The effects of inhaled warm air on nasal patency and on allergic rhinitic symptoms were studied i... more The effects of inhaled warm air on nasal patency and on allergic rhinitic symptoms were studied in 102 patients. Treatment consisted of two consecutive 30-minute sessions, during which the patient inhaled saturated, hot (42-44 degrees C) air through the nose. The treatment was repeated 1 week later. During the week following each treatment, every patient recorded his or her subjective response on a daily symptom score card. Nasal patency was determined before and after each treatment by measuring peak nasal inspiratory and expiratory air flow and by measuring the area covered with vapor formed by the exhaled air on a plate. Highly reproducible results were obtained by using these three objective methods. Inhalation of humidified warm air resulted in amelioration of allergic rhinitis symptoms and in increased nasal patency in a high proportion of patients. There were no adverse side effects. This form of therapy seemed effective in the 2-week period in which it was used and would be ...
Biocontrol agents can control pathogens by reenforcing systemic plant resistance through systemic... more Biocontrol agents can control pathogens by reenforcing systemic plant resistance through systemic acquired resistance (SAR) or induced systemic resistance (ISR). Trichoderma spp. can activate the plant immune system through ISR, priming molecular mechanisms of defense against pathogens. Entomopathogenic fungi (EPF) can infect a wide range of arthropod pests and play an important role in reducing pests’ population. Here, we investigated the mechanisms by which EPF control plant diseases. We tested two well studied EPF, Metarhizium brunneum isolate Mb7 and Beauveria bassiana as the commercial product Velifer, for their ability to induce systemic immunity and disease resistance against several fungal and bacterial phytopathogens, and their ability to promote plant growth. We compared the activity of these EPF to an established biocontrol agent, Trichoderma harzianum T39, a known inducer of systemic plant immunity and broad disease resistance. The three fungal agents were effective agai...
Fungal and bacterial pathogens generate devastating diseases and cause significant tomato crop lo... more Fungal and bacterial pathogens generate devastating diseases and cause significant tomato crop losses worldwide. Due to chemical pesticides harming the environment and human health, alternative disease control strategies, including microorganismal bio-control agents (BCAs), are increasingly sought-after in agriculture. Bio-control microorganisms such as Trichoderma spp. have been shown to activate induced systemic resistance (ISR) in the host. However, examples of highly active bio-control microorganisms in agricultural settings are still lacking, due primarily to inconsistency in bio-control efficacy, often leading to widespread disease prior to the required ISR induction in the host. As part of its plant colonization strategy, Trichoderma spp. can secrete various compounds and molecules, which can effect host priming/ISR. One of these molecules synthesized and secreted from several species of Trichoderma is the family 11 xylanase enzyme known as ethylene inducing xylanase, EIX. EI...
Las tecnologias biologicas, incluyendo el uso de microorganismos biocontroladores, estan adquirie... more Las tecnologias biologicas, incluyendo el uso de microorganismos biocontroladores, estan adquiriendo una importancia primordial en la produccion agricola. Sin embargo, la mayoria de los enfoques para el control biologico de enfermedades de las plantas ha tenido un alcance limitado. Un ejemplo de esto lo representa el hecho de que, en las ultimas decadas, en general, se han utilizado agentes de biocontrol individuales para controlar un solo patogeno. Esto puede explicar parcialmente la respuesta inconsistente que se observa frecuentemente, ya que dichos agentes individuales pueden ser inactivos en varios de los ambientes en los que se aplican o contra diferentes patogenos que atacan a la planta huesped. Lograr un control de amplio espectro de patogenos por los antagonistas que se apliquen individualmente o en consorcio sigue siendo, en gran medida, un objetivo no cumplido para la explotacion eficaz del control biologico, asi como ampliar los usos de los agentes de control biologico p...
We examined the effects of applications of N, P, K, Mg, and Ca through an irrigation solution and... more We examined the effects of applications of N, P, K, Mg, and Ca through an irrigation solution and spraying K, Ca, and Mg salts on cucumber powdery mildew (CPM, Podosphaera xanthii) in potted plants and under commercial-like conditions. Spraying CaCl2 and MgCl2, or KCl and K2SO4, decreased CPM. There were significant negative correlations between the anion-related molar concentrations of the salts and disease severity. Among the sprayed treatments, NaCl provided significantly less CPM control when applied at a low (0.05 M) concentration, as compared with CaCl2 and MgCl2. When sprayed applications of Mg and K salts were analyzed separately from the untreated control, the Cl− salts were found to be more effective than the SO4−2 salts. High N and Mg concentrations in the irrigation water delivered to young, fruit-less cucumber plants reduced CPM, whereas more CPM was observed when the irrigation solution contained a medium amount of P and a high amount of K. In contrast, mature, fruit-b...
