EFFECT OF POMEGRANATE (Punica granatumL.) FRUITS PEEL ON SOME PHYTOPATHOGENIC FUNGI AND CONTROL OF TOMATO DAMPING-OFF

ABSTRACT The aim of this study was to verify the influence of previous crops and fungicide seed treatment in the incidence and control of damping-off caused by Rhizoctonia solani in cotton seedlings under greenhouse conditions. This experiment was carried out during two years at Embrapa Western Agriculture, in Dourados, Mato Grosso do Sul State, Brazil. In addition to cotton (treated and untreated seeds) and fallow, the following cover crops were tested as previous crops: black oats, millet, corn, forage sorghum, soybean, common beans, crotalaria (Crotalaria juncea), brachiaria (Urochloa ruziziensis) and brachiaria (Urochloa ruziziensis) + crotalaria (Crotalaria juncea). The fungicide mixture used as treatment to cotton seeds was triadimenol + pencycuron + tolylfluanid (50 + 50 + 30 g a.i./100 kg seeds). Seeds from cotton and previous crops were sown in soil contained in plastic trays and pots; the seeds were placed in individual and equidistant 3cm-deep wells. Inoculation of R. solani was obtained by homogeneously distributing the fungal inoculum onto the substrate surface (2.5g/tray and 0.34g/pot). The fungus was grown for 35 days on autoclaved black oat seeds subsequently ground to powder using a mill (1mm). Damping-off was daily evaluated from the seventh day after sowing. There was a significant effect of the interaction previous crops x fungicide treatment (P<0.05). The fungicide seed treatment was efficient in controlling seedling damping-off caused by R. solani and its effect was potentiated when grasses were the previous crops. Use of grasses such as brachiaria (Urochloa ruziziensis), black oats, millet, corn and forage sorghum as previous crops, besides fallow, significantly contributed to a smaller R. solani population in the soil, which resulted in lower rates of cotton seedling damping-off. On the other hand, using cotton continuously, as well as the legumes soybeans, beans, crotalaria (Crotalaria juncea), and brachiaria (Urochloa ruziziensis) + crotalaria (Crotalaria juncea) as previous crops to cotton, was consistently associated with higher rates of seedling damping-off, contributing to the increase or at least the maintenance of R. solani inoculum in the soil. The highest damping-off percentages were observed in plots under continuous cotton cultivation without fungicide seed treatment. The present results reinforce the need of improving damping-off control in cotton seedlings by adopting integrated management programs in areas infested with R. solani.

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Biology and control of Rhizoctonia solani on rapeseed : A Review

Phytoprotection ◽

10.7202/706106ar ◽

2005 ◽

Vol 77 (3) ◽

pp. 99-111 ◽

Cited By ~ 17

Author(s):

P.R. Verma

Keyword(s):

Rhizoctonia Solani ◽

Root Rot ◽

Plant Root ◽

The United States ◽

Damping Off ◽

High Soil Moisture ◽

Breeding Programmes ◽

Phosphorus And Potassium ◽

Moderate Resistance ◽

And Control

Rhizoctonia solani AG2-1 is the principal pathogen causing damping-off and seedling and mature plant root rot (brown girdling root rot) in oilseed rape and canola (Brassica napus and B. rapa) in western Canada and the United States; AG4 isolates mainly attack adult plants and cause basai stem rot. Seedling infection by AG2-1 is favoured by cool weather atthe time of planting, whereas warm weather late in the growing season is more conducive for infection of mature plants by AG4 isolates. Survey data show that disease development is favoured by high soil moisture, low levels of nitrogen, phosphorus and potassium and high levels of copper in fine-textured soils. Moderate resistance in condiment mustard (Sinapis alba) and some other species appears to be genetically controlled and should be utilised in breeding programmes. Carboxin and iprodione in mixtures with insecticide gamma-HCH are recommended in Canada as seed treatments to control damping-off and seedling root rot, but do not control brown girdling root rot.

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Salicylic acid in the induction of resistance to beet seedling damping-off and antifungal activity against Fusarium sp., in vitro

Semina Ciências Agrárias ◽

10.5433/1679-0359.2016v37n1p67 ◽

2016 ◽

Vol 37 (1) ◽

pp. 67 ◽

Cited By ~ 2

Author(s):

Douglas Junior Bertoncelli ◽

Sérgio Miguel Mazaro ◽

Rita De Cacia Dosciatti Serrão Rocha ◽

Nean Locatelli Dalacosta ◽

Adriano Lewandowski ◽

...

