Influence of Formononetin and NaCl on Mycorrhizal Colonization and Fusarium Crown and Root Rot of Asparagus

Replanted asparagus fields commonly fail to produce a profitable stand due to alleopathic residues left behind from the previous asparagus crop, elevated densities of pathogenic Fusarium spp., and low densities of vesicular arbuscular mycorrhizae (VAM). Formononetin, a plant isoflavone that stimulates VAM spores to germinate, and sodium chloride (NaCl), a disease-suppressing amendment, were evaluated alone and in combination for their effect on reestablishing asparagus at two locations in abandoned asparagus fields. Greenhouse studies also were conducted with naturally and artificially infested soils. Formononetin was applied as a crown soak or soil drench, and NaCl was applied as a granular treatment. Feeder roots from soil cores sampled from field plots and from greenhouse transplants were assayed for colonization by VAM and for lesions caused by Fusarium oxysporum and F. proliferatum. Formononetin increased the number of VAM vesicles in roots from the field and greenhouse studies and reduced the percent root lesions caused by Fusarium spp. when compared with the nontreated controls. NaCl was more effective than formononetin in reducing the percentage of root lesions in both field and greenhouse experiment when compared with untreated plants but had no effect on VAM colonization. However, there was evidence that NaCl negated the effect of formononentin on VAM colonization. The NaCl treatment increased the May 2001 spear number by 15% and marketable spear weight by 23%. At one site, treatment with formononetin increased mean number of stalks per plant by 29% in 2000 and 14% in 2001. Both formononetin and NaCl improve growth and reduce disease of asparagus in replanted asparagus and may be useful in reestablishing asparagus in abandoned asparagus field.

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Vesicular-arbuscular mycorrhizae (VAM) improve phosphorus and zinc nutrition and growth of pigeonpea in a Vertisol

Australian Journal of Agricultural Research ◽

10.1071/ar9910835 ◽

1991 ◽

Vol 42 (5) ◽

pp. 835 ◽

Cited By ~ 22

Author(s):

NP Wellings ◽

AH Wearing ◽

JP Thompson

Keyword(s):

Root Rot ◽

Arbuscular Mycorrhizae ◽

Agricultural Practices ◽

Dry Weight ◽

Vam Fungi ◽

P Concentration ◽

Zn Concentration ◽

Vesicular Arbuscular ◽

Vam Colonization ◽

Mycorrhizal Plants

In a glasshouse trial, pigeonpea (Cajanus cajan) was grown in a Vertisol from the Darling Downs, Qld. The experimental design included two rates of inoculation with vesicular-arbuscular mycorrhizal (VAM) fungi (nil and inoculated), three rates of phosphorus (P) application and two of zinc (Zn), and inoculation (nil and inoculated) with a recently discovered pathogen of pigeonpea, Phytophthora drechsleri Tucker (Pdr). lnoculation with the pathogen was included in the factorial design to investigate any effect of VAM on root rot. Plants responded to inoculation with VAM fungi, showing that the growth of pigeonpea is highly dependent upon mycorrhizal colonization of its root system. The mycorrhizal plants yielded, on average, 3.3 times the dry weight of the non-mycorrhizal plants. Shoot dry weight and Zn concentration of the shoots were both exponentially related to per cent VAM colonization of the root length ( R2 values of 0.904 and 0.644 respectively) and P concentration was linearly related to VAM colonization (R2 = 0.888). VAM increased P concentration, P uptake, Zn concentration, Zn uptake and P/Zn ratio, indicating enhanced growth through improved P and to a lesser extent Zn nutrition. Zinc fertilizer (15 mg kg-1 soil) without Phytophthora inoculation was fungitoxic to the mycorrhizae, decreasing per cent VAM colonization and depressing plant growth. lnoculation with Pdr did not result in infection and root rot symptoms. However, it did overcome the Zn toxicity, possibly through organic chelation effects, and thereby enhanced VAM colonization. Greatest VAM colonization and best plant nutrition and growth were obtained with the combination of VAM inoculation, Pdr inoculation, Zn (15 mg kg-1) and P (10 mg kg-1). Our results indicate the importance of maintaining adequate levels of VAM fungi in soil through appropriate agricultural practices in order to maximize pigeonpea growth.

