SEEDLING BLIGHT, A FUSARIAL DISEASE OF ASPARAGUS

Incidence of seedling blight in Ontario can be correlated with proximity of mature plantations or with the presence of debris from a previous asparagus crop. As the disease was detected on seedlings grown in soil from "volunteer" plants growing in isolated habitats, the pathogen is considered to be indigenous. The pathogen penetrates directly into the embryonic region of the root tip, or through stomata on the hypocotyl, and colonizes the host both intercellularly and intracellularly. Its limitation to the cortex is regarded as unusual among the parasitic fusaria, which are mainly vascular. The fungus was identified as Fusarium oxysporum sensu Snyder & Hansen var. redolens (Wr.) Gordon. In comparison with F. moniliforme Sheldon, found to cause a root tip necrosis of asparagus seedlings, the cortical Fusarium produced less growth on basal medium plus cellulose but more growth on sucrose, and showed a greater ability to hydrolyze starch. Differing nutrient preferences are suggested as one explanation for the localized types of colonization exhibited by these two fusaria. The optimum soil temperature for disease incidence was established at 25°-30 °C. The effect of temperatures above 30 °C. is considered to be twofold: (1) inhibiting growth of the pathogen and (2) permitting the host to escape by inducing its more rapid emergence. Below 20 °C, the pre-emergence phase of the disease is favored by a retardation of the rate of emergence. Both low and high levels of soil moisture retard emergence and favor pre-emergence blight. Under greenhouse conditions, incidence of the disease usually increased more rapidly when leguminous rather than nonleguminous residues were present in the soil and there was some evidence that the saprophytic growth of the pathogen was more profuse on certain nonliving substrates.

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Influence of Soil Temperature, Soil Moisture, and Seed Burial Depth on the Emergence of Round-Leaved Mallow (Malva pusilla)

Weed Science ◽

10.1017/s0043174500051407 ◽

1990 ◽

Vol 38 (6) ◽

pp. 518-521 ◽

Cited By ~ 25

Author(s):

Robert E. Blackshaw

Keyword(s):

Soil Moisture ◽

Soil Temperature ◽

Water Content ◽

Environmental Conditions ◽

Control Strategies ◽

Cultural Control ◽

Burial Depth ◽

Moisture Regime ◽

Seed Burial ◽

Rate Of Emergence

A study was conducted under controlled environmental conditions to determine the effect of soil temperature, soil moisture, and depth of seed burial on the emergence of round-leaved mallow. Emergence occurred from 5 to 30 C but was optimal at 15 to 20 C. Soil moisture had a greater effect than soil temperature on percentage emergence. Emergence progressively declined below a soil water content of −0.28 MPa, with less than 20% emergence attained at −1.03 to −1.53 MPa. In contrast, rate of emergence of round-leaved mallow was affected more by soil temperature than by moisture. A decrease in temperature from 30 to 5 C increased the time to reach 50% emergence by 10 to 12 days over the moisture regime of this study. Emergence was greatest at depths of 0.5 to 2 cm. No emergence occurred at 8 cm or below. The potential of using the findings of this study to develop cultural control strategies for round-leaved mallow is discussed.

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Seedling blight. II. Soil in relation to seedling blight of opium poppy and peas

Australian Journal of Agricultural Research ◽

10.1071/ar9500132 ◽

1950 ◽

Vol 1 (2) ◽

pp. 132

Author(s):

HR Angell

Keyword(s):

Soil Moisture ◽

Soil Temperature ◽

Air Temperature ◽

Pythium Ultimum ◽

Opium Poppy ◽

Total Loss ◽

The Other ◽

Seedling Blight ◽

Microbial Antagonism ◽

Conditioning Factor

Three steamed soils, limed and not limed, two hosts, and one isolate of Pythium ultimum were used in an experiment. The organism, isolated from peas germinating in limed Belanglo soil, was pathogenic to both hosts. The incidence of seedling blight of peas in the three reinfested soils varied significantly. On poppy, on two of the reinfested soils, it also varied significantly, but inversely to the incidence on peas. On peas in the first sowing it was not affected by liming the soil; on poppy it was significantly reduced. Seedling blight of both hosts was associated with one organism. The contrasting results could not be correlated with the uniform conditions of soil temperature, air temperature, and soil moisture; on any one soil or soil treatment they could not be ascribed to the prevailing uniform aeration, reaction, microflora, and microbial antagonism The only conditioning factor that was varied was the steamed soil, or steamed soil modified by adding lime. Differences in the incidence of disease were associated with variation of the conditioning factor and the host. Seedling blight of peas, resulting from natural reinfestation, occurred in earlier resowings in limed than in unlimed soils. Physiogenic seedling blight of poppy also occurred, causing total loss on one soil and smaller percentages of loss on the other soils.

