Progress 08/05/16 to 06/30/21
Outputs
Target Audience:Farmers, agriculture professionals, scientists Changes/Problems:Retirement from one PI. Otherwise none. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Obj 1. Diversified crop rotation with low inorganic N and composted manure inputs was compared to a conventional (corn-soybean) rotation with normal inorganic fertilizer inputs. This is important given the diversified system exhibits a yield benefit, reduced N-loss, and a reduction of soybean sudden death syndrome (SDS). We conducted field trials to investigate the impact of a rye and oat cover crops on soybean diseases caused by SDS of soybean and seedling disease. In all trials, the cover crops did not affect soybean disease levels or soybean yield, suggesting that cover crops can be safely used before soybean. Corn residue did not affect SDS on subsequent soybean crops when two levels of residue removals and two tillage systems were tested in corn and soybean rotation. Obj 2. Results showed both rates of fluopyram significantly reduced root rot and foliar SDS disease severity and increased yield compared to the base treatment. Yield was negatively correlated with root rot at the R4/R5 stage and with foliar disease index. A 35% reduction in foliar disease and 4.4 bushels/acre increase in yield were estimated for fluopyram-amended seed treatment relative to commercial base seed treatments without fluopyram, when multiple locations evaluated. Yield benefits of fluopyram seed treatment were greater with higher disease pressure. Moderately resistant cultivars had less disease than susceptible cultivars suggesting cultivars selection is important. Various seed treatments were evaluated for control of the seedling disease caused by Rhizoctonia solani. Several seed treatments reduced R. solani and increased yield. Obj 3. The effect of Indianmeal moth/maize weevil infestations on A. flavus colonization and vice versa in non-Bt and Bt maize hybrids were evaluated. Results show the presence of the insects did not enhance A. flavus colonization, after 28 storage days, meanwhile no Indianmeal moths/maize weevils survived in grain of Bt hybrids with the respective insect resistance genes. Aflatoxin levels in the 106 A. flavus isolates inoculated on non-Bt grain increased significantly in the presence of Indianmeal moth/maize weevil, but aflatoxins in the Bt hybrids were unaffected by insect infestation. Mycotoxin reduction in Bt maize had been well-studied in the field but not in storage. This study showed Bt protection was effective against stored-grain insects Indianmeal moth and maize weevil and that the use of Bt hybrids can mitigate the risk of A. flavus infection and aflatoxin contamination related to stored-grain insects. Meta-analysis to evaluate the effects of transgenic insect resistance on fumonisins in maize (published literature), show reductions in fumonisins in grain with estimates up to 67% reduction. Obj 4. Timing of disease has a strong linear relationship with yield loss, with early onset resulting in the greatest yield loss. A meta-analysis of 52 uniform field experiments was used to determine the relationship between SDS and soybean yield. In relative percent term, for every unit of FDX increase yield will decrease by 0.5%. Management of pesticide resistance in pathogens, insects and weeds that can cross farmers' fields is a community-level challenge. To support a community-based approach to resistant management, we facilitated a community-based pilot project in Harrison County, Iowa. This group has expanded its scope to include fungicide resistance management. The team reported increasing number of farmers applying fungicides on soybeans based on an assumption they would get yield enhancement. The team reflected that while they knew this pattern of fungicide use could increase pathogen selection pressure, they were compelled to also apply fungicides to remain competitive with their neighbors. Obj 5. Root biomass influences seedling disease development more than shoot biomass in growth chamber trials to evaluate the effect of winter rye root and shoot biomass on corn seedling disease. Soil health is often correlated with cover crop biomass and too much biomass may favor corn seedling disease. Winter rye acts as a green bridge for corn seedling pathogens -- this practice may increase the risk of losses due to seedling disease. We collected soybean plants with and without iron deficiency chlorosis symptoms (IDC; damaging disease poorly understood) from six fields and made isolations of fungi and oomycetes associated with the roots. Results show that the frequency of isolation of fungi and oomycetes was very similar in IDC and healthy plants, suggesting root colonization by these fungi is not a key driver in the development of IDC. Six fungicides significantly suppressed the most aggressive isolate inoculated in the field, which suggest a potential for using fungicides as seed treatments to control Pythium damping-off. The presence of MBOA, an allelochemical produced by rye, seedling disease severity of corn was greater in vitro, suggesting allelopathy may contribute to the negative effects of a winter cereal rye cover crop on corn. Obj 6. There are no differences between bulk and rhizosphere soil communities in a soil from a diversified cropping system, there were significant differences in the conventional systema at maize growth stages with high nutrient demand, suggesting that maize in the conventional system exerts a strong rhizosphere effect that can contribute to differences in plant productivity between these two cropping systems. A collection of >400 bacterial isolates from the soil, rhizosphere and endosphere of drought-grown soybean plants was generated. We developed models predictive of nitrification in soil and the maize rhizosphere, and how cropping system influences the models, which revealed that the influence of the rhizosphere on the soil microbiome greatly influences the predictive potential, highlighting the importance of integrating how the rhizosphere potentially influences nitrogen availability into cropping system models. Obj 7. In a diversified cropping system at a stage at which the plant is poised for rapid nutrient uptake, the plant selected a more diverse prokaryotic community, with altered N cycling populations and their metabolism that may contribute to yield benefits and reduced N losses. While there is convergence in community structure during plant selection for bacterial endophytes, that structure is influenced by the rhizosphere community. In the diversified system, maize increased soil resource acquisition, which alters the microbial habitat. One possible consequence of this is greater competition for ammonium during decomposition processes which could decrease nitrification. It is tempting to conclude that one mechanism by which the diversified system at the Marsden experimental site is able to support high productivity with reduced inorganic fertilization is more efficiently coupled C and N cycles. Yet this alone may not explain the yield benefit entirely, since plant health may be better in the diversified system due to decreased fungal pathogen pressure, as well as selection of a plant-associated microbiome which stimulates plant growth directly. Obj 8. We validated CGMMV testing of treated cucurbit seeds -- existing method had been validated only for non-treated seeds. Seed lots of several cucurbit species known to be contaminated with CGMMV were treated by the "standard fungicide seed treatments" and tested in a multi-laboratory study. Results showed that treated seeds can be reliable tested for CGMMV by existing ELISA-based methods. LAMP-based diagnostic assays were developed for the late wilt pathogen of maize and several Pospiviroids. We collaborated on the development of a RT-PCR for X. vasicola pv. vasculorum diagnostic on maize seed. We investigated the occurrence of X. vasicola pv. vasculorum in corn seeds, and the importance of seed transmission in the disease epidemiology. We validated a PMMoV identification protocol and implemented a ToBRFV identification method at ISU.
Publications
|
Progress 10/01/19 to 09/30/20
Outputs
Target Audience:Much of the work done for this project directly affects farmers, agribusiness professionals, Extension personnel, and colleagues. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project has provided opportunities for training undergraduate students, graduate students, postdoctoral researchers, and visiting scientists in topics related to basic and applied plant pathology and microbial ecology. How have the results been disseminated to communities of interest?The results from many of these objectives have been disseminated through local Extension (talks, newsletters, videos, social media) or regional Extension (i.e., Crop Protection Network, Soybean Research Information Network). They have also been disseminated through talks to industries (Bayer) and other universities, at national and international conferences, and through posters and talks at local and regional conferences and symposia, in addition to publication in peer-reviewed journals. What do you plan to do during the next reporting period to accomplish the goals?We will continue to advance many of these objectives for the next reporting period.
Impacts
What was accomplished under these goals?
