scholarly journals Influence of MCPA on Fusarium oxysporum root rot and red clover growth under controlled greenhouse conditions

2006 ◽  
Vol 87 (1) ◽  
pp. 9-15
Author(s):  
Ricardo Ceballos ◽  
Graciela Palma ◽  
Fernando Perich ◽  
Fernando Pardo ◽  
Andrés Quiroz

Abstract Root rot caused by Fusarium oxysporum is a disease that reduces red clover persistence. Agronomical management of red clover includes MCPA application, and there is no information regarding the effects of this herbicide on the disease. MCPA was evaluated for its effects on F. oxysporum root rot and red clover (Trifolium pratense) growth in a greenhouse experiment. Additionally, in vitro mycelial growth and conidial germination of F. oxysporum were studied. For shoot dry weight and crown diameter of seedlings, the interaction of herbicide and inoculum was significant at 30 d. The herbicide–inoculum treatment reduced shoot dry weight by 20% at 1X rate and by 24% at 2X rate, and crown diameter was reduced by 10% at the high rate. The MCPA treatment caused a 40% reduction of root dry weight by the end of the experiment. Application of MCPA caused fusarium root rot to increase in severity on red clover seedlings and caused phytotoxicity at the high rate. Interaction with the other growth parameters was not significant, indicating that the effects of herbicide and inoculum were independent. Conidial germination and mycelial growth in vitro were reduced by MCPA. Results suggest that red clover growth could be negatively affected by F. oxysporum after MCPA application and that root rot severity increases at high rates of MCPA.

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 825-829 ◽  
Author(s):  
S. G. Taylor ◽  
D. G. Shilling ◽  
K. H. Quesenberry ◽  
G. R. Chaudhry

Whole plant and tissue culture experiments were conducted to determine the difference in phytotoxicity of 2,4-D and its metabolite, 2,4-DCP, to red clover. At the whole plant level, the mean concentration of 2,4-DCP (10 mM) required to cause 50% growth inhibition (I50) of shoot dry weight was 24 times greater than for 2,4-D (0.42 mM). Using callus tissue, the I50value for 2,4-DCP (0.28 mM) was 22 times greater than for 2,4-D (0.013 mM) based on dry weights. The callus tissue was 36 and 32 times more sensitive to 2,4-DCP and 2,4-D than shoot tissue based on dry weights, respectively. These data indicate that 2,4-DCP was less phytotoxic than 2,4-D to red clover both in vitro and in vivo.


Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1317-1323 ◽  
Author(s):  
J. X. Zhang ◽  
A. G. Xue ◽  
J. T. Tambong

Fusarium root rot is an important disease of soybean in Ontario, Canada. This study is to select antagonistic bacterial agents as effective alternatives to chemical pesticides for the control of root rots caused by Fusarium oxysporum and F. graminearum. Twenty-two Bacillus subtilis strains from soybean and corn roots were tested in dual cultures for inhibition of mycelial growth of F. oxysporum and F. graminearum. All strains significantly reduced mycelial growth of F. oxysporum by approximately 17 to 48% and of F. graminearum by 10 to 32%. Ten B. subtilis strains selected based on their larger fungal inhibition zones were evaluated against macroconidial germination. These strains inhibited the spore germination of F. oxysporum by 20 to 48% and of F. graminearum by 14 to 32% in cell-free filtrates. Under greenhouse conditions, the efficacy of seed and soil treatments with B. subtilis strains against the two Fusarium root rot pathogens was evaluated based on root rot severity, seedling emergence, plant height, and root dry weight. Six B. subtilis strains (SB01, SB04, SB23, SB24, SB28, and SB33) from soybean roots and two strains (CB01 and CH22) from corn roots significantly reduced the severity of the two Fusarium root rots in seed or soil treatments. Strains SB01, SB04, SB23, and SB24 were the most effective treatments against both pathogens in either seed or soil treatment. When applied as seed treatments, these four strains reduced root rot severity by 43 to 63% and increased emergence by 13 to 17%, plant height by 9 to 18%, and root dry weight by 8.4 to 19%. When used as soil treatments, they reduced root rot severity by 68 to 74% and increased emergence by 14 to 18%, plant height by 11 to 23%, and root dry weight by 16 to 24%. These results suggest that the novel strains of B. subtilis identified in this research can be effective alternatives to fungicides in managing Fusarium root rots of soybean, and a greater level of efficacy may be achieved when they were used as soil treatments than seed treatments.


2015 ◽  
Vol 43 (2) ◽  
pp. 554-560 ◽  
Author(s):  
Olivera STAJKOVIC-SRBINOVIC ◽  
Dušica DELIC ◽  
Nataša RASULIC ◽  
Dragan CAKMAK ◽  
Djordje KUZMANOVIC ◽  
...  

