Progress 07/01/01 to 06/30/06
Outputs
The third year of blightcast was completed including a survey of fungicide use patterns in potaoes. In 2002 costs were reduced by and average of $85/acre compared to 2001 primarily as a result of 2.0 fewer sprays and a shift to less expensive (mancozeb-based)fungicides. Blightcast was continued for the 2003 season. Studies were conducted on the long term survivability of cryogenically stored (- 80C) isolates of Rhizoctonia solani from anastomosis groups 1 through 4. Most groups survived 10 years of storage in these conditions with some exceptions in AG-2 type 2. The spatial distribution of Fuarium head blight in wheat was studied in commercial setting involving 18 fields in Northwest Minnesota. The distribution of the disease was random and field to field variation in disease incidence was determined to be associated with in-field residue and not long distance nor meso-scale movement of primary inoculum. An evaluation of semi-quantitative PCR to determine inoculum
potential on wheat heads at the Feekes 10.5 (anthesis) growth stage involving 200 field samples over 2 years revealed that PCR was unable to predict disease levels that developed in 1 hectare regions from which samples were initially collected.
Impacts
The impact of the Blightcast system was to reduce fungicide costs by an average of $85 per acre in 2002. The random distribution of FHB and the association of disease with individual fields instead of regionalized (county or township) epidemics should allow growers to focus more on residue management as an important component of their FHB control strategies. Long term storage of R. solani should allow laboratoies and scientists a means of maintaining isolate collections without the need for labor involved in continually transfering isolates. Prior to this, most labs have had to transfer isolates of this fungus at 6 month intervals to maintain viable isolate collections.
Publications
- Jenkins, J. C., and Jones, R. K. 2003. Classifying the relative host reaction in potato cultivars and breeding lines to the US-8 strain of Phytophthora infestans in Minnesota. Plant Disease 87:983-990.
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Progress 01/01/02 to 12/31/02
Outputs
Progress was made on the evaluation of a PCR diagnostic test for Fusarium head blight of wheat. Four years of testing concluded that the present methodology is not effective in using PCR as a predictive tool in decision-making for fungicide sprays in spring wheat. A two year study of the distribution of FHB in spring wheat fields in Minnesota and North Dakota found the disease to be randomly distributed and disease incidence was associated with previous crop residue. Progress was made on the evaluation of breeding lines for resistance to late blight and the efficacy of streptomycin (Agrimycin-17) for the supression of aerial stem rot of potato.
Impacts
The anticipated impact of a decision-tool for fungicide sprays in wheat was high. The negative outcome was dissappointing. The random distribution of FHB in wheat fields suggests that disease surveys can be accurately accomplished with minimal effort (1 to 7 samples/field)
Publications
- Jones, R., Wenkel, R., Jenkins, J. and Anderson, N. 2002. University of Minnesota Potato Disease Resistance Report for 2001. Pages 81-104 in: Minnesota Area II Potato Research and Promotion Council 2002. Research Reports.
- Jones, R. K., and Falk, K. 2002. Forecasting potato late blight in Minnesota. Pages 157-161 in: Minnesota Area II Potato Research and Promotion Council 2002 Research Reports.
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Progress 01/01/01 to 12/31/01
Outputs
Evaluations continued on potato breeding lines for relative resistance to Phytophthora infestans. 680 breeding lines and selections were evaluated in inoculated - misted nurseries for their reaction to US-8. 30 lines were identified with high levels of partial resistance. 124 commercial fields of spring wheat were surveyed at the soft dough stage for Fusarium head blight. The incidence of FHB was 19.4% and the severity was 2.1% in 2001. Chemical control trials continued in 2001. Metconazole was less effective than the experimental AMS-21619. Applications of AMS at high rates were more effective than lower rates and application at Feekes 10.5.4 were more effective than applications at 10.5.1
Impacts
The search continues for fungicides with improved efficacy against Fusarium head blight. AMS-21619 appears much more effective than tebuconazole in reducing FHB and reducing the mycotoxin deoxynivalenol in spring wheat and barley. The registration of AMS-21619 would greatly benefit wheat and barley producers.