Objective 1. Evaluate the impact of cover crops and crop rotation on the soil and root microbiome and plant and soil health. In field trials in Iowa, we demonstrated that planting a cereal rye cover crop at increased distances from the corn row reduced seedling disease, reduced Pythium populations (Clade B) detected in corn roots at V3, improved corn growth and development, and reduced yield drag compared to a broadcast seeding of the cover crop. We also evaluated the effect of winter cereal rye cover crop seeding method and seeding rate on seedling disease, growth and development and yield of corn. No effect of seeding rate was detected on any parameter measured. Seeding method affected rye biomass. More biomass was measured in broadcast plots compared to drilled plots. Increased biomass reduced early season corn growth and yield, increased seedling disease and reduced soil nitrate. We conducted field studies investigating the potential use of cover crops as tools to manage SDS, Fusarium root rot, white mold and iron deficiency chlorosis. Spring and fall cover crops of rye, wheat, and oats were tested in six field locations in 2020. We found that cover cropping prior to soybean did not cause a detrimental effect on soybean and did not increase risk of diseases when cover crops were terminated prior to or soon after planting the crop. However, we did find that when the cover crop termination was delayed by several weeks, soybean yield can be significantly reduced, especially in years with low soil moisture like 2020. We also conducted greenhouse and lab experiments to determine how cover crops affect disease development and pathogen growth. We found that incorporation of green manures of grasses, especially oats into infested soil, reduced SDS development in soybeans planted into that soil three weeks after green manure amendment. Although the mechanisms are not known, these findings suggest it is worth testing if green manures can provide similar suppression in field conditions. Objective 2. Examine the impacts of seed treatments on seedborne and soilborne pathogen communities and their interactions with crop plants. A study looking at the relationship between foliar symptoms (FDX) of SDS and soybean yield using 52 field experiments conducted in 5 midwestern states and Ontario Canada from 2013 to 2017 comparing crop protection products against SDS were analyzed using meta-analytic models. For every unit of FDX increase, yield decreased by 0.5%. In a second study, 200+ plants with different visual ratings of SDS from low to high were tagged and studied. Results showed that disease onset time is highly correlated with final disease severity and yield. Plots with earlier disease onset has greater disease severity at the end of the season and greater yield loss. We also evaluated various seed treatments on their efficacy to control the seedling disease caused by Rhizoctonia solani, which can cause seedling death before and after emergence. Several seed treatments reduced Rhizoctonia solani and increased yield compared to the non-treated control. Objective 3. Assess the effects of insect management practices on infection of corn plants by mycotoxigenic fungi. We completed experiments evaluating interactions between insect pests and Aspergillus flavus in stored grain. The results indicate that management of stored grain insect pests through transgenic insect resistance is valuable to protect grain in storage from increased aflatoxin contamination. Objective 4. Investigate the infection process, yield loss, and management of frogeye leaf spot, sudden death syndrome and stem canker. We completed field experiments in Iowa, Indiana, Michigan, Wisconsin and Ontario to investigate the effect of corn residue on SDS development. We compared two levels of residue removals and two tillage systems in corn and soybean rotation system. We recorded data on plant population, root rot, foliar SDS, and yield. In general, corn residue did not affect the amount of SDS on subsequent soybean crops. Management of pesticide resistance in pathogens, insects and weeds that can cross farmers' fields is a community-level challenge, may be best addressed through the local, coordinated actions of farmers, crop advisors, lenders, pesticide companies, and extension and research specialists. To support a community-based approach to resistant management, we are facilitating a community-based pilot project in Harrison County, Iowa. This group of local leaders has expanded its scope from herbicide resistance management to include fungicide resistance management. To assist the local team in advancing their effort, samples were collected from a number of soybean fields in the County with different fungicide use history. Results of the screens will assist the Harrison County team communicate the resistance management issue to other producers in the county and expand the scope of the voluntary initiative. Objective 5. Examine the interactions of crop with oomycetes and fungi, and the effect of the environment. We demonstrated through in vitro studies that in the presence of MBOA, an allelochemical produced by rye, seedling disease severity of corn was greater. This suggests that allelopathy may contribute to the negative effects of a winter cereal rye cover crop on corn. Further studies are in progress. We evaluated saponin, a plant extract, as a soybean seed treatment to control Pythium damping off. This extract may induce resistance to plant pathogens. Compared to a non-treated control, all seed treatments improved early season vigor, while several seed treatments had greater plant stand and yield. Additional field studies are needed to prove if this product can effectively reduce Pythium damping-off in the field. Objective 6. Characterize the role of the root microbiome in enhancing plant resource use efficiency. We developed machine learning models predictive of nitrification in soil and the maize rhizosphere, and how cropping system influences the models. These models revealed that the influence of the rhizosphere on the soil microbiome greatly influences the predictive potential, highlighting the importance of integrating how the rhizosphere potentially influences nitrogen availability into cropping system models. Objective 7. Investigate the efficacy of certain soil microbes for biological seed treatments We evaluated several soil microbes in the greenhouse and field for use as biological seed treatments for disease management on corn and soybean. We continued our field tests of a soilborne fungus as a seed treatment to control soilborne diseases. Field tests have shown increase in yield and reductions in Fusarium stalk rot in corn and soybean white mold. However, the efficacy of this product was affected by weather conditions at the time of application. Objective 8. Develop new methods for detection of pathogens of phytosanitary concern, focusing on the use of PCR or loop-mediated isothermal amplification (LAMP) technologies. We completed a project investigating the occurrence of Xanthomonas vasicola pv. vascolorum in corn seeds, and the important of seed transmission in the epidemiology of this pathogen. We participated in development and validation of qPCR-based methods for detection of pospiviroids and Tomato brown rugose fruit virus in tomato and pepper seeds. These methods have been implemented within the National Seed Health System (NSHS) as standard methods for phytosanitary certification to export tomato and pepper seeds from the US.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Baetsen-Young, A.M., Araldi Da Silva, G., Kandel Y.R., Jacobs, J.L., Byrne, A.M., Mueller, D.S., Smith, D.L., Teutna, A.U., Wise, K.A., Day, B., and Chilvers, M.I. 2020. Influence of Fusarium virguliforme temporal colonization of corn, tillage, and residue management on soybean sudden death syndrome and soybean yield. Plant Disease.
