Response of A-genome cotton germplasm to the seedling disease pathogens, Rhizoctonia solani and Pythium ultimum

1994 ◽  
Vol 41 (1) ◽  
pp. 9-12 ◽  
Author(s):  
M. A. Stanton ◽  
C. S. Rothrock ◽  
J. McD. Stewart
Keyword(s):  
Rhizoctonia Solani ◽  
Pythium Ultimum ◽  
Seedling Disease ◽  
A Genome

scholarly journals Deleterious Impact of a Virulent Bacteriophage on Survival and Biocontrol Activity of Pseudomonas fluorescens Strain CHA0 in Natural Soil

2002 ◽  
Vol 15 (6) ◽  
pp. 567-576 ◽  
Author(s):  
Christoph Keel ◽  
Zöhre Ucurum ◽  
Patrick Michaux ◽  
Marc Adrian ◽  
Dieter Haas
Keyword(s):  
Pseudomonas Fluorescens ◽  
Population Size ◽  
Abiotic Factors ◽  
Pythium Ultimum ◽  
Plant Diseases ◽  
Natural Soil ◽  
Lytic Bacteriophage ◽  
Resistant Variant ◽  
A Genome ◽  
Biocontrol Activity

Many biotic and abiotic factors affect the persistence and activity of beneficial pseudomonads introduced into soil to suppress plant diseases. One such factor may be the presence of virulent bacteriophages that decimate the population of the introduced bacteria, thereby reducing their beneficial effect. We have isolated a lytic bacteriophage (ΦGP100) that specifically infects the biocontrol bacterium Pseudomonas fluorescens CHA0 and some closely related Pseudomonas strains. ΦGP100 was found to be a doublestranded-DNA phage with an icosahedral head, a stubby tail, and a genome size of approximately 50 kb. Replication of ΦGP100 was negatively affected at temperatures higher than 25°C. ΦGP100 had a negative impact on the population size and the biocontrol activity of P. fluorescens strain CHA0-Rif (a rifampicin-resistant variant of CHA0) in natural soil microcosms. In the presence of ΦGP100, the population size of strain CHA0-Rif in soil and on cucumber roots was reduced more than 100-fold. As a consequence, the bacterium's capacity to protect cucumber against a root disease caused by the pathogenic oomycete Pythium ultimum was entirely abolished. In contrast, the phage affected neither root colonization and nor the disease suppressive effect of a ΦGP100-resistant variant of strain CHA0-Rif. To our knowledge, this study is the first to illustrate the potential of phages to impair biocontrol performance of beneficial bacteria released into the natural soil environment.

Gliovirin, a new antibiotic from Gliocladium virens, and its role in the biological control of Pythium ultimum

1983 ◽  
Vol 29 (3) ◽  
pp. 321-324 ◽  
Author(s):  
Charles R. Howell ◽  
Robert D. Stipanovic
Keyword(s):  
Pythium Ultimum ◽  
Similar Efficacy ◽  
Antibiotic Activity ◽  
Infested Soil ◽  
Damping Off ◽  
Potato Dextrose Broth ◽  
Seedling Disease ◽  
X Ray ◽  
Gliocladium Virens ◽  
Induced Mutant

A compound with antibiotic activity toward Pythium ultimum was isolated from potato dextrose broth shake cultures of Gliocladium virens, a common soil mycoparasite known to inhibit but not parasitize P. ultimum. The mass spectrum and an X-ray crystallograph of the purified antibiotic indicated that it was a new diketopiperazine, and we have given it the trivial name gliovirin. Gliovirin is highly toxic to P. ultimum but is inactive against other fungi associated with cotton seedling disease. The antibiotic does not persist in nonsterile soil where it is apparently inactivated by the soil microflora.An ultraviolet light induced mutant of G. virens deficient for gliovirin production was overgrown by P. ultimum in culture and did not protect cotton seedlings from damping-off in P. ultimum infested soil. A mutant with enhanced gliovirin production was more inhibitory to P. ultimum in culture than the parent isolate and showed similar efficacy as a seedling disease suppressant, even though its growth rate was reduced when compared to the parent isolate. These results indicate that gliovirin may be important to the antagonist–pathogen interaction.

