Influence of Crop Rotation on Population Density of Macrophomina phaseolina in Soil Infested with Heterodera glycines

AbstractHirsutella minnesotensis and H. rhossiliensis are endoparasites of nematodes, and their biological control potential against Heterodera glycines when cultured and applied on corn grits has been reported. In this study, the potential of liquid cultures of the two fungi was evaluated in two glasshouse experiments. Both liquid culture at 0.2, 0.4 and 0.8 g of fresh mycelium/300 cm3 soil (per pot) and solid culture at 1% (corn grits: soil, w/w) reduced nematode egg population densities in both autoclaved and unheated soils as compared with soil-only control or corn-grits control. However, the liquid culture at 0.2–0.8 g of mycelium/pot appeared to be more effective in reducing the nematode population than the solid culture of 1%. Hirsutella rhossiliensis resulted in lower nematode population density than H. minnesotensis only in unheated soil in one experiment. The soil heat treatment generally increased the nematode population density but did not affect percentage reduction of the nematode population density as compared with respective controls, except that reduction by H. rhossiliensis was greater in unheated soil than heat-treated soil in one experiment. Percentage of second-stage juveniles (J2) parasitised by fungi at the end of the experiment (60 days after planting) was generally higher with H. minnesotensis than with H. rhossiliensis. The percentage parasitism was positively correlated with initial fungal inoculation level. The soil heat treatment increased fungal parasitism in one experiment but not in the other. Plant growth was unaffected by treatments except that the soil heat treatment increased plant shoot weight as compared with unheated soil in one experiment.

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Genotypic diversity among brazilian isolates of Macrophomina phaseolina revealed by RAPD

Fitopatologia Brasileira ◽

10.1590/s0100-41582003000300009 ◽

2003 ◽

Vol 28 (3) ◽

pp. 279-285 ◽

Cited By ~ 37

Author(s):

Álvaro M. R. Almeida ◽

Ricardo V. Abdelnoor ◽

Carlos A. Arrabal Arias ◽

Valdemar P. Carvalho ◽

David S. Jacoud Filho ◽

...

Keyword(s):

Genetic Diversity ◽

Crop Rotation ◽

Genetic Resistance ◽

Its Region ◽

Genotypic Diversity ◽

Macrophomina Phaseolina ◽

Tropical Regions ◽

Single Root ◽

Average Similarity ◽

Upgma Cluster Analysis

Macrophomina phaseolina has been considered one of the most prevalent soybean (Glycine max) pathogens in Brazil. No genetic resistance has been determined in soybean and very little is known about the genetic diversity of this pathogen in tropical and sub-tropical regions. Fifty-five isolates from soybean roots were collected in different regions and analyzed through RAPD for genetic diversity. The UPGMA cluster analysis for 74 loci scored permitted identification of three divergent groups with an average similarity of 99%, 92% and 88%, respectively. The three groups corresponded to 5.45%, 59.95% and 34.6%, respectively of all isolates used. A single plant had three different haplotypes, while 10.9% of the analyzed plants had two different haplotypes. In another study the genetic similarity was evaluated among isolates from different hosts [soybean, sorghum (Sorghum bicolor), sunflower (Helianthus annuus), cowpea (Vigna unguiculata), corn (Zea mays) and wheat (Triticum aestivum)] as well as two soil samples from native areas. Results showed that more divergent isolates originated from areas with a single crop. Isolates from areas with crop rotation were less divergent, showing high similarity values and consequently formed the largest group. Amplification of the ITS region using primers ITS1 and ITS4 produced only one DNA fragment of 620 bp. None of the isolates were differentiated through PCR-RFLP. Our results demonstrated genetic variability among Brazilian isolates of M. phaseolina and showed that one single root can harbor more than one haplotype. Moreover, cultivation with crop rotation tends to induce less specialization of the pathogen isolates. Knowledge of this variation may be useful in screening soybean genotypes for resistance to charcoal rot.