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Kandel, Y.R., Hunt, C., Ames, K., Arneson, N., Bradley, C.A., Byamukama, E., Byrne, A., Chilvers, M.I., Giesler, L.J., Halvorson, J., Hooker, D.C., Kleczewski, N.M., Malvick, D.K., Markell, S., Potter, B., Pedersen, W.L., Smith, D.L., Tenuta, A.U., Telenko, D.E.P., Wise, K.A., and Mueller, D.S. 2021. Meta-analysis of soybean yield response to foliar fungicides evaluated from 2005 to 2018 in the United States and Canada. Plant Disease.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Kandel, Y.R., Bradley, C.A., Chilvers, M.I., Mathew, F.M., Tenuta, A.U., Smith, D.L., Wise, K.A., and Mueller, D.S. 2020. Relationship between sudden death syndrome caused by Fusarium virguliforme and soybean yield: a meta-analysis. Plant Disease. 104:1736-1743.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Batzer, J.C. and Mueller, D.S. 2020. Soybean fungal endophytes Alternaria and Diaporthe spp. are differentially impacted by fungicide application. Plant Disease. 104:52-59. https://doi.org/10.1094/PDIS-05-19-1001-RE
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Sjarpe, D.A., Kandel, Y.R., Chilvers, M.I., Giesler, L.J., Malvick, D.K., McCarville, M.T., Tenuta, A.U., Wise, K.A., and Mueller, D.S. 2020. Multi-location evaluation of fluopyram seed treatment and cultivar on root infection by Fusarium virguliforme, foliar symptom development, and yield of soybean. Canadian Journal of Plant Pathology. 42:192-202. doi: 10.1080/07060661.2019.1666166.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Dundore-Arias, J.P., E.A. Eloe-Fadrosh, L.M. Schriml, G.A. Beattie, F.P. Brennan, P.E. Busby, R.B. Calderon, S.C. Castle, J.B. Emerson, S.E. Everhart, K. Eversole, K.E. Frost, J.R. Herr, A.I. Huerta, A. S. Iyer-Pascuzzi, A.K. Kalil, J.E. Leach, J. Leonard, J.E. Maul, B. Prithiviraj, M. Potrykus, N.R. Redekar, J.A. Rojas, K.A.T. Silverstein, D.J. Tomso, S.G. Tringe, B.A. Vinatzer, and L.L. Kinkel. 2020. Community-driven Metadata Standards for Agricultural Microbiome Research. Phytobiomes Journal 4:115-121.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Acharya, J., Kaspar, T. and Robertson, A.E. 2020. Effect of 6-Methoxy-2-benzoxazolinone (MBOA) on Pythium species and corn seedling growth and disease. Plant Disease https://doi.org/10.1094/PDIS-04-20-0824-SC
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Kurtz, S., Acharya, J., Moorman, T., Kaspar, T., Lenssen, A., and Robertson, A.E. 2020. Seedling disease of corn caused by Pythium increases with proximity of rye. Plant Disease https:// doi.org/10.1094/PDIS-06-20-1389-SC
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Wattenburger, C.J., Gutknecht, J., Zhang, Q., Brutnell, T. P., Hofmockel, K. H., and Halverson, L. J. 2020. The rhizosphere and cropping system, but not arbuscular mycorrhizae, affect ammonia oxidizing archaea and bacteria abundances in two agricultural soils. Applied Soil Ecology 151:103540 https://doi.org/10.1016/j.apsoil.2020.103540
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Arias, S.L., Block, C.C., Mayfield, D.A., Broders, K.D., Jackson-Ziems, T.A., and Munkvold, G.P. 2020. Occurrence in seeds and potential seed transmission of Xanthomonas vasicola pv. vasculorum in maize in the United States. Phytopathology. https://doi.org/10.1094/PHYTO-08-19-0
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Cruz, D.R., Leandro, L.F.S., Mayfield, D.A., Meng, Y., and Munkvold, G.P. 2020. Effects of soil conditions on root rot of soybean caused by Fusarium graminearum. Phytopathology https://doi.org/10.1094/PHYTO-02-20-0052-R
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Logrieco, A.F., Battilani, P., Camardo Leggieri, M., Haesaert, G., Jiang, Y., Lanubile, A., Mahuku, G., Mesterhazy, A., Ortega-Beltran, A., Pasti, M.A., Smeu, I., Torres, A., Xu, J., and Munkvold, G. 2020. Perspectives on global mycotoxin issues and management from the MycoKey Maize Working Group. Plant Dis. https://doi.org/10.1094/PDIS-06-20-1322-FE
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Stulberg, M.J., Santillana, G., Studholme, D.J., Kasiborski, B., Ortiz Castro, M., Broders, K., Arias, S., Block, C., Munkvold, G., and Rascoe, J. 2020. Genomics-informed molecular detection of Xanthomonas vasicola pv. vasculorum causing bacterial leaf streak of corn. Phytopathology. In press. https://doi.org/10.1094/PHYTO-12-18-0453-R
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Raza, M.M., Harding, C., Liebman, M., and Leandro, L. F. S. 2020. Exploring the potential of high-resolution satellite imagery for the detection of soybean sudden death syndrome. Remote Sensing 12 (7), 1213. https://doi.org/10.3390/rs12071213
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Bi, L., Hu, G., Raza, M. M., Kandel, Y., Leandro, L. F. S., and Mueller, D. 2020. A gated recurrent units (GRU)-based model for early detection of soybean sudden death syndrome through time-series satellite imagery. Remote Sensing 12 (21), 3621 https://doi.org/10.3390/rs12213621
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Fiscus, M.W., Berns, K.R., Leandro, L.F.S., Mueller, D. S., Eggenberg, S., and Viggers, J. 2020. Cover Crop Effects on Soybean Sudden Death Syndrome, Iron Deficiency Chlorosis and Yield in Central Iowa. Iowa State University Research and Demonstration Farms Progress Reports. https://www.iastatedigitalpress.com/farmreports/article/id/11500/
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Schnabel M. L., Leandro L. F. S., Mueller D. S., Eggenberger S. K. and Viggers J. 2020. Cover Crop Effects on Soybean Sudden Death Syndrome, Iron Deficiency Chlorosis, and Yield. Iowa State University Research and Demonstration Farms Progress Reports 2019(1). https://www.iastatedigitalpress.com/farmreports/article/id/11292/
|
Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Much of the work done for this project directly affects farmers, agribusiness professionals, Extension personnel, and colleagues. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project provided training for an undergraduate, who successfully obtained a grant for continued research on the project. In addition, there were two graduate students who worked on this project and completed their PhD programs in 2019. How have the results been disseminated to communities of interest?The results from many of these objectives have been disseminated through local Extension (talks, newsletters, videos, social media) or regional Extension (i.e., Crop Protection Network, Soybean Research Information Network). They have also been disseminated through talks to industries (Bayer) and other universities, and at national and international conferences, in addition to publication in peer-reviewed journals. Halverson- Obj 1 and 6. Presented results on maize nitrogen use efficiency in different cropping systems at the International Phytobiomes Conference 2018. What do you plan to do during the next reporting period to accomplish the goals?We will continue to advance many of these objectives for the next reporting period.
Impacts
What was accomplished under these goals?
IMPACT: Our research increased scientific knowledge of plant problems and management solutions, which can be used by farmers, agribusiness professionals, extension personnel, and colleagues. Objective 1. We completed experiments to investigate the effect of corn residue on sudden death syndrome (SDS). We compared two levels of residue removals and two tillage systems in corn and soybean rotation system. Preliminary findings suggest that corn residue does not consistently affect SDS. We also tested how fall and spring cover crops of rye, wheat, and oats affected SDS, white mold, and iron deficiency chlorosis. We did not find any significant effects of the cover crops. We evaluated the effect of terminating a winter rye cover crop, after planting corn, on corn growth and development and seedling disease. Seedling disease was most severe on corn planted when rye was terminated 3 DBP and 6 DAP. Corn growth and development and yield was reduced following the rye cover crop. Objective 2. We conducted field experiments to determine how fungicide and nematicide seed treatments affected SDS and soybean cyst nematode (SCN). Preliminary data showed that SCN seed treatments alone did not affect SDS but when combined with ILEVO they provided better disease and yield response than ILEVO alone. We also evaluated the influence of cultivar and two rates of ILEVO on root rot and foliar symptoms of SDS. Results showed that ILEVO reduced root rot and foliar SDS severity and increased yield compared to the base treatment. Yield was negatively correlated with root rot and foliar symptoms suggesting both phases play an important role in SDS development. We also studied data on ILEVO for SDS management and yield response using a meta-analysis approach. A 35% reduction in SDS and 4.4 bu/ac (7.6%) increase in yield were estimated for ILEVO-amended seed treatment relative to base seed treatments. Objective 3. Fungal colonization and mycotoxin contamination are chronic problems that can compromise grain quality and safety in stored maize. Insect damage predisposes grain to infection by mycotoxigenic fungi. The effect of Indianmeal moth or maize weevil infestations on A. flavus colonization and vice versa in non-Bt and Bt maize hybrids were evaluated in this study. After 28 days of storage, the presence of Indianmeal moth or maize weevil did not enhance A. flavus colonization. No Indianmeal moths or maize weevils survived in grain of Bt hybrids with lepidopteran or coleopteran resistance genes, respectively. Aflatoxin levels in the 