It was previously shown that spraying with CaCl2, MgCl2, KCl, and K2SO4 and high N and Mg concent... more It was previously shown that spraying with CaCl2, MgCl2, KCl, and K2SO4 and high N and Mg concentrations in the irrigation water of potted cucumber plants reduced powdery mildew, while medium P and high K concentrations increased powdery mildew. In the present work, we tested the effect of irrigation with N, P, K, Ca, and Mg and spraying with salts on downy mildew (Pseudoperonospora cubensis) of cucumber (CDM). In potted plants, an increase in N concentration in the irrigation water resulted in a major increase in CDM severity, while an increase in K or Ca concentrations resulted in a gradual increase in CDM severity. An increase in P and Mg concentrations in the irrigation water resulted in a major CDM decrease. Spraying with Ca, Mg, and K salts with Cl and SO4 anions resulted in CDM suppression in most cases, and a negative correlation was obtained between the salt and anion molar concentrations and the CDM severity. Using NaCl sprays, both Na and Cl concentrations were negatively...
Downy mildew (caused by Peronospora belbahrii) is a severe disease of sweet basil (Ocimum basilic... more Downy mildew (caused by Peronospora belbahrii) is a severe disease of sweet basil (Ocimum basilicum) crops around the world. We examined cultural methods for reducing the severity of sweet basil downy mildew (SBDM) under commercial conditions in greenhouses and walk-in tunnels. The effects of the orientation of walk-in tunnels, air circulation in greenhouses, plant density, and soil mulch were tested. SBDM was less severe in the tunnels that were oriented north-south than in those oriented east-west, but the yields in both types of tunnels were similar. Increased air circulation reduced SBDM severity, but did not affect yield. Gray or transparent polyethylene mulch reduced SBDM severity and, in most cases, increased yield relative to bare soil/growth medium. Yellow polyethylene mulch provided a smaller amount of control. The combination of increased air circulation and yellow polyethylene mulch provided synergistic SBDM control, whereas no synergism was observed when we combined inc...
Biological control of fungal and bacterial plant pathogens Integrated control in protected crops,... more Biological control of fungal and bacterial plant pathogens Integrated control in protected crops, temperate climate Integrated control in protected crops, mediterranean climate Integration 2004 S. Michele all’Adige, Italy Proceedings of a Meeting of the WGs: Management of plant diseases and arthropod pests by BCAs and their integration in agricultural systems at S. Michele all’Adige, Trentino, Italy
ABSTRACT The purpose of this review is to examine how biochar additions to soil can affect plant ... more ABSTRACT The purpose of this review is to examine how biochar additions to soil can affect plant diseases caused by soilborne pathogens, with particular attention to mechanisms and knowledge gaps. Until now, biochar soil amendment has been reported to affect the progress of diseases caused by soilborne plant pathogens in six distinct pathosystems. Disease severity frequently exhibits a U-shaped response curve, with a minimum at some intermediate biochar dose. Alteration of plant disease intensity by biochar added to soil may result from its varied influences on the soil–rhizosphere–pathogen–plant system. These influences may involve myriad biochar properties such as nutrient content, water holding capacity, redox activity, adsorption ability, pH and content of toxic or hormone-like compounds. The direct and indirect impacts of biochar on the soil environment, host plant, pathogen and the rhizosphere microbiome can have domino effects on both plant development and disease progress
Journal of Environmental Engineering and Landscape Management, 2017
The increasing demand for soilless substrates and rising environmental concerns about the use of ... more The increasing demand for soilless substrates and rising environmental concerns about the use of non-renewable resources such as peat has led to the search for alternative constituents of growing mixtures for containerized plants. In this report we reviewed the works concerning biochar as constituent of growing media, targeting its influence on plant growth and plant disease. Biochar mostly has positive or neutral influences on plant growth compared with peat media when present in concentrations higher than 25% (v:v). However, studies of biochar influence on plant disease reveals that while lower concentrations (≤1%) of biochar often suppressed several diseases, higher concentrations (≥3%) were mostly ineffective or induced plant disease. For use as horticultural peat replacement, it is recommended that biochar feedstocks and concentrations be standardized and the potential effect of biochar on plant disease be considered, so that growers can rely on consistent and reproducible bioc...