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Soybean Stem Colonization by Genotypes A and B of Cadophora gregata Increases with Increasing Population Densities of Heterodera glycines

Plant Disease ◽

10.1094/pd-90-1297 ◽

2006 ◽

Vol 90 (10) ◽

pp. 1297-1301 ◽

Cited By ~ 4

Author(s):

G. M. Tabor ◽

G. L. Tylka ◽

C. R. Bronson

Keyword(s):

Population Density ◽

Soybean Cyst Nematode ◽

Heterodera Glycines ◽

Cyst Nematode ◽

Stem Rot ◽

Population Densities ◽

Brown Stem Rot ◽

Phialophora Gregata ◽

Soybean Genotypes ◽

Genotype A

Growth chamber experiments were conducted to investigate whether parasitism by increasing population densities of Heterodera glycines, the soybean cyst nematode, increases the incidence and severity of stem colonization by the aggressive genotype A and the mild genotype B of Cadophora gregata (Phialophora gregata), causal agents of brown stem rot of soybeans. Soybean genotypes with three combinations of resistance and susceptibility to H. glycines and genotype A of C. gregata were inoculated with each genotype of C. gregata alone or each genotype with two population densities of H. glycines eggs, 1,500 or 10,000 per 100 cm3 of soil. Stems of two H. glycines-susceptible soybeans were more colonized by both aggressive and mild genotypes of C. gregata in the presence of high than in the presence of low H. glycines population density.

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Control of Glyphosate-Resistant Giant Ragweed in Winter Wheat

Weed Technology ◽

10.1614/wt-d-15-00028.1 ◽

2015 ◽

Vol 29 (4) ◽

pp. 868-873 ◽

Cited By ~ 4

Author(s):

Kris J. Mahoney ◽

Kristen E. McNaughton ◽

Peter H. Sikkema

Keyword(s):

Population Density ◽

Winter Wheat ◽

Crop Rotation ◽

Weed Management ◽

Aboveground Biomass ◽

Field Experiments ◽

Control Population ◽

Integrated Weed Management ◽

Giant Ragweed ◽

Herbicide Treatments

Four field experiments were conducted over a 2-yr period (2012 and 2013) in winter wheat to evaluate POST herbicides for the control of glyphosate-resistant (GR) giant ragweed. POST herbicides were evaluated for winter wheat injury and GR giant ragweed control, population density, and aboveground biomass. The herbicides used in this study provided 54 to 90% and 51 to 97% control of GR giant ragweed at 4 and 8 wk after treatment (WAT), respectively. At 8 WAT, auxinic herbicide treatments or herbicide tank mix/premix treatments that contained auxinics provided 78 to 97% control of GR giant ragweed. Reductions in GR giant ragweed population density and aboveground biomass were 62 to 100% and 83 to 100%, respectively, and generally reflected the level of control. The results of this research indicate that Ontario, Canada, corn and soybean growers should continue to incorporate winter wheat into their crop rotation as one component of an integrated weed management (IWM) strategy for the control of GR giant ragweed.

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Effects of ILeVO Seed Treatment on Heterodera glycines Reproduction and Soybean Yield in Small-Plot and Strip-Trial Experiments in Iowa

Plant Disease ◽

10.1094/pdis-06-19-1132-re ◽

2020 ◽

Vol 104 (11) ◽

pp. 2914-2920 ◽

Cited By ~ 1

Author(s):

Kaitlyn M. Bissonnette ◽

Christopher C. Marett ◽

Mark P. Mullaney ◽

Gregory D. Gebhart ◽

Peter M. Kyveryga ◽

...

Keyword(s):