106 A. flavus inoculated non-Bt grain increased significantly in the presence of Indianmeal moth or maize weevil, but aflatoxins in the Bt hybrids were unaffected by insect infestation. These and other outcomes of this study demonstrated that Bt protection was effective against stored-grain insects Indianmeal moth and maize weevil and that the use of Bt hybrids can mitigate the risk of A. flavus infection and aflatoxin contamination related to stored-grain insects. Objective 4. Field experiments across the upper Midwest comparing crop protection products against SDS were analyzed using meta-analytic models. We found that for every unit of FDX increase, yield will be decreased by 0.5%. Management of pesticide resistance in pathogens, insects and weeds that can cross farmers' fields is a community-level challenge and may be best addressed through the local, coordinated actions of farmers, crop advisors, lenders, pesticide companies, and extension and research specialists. To support a community-based approach to resistant management, we are facilitating a community-based pilot project in Harrison County, Iowa. This group of local leaders has expanded its scope to include fungicide resistance management. To assist the local team, we collected samples from a number of soybean fields in the county with different fungicide use history. Results of the screens indicated that the strains were resistant to the QoI class of fungicides. This will assist the Harrison County team in communicating the resistance management issue to other producers in the county. Objective 5. We characterized approximately 800 Pythium isolates recovered from seed treatment field trials. Preliminary results suggest location, planting date and cropping history affected the diversity of species recovered. Since fungicide efficacy varies among species, these data have implications for fungicides used as seed treatments to reduce stand loss due to seedling disease. Soybean seedlings with symptoms of Pythium damping-off were collected and processed for isolation of the causal agents. Among the Pythium spp. collected, the most aggressive isolate was selected to test the efficacy of seed treatments using eight foliar fungicides in inoculated field conditions. Six of the fungicides significantly suppressed damping-off compared with the non-treated control. Our findings suggest a potential for using foliar fungicides as seed treatments to control Pythium damping-off and provide an alternative solution for managing resistance to metalaxyl/mefenoxam seed treatments in soybean production. We completed a study to determine if iron deficiency chlorosis is associated with root colonization by fungi and oomycetes. Our data showed that the frequency of isolation of fungi and oomycetes was very similar in IDC and healthy plants, suggesting that root colonization by these fungi is not a key driver in the development of IDC. Objective 6. We are exploring plant x microbiome x environment interactions influencing soybean tolerance to drought. We have observed repeatable changes in specific microbial groups in soybean roots grown under drought conditions. We are also exploring plant x microbiome interactions influencing maize nitrogen use efficiency. We collected ~200 isolates from the rhizosphere and endosphere of maize grown under different cropping systems and have determined the taxonomic identity of about 100 isolates and have begun identifying various phenotypes to enable their use in experiments to functionally analyze their impact on maize nitrogen use efficiency. Objective 7. We tested a biological control fungus against white mold and SDS of soybean. The biological control fungus can be established in soybean root when applied at early seedling stage or used as seed treatment. Treatments were made before planting by spraying the agent on soil surface. For white mold, yield increases ranged from 0-2 bu/ac. For SDS, the biological control fungus significantly reduced SDS and resulted in a 1-2 bushel yield increase compared to the non-treated control. When combined with a supplemental nutrient, further yield increases were found. Objective 8. There is a need for a validated, standard testing method for tomato- and pepper-infecting viroids in the genus Pospiviroid. A method was developed and a validation study was carried out. Several public and private labs participated. It is expected that the results of the validation study will result in approval of the method by the National Seed Health System. ToBRFV is a relatively new member of the genus Tobamovirus, and no validated seed health testing method exists. We made comparisons among several primer sets that have been published for ToBRFV, and evaluated their performance on putative ToBRFV-contaminated samples. Based on these results, a method was established for use in the ISU Seed Testing Laboratory, and we are working with academic and private-sector collaborators to organize a validation study. We also collaborated on the development of a RT-PCR based seed health assay for Xanthomonas vasicola pv. vasculorum on maize seed.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Cappelle, K.M., Munkvold, G.P., and Wolt, J.D. 2019. Meta-effect of insect resistant maize on fumonisin B1 in grain estimated by variance-weighted and replication-weighted analyses. World Mycotoxin J. 12:141-151.
- Type:
Book Chapters
Status:
Published
Year Published:
2019
Citation:
Munkvold, G.P., Arias, S.L., Taschl, I., and Gruber-Dorninger, C. 2019. Mycotoxins in Corn Occurrence, Impacts, and Management. Pp. in Corn Chemistry and Technology, 3rd Edition. Eds. Am. Assoc. Cereal Chemists, St. Paul, MN
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Stulberg, M.J., Santillana, G., Studholme, D.J., Kasiborski, B., Ortiz Castro, M., Broders, K., Arias, S., Block, C., Munkvold, G., and Rascoe, J. 2019. Genomics-informed molecular detection of Xanthomonas vasicola pv. vasculorum causing bacterial leaf streak of corn. Phytopathology. https://doi.org/10.1094/PHYTO-12-18-0453-R
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2019
Citation:
Mandap, J. A. 2019. Interactions between Aspergillus flavus and stored-grain insects in conventional and transgenic maize. M.S. Thesis, Iowa State University. 92 pp.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Acharya, J., Moorman, T., Kaspar, T., Lenssen, A., and Robertson, A.E. 2019. Cover crop rotation effects on growth and development, seedling disease and yield of corn and soybean. Plant Disease https://doi.org/10.1094/PDIS-09-19-1904-RE
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Navi, S.S., Huynh, T., Mayers, C.G. and Yang, X.B. 2018. Diversity of Pythium spp. associated with soybean damping-off, and management implications by using foliar fungicides as seed treatments. Phytopathology Research https://phytopatholres.biomedcentral.com/articles/10.1186/s42483-019-0015-9
- Type:
Journal Articles
Status:
Other
Year Published:
2019
Citation:
Sjarpe, D.A., Kandel, Y.R., Chilvers, M.I., Giesler, L.J., Malvick, D.K., McCarville, M.T., Tenuta, A.U., Wise, K.A., and Mueller, D.S. 2019. Multi-location evaluation of fluopyram seed treatment and cultivar on root infection by Fusarium virguliforme, foliar symptom development, and yield of soybean. Canadian Journal of Plant Pathology. Accepted August 2019. DOI: 10.1080/07060661.2019.1666166.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Kandel, Y.R., Bradley, C.A., Chilvers, M.I., Mathew, F.M., Tenuta, A.U., Smith, D.L., Wise, K.A., Mueller, D.S. 2019. Effect of seed treatment on sudden death syndrome and yield of soybean. Plant Disease. 103:1712-1720. doi.org/10.1094/PDIS-12-18-2199-RE.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Ghimire, K., Petrovi?, K. Kontz, B.J., Bradley, C.A., Chilvers, M.I., Mueller, D.S., Smith, D.L., Wise, K.A., Mathew, F.M. 2019. Inoculation method impacts symptom development associated with Diaporthe aspalathi, D. caulivora, and D. longicolla on soybean (Glycine max). Plant Disease. 103:677-684. doi/10.1094/PDIS-06-18-1078-RE.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Bell, T., K.L. Hockett, R.I. Alcal�-Brise�o, M. Barbercheck, G.A. Beattie, M.A. Bruns, J.E. Carlson, T. Chung, A. Collins, B. Emmett, P. Esker, K.A. Garrett, L. Glenna, B.K. Gugino, M. del Mar Jim�nez-Gasco, L. Kinkel, J. Kovac, K.P. Kowalski, G. Kuldau, J.H.J. Leveau, M.J. Michalska-Smith, J. Myrick, K. Peter, M. Fernanda Vivanco Salazar, A. Shade, N. Stopnisek, X. Tan, A.T. Welty, K. Wickings and E. Yergeau. 2019. Manipulating wild and tamed phytobiomes: Challenges and opportunities. Phytobiomes Journal 3:3-21.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Wattenburger, C., L. Halverson, and K. Hofmockel. 2019. Agricultural management affects root-associated microbiome recruitment over maize development. Phytobiomes Journal 3:246-255
|
Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Farmers, students in plant pathology and microbiology, crop advisors, and agriculture industry Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Four post-doc students and one graduate student gained training and experience in research methods. How have the results been disseminated to communities of interest?Mueller - We presented our research reports at professional meetings (Southern soybean disease workshop (SSDW), American Phytopathological Society (APS), etc.), on Crop Protection Network, many state or province level talks, seminars, media interviews, talk in field days and conferences for farmers and also published in state newsletter articles. We had over 20 media releases, several press releases, including some jointly with soybean checkoff, based on results from this project. We developed 2 regional publications through the Crop Protection Network and linked our results to the soybean checkoff website. Objective 1 (Mueller and Leandro) - We presented the results of the cover crop study in meeting with the Iowa Soybean Association, in departmental seminars, and at the north central regional meeting of the the American Phytopathological Society. Beattie - Obj 6: We presented these results at two national conferences (Wild and Tamed Phytobiomes and Soy2018), at one university (Oregon State University), and to one grower group (Practical Farmers of America) and two companies (Indigo and Bayer). Halverson- Obj 6: We presented these results at an ISU sponsored workshop on Metagenomics and in a departmental seminar series at ISU. XB Yang- We are collaborating with industry to develop biocontrol agents by evaluating different biological control product for controlling SDS and major soybean diseases. This type of products provides soybean growers an effective and economic means to control major soybean diseases. We have been working with soybean check-off. Results of our project "Evaluation and Development of Biological Control Products to Control Soybean Sudden Death Syndrome and White Mold" have been used by industry to promote biological control, especially in seed treatments aspects. I am told by one collaborative company that demands for their biological seed treatments has doubled in year to year base. XB Yang- Report of our finding helps industry develop new treatments. Underline mechanism of several new seed treatments are in-line with our finding that effective infections by endophytic pathogens occur at early germination stage, control should be carried at initial germination of the seeds. The new FMC product - Ethos XB, an in-furrow solution, is another example. What do you plan to do during the next reporting period to accomplish the goals?Leandro (Obj 1). We plan to conduct greenhouse assays on the effects of cover crops on soybean diseases, to complement the field trials. (Obj 2). Continue investigating socio-economic factors that affect initiation of pest resistance management in the early stages of resistance development, before most producers see a significant problem. Leandro (Obj 4). we plan to quantify the density of the SDS pathogen in soil samples from SDS field trials using quantitative PCR. We will then analyze the data to characterize the relationship between pathogen density in soil, the timing and severity of SDS symptons and yield. (Obj 5). We have been conducting trials in the growth chamber to evaluate the effect of winter rye root and shoot biomass on corn seedling disease. Initial data suggests that root biomass influences seedling disease development more than shoot biomass. It is not clear if this is due to higher populations of pathogens, nitrogen recycling or other factors but experiments are planned to tease these effects apart. Beattie - Obj 6: We plan to isolate soil microbes of representative taxa to generate a collection that can be used to functionally analyze their impact on water use efficiency. Halverson- Obj 6: We plan to do additional network analyses to understand the potential significance of represensentation of nitrifiers in discrete co-occurring communities (modules) and their absence in most. We also plan to isolate microbes from the maize rhizosphere that are representative of the taxa observed in phytobiome analyses to construct a synthetic microbiome. This synthetic community will enable us to functionally analyze their contribution to plant growth in systems simulating diversified and conventionally managed cropping systems.
Impacts
What was accomplished under these goals?
Overall impact statement: New knowledge was unearthed that is expected to inform strategies for best utilizing cover crops, crop rotations and insect management practices, including biological control products, for enhanced crop productivity and environmental sustainability of corn and soybean production in the Midwestern U.S. Objective 1. Evaluate the impact of cover crops and crop rotation on the soil and root microbiome and plant. We continued collecting soil, rhizosphere, and endosphere samples of soybean to assess whether increased soil C inputs of diversified cropping system soils foster different microbial assemblages than those in a conventional system. The diversified (corn-soybean-oats/alfalfa-alfalfa) rotation with low inorganic N and composted manure inputs were compared to a conventional (corn-soybean) rotation with normal inorganic fertilizer inputs. This is important given the diversified system exhibits a yield benefit, reduced N-loss, and a reduction in soybean sudden death syndrome (SDS). We also conducted field trials at three locations to investigate the impact of rye and oat cover crops on soybean diseases caused by SDS and seedling disease caused by Fusarium and Pythium species. In all trials conducted in 2018, the cover crops did not negatively affect soybean disease levels or soybean yield, which is consistent with 2017 trials. These findings are important to growers since they suggest that cover crops can be safely used before soybean. Objective 2. Examine the impacts of seed treatments on seedborne and soilborne pathogen communities. Through a meta-analysis of over 200 field trials, we evaluated the benefits of a commercially available seed treatment--lLeVo fungicide--under different disease pressure and multiple environments. Results showed cultivar selection combined with ILeVO can reduce SDS in early planted soybean (late April to mid-May). Overall, a 35% reduction in foliar disease a 7.6% increase in yield were estimated for ILeVO seed treatment. Another study focused on how SDS severity was influenced by soybean cyst nematode (SCN) population density and HG type. Soybean aphid resistance to pyrethroids is an emerging threat. We are investigating socio-economic factors that affect initiation of pest resistance management in the early stages of resistance development, before most producers see a significant problem. Despite a well-documented economic threshold for aphid management, discussions with producers indicate a belief that the economic threshold should be well below that level due to the economics of application, commodity prices, and misinformation. Objective 3. Assess the effects of insect management practices on infection of corn plants by mycotoxigenic fungi. Fusarium subglutinans (Fs) is a well-studied Fusarium spp. associated with Fusarium ear rot. However, there is limited information on the role of the closely related F. temperatum (Ft), formerly Fs group I, in Fusarium ear rot symptoms and mycotoxin contamination of grain. Field experiments were conducted for two years including manual infestation with corn earworm or European corn borer and silk channel inoculations with Fs or Ft on Bt and non-Bt maize. Ear rot severity was greater in the non-Bt hybrid in both years and inoculated treatments had significantly higher ear rot severity than non-inoculated controls. H. zea infestations increased ear rot severity in one year. Ft inoculation resulted in elevated levels of some mycotoxins compared to other treatments. This is new knowledge regarding Ft's pathogenicity and role in mycotoxin accumulation in maize. Objective 4. Investigate the infection process, yield loss, and management of sudden death syndrome (SDS) and stem canker. We conducted field trials to better understand the relationship between severity and time of onset of SDS and soybean yield. In 2018, we collected disease, pathogen and yield data from six field trials. Analysis of the data showed that timing of disease has a strong linear relationship with yield loss, with early onset resulting in the greatest yield loss. One major finding is that infections by SDS fungus occur while seeds are geminating and the pathogens are present, but not causing apparent disease. Results from greenhouse and field tests this year and in previous years show that establishment of a biological control agent in roots from seed treatment prior to pathogen infections can activate plant resistance and reduce disease. Objective 5. Examine the interactions of crop with oomycetes and fungi, and the effect of the environment. We have been conducting trials in a growth chamber to evaluate the effect of winter rye root and shoot biomass on corn seedling disease. Initial data suggests that root biomass influences seedling disease development more than shoot biomass. Two field trials were conducted this year to determine the effect of "planting green" on corn seedling disease and development. A cover crop of winter rye was seeded after soybean or after corn. In spring, rye was terminated 18 days before planting (DBP), 3 DBP, 6 days after planting (DAP) and 12 DAP. Corn seedling disease was greater in corn planted 3 days after, and 6 days before terminating rye. We also conducted field trials to characterize the fungal and oomycete communities associated with soybean plants affected by iron deficiency chlorosis (IDC). This is a damaging disease that is poorly understood. We collected soybean plants with and without IDC symptoms from six fields, and made isolations of fungi and oomycetes associated with the roots. Objective 6. Characterize the role of the root microbiome in enhancing plant resource use efficiency. We characterized the impact of soil water content on highly resolved taxonomic groups within root-associated microbial communities using differential heat trees. Reproducible patterns of microbial assembly within