A Fungicide Application Decision (FAD) Support System for Postbloom Fruit Drop of Citrus (PFD)

2002 ◽  
Vol 3 (1) ◽  
pp. 16 ◽  
Author(s):  
Natália A. R. Peres ◽  
Soonho Kim ◽  
Howard W. Beck ◽  
Nilton L. Souza ◽  
Lavern W. Timmer
Keyword(s):  
Rhizoctonia Solani ◽  
Support System ◽  
Thielaviopsis Basicola ◽  
Seedling Disease ◽  
Cotton Seedling ◽  
Fungicide Application ◽  
Disease Complex ◽  
Fruit Drop ◽  
Application Decision ◽  
Seedling Diseases

Surveys were conducted to identify fungi associated with postemergence cotton seedling disease in Missouri. Samples consisted of 10 cotton seedlings, 2 to 3 weeks after emergence, with symptoms of seedling diseases collected from a 0.25 ha area in each of 60 fields in 1997 and 1998. Four genera of fungi were cultured from the roots (Fusarium, Pythium, Rhizoctonia, and Thielaviopsis) and three species were identified: Rhizoctonia solani, Thielaviopsis basicola, and Pythiumultimum. Rhizoctonia solani, T. basicola, and P. ultimum were cultured from seedlings in 70%, 47%, and 15% of fields sampled in 1997, respectively, and 55%, 17%, and 5% of fields sampled in 1998, respectively. Repeated tests of pathogenicity confirmed that R. solani AG-4, T. basicola, and P. ultimum were major causal agents of postemergence cotton seedling disease in Missouri. This study provides the first documentation on the distribution and frequency of fungi associated with postemergence seedling disease complex of cotton based on a survey of randomly selected fields. Accepted for publication 10 July 2002. Published 31 July 2002.

Interactions of Four Herbicides with Rhizoctonia solani on Seedling Cotton

Weed Science ◽  
1968 ◽  
Vol 16 (4) ◽  
pp. 453-456 ◽  
Author(s):  
James M. Chandler ◽  
P. W. Santelmann
Keyword(s):  
Gossypium Hirsutum ◽  
Rhizoctonia Solani ◽  
Field Studies ◽  
Antagonistic Effect ◽  
Field Conditions ◽  
Growth Chamber ◽  
Seedling Disease ◽  
Low Level ◽  
High Level

Growth chamber and field studies were conducted to investigate the possibility of an interaction between the herbicides 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin), a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), 3- (m-tri-fluromethylphenyl)-1,1-dimethylurea (fluometuron), and 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne), and the seedling disease organism Rhizoctonia solani Kuehn in cotton (Gossypium hirsutum L.). When high levels of trifluralin or prometryne were used in the growth chamber, an interaction with the pathogen that was injurious to the cotton occurred. Prometryne and fluometuron produced an antagonistic effect on R. solani.Under field conditions, R. solani usually caused cotton injury. Interactions injurious to the cotton occurred between trifluralin and a low level of R. solani and between nitralin and a high level R. solani infestation. No interactions occurred with fluometuron or prometryne. In all instances, the effect occurred only when the herbicides were being used at high rates.

scholarly journals Effect of substrates to formulate Trichoderma harzianum based bio-fungicide in controlling seedling disease (Rhizoctonia solani) of brinjal

2017 ◽  
Vol 42 (1) ◽  
pp. 159-170 ◽  
Author(s):  
MI Faruk ◽  
ML Rahman
Keyword(s):  
Rhizoctonia Solani ◽  
Rice Bran ◽  
Wheat Bran ◽  
Trichoderma Harzianum ◽  
Agricultural Research ◽  
Root Weight ◽  
Agricultural Research Institute ◽  
Seedling Disease ◽  
House Condition ◽  
Shoot Weight