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Occurrence and isolation of vesicular–arbuscular mycorrhizae in cropped field soils of Saskatchewan, Canada

Canadian Journal of Microbiology ◽

10.1139/m93-082 ◽

1993 ◽

Vol 39 (6) ◽

pp. 567-575 ◽

Cited By ~ 32

Author(s):

Narayan C. Talukdar ◽

James J. Germida

Keyword(s):

Arbuscular Mycorrhizae ◽

Arbuscular Mycorrhizal ◽

Triticum Aestivum L ◽

Wheat Roots ◽

Wheat Field ◽

Vesicular Arbuscular Mycorrhizae ◽

Vesicular Arbuscular ◽

Field Soils ◽

Vam Colonization ◽

Study Sites

Soil and root samples collected from fields cropped to spring wheat (Triticum aestivum L. cv. Katepwa) and lentil (Lens esculenta L. cv. Eston) at 11 sites across four soil zones of Saskatchewan were analyzed for spore numbers, level of vesicular–arbuscular mycorrhizal (VAM) colonization, and VAM species. The number of VAM spores detected in field soils ranged from 78 to 272 per 100 g soil. Vesicular–arbuscular mycorrhizae colonized wheat and lentil at all the field study sites, but levels of colonization in the two crops varied from site to site and the differences were more pronounced in wheat than in lentil. Generally, lentil both exhibited a higher percentage of VAM colonized roots and contained more arbuscules and vesicles than wheat roots. However, wheat appeared to be colonized by different types of VAM depending on the field sites. Differences in VAM colonization were not related to the moisture and temperature gradient of the four soil zones or soil properties. Seven VAM species were isolated by enriching indigenous VAM mixtures (collected from wheat field soils of six field sites) on maize. The VAM isolated most closely resembled Acaulospora denticulata, Gigaspora decipiens, Glomus clarum, Glomus etunicatum, Glomus fasciculatum, Glomus mosseae, and Glomus versiforme. The species composition of the VAM community varied at the different field sites.Key words: VAM, Acaulospora, Gigaspora, Glomus.

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Remote Sensing for Assessing Rhizoctonia Crown and Root Rot Severity in Sugar Beet

Plant Disease ◽

10.1094/pdis-11-10-0831 ◽

2012 ◽

Vol 96 (4) ◽

pp. 497-505 ◽

Cited By ~ 17

Author(s):

Gregory J. Reynolds ◽

Carol E. Windels ◽

Ian V. MacRae ◽

Soizik Laguette

Keyword(s):

Remote Sensing ◽

Sugar Beet ◽

Root Rot ◽

Near Infrared ◽

Vegetation Indices ◽

Root Surface ◽

Near Infrared Reflectance ◽

Initial Appearance ◽

Crown And Root Rot ◽

Field Plots

Rhizoctonia crown and root rot (RCRR), caused by Rhizoctonia solani AG-2-2, is an increasingly important disease of sugar beet in Minnesota and North Dakota. Disease ratings are based on subjective, visual estimates of root rot severity (0-to-7 scale, where 0 = healthy and 7 = 100% rotted, foliage dead). Remote sensing was evaluated as an alternative method to assess RCRR. Field plots of sugar beet were inoculated with R. solani AG 2-2 IIIB at different inoculum densities at the 10-leaf stage in 2008 and 2009. Data were collected for (i) hyperspectral reflectance from the sugar beet canopy and (ii) visual ratings of RCRR in 2008 at 2, 4, 6, and 8 weeks after inoculation (WAI) and in 2009 at 2, 3, 5, and 9 WAI. Green, red, and near-infrared reflectance and several calculated narrowband and wideband vegetation indices (VIs) were correlated with visual RCRR ratings, and all resulted in strong nonlinear regressions. Values of VIs were constant until at least 26 to 50% of the root surface was rotted (RCRR = 4, wilting of foliage starting to develop) and then decreased significantly as RCRR ratings increased and plants began dying. RCRR also was detected using airborne, color-infrared imagery at 0.25- and 1-m resolution. Remote sensing can detect RCRR but not before initial appearance of foliar symptoms.