roots and in the rhizosphere occurred across four sequential cycles of plant growth at distinct soil water contents. This reproducibility provides an experimental tool to begin to identify the drivers of microbial assembly in response to soil water deficits. We continued explorations into whether increased C inputs of diversified cropping systems' soils foster different microbial assemblages resulting in tighter coupling of available N supply and demand, and smaller inorganic N pools. Data analysis suggests that maize in the conventional system exerts a strong rhizosphere effect, which could contribute to differences in plant productivity between these two cropping systems. Objective 7. Investigate the efficacy of certain soil microbes for biological seed treatments. We continue to test if infections by beneficial biological agents (fungus/bacteria) prior to endophytic-pathogen infections can reduce the risk of symptom expression of pathogenic fungi and reduce the levels of soil borne diseases. Study results show that efficacy highly depends on soil conditions and planting dates. We conducted large scale experiments in collaboration with farmers to demonstrate the efficacy of using BCA under different fertilizer condition (heavy manure and no manure) to control soybean and corn diseases. Fertilizer conditions did affect control efficacy. The large area test was successful, which had significant increase in yield. Objective 8. Develop new methods for detection of pathogens of phytosanitary concern, focusing on the use of PCR or loop- mediated isothermal amplification (LAMP) technologies. We completed a validation study for CGMMV testing of treated cucurbit seeds. The existing method had been validated only for non-treated seeds. Seedlots of several cucurbit species that are known to be contaminated with CGMMV were treated with standard fungicide seed treatments and tested in a multi-laboratory study. Results showed that treated seeds can be reliably tested for CGMMV using existing ELISA-based methods.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Leandro, L. F. S., Eggenberger, S., Chen, C., Williams, J., Beattie, G., and Liebman, M. 2018. Cropping system diversification reduces severity and incidence of soybean sudden death syndrome caused by Fusarium virguliforme. Plant Disease 102: 1748-1758
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Cruz, D. R., Ellis, M. L., Munkvold G. P. and Leandro, L. F. S. 2018. Isolate x cultivar interactions, in vitro growth and fungicide sensitivity of Fusarium oxysporum isolates causing seedling disease on soybean. Plant Disease 102: 1928-1937
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
J. Xie, J.G. Wei, R.S. Huang, X.H. Yang, X.B. Yang, 2018. First Report of Ring Spot Caused by Neopestalotiopsis clavispora on Kadsura coccinea. Plant Disease (note) vol 102 No 10:2032. https://doi.org/10.1094/PDIS-01-18-0078-PDN
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Navi, SS. Huynh, T., Mayers, C.G., Pecinovsky, K.T., and Yang, X.B. 2018. Diversity of Pythium spp. associated with soybean damping off, and management implications by using foliar fungicides as seed treatments. Phytopathological Research (a new journal by Chinese Phytopathological Society).
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Zhang, G., Allen, T.W., Bond, J.P., Fakhoury, A.M., Dorrance, A.E., Weber, L., Faske, T.R., Giesler, L.J., Hershman, D.E., Kennedy, B.S., Neves, D.L., Hollier, C.A., Kelly, H.M., Newman, M.A., Kleczewski, N.M., Koenning, S.R., Thiessen, L.D., Mehl, H.L., Zhou, T., Meyer, M.D., Mueller, D.S., Kandel, Y.R., Price III, P.P., Rupe, J.C., Sikora, E.J., Tomaso-Peterson, M., Wise, K.A., and Bradley, C.A. 2018. Widespread occurrence of quinone outside inhibitor fungicide-resistant isolates of Cercospora sojina, causal agent of frogeye leaf spot of soybean, in the United States. Plant Health Progress. 19:295-302.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Mourtzinis, S., Rattalino Edreira, J.I., Kyveryga, P.M., Licht, M.A., Naeve, S.L., Roth, A.C. Casteel, S.N., Conley, S., Lindsey, L.E., Mueller, D., Staton, M.J., Kandel, H.J., Nafziger, E.D., Grassini, I., Ciampitti, I., and Stanley, J. 2018. Sifting and winnowing: analysis of farmer field data for soybean in the US north-central region. Field Crops Research. 221:130-141.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Pierson, W.L., Kandel, Y.R., Allen, T.W., Faske, T.R., Tenuta, A.U., Wise, K.A., and Mueller, D.S. 2018. Soybean yield response to in-furrow fungicides, fertilizers and their combinations. 2018. Crop, Forage, and Turfgrass Management. 4:170073. doi:10.2134/cftm2017.10.0073.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Kandel, Y.R., Mueller, D.S., Legleiter, T., Johnson, W.G., Young, B.G., and Wise, K.A. 2018. Impact of fluopyram fungicide and preemergence herbicides on soybean injury, population, sudden death syndrome, and yield. Crop Protection. 106: 103-109.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Kandel, Y.R., McCarville, M., Adee, E.A., Bond, J.P., Chilvers, M.I., Conley, S.P., Giesler, L.J., Kelly, H. M., Malvick, D.K., Mathew, F.M., Rupe, J.C., Sweets, L.E., Tenuta, A.U., Wise, K.A., and Mueller, D. S. 2018. Benefits and profitability of fluopyram-amended seed treatments for suppressing sudden death syndrome and protecting soybean yield: a meta-analysis. Plant Disease. 102:1093-1100.
|
Progress 10/01/16 to 09/30/17
Outputs
Target Audience:farmers, students in plant pathology and microbiology, crop advisors, and agriculture industry Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Mueller and Leandro - Objective 1: We have presented the results of the cover crop study in several Extension talks, including a national webinar through the Agronomy Society on cover crops, in departmental seminars, and in national plant pathology meetings such as the American Phytopathological Society meeting. Munkvold, Objectives 3 and 8 - Posters were presented at the annual APS meeting on development of the late wilt and viroid LAMP assays as well as the seed transmission and seed health assay for Xvv. Mueller - Objective 4: We presented these data at our ICM Conference, which had over 900 attendees. We also created a slide set and shared this with colleagues across the soybean producing states and Ontario Canada. Halverson- Objective 6 and 1: We presented these results at in the Department of Agronomy at ISU, posters presented at the Ecological Society of America meeting and the Multi-omics for Microbiomes-Environmental Molecular Sciences DOE Laboratory Integration Conference, and at invited presentations at Central China Normal and Hubei Universities in Wuhan, China. Beattie - Objective 6: We presented these results at an international conference for academia and industry (Biocontrol, Biostimulants & Microbiome), one US university (Michigan State Univ), one university in Korea (Seoul National Univ), and three universities in China (Huazhong Agricultural Univ, Central China Normal Univ, and Hubei Univ). What do you plan to do during the next reporting period to accomplish the goals? Mueller and Leandro - Objective 1: We are in the process of summarizing our data on the effect of cover crops on several important soybean diseases. We plan to publish this in the next year. Due to grower concern during the last quarter of 2017, the potential interactions between soybean cyst nematodes, fungi, and soybean aphids and reduced yields were identified as a possible factor contributing to increased pesticide use and development of aphid resistance to pyrethroid insecticides. During 2018, an effort to better understand the biological and socio-economic factors that influence management behavior will be initiated in conjunction with the Iowa Pest Resistance Management Plan. (Beattie, Halverson, Leandro, Mueller, Robertson) Objective 2: We are in the process of identifying the isolates to species level. Amplicon sequencing will be done later this year to compare the oomycete communities associated with each seed treatment. Mueller - Objective 4: We plan to continue to study the importance of root rot of sudden death syndrome. We plan to combine our data with others and complete a meta-regression to identify yield loss from this phase of the disease. Leandro, Munkold, Robertson - Objective 5: We plan to publish the results from the study on environmental conditions that favor infection by F. graminearum in 2018. We will also complete the third year of the field study on iron deficiency chlorosis. Munkvold, Objectives 3 and 8 - Manuscripts are being prepared on development of the late wilt and viroid LAMP assays as well as the seed transmission and seed health assay for Xvv. Work is continuing on Xvv seed transmission. Halverson- Objective 6 and 1: We plan to publish results from studies contrasting diversified and conventional cropping systems, including how 1) maize development differentially affects rhizosphere prokaryotic and fungal communities in these two systems, 2) total resident and metabolically active soil and maize rhizosphere microbiomes shift differently, 3) soil and maize root-associated microbiomes are more robust and inter-reconnected in diversified cropping systems, and 4) the rhizosphere and soil management but not arbuscular mycorrhizae affect ammonia-oxidizing Archaea and Bacteria abundance Beattie - Objective 1: We plan to perform more comprehensive network analyses of these communities and use the results to direct laboratory studies on the functions of selected microbial groups that are distinct in their associations with soybean roots under drought conditions.
