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

Author(s):  
Kurt A. Carpenter ◽  
Adam J. Sisson ◽  
Yuba R. Kandel ◽  
Viviana Ortiz ◽  
Martin I. Chilvers ◽  
...  

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.

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1048-1058 ◽  
Author(s):  
A. L. Mila ◽  
A. L. Carriquiry ◽  
J. Zhao ◽  
X. B. Yang

Regional prevalence of soybean Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, was modeled using management practices (tillage, herbicide, manure and fertilizer application, and seed treatment with fungicide) and summer weather variables (mean monthly air temperature and precipitation for the months of June, July, August, and September) as inputs. Logistic regression analysis was used to estimate the probability of stem rot prevalence with disease data from four states in the north-central region of the United States (Illinois, Iowa, Minnesota, and Ohio). Goodness-of-fit criteria indicated that the resulting model explained well the observed frequency of occurrence. The relationship of management practices and weather variables with soybean yield was examined using multiple linear regression (R 2 = 0.27). Variables significant to SSR prevalence, including average air temperature during July and August, precipitation during July, tillage, seed treatment, liquid manure, fertilizer, and herbicide applications, were also associated with high attainable yield. The results suggested that SSR occurrence in the north-central region of the United States was associated with environments of high potential yield. Farmers' decisions about SSR management, when the effect of management practices on disease prevalence and expected attainable yield was taken into account, were examined. Bayesian decision procedures were used to combine information from our model (prediction) with farmers' subjective estimation of SSR incidence (personal estimate, based on farmers' previous experience with SSR incidence). MAXIMIN and MAXIMAX criteria were used to incorporate farmers' site-specific past experience with SSR incidence, and optimum actions were derived using the criterion of profit maximization. Our results suggest that management practices should be applied to increase attainable yield despite their association with high disease risk.


Plant Disease ◽  
2007 ◽  
Vol 91 (2) ◽  
pp. 191-194 ◽  
Author(s):  
L. E. del Río ◽  
C. A. Bradley ◽  
R. A. Henson ◽  
G. J. Endres ◽  
B. K. Hanson ◽  
...  

Sclerotinia sclerotiorum is the causal agent of Sclerotinia stem rot (SSR) of canola (Brassica napus). In North Dakota, the leading canola producer in the United States, SSR is an endemic disease. In order to estimate the impact of this disease on canola yield, field experiments were conducted from 2000 to 2004 at several locations in North Dakota and Minnesota. Experimental plots were either inoculated with laboratory-produced ascospores or infected by naturally occurring inoculum in commercial fields. Applying fungicides at different concentrations and timings during the flowering period created epiphytotics of diverse intensities. Disease incidence was measured once prior to harvesting the crop on 50 to 100 plants per plot. Results of the study indicated that 0.5% of the potential yield (equivalent to 12.75 kg/ha) was lost for every unit percentage of SSR incidence (range of 0.18 to 0.96%). Considering the current cost of fungicide applications and the market value of this commodity, a 17% SSR incidence could cause losses similar to the cost of a fungicide application. Additional efforts are required to improve current levels of tolerance of canola plants to this pathogen.


Plant Disease ◽  
2021 ◽  
Author(s):  
Richard Wade Webster ◽  
Mitchell Roth ◽  
Brian Mueller ◽  
Daren S. Mueller ◽  
Martin I Chilvers ◽  
...  

Soybean (Glycine max) farmers in the Upper Midwest region of the United States frequently experience severe yield losses due to Sclerotinia stem rot (SSR). Previous studies have revealed benefits of individual management practices on SSR. This study examined the integration of multiple control practices on the development of SSR, yield, and the economic implications of these practices. Combinations of row spacings, seeding rates, and fungicide applications were examined in multi-site field trials across the Upper Midwest from 2017-2019. These trials revealed that wide row spacing and low seeding rates individually reduced SSR levels but also reduced yields. Yields were similar across the three higher seeding rates examined. However, site-years where SSR developed showed the highest partial profits in the intermediate seeding rates. This indicates that partial profits in diseased fields were negatively impacted by high seeding rates, but this trend was not observed when SSR did not develop. Fungicides strongly reduced the development of SSR, while also increasing yields. However, there was a reduction in partial profits due to their use at a low soybean sale price, but at higher sale prices fungicide use was similar to not treating. Additionally, the production of new inoculum was predicted from disease incidence, serving as an indicator of increased risk for SSR development in future years. Overall, this study suggests the use of wide rows and low seeding rates could be useful in fields with a history of SSR, while reserving narrow rows and higher seeding rates for fields without a history of SSR.


