Managing crop losses from foliar diseases with fungicides, rotation, and tillage in the Saskatchewan Parkland

2000 ◽  
Vol 80 (1) ◽  
pp. 169-175 ◽  
Author(s):  
K. L. Bailey ◽  
A. M. Johnston ◽  
H. R. Kutcher ◽  
B. D. Gossen ◽  
R. A. A. Morrall
Keyword(s):  
Disease Severity ◽  
Seed Weight ◽  
Crop Diversity ◽  
Stem Rot ◽  
Yield Response ◽  
Reduced Tillage ◽  
Leaf Spot Disease ◽  
Sclerotinia Stem Rot ◽  
Crop Losses ◽  
Foliar Disease

The effects of three tillage systems, three crop rotations, and fungicide applications were evaluated on diseases of barley, wheat, canola and pea at Melfort, SK, from 1994 to 1998. During these years, reduced tillage did not increase crop losses due to diseases. Four-year rotations with higher proportions of broad-leaved crops and more crop diversity (i.e., canola, pea, flax, and barley) had higher yields than rotations with fewer broad-leaved crops and less crop diversity (i.e., canola, wheat, barley, and barley). However, these rotations did not influence the severity of septoria leaf blotch of wheat, net blotch of barley, the incidence of sclerotinia stem rot and blackleg of canola, or the severity of mycosphaerella blight of pea. Interplot interference may have been a factor influencing some diseases in plots, as the size was only 270 m2. Fungicide application of propiconazole on Harrington barley decreased foliar disease severity and increased yield by 23%, seed weight by 13%, and kernel plumpness by 25%. Application of azoxystrobin decreased foliar disease and increased pea yield 29% and seed weight by 7% for the pea cultivars Express and Highlight. Foliar disease severity on AC Taber wheat was reduced by application of propiconazole in 2 of 4 yr, but the yield response was very inconsistent. Similarly, AC Excel canola had inconsistent disease and yield response to applications of propiconazole and benomyl, but levels of sclerotinia stem rot and blackleg were very low in all years. These results indicate that reduced tillage will not result in significantly higher levels of disease that require fungicide inputs to maintain yield. Moving from cereal-based rotations to more diverse, broad-leaved based rotations improves the yield of cereals. However, regardless of tillage or rotation, higher yields may be obtained in barley and pea with fungicides for control of leaf spot disease in susceptible cultivars. Key words: Plant disease, rotation, tillage, fungicides, yield loss

scholarly journals Meta-Analysis of Yield Response of Hybrid Field Corn to Foliar Fungicides in the U.S. Corn Belt

2011 ◽  
Vol 101 (9) ◽  
pp. 1122-1132 ◽  
Author(s):  
P. A. Paul ◽  
L. V. Madden ◽  
C. A. Bradley ◽  
A. E. Robertson ◽  
G. P. Munkvold ◽  
...  
Keyword(s):  
United States ◽  
Disease Severity ◽  
Meta Analysis ◽  
The United States ◽  
Yield Response ◽  
Foliar Disease ◽  
Yield Increase ◽  
Field Corn ◽  
Yield Difference ◽  
Meta Analyses