Publications
- Stevens-Johnk, J., and Jones, R. K. 2001. Differentiation of three homogeneous groups of Rhizoctonia solani anastomosis group 4 by analysis of fatty acids. Phytopathology 91:821-830.
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Progress 01/01/00 to 12/31/00
Outputs
OBJECTIVES: To monitor and evaluate losses caused by significant diseases affecting small grains (wheat, barley, oats, and rye), sugar beets, and potatoes in Minnesota. To initiate cooperative research, as appropriate, into the etiology, epidemiology and control of diseases affecting these crops. APPROACH: Disease loss can be assessed by comparisons involving fungicide treated vs. nontreated crops. Information on loss can be extrapolated from this kind of information if supplemented with well conducted survey data. Such trials are typically applied in nature, conducted as replicated small plot tests either on- farm or at branch stations and with established procedures can also be combined with loss data generated from fungicide trials to create yield/quality loss information at either state or regional levels. ID problems involving diseases of unknown etiology will be pursued with available resources of the U of M and its allied agencies. PROGRESS: 2000/01 TO 2000/12;
Evaluations continued on potato varieties and breeding lines for relative resistance to Phytophthora infestans. 500 breeding linesand over 2,000 seedling populations were evaluated in 2000. Experiments identified 18 breeding lines and 6 segregating families with high levels of partial resistance to Late blight. Chemical control of Fusarium head blight on wheat and barley were each evaluated at one location in 2000. The fungicide metconazole was found to reduce FHB incidence, severity, % scabby kernels and deoxynivalenol concentration compared to no spray and was found to be more effective than tebuconazole (the currently registered alternative). A second year of PCR detection of primary inoculum of Gibberella zeae was conducted in commercial wheat fields. The fungus was found on only 3 of 138 fields sampled at anthesis. Subsequent FHB levels were found to be low (< 1% severity) in the region.
Impacts
It is estimated that the availability and use of tebuconazole (Folicur 3.6 EC) resulted in a net return to Minnesota wheat producers of $11.50/acre (above chemical and application costs). The effectiveness of this fungicide in supressing FHB and controlling Septoria leaf and glume blotch was demonstrated through activities associated with this project.
Publications
- Dill-Macky, R., and Jones, R.K. 2000. The effect of previous crop residues and tillage on Fusarium head blight of wheat. Plant Disease 84:71-76.
- Jones, R.K. 2000. Assessments of Fusarium head blight in wheat and barley in response to fungicide treatment. Plant Disease 84:1021-1030.
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Progress 01/01/99 to 12/31/99
Outputs
OBJECTIVES: To monitor and evaluate losses caused by significant diseases affecting small grains (wheat, barley, oats, and rye), sugarbeets, and potatoes in Minnesota. To initiate cooperative research, as appropriate, into the etiology, epidemiology and control of diseases affecting these crops. APPROACH: Disease loss can be assessed by comparisons involving fungicide treated vs. nontreated crops. Information on loss can be extrapolated from this kind of information if supplemented with well conducted survey data. Such trials are typically applied in nature. conducted as replicated small plot tests either on farm or at branch stages and with established procedures can also be combined with loss data generated from fungicide trials to creat yield/quality loss information at either the state or regional level. ID problems involving diseases of unknown etiology will be pursued with available resources of the U of M and its allied agencies. These include use of the
Microbial Identification System as a campus wide resource for the ID of plant pathogens of bacterial etiology. Epidemiological investigations are designed to produce information about disease development in production systems. PROGRESS: 1999/01 TO 1999/12 Evaluations continued on potato varieties and breeding lines for relative resistance to Phytophthora infestans. 490 breeding lines, and over 1,500 seedling populations and a more limited number of commercial entries were evaluated in 1999. Six breeding lines were identified with partial resistance. Chemical control of Fusarium graminearum on wheat was evaluated at one location and barley was evaluated at one location. The fungicide tebuconazole was found to reduce FHB incidence, severity, % scabby kernels and deoxynivalenol concentration in sprayed versus unsprayed. FHB levels were low in both tests. A project was initiated on the semi-quantitation of primary inoculum from wheat heads collected directly from the field. 77% of the
heads collected from commercial fields were found to be negative. FHB levels were founfd to be low in the region.
