Effects of Free Moisture and Soybean Growth Stage on Focus Expansion of Rhizoctonia Aerial Blight

Yang, Xiang; Berggren, G. T.; Snow, J. P.

doi:10.1094/phyto-80-497

Cited by 21 publications

(15 citation statements)

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“…Under favourable conditions, once a disease source is established, contacts of infected tissues with healthy ones on adjacent plants are necessary for disease spread, as it provides bridges for myceiial hyphae to progress. Yang et al (1990) coined the term 'leaf-borne' to describe pathogens with such a dispersal mechanism.…”

Section: Discussionmentioning

confidence: 99%

“…An Table 2 Repeated measures ANOVA for inoculum efficiency (IE) in ShB as affected by plant contacts, amount and location of mother lesions, leaf wetness regime, and nitrogen content of trap hills' important issue is the contact between the pathogen and its host, which can be disrupted by excessive surface moisture, as is the case of Cercospora carotae or C. beticola (Carisse and Kushaiappa, 1992). On the other hand, prolonged leaf wetness periods are necessary for the progression of hyphal strands of R. solani ou host tissues (Yang et al, 1990;Savary et al, 1995). It can be hypothesised that (i) wetness of the rice canopy favours rapid progression of myceiial strands (i.e., progress of the pathogen within and between rice hiils), and (ii) short dry periods (with high relative humidity) favour the establishment of new lesions.…”

Section: Discussionmentioning

confidence: 99%

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Effects of Plant Contact, Inoculation Pattern, Leaf Wetness Regime, and Nitrogen Supply on Inoculum Efficiency in Rice Sheath Blight

Castilla

Leaño

Elazhour

et al. 1996

Journal of Phytopathology

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An experimental design was developed which allowed the measurement of inoculum efficiency (IE) represented by lesions of a leaf‐borne disease such as rice sheath blight. In this design. IE is measured as the ratio of newly established lesions on trap plants relative to the inoculum present in a canopy, i.e. lesions artificially established on source plants, IE of the rice sheath blight pathogen, Rhizoctonia solani, was studied under semi‐controlled conditions in which the effects of the following factors were measured; contact frequency among host tissues, amount and location of inoculum in the canopy, leaf wetness regime, and nitrogen content of the host plant. The conduciveness of these factors to sheath blight infection was measured in terms of IE which was expressed as the ratio of the density of daughter lesions on trap rice hills to the density of mother lesions on the inoculated quadrat hills. IE generally declined with the three successive batches of trap hills used in the experiments. It was significantly higher at closer plant spacings and under interrupted leaf wetness regimes. IE was not affected by the amount, nor by the location, of inoculum (mother lesions) in the canopy, but was significantly lower in hills with high total nitrogen content.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effects of Plant Contact, Inoculation Pattern, Leaf Wetness Regime, and Nitrogen Supply on Inoculum Efficiency in Rice Sheath Blight

Castilla

Leaño

Elazhour

et al. 1996

Journal of Phytopathology

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“…Weather conditions conducive for Rhizoctonia web blight have been reported on soybean (3,28,29), maize (1), and perennial ryegrass turf (12,15). Fidanza et al (12) developed a warning m od el that used the mean daily relative humidity and minim um daily air tem perature to accumulate daily points.…”

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Weather-Based Forecasting of Rhizoctonia Web Blight Development on Container-Grown Azalea

Copes¹

2015

Plant Disease

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Copes, W. E. 2015. Weather-based forecasting of Rhizoctonia web blight development on container-grown azalea. Plant Dis. 99:100-105.The most reliable approach for timing fungicides to control Rhi zoctonia web blight on container-grown azalea has been a fixed calen dar date. The purpose of this study was to model periods when a pre ventive control could be applied in advance of significant increases in leaf blight intensity (LBI) in response to a daily accumulated risk value indicating conducive conditions of temperature (18 or more hours between 20 and 30°C when maximum temperature is less than 35°C), leaf wetness (16 or more hours), and/or rainfall (greater than 6.7 mm above the maximum daily irrigation). Analysis used weather measure ments taken every 30 minutes from 11 site-year datasets from 2006 to 2011, and weekly or biweekly LBI assessments. Six developmental site-year datasets were analyzed using receiver operating characteristic (ROC) curve procedures to evaluate models. Only a single model pre dicted true positives and negatives significantly greater than a 50:50 probability. Subsequently, five site-year validation datasets were evalu ated. Similar results were obtained from both the developmental and validation datasets, which produced ROC areas of 0.7715 (P = 0.0120) and 0.8393 (P = 0.0034), respectively. The practical application of weather-based forecasting for management of web blight in nurseries is discussed.

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“…Increased plant spacing can reduce humidity within the canopy of some crops by facilitating air movement and sun penetration which accelerate evaporative drying of plant surfaces, providing conditions less conducive for fungal infection (Burdon and Chilvers, 1982;Tu, 1989;Zentmyer and Bald, 1977). In addition, plant spacing can affect disease development by impacting pathogen spread (Berger, 1975) or host growth habit (Yang et al, 1990).…”

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confidence: 99%

“…In a predictive model for brown patch of ryegrass turf (another aboveground disease caused by R. solani), mean daily RH ≥75%, leaf wetness (LW) periods ≥6 h, or RH of 95% or higher for ≥8 h favored disease development (Fidanza et al, 1996). In soybean, regular periods of free moisture and a dense foliage contributed to expansion of rhizoctonia aerial blight (Yang et al, 1990). Azaleas are produced on synthetic surfaces such as polyethylene ground fabrics which likely create microclimate effects different from those experienced in row crop and turf systems.…”

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confidence: 99%

Plant Spacing Effects on Microclimate and Rhizoctonia Web Blight Development in Container-grown Azalea

Copes¹,

Scherm²

2005

HortSci

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Rhizoctonia web blight, caused by Rhizoctonia solani and binucleate Rhizoctonia spp., is an annual problem in compact cultivars of container-grown azalea (Rhododendron spp.) in the Gulf Coast states. Increasing the space between plants is commonly recommended for suppression of the disease, but experimental evidence for the effectiveness of this cultural practice in container-grown azalea is lacking. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 potted `Gumpo White' azalea plants growing in 3.8-L containers and having a canopy diameter of about 30 cm. Plant spacing within plots was 0, 6, 12, 18, or 24 cm, and plots were arranged in three randomized complete blocks. Evaporation, leaf wetness (LW), relative humidity (RH), and temperature were monitored in each plot. Disease severity increased steadily from mid-July to late August or early September, after which it leveled off or declined. Evaporation increased and the number of hours within the temperature range favorable for disease development (25 to 30 °C) decreased significantly with plant spacing (P < 0.05), but LW and RH were not significantly different among treatments. Plant spacing also had no significant effect on disease severity. Daily overhead irrigation and compact plant form likely contributed to the lack of effect of spacing on disease development.

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Effects of Free Moisture and Soybean Growth Stage on Focus Expansion of Rhizoctonia Aerial Blight

Cited by 21 publications

References 0 publications

Effects of Plant Contact, Inoculation Pattern, Leaf Wetness Regime, and Nitrogen Supply on Inoculum Efficiency in Rice Sheath Blight

Effects of Plant Contact, Inoculation Pattern, Leaf Wetness Regime, and Nitrogen Supply on Inoculum Efficiency in Rice Sheath Blight

Weather-Based Forecasting of Rhizoctonia Web Blight Development on Container-Grown Azalea

Plant Spacing Effects on Microclimate and Rhizoctonia Web Blight Development in Container-grown Azalea

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