The use of foliar fungicides on field corn has increased greatly over the past 5 years in the United States in an attempt to increase yields, despite limited evidence that use of the fungicides is consistently profitable. To assess the value of using fungicides in grain corn production, random-effects meta-analyses were performed on results from foliar fungicide experiments conducted during 2002 to 2009 in 14 states across the United States to determine the mean yield response to the fungicides azoxystrobin, pyraclostrobin, propiconazole + trifloxystrobin, and propiconazole + azoxystrobin. For all fungicides, the yield difference between treated and nontreated plots was highly variable among studies. All four fungicides resulted in a significant mean yield increase relative to the nontreated plots (P < 0.05). Mean yield difference was highest for propiconazole + trifloxystrobin (390 kg/ha), followed by propiconazole + azoxystrobin (331 kg/ha) and pyraclostrobin (256 kg/ha), and lowest for azoxystrobin (230 kg/ha). Baseline yield (mean yield in the nontreated plots) had a significant effect on yield for propiconazole + azoxystrobin (P < 0.05), whereas baseline foliar disease severity (mean severity in the nontreated plots) significantly affected the yield response to pyraclostrobin, propiconazole + trifloxystrobin, and propiconazole + azoxystrobin but not to azoxystrobin. Mean yield difference was generally higher in the lowest yield and higher disease severity categories than in the highest yield and lower disease categories. The probability of failing to recover the fungicide application cost (ploss) also was estimated for a range of grain corn prices and application costs. At the 10-year average corn grain price of $0.12/kg ($2.97/bushel) and application costs of $40 to 95/ha, ploss for disease severity <5% was 0.55 to 0.98 for pyraclostrobin, 0.62 to 0.93 for propiconazole + trifloxystrobin, 0.58 to 0.89 for propiconazole + azoxystrobin, and 0.91 to 0.99 for azoxystrobin. When disease severity was >5%, the corresponding probabilities were 0.36 to 95, 0.25 to 0.69, 0.25 to 0.64, and 0.37 to 0.98 for the four fungicides. In conclusion, the high ploss values found in most scenarios suggest that the use of these foliar fungicides is unlikely to be profitable when foliar disease severity is low and yield expectation is high.

scholarly journals Case Study of an Epidemiological Approach Dissecting Historical Soybean Sclerotinia Stem Rot Observations and Identifying Environmental Predictors of Epidemics and Yield Loss

2018 ◽  
Vol 108 (4) ◽  
pp. 469-478 ◽  
Author(s):  
Mamadou L. Fall ◽  
John F. Boyse ◽  
Dechun Wang ◽  
Jaime F. Willbur ◽  
Damon L. Smith ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Historical Data ◽  
Severity Index ◽  
Stem Rot ◽  
Total Precipitation ◽  
Disease Severity Index ◽  
Sclerotinia Stem Rot ◽  
Environmental Predictors ◽  
Epidemiological Approach

Sclerotinia sclerotiorum is a significant threat to soybean production worldwide. In this study, an epidemiological approach was used to examine 11 years of historical data from a soybean management performance trial in order to advance our understanding of Sclerotinia stem rot (SSR) development and to identify environmental predictors of SSR epidemics and associated yield losses. Recursive partitioning analysis suggested that average air temperature and total precipitation in July were the most significant variables associated with disease severity. High levels of SSR disease severity index were observed when the average temperature in July was below 19.5°C and total precipitation in July was moderate, between 20 and 108.5 mm. A biphasic sigmoidal curve accurately described the relationship between SSR disease severity index (DSI) and yield, with a DSI threshold of 22, below which minimal yield loss was observed. A 10% increase in the DSI, from 22.0 to 24.2, led to an 11% decrease in yield, from 3,308.14 to 2,951.29 kg/ha. Also, a yield threshold (3,353 kg/ha) that was higher than the annual U.S. average soybean yield (3,039.7 kg/ha) was suggested as an expected yield under low or no SSR pressure in the U.S. Midwest. These thresholds can allow soybean stakeholders to assess the value of disease control and establish an SSR baseline for cost-effective management to protect yields. Because S. sclerotiorum has more than 400 plant host species, and because having quantitative information concerning crop losses is crucial for decision making, this study shows the usefulness of historical data on SSR and, hence, can serve as a model in other SSR pathosystems (canola, dry bean, potato, pea, and so on).

