scholarly journals The Impact of Phytophthora Root Rot on Water Extraction from Soil by Roots of Field-grown Processing Tomatoes

1991 ◽  
Vol 116 (4) ◽  
pp. 603-608 ◽  
Author(s):  
J.B. Ristaino ◽  
J.M. Duniway
Keyword(s):  
Root Rot ◽  
Disease Onset ◽  
Water Extraction ◽  
Total Water ◽  
Tomato Root ◽  
Phytophthora Root Rot ◽  
Tomato Roots ◽  
The Impact ◽  
Field Plots ◽  
Processing Tomatoes

Processing tomatoes (Lycopersicon esculentum Mill.) grown in field plots with soil infested with or free of Phytophthora parasitic Dastur. were furrow-irrigated for 4 to 8 hours every 14 days (normal irrigation), for 4 to 8 hours every 28 days (less frequent irrigation), or for 4 to 8 and 24 hours on alternate irrigations every 14 days (prolonged irrigation). Disease developed more rapidly and symptom severity was greater in inoculated plants that received prolonged irrigation, whereas disease onset was delayed in inoculated plants that were irrigated less frequently. Water extraction by tomato roots from well-irrigated and noninfested soil was usually greatest at shallow depths and decreased with depth. When disease was increasing and soil moisture was high, diseased plants extracted less total water from all depths and significantly less water at shallow depths. Plants in the drier soil profiles extracted the greatest amounts of water at depths below 90 cm, and diseased plants irrigated less frequently showed reductions in water extraction at shallow depths later in the season. Tomato root systems appeared to compensate for moderate levels of root disease at shallow depths by extracting more water from deeper in the profile.

scholarly journals Unconventional alternatives for control of tomato root rot caused by Rhizoctonia solani under greenhouse conditions

2016 ◽  
Vol 56 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Amany Hamza ◽  
Ahmed Mohamed ◽  
Aly Derbalah
Keyword(s):  
Pseudomonas Fluorescens ◽  
Root Rot ◽  
Wheat Germ ◽  
Bacillus Pumilus ◽  
Growth Parameters ◽  
Gas Chromatography Mass Spectrometry ◽  
Wheat Germ Oil ◽  
Tomato Root ◽  
Effective Microorganisms ◽  
The Impact

Abstract This study was done to assess the antifungal effect of some biocontrol agents effective microorganisms (EMs1), Pseudomonas fluorescens, and Bacillus pumilus, titanium dioxide (TiO2) nanoparticles, black cumin and wheat germ oils as well as the recommended fungicide (flutolanil) against root rot of tomato. Moreover, gas chromatography-mass spectrometry (GC-MS) examination was completed to identify the bioactive compounds in plant oils (dark cumin and wheat germ). Also the impact of these medicines on some biochemical and growth parameters of tomato was examined. Flutolanil was the best treatment followed by dark cumin, TiO2, EMs1, Pseudomonas fluorescens, Bacillus pumilus and wheat germ oil, individually in both test seasons. The outcomes demonstrated a marked increase in each biochemical character (chlorophyll substance, peroxidase and polyphenoloxidase) and plant development (height and fresh and dry weight) under all the tried treatments in comparison to the controls.

scholarly journals Visualization of Interactions Between a Pathogenic and a Beneficial Fusarium Strain During Biocontrol of Tomato Foot and Root Rot

2005 ◽  
Vol 18 (7) ◽  
pp. 710-721 ◽  
Author(s):  
Annouschka Bolwerk ◽  
Anastasia L. Lagopodi ◽  
Ben J. J. Lugtenberg ◽  
Guido V. Bloemberg
Keyword(s):  
Root Rot ◽  
Laser Scanning ◽  
Root Colonization ◽  
Pathogenic Fungus ◽  
Laser Scanning Microscopy ◽  
Systemic Resistance ◽  
Confocal Laser ◽  
Tomato Root ◽  
Tomato Roots

The soilborne fungus Fusarium oxysporum f. sp. radicislycopersici causes tomato foot and root rot (TFRR), which can be controlled by the addition of the nonpathogenic fungus F. oxysporum Fo47 to the soil. To improve our understanding of the interactions between the two Fusarium strains on tomato roots during biocontrol, the fungi were labeled using different autofluorescent proteins as markers and subsequently visualized using confocal laser scanning microscopy. The results were as follows. i) An at least 50- fold excess of Fo47over F. oxysporum f. sp. radicis-lycopersici was required to obtain control of TFRR. ii) When seedlings were planted in sand infested with spores of a single fungus, Fo47 hyphae attached to the root earlier than those of F. oxysporum f. sp. radicis-lycopersici. iii) Subsequent root colonization by F. oxysporum f. sp. radicis-lycopersici was faster and to a larger extent than that by Fo47. iv) Under disease-controlling conditions, colonization of tomato roots by the pathogenic fungus was significantly reduced. v) When the inoculum concentration of Fo47 was increased, root colonization by the pathogen was arrested at the stage of initial attachment to the root. vi) The percentage of spores of Fo47 that germinates in tomato root exudate in vitro is higher than that of the pathogen F. oxysporum f. sp. radicis-lycopersici. Based on these results, the mechanisms by which Fo47 controls TFRR are discussed in terms of i) rate of spore germination and competition for nutrients before the two fungi reach the rhizoplane; ii) competition for initial sites of attachment, intercellular junctions, and nutrients on the tomato root surface; and iii) inducing systemic resistance.