Biochar, in addition to sequestering carbon, ameliorating soil, and improving plant performance, ... more Biochar, in addition to sequestering carbon, ameliorating soil, and improving plant performance, can impact foliar and soilborne plant diseases. Nevertheless, the mechanisms associated with suppression of soilborne diseases and improved plant performances are not well understood. This study is designed to establish the relationships between biochar-induced changes in rhizosphere microbial community structure, taxonomic and functional diversity, and activity with soilborne disease suppression and enhanced plant performance in a comprehensive fashion. Biochar suppressed Fusarium crown and root-rot of tomato and simultaneously improved tomato plant growth and physiological parameters. Furthermore, biochar reduced Fusarium root colonization and survival in soil, and increased the culturable counts of several biocontrol and plant growth promoting microorganisms. Illumina sequencing analyses of 16S rRNA gene revealed substantial differences in rhizosphere bacterial taxonomical composition...
Sweet basil (Ocimum basilicum) is a herbaceous annual plant that is highly susceptible to gray mo... more Sweet basil (Ocimum basilicum) is a herbaceous annual plant that is highly susceptible to gray mold, caused by Botrytis cinerea. Infections are initiated on the surface of stem wounds that are caused during harvest; the pathogen then progresses on the stem, killing leaves and secondary buds. When the infection reaches the main stem, the entire plant dies. A study of the epidemiology of the disease and of host-pathogen interactions led to the development of rules for effective disease management. The research was conducted in three steps. (i) Natural epidemics in commercial crops were monitored during the 1993 to 1994 and 1994 to 1995 growing seasons. Disease outbreaks were found to coincide with harvests during rainy days, whereas disease intensity did not change much when harvests were completed during rainless days. (ii) Studies under controlled environmental conditions revealed that cut ends of stems were highly susceptible soon after harvest, susceptibility diminished gradually,...
ABSTRACT Powdery mildew, caused by Podosphaera aphanis, is one of the major fungal diseases of cu... more ABSTRACT Powdery mildew, caused by Podosphaera aphanis, is one of the major fungal diseases of cultivated strawberry (Fragaria × ananassa Duchense) world-wide. In the present research were port the efficacy of various control agents in induced resistance in strawberry plants againstPowdery mildew. Inducers tested are Trichoderma harzianum T39, acibenzolar-S-methyl (Bion),a new protein hydrolysate inducer, an isolate of a bacterium and one of a yeast, and biochar.These agents induced systemic resistance when applied to the root zone, while the disease wasfound and measured on the leaves. In addition, we studied the effect of T39, Bion and biochar onplant defense related gene expression. We show that while Bion induced Systemic Acquired Resistance (SAR) only, as expected, T39 as well as biochar induced SAR and Induced Systemic Resistance (ISR).
ABSTRACT The soil application of biochar, the solid carbon-rich product of biomass pyrolysis, may... more ABSTRACT The soil application of biochar, the solid carbon-rich product of biomass pyrolysis, may improve soil quality and crop productivity. Recently, soil applied biochar was found to reduce severity of foliar diseases and soilborne diseases in various crops. Biochar characteristics are expected to affect its disease suppression capability, as there is a profound variability in the physical and chemical properties of biochar depending on the initial feedstock and production parameters. The aim of this research was to explore the influence of biochar produced from different feedstocks and at different production temperatures on its ability to suppress the soilborne pathogen, Rhizoctonia solani, in cucumber (Cucumis sativus L.). Biochar prepared from two feedstocks (Eucalyptus wood (EUC) and Greenhouse waste (GHW)), each produced at 350 and 600 °C were tested for their suppressive ability against damping-off at concentrations of 0–3%. In general, biochar addition at relatively lower concentrations enhanced plant growth performance and suppressed damping-off by R. solani. However, at higher concentrations, biochar was ineffective or even increased the disease incidence and severity as compared with the control, forming a U-shape response curve versus biochar concentration. Biochars produced at both low and high temperatures were equally effective against various disease parameters but suppression of disease was affected by the feedstock type. There was a significant interaction between feedstock and concentration for the final damping-off incidence and other disease parameters, indicating that each feedstock had an optimum concentration for disease control. The most effective dose for suppressing disease was 1% for EUC biochar and 0.5% for GHW biochar. In conclusion, R. solani suppression in cucumber induced by biochar soil amendment is feedstock and concentration dependent.