Impacts
Registration of Emient fungicide (tetraconazole) in sugarbeets reduced Cercospora leaf spot from growers perception if it representing their #1 problem in 88% of cases to in 1998 to less that 4% in 1999. The material was most effective in Southern Minnesota where growers have been affected the most buy this disease.
Publications
- Jenkins, J. C., Jones, R. K., and Anderson, N. A. 1999. Evaluation of AUDPC for late blight of potato to define reaction classes for screening nurseries. Phytopathology 89:S36.
- Jones, R. K. 1999. Seedling blight development and control in spring wheat damaged by Fusarium graminearum Group 2. Plant Disease 83:1013-1018.
- Jones, R. K., and Carling, D. E. 1999. Identification of Rhizoctonia solani AG-UNK from rice and rice soils in Texas as AG-11. Plant Disease 84:880. (Disease Note)
- Jones, R. K., and Mirocha, C. J. 1999. Quality parameters in small grains from Minnesota affected by Fusarium head blight. Plant Disease 83:506-511.
- Dill-Macky, R, and Jones, R. K. 1999. Effects of previous crop and tillage on Fusarium head blight of wheat. Phytopathology 89:S21.
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Progress 01/01/98 to 12/31/98
Outputs
Evaluations continued on potato varieties and breeding lines for relative resistnce to Phytophthora infestans. 465 breeding lines, 1,500 seedling populations and 20 commercial entries were evaluated in 1998. Six breeding lines were identified with partial resistance. Chemical control of Fusarium graminearum on wheat was evaluated at one location. The fungicide tebuconazole was found to reduce FHB incidance, severity, % scabby kernels and deoxynivalenol concentration in sprayed versus unsprayed wheat.
Impacts
(N/A)
Publications
- Ballen, K.G., Grahm,P.H., Jones, R.K., and Bowers, J.H. 1998. Acidity and calcium interaction affecting cell envelope stability in Rhizobium. Can. J. Microbiol. 44:582-587.
- Ruan, R., Ning, S., Song, A., Ning, A., Jones, R., and Chen, P.L. 1998. Estimation of Fusarium scab in wheat using machine vision and a neural network. Cereal Chem. 75:445-459.
- Dill-Macky, R. and Jones, R. K. 1998. The effect of previous crops and tillage on FHB of wheat. Pages 108-109. Pro.WIRF. San Diego, CA.
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Progress 01/01/97 to 12/31/97
Outputs
Evaluations continued on the efficacy of tebuconazole applications to reduce yield and quality parameters associated with Fusarium head blight (scab) of wheat and barley. Tebuconazole reduced deoxynivalenol and the percentage of Fusarium damaged kernels in 3 trials involving spring wheat. In two trials involving barley, DON levels were not significantly reduced. Evaluations of the susceptibility of commercial potato cultivars to the Late blight fungus (A2 mating type, US-8 genotype) continued for a second year. Results indicate inadequate resistance among commercial cultivars to consider modifications in intensive spray programs currently being used by producers. The efficacy of tetraconazole against Cercospora beticola (the causal agent of Cercospora leaf spot in sugarbeets) was evaluated in field trials. Sufficient activity was demonstrated to support a request for Emergency Expemption from tolerance from the Environmental Protection Agency. Tetraconazole will be
used in cunjunction with triphenyl tin hydroxide (TPTH) in an attempt to manage recent problems that have developed involving the appearance of "tin tolerant" strains of C. beticola.
Impacts
(N/A)
Publications
- McMullen, M., Jones, R.K., and Gallenberg, D. 1997. Scab of wheat and barley: A re-emerging disease of devastating impact. Plant Dis. 81:1340-1348.