2010 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
Stephen R. Koenning ◽  
J. Allen Wrather

Research must focus on management of diseases that cause extensive losses, especially when funds for research are limited. Knowledge of the losses caused by various soybean diseases is essential when prioritizing research budgets. The objective of this project was to compile estimates of soybean yield potential losses caused by diseases for each soybean producing state in the United States from 2006 to 2009. This data is of special interest since the 4-year period summarized in this report, permits an examination of the impact of soybean rust that was first reported in the United States in 2004. Thus, in addition to the goal of providing this information to aid funding agencies and scientists in prioritizing research objectives and budgets, an examination of the impact of soybean rust on soybean yield losses relative to other diseases is warranted. Yield losses caused by individual diseases varied among states and years. Soybean cyst nematode caused more yield losses than any other disease during 2006 to 2009. Seedling diseases, Phytophthora root and stem rot, sudden death syndrome, Sclerotinia stem rot, and charcoal rot ranked in the top six of diseases that caused yield loss during these years. Soybean yield losses due to soybean rust and Sclerotinia stem rot varied greatly over years, especially when compared to other diseases. Accepted for publication 21 October 2010. Published 22 November 2010.


2018 ◽  
Vol 55 (1) ◽  
pp. 105-116 ◽  
Author(s):  
NINO P. M. BANAYO ◽  
RANEE C. MABESA-TELOSA ◽  
SUDHANSHU SINGH ◽  
YOICHIRO KATO

SUMMARYMore than 10 Sub1 rice varieties carrying the submergence-tolerance gene have been released for flood-prone environments in tropical Asia. Improved management practices have been shown to enhance yields of these varieties. The objective of this study was to dissect the growth response of IR64-Sub1 to integrated crop management in a flash flood at the late vegetative stage. Field experiments were conducted at the International Rice Research Institute, Philippines in the dry and wet seasons of 2013. Complete submergence was imposed for 14 days starting at 37 days after transplanting. Integrated management practice (IMP) consisting of: (i) application of fertilizer (compared with no fertilizer use in conventional practice), (ii) use of lower seeding rate (400 vs. 800 kg ha−1) in the nursery bed, (iii) use of slightly older seedling for transplanting (30 vs. 18 day-old), and (iv) higher planting density (33.3 vs. 25.0 hills m−2) gave yields higher by 8–87% compared with the conventional practice (1.3–2.4 t ha−1) in both seasons. This was attributable to higher shoot biomass after water recession, more tillers m−2, greater leaf area expansion and shoot biomass accumulation during the recovery period, and higher filled-grain percentage at maturity. The improved management had no positive effect on panicle formation, spikelets panicle−1, and harvest index since stress was imposed at the transition period between vegetative and reproductive phases. Our results suggest the appropriate nursery management, for submergence-resilient seedlings to further alleviate damage caused by flash floods and increase the yield of Sub1 varieties in flood-prone rainfed lowlands.


Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 614-624 ◽  
Author(s):  
S. Stewart ◽  
N. Abeysekara ◽  
A. E. Robertson

Changes in pathotype structure of Phytophthora sojae populations have been attributed to deployment of race-specific resistant Rps genes in soybean that have been incorporated into commercial cultivars to reduce losses due to Phytophthora root and stem rot. To test this hypothesis, a cultivar rotation study was established from 2007 through 2010 in microplots at a site in Iowa with no history of soybean cultivation. All microplots were inoculated with P. sojae isolate PR1, race 1 (vir 7) prior to planting in year 1. Six rotations were tested: (i) continuous planting of a P. sojae-susceptible cultivar, (ii) continuous planting of a cultivar with high partial resistance to the pathogen, (iii) continuous planting of a cultivar with the Rps 1k gene, (iv) annual rotation of a susceptible with a resistant cultivar, (v) annual rotation of a partially resistant cultivar with a cultivar with the Rps 1k gene, and (vi) 4-year rotation of cultivars with Rps 1k, 1c, 3a, and 1k genes in year one, two, three, and four, respectively. The diversity of 121 isolates of P. sojae that were recovered by baiting from soil samples collected from the experiment were assessed using pathotyping and eight microsatellite markers, and compared with PR1. Changes in pathotype and multilocus genotypes (MLGs) were recorded at the second sampling date, indicating that P. sojae has the ability to evolve quickly. In total, 14 pathotypes and 21 MLGs were recovered over the 4-year experiment, and only 49 and 22% of the isolates had the same pathotype and MLG, respectively, as PR1. The number of isolates of P. sojae recovered varied among rotations, with more isolates recovered from rotations that included a cultivar with partial resistance. Gain of virulence was detected on Rps 1a, 1b, 1c, 1d, and 3a and was not dependent on rotation. Using simple-sequence repeat analysis, 10 alleles that were different from those of PR1 were detected throughout the 4-year period. Cultivar rotation affected the genetic structure of the P. sojae population. Recovery of isolates with different MLGs, genotypic diversity (G = 4.7), and gene diversity (UHe = 0.45) were greater under continuous rotation with partial resistance. Phytophthora root and stem rot causes economic losses in the north-central region of the United States annually. An improved understanding of the effect of Rps gene deployment on P. sojae diversity would lead to improved management practices and reduced losses.