Population Density ◽

Soybean Cyst Nematode ◽

Seed Treatment ◽

Heterodera Glycines ◽

Field Studies ◽

Experimental Unit ◽

Soybean Yield ◽

Yield Increase ◽

Small Plot ◽

Soybean Plants

ILeVO (fluopyram) is a fungicide seed treatment for soybean sudden death syndrome (SDS) that also has nematicidal activity. ILeVO is sold with a base of insecticide Poncho (clothianidin), nematode-protectant VOTiVO (Bacillus firmus), and Acceleron fungicides (metalaxyl, fluxapyroxad, and pyraclostrobin). Yield and reproduction of the soybean cyst nematode (SCN) (Heterodera glycines) on soybean plants grown from seed treated with ILeVO plus the base were compared with those treated with only the base in 27 small-plot experiments and 12 strip-trial experiments across Iowa from 2015 to 2017. To increase the likelihood that yield results were related to effects on SCN, data were used only from 26 small-plot experiments and 12 strip trials in which symptoms of SDS were low or nonexistent. An SCN reproductive factor (RF) was calculated for each experimental unit by dividing the SCN population density at harvest by the population density at planting. ILeVO significantly reduced SCN RF by 50% in one strip-trial experiment and by 36 to 60% in four small-plot experiments but yields were not increased by ILeVO in any of those five experiments. Soybean yields were 2.8 to 3.7 bushels/acre (bu/ac) (188.3 to 248.8 kg/ha) greater with ILeVO in three small-plot experiments but SCN RF was not reduced in those experiments. Also, yield was 1.9 bu/ac (127.8 kg/ha) greater with ILeVO in one strip-trial experiment in 2016 but SCN samples were not collected at harvest from the study to assess the possible effects of ILeVO on SCN reproduction. When strip-trial data from 2015 and 2016 were combined, there was a small but significant 0.8 bu/ac (52.2 kg/ha) yield increase with ILeVO. Overall, the effects of ILeVO on SCN reproduction and soybean yield were variable in these field studies.

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Response of Heterodera glycines and Soybean Cultivar to Tillage and Row Spacing

Plant Disease ◽

10.1094/pdis.2001.85.3.311 ◽

2001 ◽

Vol 85 (3) ◽

pp. 311-316 ◽

Cited By ~ 21

Author(s):

S. Y. Chen ◽

W. C. Stienstra ◽

W. E. Lueschen ◽

T. R. Hoverstad

Keyword(s):

Population Density ◽

Soybean Cyst Nematode ◽

Heterodera Glycines ◽

Resistant Cultivar ◽

Row Spacing ◽

Initial Population ◽

Susceptible Cultivar ◽

Nematode Density ◽

Nematode Reproduction ◽

Resistant Cultivars

Heterodera glycines, commonly known as the soybean cyst nematode (SCN), has become a major factor in soybean production in the Midwest United States. The influence of five tillage treatments and two treatments of row spacing on SCN population dynamics and yield of SCN-resistant and -susceptible soybean cultivars was investigated in a corn-soybean rotation system in southern Minnesota from 1993 to 1996. No effects of tillage and row spacing were observed on nematode population density. As expected, the susceptible cultivar Sturdy consistently supported higher nematode densities than did the resistant cultivar Bell in 1993 to 1995 and Freeborn in 1996. Nematode reproduction varied among years. Predicted nematode density at equilibrium was 3,800, 13,000, 12,000, and 27,000 eggs per 100 cm3 of soil in plots with the susceptible cultivar and 480, 240, 430, and 700 eggs per 100 cm3 of soil in plots with the resistant cultivars in 1993, 1994, 1995, and 1996, respectively. The effects of tillage and row spacing on soybean yield were inconsistent. The resistant cultivars yielded 653, 195, and 435 kg/ha more (P < 0.05) than the susceptible cultivar in 1994, 1995, and 1996, respectively, but no yield difference between susceptible and resistant cultivars was observed in 1993. Planting resistant cv. Bell increased the yield of the following susceptible cv. Sturdy compared with continual planting of the susceptible cultivar. A sequence with continued resistant cultivar or cultivars, however, produced a higher overall yield and lower nematode density at the end of the 4-year rotation cycle than any sequence in which the susceptible cultivar was included. Yield of resistant and susceptible cultivars was negatively related to the SCN initial population density.

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Effects of Broccoli Rotation on Lettuce Drop Caused by Sclerotinia minor and on the Population Density of Sclerotia in Soil

Plant Disease ◽

10.1094/pdis.2003.87.2.159 ◽

2003 ◽

Vol 87 (2) ◽

pp. 159-166 ◽

Cited By ~ 33

Author(s):

Jianjun Hao ◽

Krishna V. Subbarao ◽

Steven T. Koike

Keyword(s):