Efficacy of three different substrates viz., rice bran, wheat bran, grass pea bran and their combinations with mustard oilcake (MOC) were tested to formulate a suitable Trichoderma harzianum based bio-fungicide for controlling seedling disease of brinjal caused by Rhizoctonia solani in tray soil as well as in seedbed soil under net house condition of Bangladesh Agricultural Research Institute (BARI), Gazipur during 2010 to 2014. The results of three years experiments revealed that T. harzianum bio-fungicides formulated in five different combinations of substrates viz., (1) rice bran + wheat bran, (2) rice bran + mustard oilcake (MOC) (3) rice bran + grasspea bran, (4) rice bran + wheat bran + MOC and (5) rice bran + grasspea bran +MOC were equally effective to control the soil borne seedling disease of brinjal caused by Rhizoctonia solani in tray soil and seedbed condition. In addition, vegetative growth of brinjal seedlings viz., shoot length, shoot weight, root length and root weight were enhanced significantly by the T. harzianum bio-fungicides in R. solani inoculated seedbed condition.Bangladesh J. Agril. Res. 42(1): 159-170, March 2017

scholarly journals Utilisation d'une souche indigène de Trichoderma harzianum contre cinq agents pathogènes chez le concombre et la tomate de serre au Québec

2005 ◽  
Vol 83 (2) ◽  
pp. 73-87 ◽  
Author(s):  
J. Caron ◽  
L. Laverdière ◽  
P.O. Thibodeau ◽  
R.R. Bélanger
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Oxysporum ◽  
Sclerotinia Sclerotiorum ◽  
Verticillium Dahliae ◽  
Trichoderma Harzianum ◽  
Pythium Ultimum

Le potentiel antagoniste du biofongicide à base de Trichoderma harzianum MAUL-20, isolé au Québec, a été testé contre cinq agents telluriques phytopathogènes(Fusarium oxysporum f. sp. radicis-lycopersici (FORL), Pythium ultimum, Rhizoctonia solani, Sclerotinia sclerotiorum et Verticillium dahliae) du concombre et de la tomate de serre. Le biofongicide a démontré une efficacité contre P. ultimum et R. solani chez le concombre et la tomate et contre FORL chez la tomate. De plus, T. harzianum MAUL-20 a eu un effet stimulant sur le développement des plants de concombre lorsque cultivés, sans agents pathogènes, dans un substrat organique alimenté du biofongicide. L'efficacité de T. harzianum MAUL-20 a été comparée à celle du biofongicide américain Rootshield™ (Trichoderma harzianum KRL-AG2) et le premier a démontré une activité antagoniste égale ou supérieure à celle de Rootshield™.

Some factors affecting the development and biocontrol of cotton seedling disease

1995 ◽  
Vol 35 (6) ◽  
pp. 771 ◽  
Author(s):  
HJ Ogle ◽  
AM Stirling ◽  
PJ Dart
Keyword(s):  
Pythium Ultimum ◽  
Disease Development ◽  
Symptom Development ◽  
Night Temperature ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Susceptibility To Infection ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Number Of Seeds

The effects of temperature and cultivar on disease development in cotton were investigated in addition to the duration of susceptibility to infection and the timing of infection by Pythium ultimum and Rhizoctonia solani. Symptom development was also monitored. Disease was more severe at day/night temperature regimes of 20/15, 25/20, and 30/25�C than at 35/30�C. Disease development differed significantly between cotton cvv. Deltapine 90 and Siokra 1-4 at 30/25�C and 35/30�C. In glasshouse trials in field soil, both R. solani and P ultimum were isolated from seeds as early as 2 h after inoculation, although most seeds were not infected with P. ultimum until 10 h after inoculation and with R. solani until 24 h after inoculation. Increasing the duration of exposure to inoculum increased the number of seeds infected and reduced the number of plants surviving. Seedlings were resistant to P. ultimum infection by 14 days after sowing but were not resistant to infection by R. solani until 28 days after sowing.

Root-rot resistance in common bean

1993 ◽  
Vol 73 (1) ◽  
pp. 365-367 ◽  
Author(s):  
J. C. Tu ◽  
S. J. Park
Keyword(s):  
Phaseolus Vulgaris ◽  
Rhizoctonia Solani ◽  
Common Bean ◽  
Fusarium Oxysporum ◽  
Key Words ◽  
Fusarium Solani ◽  
Root Rot ◽  
Pythium Ultimum ◽  
Growth Room

A bean (Phaseolus vulgaris) line, A - 300, resistant to Rhizoctonia solani and Fusarium oxysporum was introduced into Ontario from Colombia. The results of tests conducted in a root-rot nursery, in a greenhouse and in a growth room showed that this bean line is resistant to Fusarium solani f. sp. phaseoli and Pythium ultimum. Key words: Bean, Phaseolus vulgaris, root rot resistance

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