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Influence of weather factors, soil temperature and moisture on collar rot disease of betel vine (Piper betle L.) under coastal saline zone of West Bengal

Journal of Agrometeorology ◽

10.54386/jam.v23i4.148 ◽

2021 ◽

Vol 23 (4) ◽

pp. 428-434

Author(s):

PRABIR KUMAR GARAIN ◽

BHOLANATH MONDAL ◽

SUBRATA DUTTA

Keyword(s):

Soil Moisture ◽

Relative Humidity ◽

Soil Temperature ◽

Disease Incidence ◽

Maximum Temperature ◽

Piper Betle ◽

Weather Factors ◽

Collar Rot ◽

Minimum Relative Humidity ◽

Rot Disease

A study was conducted to find out the influence of weather factors, soil temperature and soil moisture on the incidence of Sclerotium rolfsii Sacc. induced collar rot disease in betelvine (Piper betle L.), during 2016 to 2018. Fourteen soil and weather factors, taken from the agrometeorological observatory located at instructional farm of Ramkrishna Ashram Krishi Vigyan Kendra, Nimpith and recorded from a nearby betelvine boroj, were subjected to multiple regression, binary logistic regression and canonical discriminant analysis to develop a suitable disease forewarning model. The binary logistic model, Y(0/1) = 5.899 + 0.865 (Tmax) – 0.569 (SM) + 0.097 (BRHmin) was able to predict the disease risk with 78 per cent accuracy and correctly classified 94 per cent of cases during model validation in 2018. The weekly averages of maximum temperature (Tmax), soil moisture (SM) and minimum relative humidity inside the boroj (BRHmin) were found to be the most significant predictors of disease incidence, in this model. The soil moisture at 69 - 72 per cent of field capacity, minimum temperature of 25 - 27oC, maximum temperature of 33 - 36oC, average soil temperature of 28 - 30oC, minimum relative humidity of 60 - 72 per cent inside the boroj and maximum relative humidity of 83 - 89 per cent inside the boroj were found to be highly congenial for collar rot disease incidence in betelvine under coastal saline zone of West Bengal.

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Forecasting model for disease risk period in chickpea x collar rot pathosystem

Journal of Agrometeorology ◽

10.54386/jam.v24i1.780 ◽

2022 ◽

Vol 24 (1) ◽

Author(s):

SANJU TAMANG ◽

POLY SAHA

Keyword(s):

Soil Moisture ◽

Soil Temperature ◽

Disease Risk ◽

Disease Incidence ◽

Sclerotium Rolfsii ◽

Forecasting Model ◽

P Value ◽

Crop Failure ◽

Collar Rot ◽

Risk Period

Collar rot caused by Sclerotium rolfsii Sacc. is one of the major biotic constraints of chickpea production worldwide. It is soil-borne fungi having wider host range and infection mainly occurs at the juvenile stage of crop growth resulting crop failure in no time. The pathogen is greatly influenced by soil temperature (ST) and soil moisture (SM) therefore, experiment formulated to develop a suitable forecasting model for its future use in computer simulation of plant disease prognostication by feeding only soil temperature and moisture data. The popular desi type chickpea variety Anuradha sown at different dates to get a range of soil temperature and soil moisture combination and its corresponding effect on disease incidence was recorded under natural epiphytotic conditions. The data obtained were analyzed using binary logistic regression and discriminant analysis to assess disease risk and non-risk period. The model developed was Y'= -73.9 + 1.251 SM + 0.017 ST. The outcome recorded, a unique statistically significant contribution of soil moisture (p value=0.029) on the establishment of the disease whereas, the effect of soil temperature was detected as statistically non-significant. The model developed and the correctness of the model determined to predict the disease severity with 80 % accuracy.

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Soil Temperature, Soil Moisture, and Seed Burial Depth Effects on Redstem Filaree (Erodium cicutarium) Emergence

Weed Science ◽

10.1017/s0043174500057234 ◽

1992 ◽

Vol 40 (2) ◽

pp. 204-207 ◽

Cited By ~ 26

Author(s):

Robert E. Blackshaw

Keyword(s):

Soil Moisture ◽

Soil Temperature ◽

Environmental Conditions ◽

Burial Depth ◽

Moist Soil ◽

Seed Burial ◽

Erodium Cicutarium ◽

Rate Of Emergence ◽

Water Contents ◽

Depth Effects

A study was conducted under controlled environmental conditions to determine the effect of soil temperature, soil moisture, and depth of seed burial on the emergence of redstem filaree. Emergence occurred from 5 to 30 C but was optimal at 5 to 15 C. Redstem filaree emergence was optimal in moist soil with water contents of −0.03 to −0.28 MPa. Emergence progressively decreased as soil moisture was lowered below these levels, with less than 25% emergence attained at −1.53 MPa regardless of soil temperature. Almost no germination was observed in warm (30 C), dry (-1.03 to −1.53 MPa) soils. Rate of emergence was affected more by soil temperature than by moisture. A decrease in temperature from 20 to 5 C increased the time to reach 50% emergence by 6 to 8 d but a decrease in soil moisture from −0.03 to −1.53 MPa increased the time to reach 50% emergence by only 1 to 2 d. Emergence was greatest at soil depths of 1 cm or less. No emergence occurred at depths of 8 cm or below.

