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 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.

Soil Temperature and Moisture Conditions Under and Around an Animal Shelter

1963 ◽  
Vol 6 (4) ◽  
pp. 0284-0287
Author(s):  
Albert E. Powell
Keyword(s):  
Soil Temperature ◽  
Animal Shelter ◽  
Moisture Conditions ◽  
Soil Temperature And Moisture

THE EFFECT OF TILLAGE ON SOIL TEMPERATURE AND CORN (Zea mays L.) GROWTH IN MANITOBA

1984 ◽  
Vol 64 (1) ◽  
pp. 59-67 ◽  
Author(s):  
D. A. WALL ◽  
E. H. STOBBE
Keyword(s):  
Soil Temperature ◽  
Crop Residues ◽  
Zea Mays L ◽  
Marked Effect ◽  
Zero Tillage ◽  
Previous Crop ◽  
Soil Temperatures ◽  
Lower Maximum ◽  
Strip Tillage ◽  
Tillage Operations

The degree of tillage, presence of previous crop residues and the timing of tillage operations had a marked effect on soil temperatures. Zero tillage and the retention of the previous crop residues tended to depress the maximum soil temperatures at the 5.0-cm depth. Removal of crop residues from zero tillage plots resulted in an increase in maximum soil temperatures. Fall tillage resulted in lower maximum and higher minimum soil temperatures than where tillage was performed in the spring. Soil temperatures in the row were warmer than those recorded in the inter-row area of both the zero tillage and rotovated strip tillage treatments.Key words: Tillage, crop residues, soil temperature, corn

Effect of soil environment on infection of subterranean clover by Meloidogyne arenaria

1992 ◽  
Vol 43 (1) ◽  
pp. 87 ◽  
Author(s):  
SH Pung ◽  
MJ Barbetti ◽  
K Sivasithamparam
Keyword(s):  
Soil Temperature ◽  
First Generation ◽  
Soil Moisture Content ◽  
Lateral Roots ◽  
Subterranean Clover ◽  
Growing Season ◽  
Pot Experiment ◽  
Meloidogyne Arenaria ◽  
Soil Environment ◽  
Soil Temperatures

The effect of environmental factors on Meloidogyne arenaria and its infectivity on subterranean clover were investigated both in a naturally infested subterranean clover pasture and under controlled conditions in a pot experiment. In the field, the nematode population was altered by seasonal changes during the sampling periods in 1987 and 1988. The hatching of M. arenaria was determined by the germination of subterranean clover brought about by the opening seasonal rains in April or May. The first generation of M. arenaria in subterranean clover roots appeared to develop and reproduce more rapidly while the soil temperature was still relatively high (>15�C) in May-June and the second generation developed as soil temperature increased between September and November. These findings were consistent with observations from the pot experiment, where M. arenaria gall production and its development and reproduction in both the tap and lateral roots were greater at 20/15�C and 25/20�C than at 15/10�C. In 1987, egg masses of M. arenaria were first observed approximately 6 weeks after the commencement of the growing season, while in 1988 they appeared only after about 15 weeks. This may be attributed to a delay in the opening seasonal rains in 1988 compared with 1987, as well as cooler soil temperatures in 1988. The pF values in the field soils sampled in this study ranged from non-inhibitive to inhibitive suction, with values from 1.8 to 4.8. Greater nematode infection in the tap roots at moisture levels of pF 1.28 and 0.97, but not at 0.71, may be related to better nematode mobility at the higher soil moisture content and its preference for tap roots under more favourable conditions.

Root rot caused by Pythium irregulare Buisman, an important factor in the decline of established subterranean clover pastures

1974 ◽  
Vol 25 (4) ◽  
pp. 537 ◽  
Author(s):  
GE Stovold
Keyword(s):  
Root Rot ◽  
Subterranean Clover ◽  
Common Disease ◽  
Crop Species ◽  
Pythium Irregulare ◽  
Factors Affecting ◽  
South Wales ◽  
Matter Production ◽  
Pathogenicity Tests

