Foliar Fungicides Research Articles

Foliar fungicide (pyraclostrobin) application on corn and its effects on corn silage composition

The objective of this study was to determine the effects of various applications of foliar fungicide on corn ensiled as corn silage. Treatments were replicated once and assigned to one of eight 0.4-ha plots of corn as follows: control (CON), plants receiving no foliar fungicide application; treatment 1 (V5), where plants received a mixture of pyraclotrobin and fluxapyroxad foliar fungicide (Priaxor, BASF Corp.) at corn vegetative stage 5 (V5); treatment 2 (V5+R1), where plants received two applications of foliar fungicide, a mixture of pyraclotrobin and fluxapyroxad at V5 and a mixture of pyraclostrobin+metconazole foliar fungicide (Headline AMP; BASF Corp.) at corn reproductive stage 1 (R1); treatment 3 (R1), in which plants received one application of pyraclostrobin+metconazole foliar fungicide at R1. Samples of corn for corn silage were collected at harvest, prepared as 0.9-kg mini-silos and vacuum sealed. These were ensiled for 0, 30, 90, and 150 d postharvest then frozen for later analysis. Applications of fungicide on corn, later ensiled as corn silage resulted in less (P<0.001) DM content (319, 315, and 317g/kg for V5, V5+R1, and R1, respectively) compared with untreated corn silage (CON; 335g/kg). Corn silage from R1 resulted in a lower (P=0.03) concentration of lignin (20g/kg DM) and greater (P=0.001) concentration of lactic acid (55.0g/kg DM) when compared with corn silage from other treatments (lignin: 24, 24, and 26g/kg DM for CON, V5, and V5+R1, respectively; and lactic acid: 46.5, 50.1, and 50.9g/kg DM for CON, V5, and V5+R1, respectively). Treatment R1 had a greater (P=0.03) concentration of water soluble carbohydrates at 0 and 150 d postharvest (123 and 31.5g/kg DM for 0 and 150 d, respectively; and an increased lactic acid concentration at 90 d (71.1g/kg DM for R1 vs. 63.4, 68.4, and 69.2g/kg DM for CON, V5, and V5+R1, respectively) when compared to the other treatments. Results suggested that fungicide application on corn at V5 or R1 may enhance the nutritive and fermentative profile when ensiled for feeding ruminants.

Effect of mineral nutrients, seed treatment and foliar fungicides on spot blotch (Bipolaris sorokiniana) severity and agronomic performance of wheat (Triticum aestivum) in hot-humid environment of eastern Gangetic plain in India

Spot blotch disease [Bipolaris sorokiniana (Sacc.)] is one of the most serious biotic constraint affecting wheat production in India. The effect of balanced macro- and micro-fertilization, fungicidal seed treatment and foliar fungicides either individually or in combination were assessed for their impact on spot blotch severity, grain yield, and other yield attributing characters during 2012-13 and 2013-14. Average maximum temperature (27.0°C) and high relative humidity (&gt;90%) in February and March during both the years favoured disease development and spread. In vitro analysis of untreated pre-sown seeds using a blotter paper test revealed 19.2% and 32.5% seed infection with B. sorokiniana during 2012-13 and 2013-14, respectively. At the end of each cropping season, seed infection in harvested seed lots ranged from 5-6% in treatments with a combination of balanced fertility, seed treatment and foliar fungicide, 13% following two sprays of propiconazole, and 71% in control treatment. Application of balanced nutrition alone reduced AUDPC by 37% and increased grain yield up to 26%. However, the combined influence of balanced nutrition, carboxin + thiram seed treatment and two foliar sprays of propiconazole resulted in a 99% reduction in AUDPC values with 60% higher grain yield (6.30 t/ha), 45% higher TKW (41.33 g) and significant increase in other yield attributes. The current study illustrates the role of a combination of crop and disease management practices in the control of spot blotch and improving the agronomic performance of wheat in eastern plains of India.

Influence of Foliar Fungicide Treatment on Lipolytic Enzyme Activity of Whole Wheat

Lipolytic enzymes play a key role in the deterioration of whole wheat flour upon storage but may also be involved in plant disease and stress tolerance while the crop is in the field. Therefore, the purpose of this study was to determine the effect of foliar fungicide treatment on lipolytic activity in wheat. A significant cultivar × fungicide × year interaction for esterase (p‐nitrophenyl butyrate as substrate [EA‐B]) and lipoxygenase (LOX) activities was observed; however, a large portion of the variability was owing to year (environment). Fungicide influenced lipase (olive oil as substrate [LA‐O]), EA‐B, and LOX activities. Lipase (p‐nitrophenyl palmitate as substrate [LA‐P]) showed variation in terms of cultivar and year rather than the application of fungicide. Partial correlation (year as a partial variable) between LA‐P and EA‐B activities was observed (r = 0.78, P &lt; 0.001), although neither was correlated with LA‐O. The influence of foliar fungicide on lipolytic enzyme activities depends mostly on growing conditions but is also affected by disease stress, disease resistance of the varieties tested, and the substrate being used in the assay.