The effects of inhaled warm air on nasal patency and on allergic rhinitic symptoms were studied i... more The effects of inhaled warm air on nasal patency and on allergic rhinitic symptoms were studied in 102 patients. Treatment consisted of two consecutive 30-minute sessions, during which the patient inhaled saturated, hot (42-44 degrees C) air through the nose. The treatment was repeated 1 week later. During the week following each treatment, every patient recorded his or her subjective response on a daily symptom score card. Nasal patency was determined before and after each treatment by measuring peak nasal inspiratory and expiratory air flow and by measuring the area covered with vapor formed by the exhaled air on a plate. Highly reproducible results were obtained by using these three objective methods. Inhalation of humidified warm air resulted in amelioration of allergic rhinitis symptoms and in increased nasal patency in a high proportion of patients. There were no adverse side effects. This form of therapy seemed effective in the 2-week period in which it was used and would be ...
Biocontrol agents can control pathogens by reenforcing systemic plant resistance through systemic... more Biocontrol agents can control pathogens by reenforcing systemic plant resistance through systemic acquired resistance (SAR) or induced systemic resistance (ISR). Trichoderma spp. can activate the plant immune system through ISR, priming molecular mechanisms of defense against pathogens. Entomopathogenic fungi (EPF) can infect a wide range of arthropod pests and play an important role in reducing pests’ population. Here, we investigated the mechanisms by which EPF control plant diseases. We tested two well studied EPF, Metarhizium brunneum isolate Mb7 and Beauveria bassiana as the commercial product Velifer, for their ability to induce systemic immunity and disease resistance against several fungal and bacterial phytopathogens, and their ability to promote plant growth. We compared the activity of these EPF to an established biocontrol agent, Trichoderma harzianum T39, a known inducer of systemic plant immunity and broad disease resistance. The three fungal agents were effective agai...
Fungal and bacterial pathogens generate devastating diseases and cause significant tomato crop lo... more Fungal and bacterial pathogens generate devastating diseases and cause significant tomato crop losses worldwide. Due to chemical pesticides harming the environment and human health, alternative disease control strategies, including microorganismal bio-control agents (BCAs), are increasingly sought-after in agriculture. Bio-control microorganisms such as Trichoderma spp. have been shown to activate induced systemic resistance (ISR) in the host. However, examples of highly active bio-control microorganisms in agricultural settings are still lacking, due primarily to inconsistency in bio-control efficacy, often leading to widespread disease prior to the required ISR induction in the host. As part of its plant colonization strategy, Trichoderma spp. can secrete various compounds and molecules, which can effect host priming/ISR. One of these molecules synthesized and secreted from several species of Trichoderma is the family 11 xylanase enzyme known as ethylene inducing xylanase, EIX. EI...
Las tecnologias biologicas, incluyendo el uso de microorganismos biocontroladores, estan adquirie... more Las tecnologias biologicas, incluyendo el uso de microorganismos biocontroladores, estan adquiriendo una importancia primordial en la produccion agricola. Sin embargo, la mayoria de los enfoques para el control biologico de enfermedades de las plantas ha tenido un alcance limitado. Un ejemplo de esto lo representa el hecho de que, en las ultimas decadas, en general, se han utilizado agentes de biocontrol individuales para controlar un solo patogeno. Esto puede explicar parcialmente la respuesta inconsistente que se observa frecuentemente, ya que dichos agentes individuales pueden ser inactivos en varios de los ambientes en los que se aplican o contra diferentes patogenos que atacan a la planta huesped. Lograr un control de amplio espectro de patogenos por los antagonistas que se apliquen individualmente o en consorcio sigue siendo, en gran medida, un objetivo no cumplido para la explotacion eficaz del control biologico, asi como ampliar los usos de los agentes de control biologico p...
We examined the effects of applications of N, P, K, Mg, and Ca through an irrigation solution and... more We examined the effects of applications of N, P, K, Mg, and Ca through an irrigation solution and spraying K, Ca, and Mg salts on cucumber powdery mildew (CPM, Podosphaera xanthii) in potted plants and under commercial-like conditions. Spraying CaCl2 and MgCl2, or KCl and K2SO4, decreased CPM. There were significant negative correlations between the anion-related molar concentrations of the salts and disease severity. Among the sprayed treatments, NaCl provided significantly less CPM control when applied at a low (0.05 M) concentration, as compared with CaCl2 and MgCl2. When sprayed applications of Mg and K salts were analyzed separately from the untreated control, the Cl− salts were found to be more effective than the SO4−2 salts. High N and Mg concentrations in the irrigation water delivered to young, fruit-less cucumber plants reduced CPM, whereas more CPM was observed when the irrigation solution contained a medium amount of P and a high amount of K. In contrast, mature, fruit-b...