Evaluation of disease forecasting variables for sclerotinia stem rot (Sclerotinia sclerotiorum) of canola

2000 ◽  
Vol 80 (4) ◽  
pp. 889-898 ◽  
Author(s):  
M. Bom ◽  
G. J. Boland
Keyword(s):  
Soil Moisture ◽  
Disease Severity ◽  
Sclerotinia Sclerotiorum ◽  
Prediction Models ◽  
Disease Incidence ◽  
Stem Rot ◽  
Disease Prediction ◽  
Strong Correlations ◽  
Sclerotinia Stem Rot ◽  
Spring Canola

Selected environmental, crop and pathogen variables were sampled weekly from winter and spring canola crops before and during flowering and evaluated for the ability to predict sclerotinia stem rot, caused by Sclertinia sclerotirum. Linear and nonlinear relationships were examined among variables but, because no strong correlations were observed between final disease incidence and any of the variables tested, a categorical approach (e.g., disease severity) was used instead. Disease severity in individual crops was categorized as low (< 20% diseased plants) or high (> 20% disease), and differences in weekly rainfall, soil moisture, crop height, percentage of petal infestation, and number of apothecia m−2 and clumps of apothecia m−2 were significantly associated with differences in disease severity within or between years. Two disease prediction models were compared for the ability to predict low or high disease severities using petal infestation alone, or petal infestation in combination with soil moisture. The model that included petal infestation and soil moisture predicted more fields correctly than the model using petal infestation alone, but the accuracy of both was affected by the timing of soil moisture measurements in relation to petal infestation, and threshold values used in discriminating categories of soil moisture and petal infestation. Key words: Brassica rapa, Brassica napus, Sclerotinia sclerotiorum, disease prediction

scholarly journals Suppression of Sclerotinia Stem Rot of Soybean by Lactofen Herbicide Treatment

1999 ◽  
Vol 89 (7) ◽  
pp. 598-602 ◽  
Author(s):  
E. K. Dann ◽  
B. W. Diers ◽  
R. Hammerschmidt
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Lesion Size ◽  
Stem Rot ◽  
Growth Stages ◽  
Sclerotinia Stem Rot ◽  
High Disease Severity ◽  
Disease Pressure ◽  
Seed Yields ◽  
Field Plots

Severity of Sclerotinia stem rot of soybean after treatment with lactofen (Cobra) and other herbicides was assessed in field experiments conducted in Michigan from 1995 to 1997. At sites where disease pressure was high, disease severity was reduced 40 to 60% compared with controls when lactofen was applied at the V3 (1995 and 1996) or R1 (1997) growth stages. Corresponding seed yields were unchanged or up to 20% greater when lactofen was applied at the R1 stage in 1997. Disease severity was not reduced by lactofen treatments in years and at sites where disease pressure was low to medium, and corresponding yields often were reduced by ≈10%. High levels of glyceollin accumulated in lactofen-injured leaves collected from field plots in 1996 and 1997. High glyceollin content in lactofen-treated leaves was associated with significant reductions in lesion size when leaves were challenge-inoculated with Sclerotinia sclerotiorum.

Meta-Analytic and Economic Approaches for Evaluation of Pesticide Impact on Sclerotinia Stem Rot Control and Soybean Yield in the North Central United States

2019 ◽  
Vol 109 (7) ◽  
pp. 1157-1170 ◽  
Author(s):  
Jaime F. Willbur ◽  
Paul D. Mitchell ◽  
Mamadou L. Fall ◽  
Adam M. Byrne ◽  
Scott A. Chapman ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Severity Index ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Soybean Yield ◽  
The North ◽  
Central United States ◽  
Meta Analyses ◽  
The Impact

As complete host resistance in soybean has not been achieved, Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum continues to be of major economic concern for farmers. Thus, chemical control remains a prevalent disease management strategy. Pesticide evaluations were conducted in Illinois, Iowa, Michigan, Minnesota, New Jersey, and Wisconsin from 2009 to 2016, for a total of 25 site-years (n = 2,057 plot-level data points). These studies were used in network meta-analyses to evaluate the impact of 10 popular pesticide active ingredients, and seven common application timings on SSR control and yield benefit, compared with not treating with a pesticide. Boscalid and picoxystrobin frequently offered the best reductions in disease severity and best yield benefit (P < 0.0001). Pesticide applications (one- or two-spray programs) made during the bloom period provided significant reductions in disease severity index (DIX) (P < 0.0001) and led to significant yield benefits (P = 0.0009). Data from these studies were also used in nonlinear regression analyses to determine the effect of DIX on soybean yield. A three-parameter logistic model was found to best describe soybean yield loss (pseudo-R2 = 0.309). In modern soybean cultivars, yield loss due to SSR does not occur until 20 to 25% DIX, and considerable yield loss (−697 kg ha−1 or −10 bu acre−1) is observed at 68% DIX. Further analyses identified several pesticides and programs that resulted in greater than 60% probability for return on investment under high disease levels.