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Progress 01/01/96 to 12/30/96
Outputs
Fusarium head blight or scab was epidemic in Minnesota in 1993 and 1994. Estimates yield losses of 33% and 18% were attributed to this disease in these years. In 1996, due to the deployment of moderately resistant varieties, and less favorable weather, yield losses were reduced to 5%. Chemical control screening was initiated in 1994. Benomyl and tebuconazole were identified as compounds that would reduce the incidence and severity of Fusarium head blight (FHB). In 1996, new compounds were added to screening trials including Quadris (azoxystrobin), Acti-Guard (CGA 254704) and RH-141647. These materials provided some reduction in FHB but were less effective than benomyl or tebuconazole. Biological control was also investigated. Strains of the Erwinia herbicola group as well as certain isolates of BAcillus spp. reduced FHB in field trials on wheat and barley but were significantly less effective than fungicide standards included in the trials. 32 commercial potato
varieties were inoculated and screened for their reaction to Phytophthora infestans (US-8 strain, A2 mating type) in field trials. All varieties were scored as susceptible except the white tablestock cultivar "Elba" was scored as moderately resistant (MR). The cultivars "Sebago" and "Kennebec" were identified as moderately susceptible (MS). Sebago had the lowest incidence of tuber rot at harvest (1.8%). Certain breeding lines were tested & found to be highly resistant but not commercially acceptable.
Impacts
(N/A)
Publications
- Bowers, J.H., Kinkel, L.L., and Jones, R.K. 1996. Influence of disease-suppressive strains of Streptomyces on the native Streptomyces communityin soil as determined by the analysis of cellular fatty acids. Can. J. Microbiol. 42:27-37.
- Ndowora, T.C.R., Kinkel, L.L., Jones, R.K., and Anderson, N.A. 1996. Fatty acid analysis of pathogenic and suppressive strains of Streptomyces species isolated in Minnesota. Phytopathology 86:138-143.
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Progress 01/01/95 to 12/30/95
Outputs
Fusarium head blight on scab was epidemic in Minnesota in 1993 and 1994. Estimated yield losses of 33% and 18% were attributed to this disease in these years. In 1995, due to the deployment of moderately resistant varieties, yield losses were reduced to 8%. Chemical control screening was initiated in 1994. Benomyl and tebuconazole were identified as compounds that would reduce the incidence and severity of Fusarium head blight (FHB). Emergency registration of propiconazole was requested in 1995 to supplement Section 2ee registrations of benomyl. This request was denied by EPA citing reside concerns (Delaney Amendment). Multi-state trials were initiated in 1995 to evaluate the efficacy of difenoconazole, fenbuconazole, fludioxonil and other compounds relative to benomyl, tebuconazole and propiconazole. Fludioxonil was found to reduce FHB, increase yields and reduce contamination with deoxynivalenol (DON). Biological control was also investigated. Strains of the Erwinia
herbicola group as well as certain isolates of Bacillus spp. reduced the growth of Fusarium graminearum in vitro. Further analysis of these strains is planned. Fatty acid analysis successfully differentiated populations of pathogenic Streptomyces scabies from diverse locations around the world from strains that suppress the development of potato scab. Pathogenic isolates could be accurately characterized and grouped.
Impacts
(N/A)
Publications
- BOWERS, J. H., KINKEL, L.L. AND JONES, R.K. 1995. Classification of pathogenic strains of Streptomyces spp. using fatty acid analysis. Phytopathology 85:1188.
- MILUS, E.A., ROTHROCK, C.S., LORINCE, T. AND JONES, R.K. 1995. Ecology of seedborne Pantoea agglomerans & Enterobacter agglomerans on wheat. p. 88. Proceed. 6th Inter. Symp. on Microbiology of Aerial Plant Surfaces. Bandol France.
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Progress 01/01/94 to 12/30/94
Outputs
Fusarium head blight or scab was epidemic in Minnesota in 1993 & 1994. A survey of deoxynivalenol (DON) contamination in samples from commercial wheat, barley & oat fields was conducted in 1993 (303 samples) & 1994 (251 samples). The mean concentration of DON in 1993 as determined by HPLC was 8.4, 7.1, and 1.3 ug/kg for the three crops respectively. In 1994, GC-MS was used to determine the DON concentrations which averaged 6.8, 11.7, and 1.8 ug/kg. Dollar loss figures resulting from the FHB epidemics were calculated for wheat and exceeded $347 million in 1993 & $268 million in 1994. Chemical control of Fusarium head blight and seedling blight caused by Fusarium graminearum was evaluated on Hard Red Spring Wheat at multiple locations in 1994. Registered rates of maneb, thiabendazole, & difenconazole seed treatments were effective in controlling seedling blight. Head blight & deoxynivalenol contamination were significantly reduced with 2x to 3x rates of mancozeb,
benomyl, or tebuconazole applied to heads of the FHB susceptible variety Norm. Yield and test weight were significantly increased with these treatments. Iprodione significantly increased head blight ratings and DON at harvest while reducing yields and test weight compared to the unsprayed check. Fatty acid analysis successfully differentiated populations of pathogenic Streptomyces scabies from strains that suppress the development of potato scab.