Effect of two-component cultivar mixtures on development of wheat yellow rust disease in the field and greenhouse in the Nepal Himalayas

Wheat yellow rust (WYR), caused by Puccinia striiformis f. sp. tritici (PST), is a major disease of wheat, and deployment of a single cultivar often leads to disease epidemics. Effect of inoculum level, foliar fungicide spray, and wheat cultivar mixtures were evaluated on disease development in the field and greenhouse in Nepal. Treatments were arranged in a split–split plot design with three replications in both experiments. Two inoculum levels of PST (low and high) were main plot factors; nontreated control and foliar spray of fungicides (Mancozeb and Bayleton) were subplot factors; and two-component cultivar mixtures, composed of different ratios of a susceptible (S) and a resistant (R) cultivars (90:10, 80:20, and 50:50, 100:0, and 0:100) were sub–subplot factors. WYR severity was assessed at different time intervals, and disease development was calculated as area under the disease progress curve (AUDPC). Inoculum level did not cause significant differences in AUDPC in the field but did in the greenhouse. Foliar spray of fungicides reduced the AUDPC in the greenhouse and field. In both experiments, AUDPC values were low in cultivar mixtures compared with a pure stand of a susceptible cultivar. As the proportion of resistant cultivar increased compared with the susceptible cultivar in the S:R mixture component, disease severity decreased with a consequent increase in grain yield. The greater yield obtained with cultivar mixtures compared with only the susceptible cultivar, independent of inoculum level and fungicide spray in the field, revealed a promising strategy to manage WYR in Nepal.

363 Effects of foliar fungicide on whole plant brown midrib and floury corn varieties

363 Effects of foliar fungicide on whole plant brown midrib and floury corn varieties

Corn, Soybean, and Wheat Yield Response to Crop Rotation, Nitrogen Rates, and Foliar Fungicide Application

Crop rotations involving corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] are well‐known production systems across the Midwestern United States, but the addition of wheat (Triticum aestivum L.) in the rotation has received less attention. Additionally, the interactive effect of crop rotation with nitrogen (N) fertilizer and foliar fungicide application on yields for these three crops is not yet well understood. Data were collected in Wisconsin from a long‐term crop rotation experiment during 2013 to 2015 to measure corn (grain and silage), soybean, and wheat yield response to crop rotation frequency (seven rotations involving corn, soybean, and wheat), six levels of N, and foliar fungicide use. During the 3 yr of the experiment, minimal interactive effects were detected, which suggested that the examined management decisions can remain separate for growers in Wisconsin. Yearly crop rotation of corn and soybean increased corn grain yields in 2014 by 15 to 18% and soybean yields by 24 to 31% in 2015 compared with continuous cropping. No other crop rotation effect was observed. Fungicide use at the V5 growth stage for corn, at R3 for soybean, and at GS9 for wheat, increased wheat (7.4–16.8%) and soybean yield (3.6–5.4%) but not corn grain or silage yields. Nitrogen application was more beneficial for corn compared with wheat and soybean. The effect of N on soybean was similar across all rotations, and grain yields increased when N rate was higher than 100 kg ha−1. The data suggest that N rate recommendations should be based on crop needs, regardless the rotation system.

Foliar fungicide (pyraclostrobin) application effects on plant composition of a silage variety corn