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Local reduction of mycorrhizal arbuscule frequency in enriched soil microsites

Canadian Journal of Botany ◽

10.1139/b94-125 ◽

1994 ◽

Vol 72 (7) ◽

pp. 998-1001 ◽

Cited By ~ 32

Author(s):

S. E. Duke ◽

R. B. Jackson ◽

M. M. Caldwell

Keyword(s):

Arbuscular Mycorrhizae ◽

Plant Root ◽

Arbuscular Mycorrhizal ◽

Soil Heterogeneity ◽

Water Control ◽

Local Reduction ◽

Vesicular Arbuscular ◽

Vam Colonization ◽

Development Regulation ◽

Control Patch

Increased nutrient availability reduces vesicular–arbuscular mycorrhizal (VAM) associations with plants, but whether increased nutrients in small volumes of soil affect local VAM colonization is not known. In a field experiment we investigated VAM colonization at different times following fertilization of small soil patches. Soil volumes of ~ 1000 cm3 were treated with a nutrient solution (enriched patch) or distilled water (control patch) on opposite sides of individual plants of the tussock grass Agropyron desertorum and the shrub Artemisia tridentata. Agropyron had significantly lower (p = 0.03) arbuscular infection in the locally enriched patches compared to control patches (32 and 40%, respectively). This reduced arbuscule frequency was apparent at the first sampling (3 days following treatment application) and remained lower in each subsequent sampling (as much as 30% lower than the control patches). Artemisia revealed a similar pattern in arbuscule frequency but was not statistically significant. Our results suggest that a plant can locally reduce VAM development, since arbuscule frequency specifically was locally reduced even though vesicle and overall infection was not. Since mycorrhizal infection does not increase, we conclude that increased plant root proliferation and uptake capacity are likely to be more important for the exploitation of temporary nutrient pulses or patches than is increased mycorrhizal activity. Key words: arbuscule, nutrient exploitation, phosphorus, reduced development, regulation of colonization, soil heterogeneity, vesicular–arbuscular mycorrhizae.

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Effect of Biochar Amendments on Mycorrhizal Associations and Fusarium Crown and Root Rot of Asparagus in Replant Soils

Plant Disease ◽

10.1094/pdis-10-10-0741 ◽

2011 ◽

Vol 95 (8) ◽

pp. 960-966 ◽

Cited By ~ 114

Author(s):

Wade H. Elmer ◽

Joseph J. Pignatello

Keyword(s):

Root Rot ◽

Root Colonization ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

First Year ◽

Root Weight ◽

Fusarium Spp ◽

Biomass Waste ◽

Mycorrhizal Associations ◽

Crown And Root Rot

Pyrolyzed biomass waste, commonly called biochar, has attracted interest as a soil amendment. A commercial prototype biochar produced by fast pyrolysis of hardwood dust was examined in soils to determine if it could reduce the damaging effect of allelopathy on arbuscular mycorrhizal (AM) root colonization and on Fusarium crown and root rot of asparagus. In greenhouse studies, biochar added at 1.5 and 3.0% (wt/wt) to asparagus field soil caused proportional increases in root weights and linear reductions in the percentage of root lesions caused by Fusarium oxysporum f. sp. asparagi and F. proliferatum compared with a control. Concomitant with these effects was a 100% increase in root colonization by AM fungi at the 3.0% rate. Addition of aromatic acids (cinnamic, coumaric, and ferulic) that are known allelopathic agents affecting asparagus reduced AM colonization but the deleterious effects were not observed following the application of biochar at the higher rate. When dried, ground, asparagus root and crown tissues infested with Fusarium spp. were added to soilless potting mix at 0, 1, or 5 g/liter of potting mix and then planted with asparagus, there was a decrease in asparagus root weight and increase in disease at 1 g/liter of potting mix but results were inconsistent at the higher residue rate. However, when biochar was added at 35 g/liter of potting mix (roughly 10%, vol/vol), these adverse effects on root weight and disease were equal to the nontreated controls. A small demonstration was conducted in field microplots. Those plots amended with biochar (3.5% [wt/wt] soil) produced asparagus plants with more AM colonization in the first year of growth but, in the subsequent year, biochar-treated plants were reduced in size, possibly due to greater than average precipitation and the ability of biochar to retain moisture that, in turn, may have created conditions conducive to root rot. These studies provide evidence that biochar may be useful in overcoming the deleterious effects of allelopathic residues in replant soils on asparagus.