Impacts
(N/A)
Publications
- BOWERS, J. H., KINKEL, L.L., AND JONES, R.K. 1994. Evaluation of clustering approaches in the classification of Streptomyces spp. using fatty acid analysis. Phytopathology 84:1130.
- JOHNK, J.S., AND JONES, R.K. 1994. Comparison of whole-cell fatty acid compositions in intraspecific groups of Rhizoctonia solani AG-1. Phytopathology 84:271-275.
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Progress 01/01/93 to 12/30/93
Outputs
An evaluation of a newly developed decision-aid to assist producers with predicting a profitable outcome from foliar fungicide applications to Hard Red Spring Wheat was conducted in 9 locations in the Red River Valley. This decision-aid was the product of 20 field trials conducted as part of this project from 1989-1992. Sites were selected in which the decision-aid outcome was to "spray" (4 sites) or "do not spray" (5 sites). All "spray" sites were destroyed by an epidemic of Fusarium head blight (not controlled by the treatments) and 5 of the 9 sites were not harvested. Four "do not spray" sites showed no significant difference in yield that could be associated with treatment. Fatty acid analysis successfully differentiated genetically related groups of Rhizoctonia solani that cause major diseases of sugarbeets, soybean, peanut and cucumber. All these populations were previously found to belong to anastomosis group 4 (AG-4) and could be differentiated into 3 DNA
homology groups (HG-1, HG-2, and HG-3). Fatty acid analysis identified 18 of 20 isolates from sugarbeet and 19 of 20 isolates from soybean as having profiles that match HG-2. Isolates from peanut (20 of 20) had profiles consistent with HG-1. Isolates causing belly rot of cucumber were distributed amongst all three homology groups: HG-1 (5), HG-2 (5), and HG-3 (5). Two isolates from sugarbeet and one isolate from soybean were characterized as HG-3. This is the first report of HG-3 isolates from Minnesota.
Impacts
(N/A)
Publications
- BOWERS, J. H., KINKEL, L. L., JONES, R. K., and ANDERSON, N. A. 1993. Development of Fatty acid libraries to track Streptomyces spp. in soil. Phytopathology 83:(in press). (abst.).
- JOHNK, J. S., and JONES, R. K. 1993. Differentiation of populations of AG-2-2 of Rhizoctonia solani by analysis of cellular fatty acids. Phytopathology 83:278-283.
- JOHNK, J. S., JONES, R. K., SHEW, H. D., and CARLING, D. E. 1993. Characterization of populations of Rhizoctonia solani from potato and tobacco. Phytopathology 83:854-859.
- JOHNK, J. S., and JONES, R. K. 1993. Comparison of whole-cell fatty acid compositions in intraspecific groups of Rhizoctonia solani AG-1 Phytopathology 83:(accepted for publication 10/28/93).
- NDOWORA, T. C. R., KINKEL, L. L., JONES, R. K., and ANDERSON, N. A. 1993. Differentiation of Streptomyces strains by analysis of cellular fatty acids. Phytopathology 83:(in press). (abst.).
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Progress 01/01/92 to 12/30/92
Outputs
An economic assessment of foliar fungicide applications on Hard Red Spring Wheatat 5 locations in the Red River Valley of Minnesota showed fungicide treatment statistically increased yield and provided an economic return in 4 of 5 tests. An economic return of $9.00 per hectare (above the cost of the fungicide program) was observed in one trial as a result of treatment with mancozeb or propiconazole. Significant differences in protein content and test weight were not observed. Leaf rust, caused by Puccinia recondita, and Glume blotch, caused by Septoria nodorum, were the predominant diseases controlled. Fatty acid analysis successfully differentiated genetically related groups of Rhizoctonia solani causing major diseases of sugarbeets, corn, and turfgrass. Vitamin requirements, fusion of vegetative parts of the fungal tissues, and characteristics of the fungal growth on culture medium were not capable of differentiating these subgroupings. Fatty acid anaylsis also
successfully differentiated important subgroupings of strains causing significant diseases of potato from those causing target spot disease of tobacco. This is the first report of the relationship between the potato and the tobacco strains of R. solani.