It was previously shown that spraying with CaCl2, MgCl2, KCl, and K2SO4 and high N and Mg concent... more It was previously shown that spraying with CaCl2, MgCl2, KCl, and K2SO4 and high N and Mg concentrations in the irrigation water of potted cucumber plants reduced powdery mildew, while medium P and high K concentrations increased powdery mildew. In the present work, we tested the effect of irrigation with N, P, K, Ca, and Mg and spraying with salts on downy mildew (Pseudoperonospora cubensis) of cucumber (CDM). In potted plants, an increase in N concentration in the irrigation water resulted in a major increase in CDM severity, while an increase in K or Ca concentrations resulted in a gradual increase in CDM severity. An increase in P and Mg concentrations in the irrigation water resulted in a major CDM decrease. Spraying with Ca, Mg, and K salts with Cl and SO4 anions resulted in CDM suppression in most cases, and a negative correlation was obtained between the salt and anion molar concentrations and the CDM severity. Using NaCl sprays, both Na and Cl concentrations were negatively...
Downy mildew (caused by Peronospora belbahrii) is a severe disease of sweet basil (Ocimum basilic... more Downy mildew (caused by Peronospora belbahrii) is a severe disease of sweet basil (Ocimum basilicum) crops around the world. We examined cultural methods for reducing the severity of sweet basil downy mildew (SBDM) under commercial conditions in greenhouses and walk-in tunnels. The effects of the orientation of walk-in tunnels, air circulation in greenhouses, plant density, and soil mulch were tested. SBDM was less severe in the tunnels that were oriented north-south than in those oriented east-west, but the yields in both types of tunnels were similar. Increased air circulation reduced SBDM severity, but did not affect yield. Gray or transparent polyethylene mulch reduced SBDM severity and, in most cases, increased yield relative to bare soil/growth medium. Yellow polyethylene mulch provided a smaller amount of control. The combination of increased air circulation and yellow polyethylene mulch provided synergistic SBDM control, whereas no synergism was observed when we combined inc...
Biological control of fungal and bacterial plant pathogens Integrated control in protected crops,... more Biological control of fungal and bacterial plant pathogens Integrated control in protected crops, temperate climate Integrated control in protected crops, mediterranean climate Integration 2004 S. Michele all’Adige, Italy Proceedings of a Meeting of the WGs: Management of plant diseases and arthropod pests by BCAs and their integration in agricultural systems at S. Michele all’Adige, Trentino, Italy
ABSTRACT The purpose of this review is to examine how biochar additions to soil can affect plant ... more ABSTRACT The purpose of this review is to examine how biochar additions to soil can affect plant diseases caused by soilborne pathogens, with particular attention to mechanisms and knowledge gaps. Until now, biochar soil amendment has been reported to affect the progress of diseases caused by soilborne plant pathogens in six distinct pathosystems. Disease severity frequently exhibits a U-shaped response curve, with a minimum at some intermediate biochar dose. Alteration of plant disease intensity by biochar added to soil may result from its varied influences on the soil–rhizosphere–pathogen–plant system. These influences may involve myriad biochar properties such as nutrient content, water holding capacity, redox activity, adsorption ability, pH and content of toxic or hormone-like compounds. The direct and indirect impacts of biochar on the soil environment, host plant, pathogen and the rhizosphere microbiome can have domino effects on both plant development and disease progress
Journal of Environmental Engineering and Landscape Management, 2017
The increasing demand for soilless substrates and rising environmental concerns about the use of ... more The increasing demand for soilless substrates and rising environmental concerns about the use of non-renewable resources such as peat has led to the search for alternative constituents of growing mixtures for containerized plants. In this report we reviewed the works concerning biochar as constituent of growing media, targeting its influence on plant growth and plant disease. Biochar mostly has positive or neutral influences on plant growth compared with peat media when present in concentrations higher than 25% (v:v). However, studies of biochar influence on plant disease reveals that while lower concentrations (≤1%) of biochar often suppressed several diseases, higher concentrations (≥3%) were mostly ineffective or induced plant disease. For use as horticultural peat replacement, it is recommended that biochar feedstocks and concentrations be standardized and the potential effect of biochar on plant disease be considered, so that growers can rely on consistent and reproducible bioc...