In the present study the effects of Rhizobium inoculation and lime application on the mineral composition (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, B) of red clover (Trifolium pratense L.), in very acid soil were evaluated. Inoculation with Rhizobium leguminosarum bv. trifolii significantly increased shoot dry weight (SDW) of red clover plants (three times greater), as well as N, Mg, Fe, Mn and Cu contents in plants compared to the control. Application of lime and Rhizobium together, depending on the lime rate (3, 6 or 9 t ha-1 of lime) and the cut, increased SDW significantly, but decreased the contents of N, P, K, Mg, Mn, Zn and B in plants. Regardless of the changes, in all treatments in both cuts, contents of N, K, Ca, Mg, Mn and Zn in plants were among sufficiency levels (Mg content was elevated in the second cut), while Fe content was mainly high, as well as Cu (in the second cut). Contents of P and B in plants were somewhat lower than sufficiency levels, but above critical level. Therefore, red clover can be grown with satisfactory yield and mineral composition in acid soil with Rhizobium inoculation only, but the application of P and B fertilization is desirable.


2014 ◽  
Vol 40 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Zayame Vegette Pinto ◽  
Matheus Aparecido Pereira Cipriano ◽  
Amaury da Silva dos Santos ◽  
Ludwig Heinrich Pfenning ◽  
Flávia Rodrigues Alves Patrício

Bottom rot, caused by Rhizoctonia solani AG 1-IB, is an important disease affecting lettuce in Brazil, where its biological control with Trichoderma was not developed yet. The present study was carried out with the aim of selecting Trichoderma isolates to be used in the control of lettuce bottom rot. Forty-six Trichoderma isolates, obtained with baits containing mycelia of the pathogen, were evaluated in experiments carried out in vitro and in vivo in a greenhouse in two steps. In the laboratory, the isolates were evaluated for their capabilities of parasitizing and producing toxic metabolic substances that could inhibit the pathogen mycelial growth. In the first step of the in vivo experiments, the number and the dry weight of lettuce seedlings of the cultivar White Boston were evaluated. In the second step, 12 isolates that were efficient in the first step and showed rapid growth and abundant sporulation in the laboratory were tested for their capability of controlling bottom rot in two repeated experiments, and had their species identified. The majority of the isolates of Trichoderma spp. (76%) showed high capacity for parasitism and 50% of them produced toxic metabolites capable of inhibiting 60-100% of R. solani AG1-IB mycelial growth. Twenty-four isolates increased the number and 23 isolates increased the dry weight of lettuce seedlings inoculated with the pathogen in the first step of the in vivo experiments.In both experiments of the second step, two isolates of T. virens, IBLF 04 and IBLF 50, reduced the severity of bottom rot and increased the number and the dry weight of lettuce seedlings inoculated with R. solani AG1-IB. These isolates had shown a high capacity for parasitism and production of toxic metabolic substances, indicating that the in vitro and in vivo steps employed in the present study were efficient in selecting antagonists to be used for the control of lettuce bottom rot.


Nativa ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
Marcos Vinícius Marques Pinheiro ◽  
Ana Cristina Portugal Pinto De Carvalho ◽  
Fabrina Bolzan Martins

No intuito de elevar as taxas de sobrevivência durante a etapa de aclimatização e posterior plantio a campo, avaliou-se o enraizamento in vitro de bananeira cv. Pacovan, em diferentes concentrações de sais MS e de sacarose. Utilizou-se DIC, esquema fatorial (6x2x3), com seis meios de cultura [sendo três concentrações de nutrientes do meio MS (100%; 50% de macronutrientes; e 50% dos sais macro e micronutrientes), e duas concentrações de sacarose (1,5/3,0%)], dois fotoperíodos (12/16 h) e três tempos de cultivo (21, 28 ou 35 dias) e seis repetições/tratamento. Analisaram-se: altura da planta, número de folhas/planta, massas frescas e secas das partes aérea e radicular. Para altura da planta, massa fresca da parte aérea e radicular, o meio MS 50% dos sais + sacarose (1,5%) com fotoperíodo de 16 h e tempo de cultivo de 35 dias foi satisfatório. Para massa seca da parte aérea foi MS 50% de sais + sacarose (3%), e para massa seca da parte radicular, MS 100% + sacarose (3%) (em 12hs/28 dias e 16hs/21 dias). Para o alongamento/enraizamento in vitro da bananeira cv. Pacovan sugere-se MS 50% de sais (macro e micronutrientes), redução ou manutenção de sacarose (1,5 ou 3%) em 16h/35 dias de cultivo.Palavra-chave: Musa spp., propagação in vitro, sistema radicular. CHANGES IN CULTURE MEDIUM, PHOTOPERIOD AND TIME OF CULTIVATION AFFECT THE IN VITRO ELONGATION AND ROOTING OF BANANA CV. PACOVAN ABSTRACT:In order to achieve high rates of survival during the acclimatization and later planting in the field, was evaluated the in vitro of banana cv. Pacovan plants under different concentrations of sucrose and MS basal salt mixture. The experiment was assembled in a DIC, in 6x2x3, six different culture media [three different MS salt mixture concentrations (100%; 50% of macronutrients; and 50% of macro/micronutrients) and two sucrose concentrations (1.5/3%)], two photoperiods (12/16 hours) and three cultivation times (21, 28 or 35 days). Each treatment was composed by 6 replicates. Plant height, number of leaves/plant, fresh and dry weight of roots and shoots, were analyzed. Satisfactory results for plant height and shoot and root fresh biomass were observed in MS with macro/micronutrients (50%) + sucrose (3%), 16 hours/35 days. The highest values of shoot dry weight were observed in MS with macro/micronutrients (50%) + sucrose (3%); the highest root dry weight was achieved with MS 100% + sucrose (3%) (12hs/28 and 16hs/21 days). The suggested medium for the in vitro elongation and rooting stage of banana cv. Pacovan is the MS with 50% of salts (macro and micronutrients), reduction or maintenance of sucrose (1.5 or 3%) in 16h/35 days of cultivation.Keywords: Musa spp., in vitro propagation, root system. DOI:


2001 ◽  
Vol 41 (5) ◽  
pp. 697 ◽  
Author(s):  
D. R. Beasley ◽  
D. C. Joyce ◽  
L. M. Coates ◽  
A. H. Wearing

Saprophytic bacteria, yeasts and filamentous fungi were isolated from Geraldton waxflower flowers and screened to identify potential antagonism towards Botrytis cinerea. Isolates from other sources (e.g. avocado) were also tested. Isolates were initially screened in vitro for inhibition of B. cinerea conidial germination, germ tube elongation and mycelial growth. The most antagonistic bacteria, yeasts and fungi were selected for further testing on detached waxflower flowers. Conidia of the pathogen were mixed with conidia or cells of the selected antagonists, co-inoculated onto waxflower flowers, and the flowers were sealed in glass jars and incubated at 20˚C. The number of days required for the pathogen to cause flower abscission was determined. The most antagonistic bacterial isolate, Pseudomonas sp. 677, significantly reduced conidial germination and retarded germ tube elongation of B. cinerea. None of the yeast or fungal isolates tested was found to significantly reduce conidial germination or retard germ tube elongation, but several significantly inhibited growth of B. cinerea. Fusarium sp., Epicoccum sp. and Trichoderma spp. were the most antagonistic of these isolates. Of the isolates tested on waxflower, Pseudomonas sp. 677 was highly antagonistic towards B. cinerea and delayed waxflower abscission by about 3 days. Trichoderma harzianum also significantly delayed flower abscission. However, as with most of the fungal antagonists used, inoculation of waxflower flowers with this isolate resulted in unsightly mycelial growth.


2017 ◽  
Vol 6 (9) ◽  
pp. 1676 ◽  
Author(s):  
Ramaraju Cherkupally ◽  
Srinivasa Reddy Kota ◽  
Hindumathi Amballa ◽  
Bhumi Narasimha Reddy

The antifungal activity of aqueous extracts of nine plants viz, Azadirachta indica, Parthenium hysterophorus, Momordica charantia, Allium sativum, Eucalyptus globules, Calotropis procera, Aloe vera, Beta vulgaris and Datura stramonium were assessed in vitro against Fusarium oxysporum f. sp. melongenae, Rhizoctonia solani and Macrophomina phaseolina, the soil borne phytopathogens. The assessment of fungitoxic effect was carried out by using three different concentrations i.e., 5, 10 and 20% against the test fungi, in terms of percentage of mycelial growth inhibition. The extract of A. sativum completely inhibited the mycelial growth of M. phaseolina at all the concentrations. The extracts of D. stramonium and E. globulus inhibited the mycelial growth of R. solani of 72%, and 70.7% respectively at 20% concentration, that of A. sativum, E. globulus and D. stramonium exhibited inhibition percentage of 63.3%, 61.8% and 61.1% respectively at 20% concentration on Fusarium oxysporum f. sp. melongenae. The application of plant extracts for disease management could be less expensive, easily available, non-polluting and eco-friendly.


Author(s):  
N. Kiran Kumar ◽  
P. Nagamani ◽  
K. Viswanath ◽  
L. Prasanthi

Background: The plant growth promotion and efficacy against phytopathogens by the endophytic bacteria are being focused now due to their ecofriendly nature. Methods: Endophytic bacteria (24 nos) isolated from the roots, stems and leaves of black gram plants collected from different locations were tested for their potential to inhibit the growth of R. bataticola under in vitro and in vivo conditions. Result: The leaf endophyte BLE 4 exhibited maximum inhibition (79.6%) of R. bataticola followed by BSE 4 (77.4%), BSE 7 (77.0%) and BLE 1 (74.0%). Among these 4 isolates tested as seed treatment and soil application, there was significant increase in dry weight (7.1 g), plant height (37.7 cm), number of branches (13.2) and number of pods (26.2) in BLE 4 treated plots. Whereas, the incidence of dry root rot and yield were insignificant. In the screening study of isolates for their phosphate solubilization potential, protease activity, siderophore and HCN production, no single isolate possessed all the properties, but siderophore production, protease activity and phosphate solubilization were found in BSE 4, BRE 3, BRE 5 and BRE 10 isolates. 


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