Impacts
(N/A)
Publications
- JOHNK, J.S. and JONES, R.K. 1992. Differentiation of populations of AG-2-2 of Rhizoctonia solani by analysis of cellular fatty acids. Phytopathology 82: (accepted for publication 10/30/92).
- JOHNK, J.S. and JONES, R.K. 1992. Isolates of Rhizoctonia solani causing leaf spot of tobacco are characterized as AG-3. Phytopathology 82:1139. (abst.).
- JOHNK, J.S. and JONES, R.K. 1992. Relationships between populations of Rhizoctonia solani AG-2-2 from mat rush, sugarbeet, corn and St. Augustine grass. Phytopathology 82:1974 (abst.).
- JOHNK, J.S. and JONES, R.K. 1992. EBDC's and alternative fungicides for control of early blight in potatoes. Phytopathology 82:992-993 (abst.).
- JONES, R.K. and WINDELS, C.E. 1991. A Management Model for Cercospora Leaf Spot of Sugarbeets. AG-FO-5643-E. Minnesota Extension Service, St. Paul. 8 pp.
- MUNAR, M., SEBREE, B., SCHWARZ, P., STEFFENSON, B., JONES, R. and LUKECH, J. 1992. Efficacy of fungicides for the control of stem rust and residues in barley and malt. J. Am. Soc. of Brewing Chemists 56: (in-press).
- OELKE, E.A., DURGAN, B.R., CAVANAUGH, K.J., JONES, R.K., NOETZEL, D.M., REHM, G.W., TRUE, J.W. and WILCKE, W.F. 1992. Hard Red Spring Wheat & Spring Barley Production Guide. AG-MI-5868-D. Minnesota Extension Service, St. Paul. 77 pp.
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Progress 01/01/91 to 12/30/91
Outputs
An economic assessment of foliar fungicide applications on Hard Red Spring Wheatat 5 locations in the Red River Valley of Minnesota showed fungicide treatments not profitable in 4 of 5 tests. An economic return was observed in one trial where propiconazole and mancozeb treatments were significantly higher in yield and test weight compared to unsprayed. Tan spot, caused by Pyrenophora tritici-repentis was the prodominant disease controlled. Chemical alternatives to ethylene bis dithiocarbamate (EBDC) fungicides that are presently under special review by the Environmental Protection Agency were evaluated on potatoes for control of Early blight (caused by Alternaria solani). Chlorothalonil and tri-phenly tin hydroxide are federally registered fungicides that provide acceptable alternatives to the EBDC's. Copper hydroxide was ineffective in controlling this disease.
Impacts
(N/A)
Publications
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Progress 01/01/90 to 12/30/90
Outputs
Work continued on developing a decision-aid for profitable use of foliar fungicides in spring wheat. Two years of four year study now complete. Mancozeb and propiconazole applications to Hard Red Spring Wheat variety Marshall (resistant to leaf rust and stem rust) appear unprofitable for control of tan spot and Septoria spp. in the Red River Valley of Minnesota. Powdery mildew control with propiconazole appears profitable at labeled rates and timings. Early blight (Alternaria solani) could be profitably controlled with registered alternatives to the EBDC fungicides (currently under E.P.A. reregistration and proposed for cancellation). Chlorothalonil and tri-phenyl tin hydroxide were as cost effective as mancozeb. Iprodione was also effective but cost-prohibitive. Fixed coppers were ineffective in controlling early blight on the moderately resistant variety Russet Burbank grown under irrigation.
Impacts
(N/A)
Publications
- JOHNK, J.S. and JONES, R.K. 1990. Characterization of Rhizoctonia solani by gas-liquid chromatography of cellular fatty acids. Phytopathology 80: (In press).
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