Keyword(s):

Salicylic Acid ◽

Antifungal Activity ◽

Mycelial Growth ◽

Experimental Unit ◽

Damping Off ◽

Potato Dextrose Agar Medium ◽

Seedling Length ◽

Fusarium Sp ◽

And Control

The damping off is the main disease that affects the beet crop during the seedling production. The aim of this study was to evaluate different salicylic acid (SA) concentrations for resistance induction against damping-off in beet seedling and its antifungal activity against Fusarium sp., in vitro condition. Treatment of beet seed was with SA solution by immersion during 5 minutes in the 0.5, 1.0, 1.5 and 2.0 mM concentrations and control (distilled water). It was used four replications with 20 cells by experimental unit. The experiment was carried out for 14 days in cultivate chamber with temperature (23 oC ± 2°C), lighting (12 hours photoperiod) and humidity (70% ± 10%) controlled. After this time, the germination, damping off incidence, seedling length and fresh mass matter weight were evaluated. It was evaluated also in the seedling tissue the phenylalanine ammonia-lyase (PAL), ?-1.3 glucanase and chitinase level enzymes. In the in vitro the SA was putted in PDA (potato-dextrose-agar) medium, where the Fusarium sp. mycelial growth was evaluated. The SA applied for seeds treatment didn’t had effect significant on damping off of beet seedlings, but it induced the activity of ?-1.3 glucanase enzyme, it being this higher in nine times when compared the treatment control. The SA acted in the Fusarium sp. in vitro control with fungitoxic action, suppressed mycelial growth in 28% if compared to control.

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First Report of Cylindrocarpon destructans as a Root Pathogen of Mediterranean Quercus Species in Spain

Plant Disease ◽

10.1094/pdis.2002.86.6.693c ◽

2002 ◽

Vol 86 (6) ◽

pp. 693-693 ◽

Cited By ~ 3

Author(s):

M. E. Sánchez ◽

F. Lora ◽

A. Trapero

Keyword(s):

Root Rot ◽

Peat Soil ◽

Phytopathogenic Fungi ◽

Potting Medium ◽

Quercus Species ◽

Significant Difference ◽

Root Necrosis ◽

Quercus Spp ◽

Forest Nurseries ◽

And Control

Cylindrocarpon spp. have been described as producing root rot in Quercus spp. in forest nurseries, mostly when the host plants were weakened (1). To our knowledge, this is the first description of root rot of Mediterranean Quercus (Q. ilex, Q. suber, and Q. faginea) seedlings caused by C. destructans. In spring 2000, heavy mortality of Quercus seedlings was recorded in a nursery in southeastern Spain. The affected plants were 9 months old and growing in the open air in fertilized peat. Symptoms consisted of browning and wilting of leaves, with extensive necrosis of feeder roots. C. destructans (macroconidia averaging 36 × 6 μm, 1 to 3 septate; microconidia 10 × 3 μm; chlamydospores rough, single, or in chains, averaging 9 μm in diameter) was consistently isolated from the necrotic rootlets. Pathogenicity of one isolate from Q. faginea and of a mixture of isolates from the three affected Quercus spp. was determined. Fungal isolates were grown on potato dextrose agar plates for 1 month to allow chlamydospore production, and the inocula were prepared by mixing the contents of three colonized plates with 125 ml of sterile water. Six replicates of 12-month-old Q. ilex and Q. suber seedlings were inoculated by mixing the inoculum from the three plates with the potting medium prior to planting the seedling. All inoculated and control plants (only water added) were grown in a sand-lime-peat soil mixture under greenhouse conditions and watered as needed. After 5 weeks, all the inoculated plants showed extensive root necrosis accompanied by crown symptoms and rapid plant death. No symptoms were evident in control plants, and they produced new rootlets. No significant difference in pathogenicity was noted between the single isolate compared with the mixture of isolates, and the Quercus species did not significantly differ in susceptibility to root rot. C. destructans was easily recovered from necrotic roots. Reference: (1) D. Brayford. Cylindrocarpon. Pages 103–106 In: Methods for Research on Soilborne Phytopathogenic Fungi. American Phytopathological Society, St. Paul, MN, 1992.

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A REVIEW OF DAMPING-OFF OF DOUGLAS FIR SEEDLINGS IN BRITISH COLUMBIA

The Forestry Chronicle ◽

10.5558/tfc30407-4 ◽

1954 ◽

Vol 30 (4) ◽

pp. 407-410 ◽

Cited By ~ 1

Author(s):

P. J. Salisbury

Keyword(s):

British Columbia ◽

Control Measures ◽

Effective Control ◽

Damping Off ◽

Natural Control ◽

Cover Soil ◽

Low Degree ◽

Nursery Practices ◽

Forest Nurseries ◽

And Control

Except in new nurseries, damping-off in British Columbia forest nurseries has remained below serious levels. Modification of nursery practices has served to reduce losses. The use of a suitable, sandy cover soil has been effective. Lowered fertility of the soil, though a problem in itself, appears to decrease incidence of damping-off. The acidity of the soil in coast nurseries may have afforded some natural control of the disease. From investigations on the control of damping-off, there appears to be promise in the use of peat as a planting medium for stratified seed, and, based on experiments with unstratified seed, in the application of fungicides to cover soil. In view of the present low degree of the disease, there would appear to be an opportunity for research directed to the biology and control of fungi known to be capable of causing sudden outbreaks, without the urgent need of finding immediately effective control measures.