Population Density ◽

Crop Rotation ◽

Management Strategy ◽

Field Experiments ◽

Disease Incidence ◽

Inoculum Density ◽

First Year ◽

Sclerotinia Minor ◽

Fallow Period ◽

Lettuce Drop

Field experiments were conducted at Spence Road site and at the Hartnell College East Campus site in Salinas, CA, to determine the effects of crop rotation with broccoli or a fallow period on lettuce drop caused by Sclerotinia minor and the density of pathogen sclerotia in the soil. Treatments at the Spence Road site with low inoculum density (<7 sclerotia per 100 cm3 of soil) distributed randomly included: successive crops of lettuce (LLL), lettuce rotated with broccoli (LBL), and lettuce followed by a fallow period (LFL). Treatments at the Hartnell site with high inoculum density (>7 sclerotia per 100 cm3 of soil) distributed uniformly included: continuous lettuce (LLLL), broccoli-lettuce-broccoli-lettuce (BLBL), broccoli-broccoli-lettuce-lettuce (BBLL), and fallow-lettuce-fallow-lettuce (FLFL). At the Spence Road site, continuous lettuce did not increase lettuce drop incidence for at least 2 years, although an increase in soilborne sclerotia was observed annually but was below the threshold at which a correlation between inoculum density and disease incidence is observed. Rotation with broccoli resulted in small reductions in disease incidence only in the first year. The density of sclerotia was lowest in the LFL treatment, and the highest in the LLL. At the Hartnell site, rotation with broccoli significantly reduced both sclerotia and lettuce drop incidence. The number of broccoli crops rather than the sequence of lettuce rotations with broccoli was critical for reducing the numbers of S. minor sclerotia in soil. Fallowing after a lettuce crop resulted in marginal reductions in sclerotia and lettuce drop incidence. Viability of recovered sclerotia was not significantly different between treatments, although differences between seasons were detected. Results suggest that rotations with broccoli can be a practical lettuce drop management strategy.

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Evaluation of the Combined Effect of Heterodera glycines and Macrophomina phaseolina on Soybean Yield in Naturally Infested Fields with Spatial Regression Analysis and in Greenhouse Studies

Phytopathology ◽

10.1094/phyto-03-19-0087-r ◽

2020 ◽

Vol 110 (2) ◽

pp. 406-417

Author(s):

H. D. Lopez-Nicora ◽

J. K. Carr ◽

P. A. Paul ◽

A. E. Dorrance ◽

T. I. Ralston ◽

...

Keyword(s):

Regression Models ◽

Heterodera Glycines ◽

Spatial Regression ◽

Macrophomina Phaseolina ◽

Combined Effect ◽

Fungal Colonization ◽

Population Densities ◽

Soybean Yield ◽

Spatial Regression Models ◽

Spatial Regression Analysis

Heterodera glycines, the soybean cyst nematode, and Macrophomina phaseolina, causal agent of charcoal rot, are economically important soybean pathogens. The impact and effect of these pathogens on soybean yield in coinfested fields in the Midwest production region is not known. Both pathogens are soilborne, with spatially aggregated distribution and effects. Spatial regression analysis, therefore, is an appropriate method to account for the spatial dependency in either the dependent variable or regression error term from data produced in fields naturally infested with H. glycines and M. phaseolina. The objectives of this study were twofold: to evaluate the combined effect of H. glycines and M. phaseolina on soybean yield in naturally infested commercial fields with ordinary least squares and spatial regression models; and to evaluate, under environmentally controlled conditions, the combined effect of H. glycines and M. phaseolina through nematode reproduction and plant tissue fungal colonization. Six trials were conducted in fields naturally infested with H. glycines and M. phaseolina in Ohio. Systematic-grid sampling was used to determine the population densities of H. glycines and M. phaseolina, and soybean yield estimates. Though not used in any statistical analysis, M. phaseolina colony forming units from plant tissue, charcoal rot severity, and H. glycines type were also recorded and summarized. In two greenhouse experiments, treatments consisted of H. glycines alone, M. phaseolina alone, and coinfestation of soybean with both pathogens. Moran’s I test indicated that the yield from five fields was spatially correlated (P < 0.05) and aggregated. In these fields, to account for spatial dependence, spatial regression models were fitted to the data. Spatial regression analyses revealed a significant interaction effect between H. glycines and M. phaseolina on soybean yield for fields with high initial population densities of both pathogens. In the greenhouse experiments, H. glycines reproduction was significantly (P < 0.05) reduced in the presence of M. phaseolina; however, soybean tissue fungal colonization was not affected by the presence of H. glycines. The direct mechanisms by which H. glycines and M. phaseolina interact were not demonstrated in this study. Future studies must be conducted in the field and greenhouse to better understand this interaction effect.

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