Glyphosate-Resistant Soybean Management System Effect on Sclerotinia Stem Rot

2005 ◽  
Vol 19 (3) ◽  
pp. 580-588 ◽  
Author(s):  
Chad D. Lee ◽  
Karen A. Renner ◽  
Donald Penner ◽  
Ray Hammerschmidt ◽  
James D. Kelly
Keyword(s):  
Disease Severity ◽  
Management System ◽  
Target Population ◽  
Stem Rot ◽  
Row Spacing ◽  
Sclerotinia Stem Rot ◽  
System Effect ◽  
Entire Study ◽  
The Impact ◽  
Severity Indexes

The impact of the management variables soybean cultivar, row spacing, population density, and shading was evaluated on the incidence of Sclerotinia stem rot (SSR) on glyphosate-resistant soybeans in an irrigated glyphosate-resistant soybean management system. Soybean canopy development, flower number, soil moisture, disease severity, and soybean yield were evaluated on three glyphosate-resistant cultivars, Pioneer ‘92B71’ (upright), Asgrow ‘AG2701’ (bushy), and Asgrow ‘AG2702’ (bushy). Three different row spacing–target population combinations of 76 cm, 430,000 seeds/ha; 19 cm, 430,000 seeds/ha; and 19 cm, 560,000 seeds/ha were evaluated. Cultivars 92B71 and AG2701 had 42 and 15% lower disease severity indexes and 38 and 19% greater yields than AG2702, respectively. The actual average population of 92B71 was 9 and 20% lower than actual average populations of AG2701 and AG2702, respectively. Disease severity indexes were lower and yield was higher when population was reduced from 560,000 seeds/ha to 430,000 seeds/ha in 19-cm rows. When averaged over the entire study, population was positively correlated with disease severity index (r2= 0.33; P < 0.0001) and negatively correlated with yield (r2= −0.13; P = 0.0140). Reduction of soybean population was more important than increasing row spacing to manage SSR in an irrigated system. Average actual spacing between plants within a row was 18 and 4 cm for 19- and 76-cm rows, respectively, at a target population of 430,000 seeds/ha, which may have contributed to greater plant-to-plant transfer of theSclerotinia sclerotiorumpathogen in the 76-cm rows.

scholarly journals Selected Soybean Plant Introductions with Partial Resistance to Sclerotinia sclerotiorum

Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 971-980 ◽  
Author(s):  
D. D. Hoffman ◽  
B. W. Diers ◽  
G. L. Hartman ◽  
C. D. Nickell ◽  
R. L. Nelson ◽  
...  
Keyword(s):  
United States ◽  
Disease Severity ◽  
Partial Resistance ◽  
Germ Plasm ◽  
Agronomic Traits ◽  
Field Tests ◽  
The United States ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Plant Introductions

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and Canada in replicated large plots from 1998 to 2000. The PIs in the MG I to III tests in Urbana, IL were evaluated for agronomic traits from 1998 to 2000. The selected PIs also were evaluated with an excised leaf inoculation and petiole inoculation technique. After the 1995 to 1997 evaluations, all but 68 PIs were eliminated because of their susceptibility to Sclerotinia stem rot. In field tests in Urbana, higher disease severity in selected MG I to III PIs was significantly (P< 0.05) associated with taller plant heights and greater canopy closure. All other agronomic traits evaluated were not associated or were inconsistently associated with disease severity. MG I to III PIs 153.282, 189.931, 196.157, 398.637, 417.201, 423.818, and 561.331 had high levels of resistance and had canopies similar to the resistant checks. The resistance ratings from the petiole inoculation technique had a high and significant (P< 0.01) correlation with disease severity in the MG I and II field tests. The partially resistant PIs identified in this study can be valuable in incorporating Sclerotinia stem rot resistance into elite germ plasm.