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Organic amendments conditions on the control of Fusarium crown and root rot of asparagus caused by three Fusarium spp.

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2015134-7905 ◽

2015 ◽

Vol 13 (4) ◽

pp. e1009

Author(s):

Ana I. Borrego-Benjumea ◽

José M. Melero-Vara ◽

María J. Basallote-Ureba

Keyword(s):

Fusarium Oxysporum ◽

Incubation Period ◽

Root Rot ◽

Poultry Manure ◽

Organic Amendments ◽

Fresh Weight ◽

Fusarium Spp ◽

Lower Severity ◽

Crown And Root Rot ◽

Olive Residue

Fusarium oxysporum (Fo), F. proliferatum (Fp) and F. solani (Fs) are causal agents associated with roots of asparagus affected by crown and root rot, a disease inflicting serious losses worldwide. The propagule viability of Fusarium spp. was determined on substrate artificially infested with Fo5, Fp3 or Fs2 isolates, amended with either poultry manure (PM), its pellet (PPM), or olive residue compost (ORC) and, thereafter, incubated at 30 or 35°C for different periods. Inoculum viability was significantly affected by these organic amendments (OAs) in combination with temperature and incubation period. The greatest reduction in viability of Fo5 and Fs2 occurred with PPM and loss of viability achieved was higher at 35°C than at 30ºC, and longer incubation period (45 days). However, the viability of Fp3 did not decrease greatly in most of the treatments, as compared to the infested and un-amended control, when incubated at 30ºC. After incubation, seedlings of asparagus `Grande´ were transplanted into pots containing substrates infested with the different species of Fusarium. After three months in greenhouse, symptoms severity in roots showed highly significant decreases, but Fp3 caused lower severity than Fo5 and Fs2. Severity reduction was particularly high at 30ºC (by 15 days incubation for Fs2 and by 30-45 days for Fo5), after PPM treatment, as well as PM-2% for Fo5 and Fs2 incubated during 30 and 45 days at both temperatures, and with ORC (15-30 days incubation). Moreover, assessment of plants fresh weight showed significantly high increases in Fo5 and Fs2, with some rates of the three OAs tested, depending on incubation period and temperature.

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The Effect of Four Composts on the Establishment of Vesicular–Arbuscular Mycorrhizae in Soilless Media

HortScience ◽

10.21273/hortsci.32.3.539d ◽

1997 ◽

Vol 32 (3) ◽

pp. 539D-539

Author(s):

Michelle Miller ◽

Robert Linderman ◽

Leslie Fuchigami

Keyword(s):

Arbuscular Mycorrhizae ◽

Growth Parameters ◽

Fungal Spore ◽

Exchange Capacity ◽

Mycorrhizal Colonization ◽

Mushroom Compost ◽

Vesicular Arbuscular Mycorrhizae ◽

Vesicular Arbuscular ◽

Vam Colonization ◽

Mineral Soils

The beneficial use of vesicular–arbuscular mycorrhizae (VAM) in mineral soils is well-documented, but little is known about the effect of soilless mixes on mycorrhizal colonization of roots. Previous research indicates that mycorrhizal colonization is affected by pH, soluble salts, phosphorus levels, cation exchange capacity, percent organic matter, and some peats. No other research has been published, to our knowledge, on the role of commonly used horticultural composts and mycorrhizal establishment. This study examined four different composts for their effect on VAM establishment using onion roots as an indicator. The composts used in the study were vermicompost, spent mushroom compost, yard waste compost, and processed manure fiber. Plant growth parameters, phosphorus (P) levels and rate of desorption, and microbial populations were analyzed in relation to the percent of VAM colonization of the roots. Significant differences were found in percent VAM colonization between composts. The primary factors influencing VAM colonization were the initial levels of P in the blends and the rate and amount of P released. The experiment raised questions about the balance between mineralized P and organic P in composts and their effect on VAM fungal spore germination.