The objective of this study was to determine the effect of foliar fungicide applied at various times during the growing season of corn on the chemical composition of corn leaves, corn ears, and corn stalks. Treatments were replicated once and assigned to 1 of 8 0.4-ha plots of corn, as follows: control (CON), corn receiving no foliar fungicide application; treatment 1 (V5), where corn received a mixture of pyraclotrobin and fluxapyroxad foliar fungicide (Priaxor, BASF Corp.) corn vegetative stage 5 (V5); treatment 2 (V5+R1), where corn received two applications of foliar fungicide, a mixture of pyraclotrobin and fluxapyroxad at V5 and a mixture of pyraclostrobin+metconazole foliar fungicide (Headline AMP; BASF Corp.) at corn reproductive stage 1 (R1); and treatment 3 (R1), in which corn received one application of pyraclostrobin+metconazole foliar fungicide at R1. Evaluators at R1 and corn reproductive phase 3 (R3) reported signs of Gray Leaf Spot and Northern Leaf Blight on the foliage. Twenty-four individual corn plants from each treatment were collected at R1 and R3 for weight and length measurement. At each collection, corn was disassembled into leaves, stalks, flag leaf, and ears for chemical analysis. At R3, corn in V5+R1 and R1 had less yellow leaves than CON and V5 (1.7, 1.5, 0.83 and 0.88 for CON, V5, V5+R1 and R1, respectively; P=0.03), and treated corn were taller than untreated (2.5, 2.9, 3.1, and 2.8m for CON, V5, V5+R1, and R1, respectively; P=0.02). Fungicide treated corn stalks had greater lignin content (56, 64, and 50g/kg DM for V5, V5+R1, and R1, respectively) compared with untreated (46g/kg DM; P=0.03), with the greatest concentration from corn stalks in V5+R1. Fungicide treated corn leaves had less ADF content (331, 283, and 330g/kg DM for V5, V5+R1, and R1; P=0.01) and NDF content (584, 524, and 554g/kg DM for V5, V5+R1, and R1; P=0.02) compared with untreated leaves (333g/kg DM ADF; 569g/kg DM NDF, respectively). In conclusion, results suggest that applications of foliar fungicide at V5 and R1 together may have a synergistic interaction on the fibrous content within the corn leaves, producing a higher quality feedstuff for ruminants when fungal disease is present.

Effects of Foliar Fungicide Application on Corn Plants on the Composition of Corn Silage for Ruminant Diets

An increasing global population, decreasing amount of arable land available for crop production in the United States, and an increased global demand for protein in the human diet encourage crop and livestock producers to seek solutions to improve the efficiency of producing large crop yields. Corn silage is one of the most commonly used forages included in dairy diets in the United States. For producers, feed costs are often the most expensive part of the operating budget. Corn yield losses may increase the cost of feed and limit herd size. The complex interaction of fungi and corn plants in the field threaten yields, decreasing the efficiency of food production and, also, the nutritive quality and value of feedstuffs for ruminants. By metabolizing sugar compounds within the plant cell, fungal infections on corn plants reduce the nutritional contents available for ruminant diets. Applications of fungicides can aid in protecting corn plants from fungal infection, therefore, limiting yield losses and increasing the nutritive quality of the plant material. The field of knowledge of feeding ruminants corn silage from corn treated with foliar fungicide is still narrow, but findings from previous research highlight the negatives of making and feeding silage from diseased corn plants. This review will summarize the knowledge available on fungi and plant relationship, limiting plant infection by applying fungicide, and how corn silage from corn with fungicide application affects dairy cow performance. It is concluded fungicide application on corn used to make corn silage for dairy cows may improve the nutritional composition of the feedstuff, as defined by increases in milk components and feed conversion, reductions in fiber concentrations, and improvements in ruminal digestibility.

HEAVY METALS IN VINEYARDS AND ORCHARD SOILS

ABSTRACT The application of foliar fungicides in vineyards and orchards can increase soil concentration of heavy metals such as copper (Cu) and zinc (Zn), up to the toxicity threshold for fruit trees and cover crops. However, some agronomic practices, such as liming, addition of organic fertilizers, cultivation of soil cover crops and inoculation of young plants with arbuscular mycorrhizal fungi can decrease the availability and the potential of heavy metal toxicity to fruit trees. This review aims to compile and present information about the effects of increasing concentrations of heavy metals, especially Cu and Zn, on soils cultivated with fruit trees and provides some agronomic practices of remediation. Information about the sources of heavy metals found in soils cultivated with fruit trees are presented; mechanisms of absorption, transport, accumulation and potential toxicity to plants are described.

Expression of catalase, alcohol dehydrogenase, and malate dehydrogenase in rot grains upon fungicide use on maize hybrids grown at different spacings.