Effect of crop rotation and soil amendments on Sclerotinia stem rot on soybean in two soils

2007 ◽  
Vol 87 (3) ◽  
pp. 605-614 ◽  
Author(s):  
G. Rousseau ◽  
S. Rioux ◽  
D. Dostaler
Keyword(s):  
Disease Severity ◽  
Crop Rotation ◽  
Redundancy Analysis ◽  
Sandy Loam ◽  
Soil Amendments ◽  
Severity Index ◽  
Stem Rot ◽  
Disease Severity Index ◽  
Clay Loam ◽  
Sclerotinia Stem Rot

The effect of 4-yr soybean rotations with corn (CCCS vs. CCSS vs. SSSS) and soil amendments (urban compost vs. mineral fertilizer) on Sclerotinia stem rot of soybean (disease severity index, apothecia number, sclerotia survival), caused by Sclerotinia sclerotiorum, was studied on two soils (clay loam and sandy loam) at Saint-Hyacinthe, in southwestern Québec, from 1999 to 2002. In 2002, the 3-yr-corn rotation had a significant effect on the disease severity index (DSI) at the clay loam site; DSI was greatly reduced by rotation (5.2%) compared with monoculture (44.3%). At the sandy loam site, an interaction between rotation and fertility amendments reduced DSI from 71.7% in the monoculture to 37.8% in the 3-yr-corn rotation amended with compost. Canonical redundancy analysis (RDA) of the DSI-apothecia matrix in 2002 confirmed the suppressiveness of the 3-yr-corn rotation and revealed a significant conducive effect on DSI of compost at the clay loam site. At the sandy loam site, RDA of the DSI-apothecia matrix confirmed suppressive interaction between corn-soybean rotations and compost amendment. Key words: Sclerotinia stem rot of soybean, crop rotation, urban compost, multiple regression, canonical redundancy analysis, permutations test

Effects of Mowing, Seeding Rate, and Foliar Fungicide on Soybean Sclerotinia Stem Rot and Yield

2021 ◽  
Author(s):  
Kurt A. Carpenter ◽  
Adam J. Sisson ◽  
Yuba R. Kandel ◽  
Viviana Ortiz ◽  
Martin I. Chilvers ◽  
...  
Keyword(s):  
Management Practices ◽  
Management Practice ◽  
The United States ◽  
Field Trials ◽  
Cultural Practice ◽  
Stem Rot ◽  
Yield Response ◽  
Sclerotinia Stem Rot ◽  
Seeding Rate ◽  
Potential Yield

Sclerotinia stem rot (SSR or white mold), caused by Sclerotinia sclerotiorum (Lib.) DeBary, is an economically important fungal disease of soybean. SSR routinely causes yield loss in the upper Corn Belt of the United States due to wet, humid conditions that coincide with moderate temperatures. This study investigated the novel cultural practice of mechanical cutting, or mowing, as an SSR management practice across multiple seeding rates. Mowing soybean during early vegetative growth alters plant architecture and growth habit. This results in a microclimate within the canopy less suitable for disease development. Field trials were conducted in Iowa, Illinois, Michigan, and Wisconsin in 2017 and 2018. Experimental design was a randomized complete block with four replications. Treatments included mowing (mowing and no mowing), seeding rate (197,684, 271,816, and 345,947 seeds/ha), and fungicide application (boscalid, Endura, and no fungicide). Soybean was mowed at approximately the V4 (four unfolded trifoliate leaves) growth stage. Mowing reduced disease in multiple locations; however, it also reduced yield in most of the locations. In general, there was less SSR in plots with lower seeding rates. Fungicide significantly reduced SSR in two of the five site-years for which disease was observed. Significant yield response to fungicide was also observed in two of the nine total field trials. Results indicate cultural practices such as mowing and reduced seeding rate can decrease SSR severity but also can impact potential yield. Additionally, yield response to SSR management practices may not be observed if disease is absent or at low levels.

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