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Survey of vesicular–arbuscular mycorrhizae in lettuce production in relation to management and soil factors

The Journal of Agricultural Science ◽

10.1017/s0021859697005212 ◽

1998 ◽

Vol 130 (2) ◽

pp. 173-182 ◽

Cited By ~ 30

Author(s):

R. L. MILLER ◽

L. E. JACKSON

Keyword(s):

Arbuscular Mycorrhizae ◽

Management Practices ◽

Root Colonization ◽

Soil Conditions ◽

Multivariate Statistical ◽

Spore Number ◽

Vesicular Arbuscular Mycorrhizae ◽

Wide Range ◽

Vesicular Arbuscular ◽

Vam Colonization

The occurrence of vesicular–arbuscular mycorrhizae (VAM) root colonization and spore number in soil was assessed for 18 fields under intensive lettuce (Lactuca sativa L.) production in California during July and August of 1995. Data on management practices and soil characteristics were compiled for each field, and included a wide range of conditions. The relationship between these factors and the occurrence of VAM in these fields was explored with multivariate statistical analysis. VAM colonization of lettuce tended to decrease with the use of chemical inputs, such as pesticides and high amounts of P and N fertilizers. Addition of soil organic matter amendments, the occurrence of other host crops in the rotation, and soil carbon[ratio ]phosphorus and carbon[ratio ]nitrogen ratios, were positively associated with VAM colonization of lettuce roots. The number of VAM spores in soil was strongly correlated with the number of other host crops in the rotation, the occurrence of weed hosts and sampling date, but was more affected by general soil conditions than by management inputs. Higher total soil N, C and P, as well as CEC, were inversely related to soil spore number. A glasshouse study of the two primary lettuce types sampled in the field showed no significant differences in the extent of root colonization under similar growing conditions. The results of this study are compared with other studies on the effects of management and soil conditions on mycorrhizal occurrence in agriculture.

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Use of Fungicides and Biological Controls in the Suppression of Fusarium Crown and Root Rot of Asparagus Under Greenhouse and Growth Chamber Conditions

Plant Disease ◽

10.1094/pdis.2002.86.5.493 ◽

2002 ◽

Vol 86 (5) ◽

pp. 493-498 ◽

Cited By ~ 31

Author(s):

T. C. Reid ◽

M. K. Hausbeck ◽

K. Kizilkaya

Keyword(s):

Biological Control ◽

Root Rot ◽

Field Experiments ◽

Growth Chamber ◽

Root Weight ◽

Fusarium Spp ◽

Crown And Root Rot ◽

Control Disease ◽

Disease Pressure ◽

Commercial Field

Growth chamber, greenhouse, and field experiments were conducted with fungicides and biological control agents, including nonpathogenic isolates of Fusarium oxysporum, to test their ability to control disease caused by F. oxysporum f. sp. asparagi and F. proliferatum. In greenhouse studies with asparagus seedlings in soil, Trichoderma harzianum strain T-22, benomyl, and fludioxonil treatments increased root weight and decreased root disease compared with the infested control when a low level of F. oxysporum f. sp. asparagi and F. proliferatum was used. The fungicide fludioxonil limited plant death caused by Fusarium spp. at high inoculum levels, whereas T. harzianum strain T-22 was not effective. Nonpathogenic isolates of F. oxysporum were effective in limiting Fusarium disease on asparagus seedlings in culture tubes, although isolates differed in their ability to control disease caused by F. oxysporum f. sp. asparagi and F. proliferatum. In greenhouse studies, no significant differences in plant death were found between asparagus plants growing in media infested with F. oxysporum f. sp. asparagi and F. proliferatum and left untreated, and those treated with nonpathogenic F. oxysporum. The efficacy of fungicides and biological control products to control Fusarium crown and root rot under commercial field conditions could not be evaluated due to low disease pressure.

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