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Relationships of Preharvest Weather Conditions and Soil Factors to Susceptibility of Sweetpotato to Postharvest Decay Caused by Rhizopus stolonifer and Dickeya dadantii

Plant Disease ◽

10.1094/pdis-11-14-1143-re ◽

2015 ◽

Vol 99 (6) ◽

pp. 848-857 ◽

Cited By ~ 6

Author(s):

Brooke A. Edmunds ◽

Christopher A. Clark ◽

Arthur Q. Villordon ◽

Gerald J. Holmes

Keyword(s):

North Carolina ◽

Soil Moisture ◽

Soil Temperature ◽

Air Temperature ◽

Root Rot ◽

Disease Incidence ◽

Soft Rot ◽

Storage Roots ◽

Dickeya Dadantii ◽

High Soil Temperature

Postharvest soft rots of sweetpotato caused by Rhizopus stolonifer (Rhizopus soft rot) and Dickeya dadantii (bacterial root rot) occur sporadically and can result in significant losses. A 3-year field study related preharvest conditions, including soil texture, chemistry, and fertility; air temperature; soil temperature and moisture; and various cultural practices (153 total variables), to postharvest susceptibility to both diseases in 75 sweetpotato fields in North Carolina and 63 sweetpotato fields in Louisiana. Storage roots were sampled from each field, cured, stored, and inoculated with each pathogen after 100 to 120 days in storage. Disease susceptibility was measured as incidence of diseased storage roots 10 days following inoculation. There was wide variation from field to field in incidence of both diseases (0 to 100% for Rhizopus soft rot and 5 to 95% for bacterial root rot) in both states in each year. Correlations between disease incidence and each of the preharvest variables revealed numerous significant correlations but the variables that correlated with disease incidence were different between North Carolina and Louisiana. Models for both diseases were built by first using forward stepwise regression to identify variables of interest, followed by a mixed-model analysis to produce a final reduced model. For North Carolina fields, postharvest Rhizopus soft rot susceptibility was described by the percentage of the soil cation exchange capacity occupied by calcium, amount of plant-available soil phosphorus, percent soil humic matter, mean air temperature, mean volumetric soil moisture at 40 cm in depth, and mean soil temperature at 2 cm in depth. Postharvest bacterial soft rot susceptibility was described by soil pH and the number of days of high soil temperature late in the season. For Louisiana fields, Rhizopus soft rot susceptibility was described by a complex of variables, including late-season air and soil temperature and late-season days of extreme soil moisture. For bacterial root rot, days of low air temperature and days of high soil temperature late in the season as well as days of low soil moisture best described variation. Although the influence of preharvest variables on postharvest susceptibility was profound for each disease, the complexity of factors involved and differences between the data for the two states makes development of a predictive system extremely difficult.

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Potential Soil Respiration in Forest Soil according to Soil Temperature and Soil Moisture Change

Korean Journal of Nature Conservation ◽

10.30960/kjnc.2009.7.4.191 ◽

2009 ◽

Vol 7 (4) ◽

pp. 191-201

Author(s):

Eunhye LEE ◽

Jaeseok LEE

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Soil Temperature ◽

Forest Soil ◽

Moisture Change

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Ecological responses of Stipa steppe in Inner Mongolia to experimentally increased temperature and precipitation. 3. Soil respiration

The Rangeland Journal ◽

10.1071/rj16083 ◽

2018 ◽

Vol 40 (2) ◽

pp. 153 ◽

Cited By ~ 6

Author(s):

Xuexia Wang ◽

Yali Chen ◽

Yulong Yan ◽

Zhiqiang Wan ◽

Ran Chao ◽

...

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Soil Temperature ◽

Respiration Rate ◽

Inner Mongolia ◽

Growing Season ◽

Climatic Warming ◽

Soil Respiration Rate ◽

Natural Rainfall ◽

Temperature And Precipitation

The response of soil respiration to simulated climatic warming and increased precipitation was evaluated on the arid–semi-arid Stipa steppe of Inner Mongolia. Soil respiration rate had a single peak during the growing season, reaching a maximum in July under all treatments. Soil temperature, soil moisture and their interaction influenced the soil respiration rate. Relative to the control, warming alone reduced the soil respiration rate by 15.6 ± 7.0%, whereas increased precipitation alone increased the soil respiration rate by 52.6 ± 42.1%. The combination of warming and increased precipitation increased the soil respiration rate by 22.4 ± 11.2%. When temperature was increased, soil respiration rate was more sensitive to soil moisture than to soil temperature, although the reverse applied when precipitation was increased. Under the experimental precipitation (20% above natural rainfall) applied in the experiment, soil moisture was the primary factor limiting soil respiration, but soil temperature may become limiting under higher soil moisture levels.

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