Cultivars and fungicides affect Phytophthora root rot in processing tomatoes

2001 ◽  
Vol 30 (4) ◽  
pp. 309 ◽  
Author(s):  
W. S. Washington ◽  
Patricia McGee ◽  
Sze P. Flett ◽  
P. H. Jerie ◽  
W. J. Ashcroft
Keyword(s):  
Root Rot ◽  
Phytophthora Root Rot ◽  
Processing Tomatoes

Control of Phytophthora root rot in processing tomatoes by metalaxyl and fosetyl-Al

1991 ◽  
Vol 31 (2) ◽  
pp. 279 ◽  
Author(s):  
SP Flett ◽  
WJ Ashcroft ◽  
PH Jerie ◽  
PA Taylor
Keyword(s):  
Lycopersicon Esculentum ◽  
Disease Severity ◽  
Root Rot ◽  
Foliar Spray ◽  
Phytophthora Nicotianae ◽  
Phytophthora Root Rot ◽  
Greenhouse Experiments ◽  
Soil Drench ◽  
Crop Development ◽  
Processing Tomatoes

The efficacies of metalaxyl and fosetyl-A1 were evaluated for the control of root rot in tomatoes (Lycopersicon esculentum Mill.) caused by Phytophthora nicotianae var. nicotianae in a greenhouse and in the field. In greenhouse experiments, disease severity was significantly (P<0.05) reduced with metalaxyl applied at rates of 1.5-25 g a.i./L as a soil drench and with fosetyl-A1 applied as a foliar spray at 3.2 g a.i./L. In the field, disease severity was reduced by applications of metalaxyl at rates up to 3 kg a.i./ha banded below the fertiliser at sowing and with additional applications to the bed shoulders at regular intervals for a period of 10 weeks after sowing. Metalaxyl treatments applied at sowing significantly reduced root rot severity for the first 12 weeks of crop development but failed to provide season-long protection. Yield of tomatoes at harvest was not significantly increased by the fungicide treatments, The use of metalaxyl granules in the field to control P. nicotianae root rot is not recommended.

scholarly journals Phytophthora root rot: its impact in botanic gardens and on threatened species conservation

2020 ◽  
pp. 89-104
Author(s):  
Brett Summerell ◽  
Edward Liew
Keyword(s):  
Threatened Species ◽  
Root Rot ◽  
Species Conservation ◽  
Phytophthora Species ◽  
Ex Situ ◽  
Botanic Gardens ◽  
Natural Ecosystems ◽  
Phytophthora Root Rot ◽  
A Site ◽  
The Impact

Phytophthora root rot is one of the most devastating diseases of perennial plants worldwide, affecting plants in food production, amenity plantings and in natural ecosystems. The impact of these diseases in botanic gardens can be substantial and can affect how a site may be used for months and years ahead. Management is critically dependent on avoidance of the introduction of the pathogen and effective hygiene protocols are key to achieving this. Additionally, botanic gardens have a key role to play in protecting plants and enhancing conservation outcomes through surveillance, education and ex situ conservation programmes, as well as through the recognition that they can be critical as sentinel sites to detect new incursions of pests anddiseases. The impact of several Phytophthora species on the in situ and ex situ management of the critically endangered Wollemia nobilis (Wollemi pine), which is highly susceptible to phytophthora root rot, is used to highlight the need to ensure management of these pathogens is a critical component of threatened species recovery and management.

scholarly journals Cellulase Activity as a Mechanism for Suppression of Phytophthora Root Rot in Mulches

2011 ◽  
Vol 101 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Brantlee Spakes Richter ◽  
Kelly Ivors ◽  
Wei Shi ◽  
D. M. Benson
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Cellulase Activity ◽  
Enzyme Concentration ◽  
Disease Suppression ◽  
In Vitro Assays ◽  
Infested Soil ◽  
Phytophthora Root Rot ◽  
Standard Curve

Wood-based mulches are used in avocado production and are being tested on Fraser fir for reduction of Phytophthora root rot, caused by Phytophthora cinnamomi. Research with avocado has suggested a role of microbial cellulase enzymes in pathogen suppression through effects on the cellulosic cell walls of Phytophthora. This work was conducted to determine whether cellulase activity could account for disease suppression in mulch systems. A standard curve was developed to correlate cellulase activity in mulches with concentrations of a cellulase product. Based on this curve, cellulase activity in mulch samples was equivalent to a cellulase enzyme concentration of 25 U ml–1 or greater of product. Sustained exposure of P. cinnamomi to cellulase at 10 to 50 U ml–1 significantly reduced sporangia production, but biomass was only reduced with concentrations over 100 U ml–1. In a lupine bioassay, cellulase was applied to infested soil at 100 or 1,000 U ml–1 with three timings. Cellulase activity diminished by 47% between 1 and 15 days after application. Cellulase applied at 100 U ml–1 2 weeks before planting yielded activity of 20.08 μmol glucose equivalents per gram of soil water (GE g–1 aq) at planting, a level equivalent to mulch samples. Cellulase activity at planting ranged from 3.35 to 48.67 μmol GE g–1 aq, but no treatment significantly affected disease progress. Based on in vitro assays, cellulase activity in mulch was sufficient to impair sporangia production of P. cinnamomi, but not always sufficient to impact vegetative biomass.

Sign in / Sign up

Export Citation Format

Share Document