterranean clover in natural soil.

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.

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