Plant Disease ◽  
2015 ◽  
Vol 99 (7) ◽  
pp. 969-975 ◽  
Author(s):  
Congying Xu ◽  
Xiaoyu Liang ◽  
Yiping Hou ◽  
Mingguo Zhou

We determined the effects and efficacy of benzothiostrobin, a new strobilurin-derived fungicide, against the plant-pathogenic fungus Sclerotinia sclerotiorum (the causal agent of Sclerotinia stem rot). Mycelial growth and sclerotial germination in vitro were strongly inhibited by benzothiostrobin in the presence of salicylhydroxamic acid. On detached rapeseed leaves, benzothiostrobin at 40 μg/ml reduced lesion development by 87%. No cross-resistance was detected between benzothiostrobin and carbendazim, iprodione, fludioxonil, or boscalid. A formulated mixture of benzothiostrobin and fluazinam at 1:1 had synergistic activity against S. sclerotiorum in vitro. In field trials, benzothiostrobin alone or formulated with fluazinam at 1:1 (150 g a.i. ha−1) was significantly (P < 0.05) superior to iprodione in controlling Sclerotinia stem rot of rapeseed. These results suggest that benzothiostrobin has substantial potential for the control of Sclerotinia stem rot.


2006 ◽  
Vol 36 (7) ◽  
pp. 1674-1683 ◽  
Author(s):  
Changyou Sun

State forestry best management practice (BMP) programs have been widely developed and implemented to prevent nonpoint source water pollution in the past three decades. The unanswered question is how forestry BMPs have affected the welfare positions of consumers, mills, loggers, and forest landowners. A Muth-type equilibrium displacement model was constructed to examine welfare changes of these stakeholders. The model considered a two-stage vertical production system with variable proportion production technology and imperfect market structure. Industrial mills experienced little welfare loss from forestry BMP regulation. Consumers had the largest absolute welfare loss, and loggers had the largest relative welfare loss in the base scenario. The supply elasticity of harvesting services had the greatest impact on the relative incidence of welfare losses between landowners and loggers, and in the long run their welfare losses were comparable. These results may help to improve future state forestry BMP guidelines and design incentive systems for increasing implementation rates.


Land ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1402
Author(s):  
Jason A. Hubbart

Best management practices (BMP) are defined in the United States Clean Water Act (CWA) as practices or measures that have been demonstrated to be successful in protecting a given water resource from nonpoint source pollution. Unfortunately, the greatest majority of BMPs remain unvalidated in terms of demonstrations of success. Further, there is not a broadly accepted or standardized process of BMP implementation and monitoring methods. Conceivably, if standardized BMP validations were a possibility, practices would be much more transferrable, comparable, and prescriptive. The purpose of this brief communication is to present a generalized yet integrated and customizable BMP decision-making process to encourage decision makers to more deliberately work towards the establishment of standardized approaches to BMP monitoring and validation in mixed-use and/or municipal watersheds. Decision-making processes and challenges to BMP implementation and monitoring are presented that should be considered to advance the practice(s) of BMP implementation. Acceptance of standard approaches may result in more organized and transferrable BMP implementation policies and increased confidence in the responsible use of taxpayer dollars through broad acceptance of methods that yield predictable and replicable results.


Plant Disease ◽  
2020 ◽  
Author(s):  
Yuba Raj Kandel ◽  
Catherine L. Hunt ◽  
Keith A Ames ◽  
Nicholas Arneson ◽  
Carl Bradley ◽  
...  

Random-effect meta-analyses were performed on data from 240 field trials conducted between 2005 and 2018 across nine U.S. states and Ontario, Canada, to quantify the yield response of soybean after application of foliar fungicides at beginning pod (R3). Meta-analysis showed that the overall mean yield response when fungicide was used compared to not applying a fungicide was 2.7% (110 kg/ha). Moderator variables were also investigated and included fungicide group, growing season, planting date, and base yield, which all significantly influenced the yield response. There was also evidence that precipitation from the time of planting to the R3 growth stage influenced yield when fungicide was used (P = 0.059). Fungicides containing a premix of active ingredients from multiple groups (either two or three ingredients) increased the yield by 3.0% over not applying a fungicide. The highest and lowest yield responses were observed in 2005 and 2007, respectively. Better yield response to fungicides (a 3.0% increase) occurred when soybeans were planted not later than 21 May and when total precipitation between planting and the R3 application date was above historic averages. Temperatures during the season did not influence the yield response . Yield response to fungicide was higher (a 4.7% increase) in average yield category (no spray control yield 2878 to 3758 kg/ha) and then gradually decreased with increasing base yield. Partial economic analyses indicated that use of foliar fungicides is less likely to be profitable when foliar diseases are absent or at low levels.


Sign in / Sign up

Export Citation Format

Share Document