Impacts
What was accomplished under these goals?
IMPACTS: described under each objective Obj 1. Evaluate the impact of cover crops and crop rotation on the soil and root microbiome and plant. Soybean sudden death syndrome (SDS), caused by Fusarium virguliforme, is a major soybean disease affecting soybean production in the United States. F. virguliforme is able to colonize many plant species, and the inadvertent use of a host plant as a cover crop may increase F. virguliforme inoculum in the soil and thus the likelihood of disease. We investigated the possibility by evaluating the susceptibility of cover crop species to F. virguliforme. In general, the Brassica and grass species tested did not develop typical SDS symptoms and showed minimal or no pathogen DNA associated with roots; thus, we did not consider these to be hosts of F. virguliforme. We also conducted field trials at three locations in Iowa to investigate the impact of a rye cover crop on soybean seedling diseases caused by diverse pathogens including several Fusarium and Pythium species. In all trials, the rye cover crop did not have negative effects on soybean health and productivity. Obj 2. Examine the impacts of seed treatments on seedborne and soilborne pathogen communities and their interactions with crop plants. We initiated a study of the effect of seed treatments on oomycete communities associated with corn seedlings. Field trials comparing the effect of 5 seed treatments that contained various fungicides targeted against oomycetes were established at 3 locations in Iowa. A base seed treatment that contained fungicides against fungal pathogens was used as a control. Corn seedlings were collected at growth stage V2-V3 from each trial. Isolations on oomycete-specific media were done from the roots of each corn seedling. Root samples from each seedling were also collected. Over 10,000 oomycete isolates were collected. Obj 3. Assess the effects of insect management practices on infection of corn plants by mycotoxigenic fungi. We proceeded with data analysis for field experiments conducted in 2016 that aim to assess the influence of Lepidopteran insects on infection by Fusarium temperatum and Fusarium subglutinans. There were significant differences in mycotoxin profiles among inoculated treatments. Treatments inoculated with F. subglutinans were higher in fusaric acid and fusaproliferin, but lower in beauvericin, compared to F. temperatum-inoculated treatments. Corn earworm infestation caused increased severity of ear rot and moniliformin levels in grain. Control of Lepidopteran insects using transgenic Bt hybrid resulted in lower levels of some mycotoxins, including beauvericin, fumonisins, and fusaproliferin, depending on the fungal inoculation treatment. Obj 4. Investigate the infection process, yield loss, and management of sudden death syndrome and stem canker. We finished a project looking at the importance of the root rot phase of sudden death syndrome on soybean yield. This disease has characteristic foliar symptoms that occur late in the season when there is abundant soil moisture, but the disease starts earlier as a root rot. The impact of the root rot phase of this disease is unknown. In 2017, we conducted field trials at multiple locations in Iowa and other Midwestern states and modeled the relationship between foliar disease, root disease and yield. This research made an important contribution for scientists and farmers, since it showed that the root rot phase caused significant damage even in the absence of foliar symptoms. Obj 5. Examine the interactions of crop with oomycetes and fungi, and the effect of the environment. Corn and soybeans can get infected by a variety of oomycetes and fungi that can result in serious losses for growers. We conducted controlled environment experiments to understand the effect of soil moisture, soil texture, and pH on soybean root rot cause by Fusarium graminearum. We found that pH 6 and dry soil conditions were optimal for disease development, resulting in detrimental effects on plant development. We also conducted field trials to characterize the fungal and oomycete communities associated with soybean plants affected by iron deficiency chlorosis. This research is ongoing and has the potential to improve management of iron deficiency chlorosis by clarifying the role of pathogens in disease development. Obj 6. Characterize the role of the root microbiome in enhancing plant resource use efficiency. We concluded a series of experiments. We found that the cropping system (diversified versus conventional) had the least impact on prokaryotic communities on roots during vegetative stage 11 (high nutrient demand), and the greatest impact on fungal communities on roots at vegetative stage 4 (low nutrient demand). Results showed that prokaryotic and fungal communities assemble differently based on agricultural management, suggesting distinct roles in supporting plant health. Findings support the possibility that increased soil C inputs in the diversified cropping systems foster microbial assemblages that may more tightly couple available N supply and demand and therefore reduce the inorganic N pools that contribute to nutrient leaching and loss. Moreover, the results suggest that ammonia-oxidizing bacteria play a fundamental role in shaping microbial communities in temperate agroecosystems with relatively high rates of N mineralization. These findings are aimed at developing sustainable agricultural management practices that are deployable in the Midwestern US. We also explored the structure of the microbial communities on soybean roots under conditions of high and low water availability. This approach was effective in illustrating which microbes co-occur, and therefore likely interact, with each other, thus highlighting potentially functional consortia that may play a role in protecting soybean plants from drought tolerance. Obj 7. Investigate the efficacy of certain soil microbes for biological seed treatments. Field experiments were conducted in commercial farms in northwestern Iowa to evaluate effects of biological control agent on disease control and yield improvement. Tests were made with commercial farming practices for corn production. Multiple diseases were suppressed after application including root rot and stalk rot of corn. After harvest, yield maps showed increase up to 10 bushels per acre after treatment compared with control in all farms participating in our test. A farmer who participated in the test was excited with the results and would like to use this approach for disease management for all his acres in coming season. Previously, he had used the BCA in soybean for white mold and SDS control in a 50-acre field which had severe white mold over years. Yield increase of 8 bushels per acre was achieved with this control approach. Obj 8. Develop new methods for detection of pathogens of phytosanitary concern. Work was completed on the development of a LAMP assay for Magnaporthiopsis maydis, the cause of late wilt of maize. The assay is capable of detecting one contaminated seed in 1,000 and it did not cross-react with 18 other fungal taxa that are either closely related to M. maydis and/or commonly found in maize kernels. Additionally, seed transmission of M. maydis was investigated by planting approximately 1,000 inoculated seeds and assaying the seedlings. The fungus was detected in 0.0094% of plants that emerged. Another LAMP assay was developed for pospiviroids that can be found in tomato seeds. The method successfully detected PSTVd, TASVd, and TCDVd in seeds from inoculated plants but did not react positively with other pospiviroids or viroids outside the pospiviroid genus. PCR and culture plate assays were developed for the detection of Xanthomonas vasicola pv. vasculorum Xvv in maize seeds. A seed extraction procedure was optimized, a selective medium was developed, and existing PCR primers were adapted into qPCR assay to detect the bacterium in seeds.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Phillips, X.A., Singh, A.K., Kandel, Y.R., and Mueller, D.S. 2017. Effect of pod removal, foliar fungicides and cultivar on green stem disorder. Agronomy Journal. 109:1-9 doi:10.2134/agronj2017.04.0203