Biochar, in addition to sequestering carbon, ameliorating soil, and improving plant performance, ... more Biochar, in addition to sequestering carbon, ameliorating soil, and improving plant performance, can impact foliar and soilborne plant diseases. Nevertheless, the mechanisms associated with suppression of soilborne diseases and improved plant performances are not well understood. This study is designed to establish the relationships between biochar-induced changes in rhizosphere microbial community structure, taxonomic and functional diversity, and activity with soilborne disease suppression and enhanced plant performance in a comprehensive fashion. Biochar suppressed Fusarium crown and root-rot of tomato and simultaneously improved tomato plant growth and physiological parameters. Furthermore, biochar reduced Fusarium root colonization and survival in soil, and increased the culturable counts of several biocontrol and plant growth promoting microorganisms. Illumina sequencing analyses of 16S rRNA gene revealed substantial differences in rhizosphere bacterial taxonomical composition...
Sweet basil (Ocimum basilicum) is a herbaceous annual plant that is highly susceptible to gray mo... more Sweet basil (Ocimum basilicum) is a herbaceous annual plant that is highly susceptible to gray mold, caused by Botrytis cinerea. Infections are initiated on the surface of stem wounds that are caused during harvest; the pathogen then progresses on the stem, killing leaves and secondary buds. When the infection reaches the main stem, the entire plant dies. A study of the epidemiology of the disease and of host-pathogen interactions led to the development of rules for effective disease management. The research was conducted in three steps. (i) Natural epidemics in commercial crops were monitored during the 1993 to 1994 and 1994 to 1995 growing seasons. Disease outbreaks were found to coincide with harvests during rainy days, whereas disease intensity did not change much when harvests were completed during rainless days. (ii) Studies under controlled environmental conditions revealed that cut ends of stems were highly susceptible soon after harvest, susceptibility diminished gradually,...
ABSTRACT Powdery mildew, caused by Podosphaera aphanis, is one of the major fungal diseases of cu... more ABSTRACT Powdery mildew, caused by Podosphaera aphanis, is one of the major fungal diseases of cultivated strawberry (Fragaria × ananassa Duchense) world-wide. In the present research were port the efficacy of various control agents in induced resistance in strawberry plants againstPowdery mildew. Inducers tested are Trichoderma harzianum T39, acibenzolar-S-methyl (Bion),a new protein hydrolysate inducer, an isolate of a bacterium and one of a yeast, and biochar.These agents induced systemic resistance when applied to the root zone, while the disease wasfound and measured on the leaves. In addition, we studied the effect of T39, Bion and biochar onplant defense related gene expression. We show that while Bion induced Systemic Acquired Resistance (SAR) only, as expected, T39 as well as biochar induced SAR and Induced Systemic Resistance (ISR).
ABSTRACT The soil application of biochar, the solid carbon-rich product of biomass pyrolysis, may... more ABSTRACT The soil application of biochar, the solid carbon-rich product of biomass pyrolysis, may improve soil quality and crop productivity. Recently, soil applied biochar was found to reduce severity of foliar diseases and soilborne diseases in various crops. Biochar characteristics are expected to affect its disease suppression capability, as there is a profound variability in the physical and chemical properties of biochar depending on the initial feedstock and production parameters. The aim of this research was to explore the influence of biochar produced from different feedstocks and at different production temperatures on its ability to suppress the soilborne pathogen, Rhizoctonia solani, in cucumber (Cucumis sativus L.). Biochar prepared from two feedstocks (Eucalyptus wood (EUC) and Greenhouse waste (GHW)), each produced at 350 and 600 °C were tested for their suppressive ability against damping-off at concentrations of 0–3%. In general, biochar addition at relatively lower concentrations enhanced plant growth performance and suppressed damping-off by R. solani. However, at higher concentrations, biochar was ineffective or even increased the disease incidence and severity as compared with the control, forming a U-shape response curve versus biochar concentration. Biochars produced at both low and high temperatures were equally effective against various disease parameters but suppression of disease was affected by the feedstock type. There was a significant interaction between feedstock and concentration for the final damping-off incidence and other disease parameters, indicating that each feedstock had an optimum concentration for disease control. The most effective dose for suppressing disease was 1% for EUC biochar and 0.5% for GHW biochar. In conclusion, R. solani suppression in cucumber induced by biochar soil amendment is feedstock and concentration dependent.
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Papers by Yigal Elad