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Mutation of a degS Homologue in Enterobacter cloacae Decreases Colonization and Biological Control of Damping-Off on Cucumber

Phytopathology ◽

10.1094/phyto-03-10-0076 ◽

2011 ◽

Vol 101 (2) ◽

pp. 271-280 ◽

Cited By ~ 4

Author(s):

Daniel P. Roberts ◽

Scott M. Lohrke ◽

Laurie McKenna ◽

Dilip K. Lakshman ◽

Hyesuk Kong ◽

...

Keyword(s):

Stress Response ◽

Enterobacter Cloacae ◽

Pythium Ultimum ◽

Damping Off ◽

E Coli ◽

Transposon Insertion ◽

Acidic Conditions ◽

And Control ◽

First Time ◽

Reducing Stress

We have been using mutagenesis to determine how biocontrol bacteria such as Enterobacter cloacae 501R3 deal with complex nutritional environments found in association with plants. E. cloacae C10, a mutant of 501R3 with a transposon insertion in degS, was diminished in growth on synthetic cucumber root exudate (SRE), colonization of cucumber seed and roots, and control of damping-off of cucumber caused by Pythium ultimum. DegS, a periplasmic serine protease in the closely related bacterium Escherichia coli K12, is required for the RpoE-mediated stress response. C10 containing wild-type degS from 501R3 or from E. coli K12 on pBeloBAC11 was significantly increased in growth on SRE, colonization of cucumber roots, and control of P. ultimum relative to C10 containing pBeloBAC11 alone. C10 and 501R3 were similar in sensitivity to acidic conditions, plant-derived phenolic compounds, oxidative stress caused by hydrogen peroxide, dessication, and high osmoticum; stress conditions potentially associated with plants. This study demonstrates a role for degS in the spermosphere and rhizosphere during colonization and disease control by Enterobacter cloacae. This study implicates, for the first time, the involvement of DegS and, by extension, the RpoE-mediated stress response, in reducing stress on E. cloacae resulting from the complex nutritional environments in the spermosphere and rhizosphere.

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Isolation, identification, carbon utilization profile and control of Pythium graminicola , the causal agent of chilli damping‐off

Journal of Phytopathology ◽

10.1111/jph.12872 ◽

2019 ◽

Vol 168 (2) ◽

pp. 88-102 ◽

Cited By ~ 1

Author(s):

Manish Kumar Dubey ◽

Andleeb Zehra ◽

Mohd. Aamir ◽

Mukesh Yadav ◽

Swarnmala Samal ◽

...

Keyword(s):

Causal Agent ◽

Damping Off ◽

Carbon Utilization ◽

Carbon Utilization Profile ◽

And Control

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Antifungal Activity of Selected IndigenousPseudomonasandBacillusfrom the Soybean Rhizosphere

International Journal of Microbiology ◽

10.1155/2009/572049 ◽

2009 ◽

Vol 2009 ◽

pp. 1-9 ◽

Cited By ~ 18

Author(s):

M. León ◽

P. M. Yaryura ◽

M. S. Montecchia ◽

A. I. Hernández ◽

O. S. Correa ◽

...

Keyword(s):

Antifungal Activity ◽

Seedling Emergence ◽

Pythium Ultimum ◽

Phytopathogenic Fungi ◽

Soybean Seeds ◽

Damping Off ◽

Bacterial Strains ◽

Protected Plants ◽

Soybean Plants

The purpose of this study was to isolate and select indigenous soilPseudomonasandBacillusbacteria capable of developing multiple mechanisms of action related to the biocontrol of phytopathogenic fungi affecting soybean crops. The screening procedure consisted of antagonism tests against a panel of phytopathogenic fungi, taxonomic identification, detection by PCR of several genes related to antifungal activity, in vitro detection of the antifungal products, and root colonization assays. Two isolates, identified and designated asPseudomonas fluorescensBNM296 andBacillus amyloliquefaciensBNM340, were selected for further studies. These isolates protected plants against the damping-off caused byPythium ultimumand were able to increase the seedling emergence rate after inoculation of soybean seeds with each bacterium. Also, the shoot nitrogen content was higher in plants when seeds were inoculated with BNM296. The polyphasic approach of this work allowed us to select two indigenous bacterial strains that promoted the early development of soybean plants.

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