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Rattalino Edreira, J.I., Mourtzinis, S., Conley, S.P., Roth, A.C., Ciampitti, I.A., Licht, M.A., Kyveryga, P.M., Kandel, H., Lindsey, L.E., Mueller, D.S., Naeve, S.L., Nafziger, E., Specht, J.E., Stanley, J., Staton, M.J., and Grassini, P. 2017. Assessing causes of yield gaps in agricultural areas with diversity in climate and soils. Agricultural and Forest Meteorology. 247:170-180.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Coser, R.V., Chowda R., Zhang, J., Mueller, D.S., Mengistu, A., Wise, K.A., Allen T.W., Singh A., and Singh A.K. 2017. Genetic architecture of charcoal rot (Macrophomina phaseolina) resistance in soybean revealed using a diverse panel. Frontiers in Plant Science. Published: 21 September 2017. doi: 10.3389/fpls.2017.01626
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Anderson, N.R., Irizarry, M.D., Bloomingdale, C.A., Smith, D.L., Bradley, C.A., Deland, D.P., Kleczewski, N.M., Sikora, E.J., Wise, K.A., and Mueller, D.S. 2017. Effects of Soybean vein necrosis virus on yield and seed quality of soybean. Canadian Journal Plant Pathology. 39(3): 334-341 DOI: 10.1080/07060661.2017.1354333
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Kandel, Y.R., Wise, K.A., Bradley, C.A., Chilvers, M.I., Byrne, A.M., Tenuta, A.U., Faghihi, J., Wiggs, S., and Mueller, D.S. 2017. Effect of soybean cyst nematode resistance source and seed treatment on population densities of Heterodera glycines, sudden death syndrome, and yield of soybean. Plant Disease. 101:2137-2143.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Moellers, T.C., Singh, A., Zhang, J., Brungardt, J., Kabbage, M., Mueller, D.S., Grau, C.R., Ranjan, A., Smith, D.L., Chowda-Reddy, R.V., and Singh, A.K. 2017. Main and epistatic loci studies in soybean for Sclerotinia sclerotiorum resistance reveal multiple modes of resistance in multi-environments. Scientific Reports. 7:3554 doi:10.1038/s41598-017-03695-9
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Gaspar, A.P., Mueller, D.S., Wise, K.A., Chilvers, M.I., Tenuta, A.U., and Conley, S.P. 2017. Response of broad spectrum and target specific seed treatments and seeding rate on soybean seed yield, profitability, and economic risk. Crop Science. 56:1-12.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Romero Luna, M.P., Mueller, D.S., Mengistu, A., Singh, A.K., Hartman, G.L., and Wise, K.A. 2017. Advancing our understanding of charcoal rot in soybeans. Journal Integrated Pest Management. 2017; 8 (1): 1-8. doi: 10.1093/jipm/pmw020.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Kobayashi-Leonel, R., Harbach, C., Mueller, D., Tylka, G., and Leandro, L. 2017. Cover crop host range of Fusarium virguliforme, causal agent of soybean sudden death syndrome, and Heterodera glycines, the soybean cyst nematode. J. Soil and Water Conservation. 72:575-583.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Han, G., Kandel, Y., Leandro, L., Helmers, M., Schott, L., and Mueller, D. 2017. Influence of drainage on soybean seedling health. J. Soil and Water Conservation. 72:266-271 doi:10.2489/jswc.72.3.266
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Abdelsamad, N. A., Baumbach, J., Bhattacharyya, M. K., and Leandro, L. F. S. 2017. Soybean sudden death syndrome caused by Fusarium virguliforme is impaired by prolonged flooding and anaerobic conditions. Plant Disease 101(5):712-719. DOI: 10.1094/PDIS-04-16-0534-RE
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Srour, A. Y., Gibson, D. J., Leandro, L. F. S., Malvick, D. K., Bond, J. P., and Fakhoury, A. M. 2017. Unraveling microbial and edaphic factors affecting the development of sudden death syndrome in soybean. Phytobiomes 1(2):91-101. DOI: 10.1094/PBIOMES-02-17-0009-R.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
da Silva, M.P., Tylka, G.L., and Munkvold, G. P. 2017. Seed treatment effects on maize seedlings co-infected with Rhizoctonia solani and Pratylenchus penetrans. Plant Dis. 101:957-963.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Meng, Y., Hao, J., Mayfield, D., Luo, L., Munkvold, G.P., and Li, J. 2017. Roles of genotype-determined mycotoxins in Fusarium graminearum causing maize seedling blight. Plant Dis. 101:1103-1112.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Munkvold, G.P., Weieneth, L., Proctor, R., Busman, M., Blandino, M., Susca, A., Logrieco, A., and Moretti, A. 2017. Pathogenicity of fumonisin-producing and nonproducing strains of Aspergillus species in section Nigri to maize ears and seedlings. Plant Dis. https://doi.org/10.1094/PDIS-01-17-0103-RE
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Kobayashi-Leonel, R. 2017. Studies on cover crops and sudden death syndrome of soybean. Iowa State University. Masters Thesis
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Sjarpe, D.A. 2017. Effect of seed treatments and soybean cultivars on root rot caused by Fusarium virguliforme. Iowa State University. Masters Thesis.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Wattenburger CJ. 2017. The root-associated microbiome and agricultural nitrogen use efficiency. Iowa State University. Masters Thesis
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Progress 08/05/16 to 09/30/16
Outputs
Target Audience:Plant pathologists; soil and water conservationists; agricultural advisors Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?ISU Extension and Outreach events (e.g. Ag Chem dealer Update meetings, Integrated Crop Management Conference, Crop Advantage Series), Commodity events (e.g. Iowa Soybean Association Research Conference), various industry events. What do you plan to do during the next reporting period to accomplish the goals?Secure land and plan field trials for 2017 growing season. Draft manuscripts for peer-reviewed journals.
Impacts
What was accomplished under these goals?
Overall impact statement: This is only a two-month period that falls immediately after the growing season. At this time we are processing data from the previous season, setting up greenhouse studies and planning for the next growing season. A few students did finish up their projects and publications are in review. Objective 1... Evaluate the impact of cover crops and crop rotation on the soil and root microbiome and plant. We are evaluating the impact of cover crops on multiple soybean pathogens, including Fusarium and Pythium spp. The project involving sudden death syndrome was complete and the paper was submitted to the Journal of Soil and Water Conservation. Stand counts for cover crops that were seeded in the Fall were evaluated. Molecular methods to detect microbes associated with cover crops and cash crops were developed. Objective 2... Examine the impacts of seed treatments on seedborne and soilborne pathogen communities and their interactions with crop plants. Field experiments are under way to evaluate effects of experimental seed treatment on yield of corn and soybeans. We continue to process DNA from roots sampled in 2016 to evaluate if seed treatments have an effect on the amount of the pathogen in soybean roots. Growth chamber studies demonstrated that a period of cold stress 1 to 4 days after planting reduced soybean emergence due to Pythium infection. Treating the seed with a seed treatment negated the effect of cold stress soon after planting on the increased susceptibility of soybean to Pythium. Objective 3... Assess the effects of insect management practices on infection of corn plants by mycotoxigenic fungi. Field experiments are under way to evaluate effects of European corn borer and corn earworm infestations on severity of ear rot caused by Fusarium subglutinans and Fusarium temperatum, as well as contamination of grain by multiple Fusarium mycotoxins. Objective 4... Investigate the infection process, yield loss, and management of sudden death syndrome and stem canker. We continue to evaluate how soybean stem diseases such as SDS and stem canker affect soybean yield. We are processing data on distinguishing between root rot and foliar symptoms of SDS. Objective 5... Examine the interactions of crop with oomycetes and fungi, and the effect of the environment. Growth chamber studies are in progress to examine the interaction of Pythium species with Fusarium species in the soybean seedling blight pathosystem. Objective 6... Characterize the role of the root microbiome in enhancing plant resource use efficiency. Nothing to report. Objective 7... Investigate the efficacy of certain soil microbes for biological seed treatments. Data from soybean-Pythium field trials done in 2016 were summarized in preparation for field trial evaluations in 2017. Objective 8... Develop new methods for detection of pathogens of phytosanitary concern, focusing on the use of PCR or loop- mediated isothermal amplification (LAMP) technologies. LAMP methods are under development for Harpophora maydis in corn seed and Tomato apical stunt viroid in tomato seed.
Publications
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