The problem of poor re-establishment and poor seasonal production in long-term subterranean clover pastures has been recognized for some time, particularly on the Southern Tableland and Slopes regions of New South Wales. Field and laboratory investigations showed that rotting of the lateral feeder roots was a common disease of subterranean clover during the cool part of the growing season. Isolations made from diseased roots yielded a predominance of Pythium spp. of which Pythiurn irregulare was the most common. Pathogenicity tests demonstrated that P. irregulare consistently caused damping-off of germinating subterranean clover. This fungus also infected established plants and at low temperatures caused severe reduction of dry matter production. Symptoms produced on artificially inoculated plants were identical with those observed on plants infected in the field. Soil moisture and the level of fungal inoculum added did not have a critical effect on the severity of root disease. A range of other important pasture and crop species were also artificially infected with P. irregulare, with resulting necrosis of feeder roots. In vitro studies of factors affecting the growth of P. irregulare showed that this pathogen was well adapted to survive and cause disease in cold wet soils, the conditions most favourable for root rot in the field. The importance of P. irregulare as a pathogen of established plants and possible means of reducing its effect on the growth of subterranean clover are discussed.

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.

STUDIES ON RHIZOCTONIA SOLANI KÜHN.: IV. EFFECT OF SOIL TEMPERATURE AND MOISTURE ON VIRULENCE

1938 ◽  
Vol 16c (5) ◽  
pp. 203-213 ◽  
Author(s):  
G. B. Sanford
Keyword(s):  
Growth Rate ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Temperature ◽  
Growth Rates ◽  
Nutrient Medium ◽  
Soil Moisture Content ◽  
Soil Temperatures ◽  
Dry Soil ◽  
Soil Temperature And Moisture

The effects of soil temperatures between 16° and 25 °C., and of soil moisture content between 19 and 40% of the moisture-holding capacity, on the virulence and type of attack of Rhizodonia Solani on young potato sprouts, were studied under controlled conditions and the results from 13 separate tests are discussed. The comparative growth rates of the pathogen on nutrient agar and in soil are outlined.At 25 °C. the disease diminished very abruptly. Between 23° and 16 °C., the pathogen appeared equally virulent throughout the range of soil moisture mentioned. The fluctuations which occurred in separate tests were not definite or consistent enough to warrant a conclusion that the virulence is greater at 16° than at 23°, or that a dry soil is more or less favorable to it than a wet one.In a fertile, steam sterilized loam, at medium moisture content, it required about ten days for the pathogen to grow as far as it did on the surface of a nutrient medium in four days. The growth rate at either 23° or 16 °C. was slightly higher in a wet soil than in one of medium moisture content, but in a dry soil the rate was somewhat less at 23° than at 16° in a medium or wet soil. Even in a fairly dry soil (19% moisture-holding capacity) at 16° the growth of the pathogen covered a distance of 5 cm. in ten days, which would appear adequate for infection of young sprouts from a set bearing viable sclerotia.The effort of the host to recover, by means of secondary and tertiary sprouts from the attacked primary sprout, was better in a wet soil than in a dry one at both 16° and 23 °C. The best effort was in a wet soil at 23°. A distinction is made between the effects of soil moisture and temperature in stimulating growth of the host, and their effect on parasitism itself.The remarkable tendency of the secondary sprouts to escape infection, regardless of soil temperature and soil moisture, is indicated. There was evidence that certain factors other than soil temperature and moisture may play an important role in the parasitism of R. Solani.

Effect of Soil Temperature and Moisture on Glyphosate and Photoassimilate Distribution in Quackgrass (Agropyron repens)

Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 402-407 ◽  
Author(s):  
Thomas B. Klevorn ◽  
Donald L. Wyse
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Soil Temperature ◽  
Soil Temperatures ◽  
Growth Chambers ◽  
Rhizome Buds ◽  
Rhizome System ◽  
Soil Temperature And Moisture ◽  
Agropyron Repens

Experiments were conducted in growth chambers to evaluate the effect of soil temperature and soil moisture on the distribution of14C-photoassimilates and14C-glyphosate [N-(phosphonomethyl) glycine] in quackgrass [Agropyron repens(L.) Beauv. ♯3AGRRE]. When14C-glyphosate was applied to leaves, the radioactivity was less in the rhizome buds of plants exposed to 7-C soil temperature than in plants exposed to 12- and 18-C soil temperatures after 2 days. In plants with leaves exposed to14CO2, the radioactivity from14C-photoassimilates was greatest in rhizomes and rhizome buds of plants at the 12-C soil temperature. As soil moisture levels were decreased, uptake of C-glyphosate into leaves declined, and transport to the daughter shoots, rhizomes, and rhizome buds was reduced. The concentration of14C-photoassimilates in the rhizome system of water-stressed quackgrass plants was similar to that in nonstressed plants. This study shows that the patterns of glyphosate distribution differ from those of photoassimilate distribution in quackgrass plants exposed to water stress.

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