In this study, we evaluated the fungicide effect on the incidence of rot grains and expression of catalase (CAT), alcohol dehydrogenase (ADH), and malate dehydrogenase (MDH) enzymes in commercial maize hybrids grown with conventional and reduced spacing in Guarapuava, PR, Brazil. The experiment was designed in random blocks with a 3 × 8-factorial scheme, totaling 24 treatments. The first factor constituted three levels, the first with foliar fungicide application [150.0 g/L trifloxystrobin (15.0%, w/v) + 175.0 g/L prothioconazole (17.5%, w/v)] at a dose of 0.4 L/ha at V8-stage eight expanded leaves and the second with an application of 0.5 L/ha at VT-tasseling and check (no fungicide application) stage. The second factor comprised eight maize hybrids that were divided into two groups, complex (AG 9045PRO, AG 8041PRO, DKB245PRO2, and 2B707PW) and susceptible (P 32R48H, DKB390PRO, P 30F53H, and P 30R50H), according to their reaction to the causative fungus, totaling 72 plots at each site in the crop of 2013/2014. The percentage of rot grains and the expression of CAT, ADH, and MDH were evaluated for each hybrid. The percentage of rot grains was influenced by the hybrid and fungicide used. The (trifloxystrobin + prothioconazole) reduced the incidence of rot grains, with relatively higher reduction in the hybrids considered susceptible. The higher expression of CAT enzyme was related to the higher incidence of rot grains because of grain deterioration, depending on the hybrids evaluated. A higher expression of ADH and MDH enzymes was observed in the maize hybrids belonging to the group considered tolerant.

Impact of Foliar Fungicides on Gibberella Ear Rot and Deoxynivalenol Levels in Indiana Corn

Gibberella ear rot, caused by the fungus Fusarium graminearum (Schawbe), can cause significant yield reductions in corn (Zea mays L.) as well as reduce grain quality. Field experiments were conducted at two locations in Indiana to assess the impact of commercially available fungicides on Gibberella ear rot severity and deoxynivalenol (DON) accumulation in hybrid corn grain. The experiments were arranged in a random complete block design with both inoculated and noninoculated treatments. Three fungicides—azoxystrobin + propiconazole, prothioconazole, and pyraclostrobin—were applied during silking (R1), and Gibberella ear rot severity, DON accumulation in grain, and corn yield were measured. Inoculated treatments had higher disease severity and DON and lower yield (P &lt; 0.001) compared with noninoculated treatments. Fungicides reduced Gibberella ear rot severity in two location-years, but did not reduce DON in those experiments. All other fungicide treatments in all locations and years did not reduce disease severity or DON when compared with treatments not sprayed with fungicide. No fungicide increased DON levels in grain in any location or year. These results indicate that fungicide applications during the silking stage of corn may not consistently reduce DON levels in hybrid corn.

Using Unmanned Aircraft Systems for Early Detection of Soybean Diseases

As the interest in Unmanned Aerial Systems (UAS) has increased, so has the interest in the application of these systems for use in agriculture. A variety of sensors, including Multi-Spectral, Near-Infrared, Thermal, and True-Color have the potential to benefit farmers when mounted to a UAS. But as this is an emerging field, there is little data available to demonstrate their use for early detection of plant diseases in crop production. In 2016, a preliminary study was launched to examine the potential of using aerial imagery from UAS to detect diseases in soybean crops. Two irrigated fields in Alabama were selected: Experiment 1, a 50-hectare field, and Experiment 2, a 5-hectare field. Each trial consisted of replicated plots using two foliar fungicide treatments and an untreated control. Aerial imagery (multi-spectral and true-color) was collected on a biweekly basis during this study. Using multi-spectral imagery, both the Normalized Difference Vegetative Index (NDVI) and Normalized Difference Red Edge Index (NDRE) were generated and compared to direct observations in the field. Disease severity of soybean rust, charcoal rot and Cercospora leaf blight were monitored on a biweekly basis and correlated to the UAS imagery. Preliminary results indicated plant stress can be detected using UAS imagery. In Experiment 1, stress associated with charcoal rot was visible in the NDRE imagery. This was of interest because at the time of flight, while it was noted that plants were yellowing, the root and stem disease itself had not been identified by direct observation. In Experiment 2, soybean rust was observed by direct observation and in both the NDRE and NDVI imagery. Soybean rust did have a negative impact on yield in Experiment 2, however severe drought conditions may have negated the yield loss likely caused by the development of charcoal rot in Experiment 1.

Factors Affecting the Development and Severity of Goss's Bacterial Wilt and Leaf Blight of Corn, Caused by Clavibacter michiganensis subsp. nebraskensis.

Goss's bacterial wilt and leaf blight, which is caused by Clavibacter michiganensis subsp. nebraskensis, is a disease of corn (Zea mays) that has been increasingly reported across the Midwest since its reemergence in western Nebraska, northeastern Colorado, and southeastern Wyoming during the 2006 growing season. The objective of this study was to identify environmental and agronomic factors contributing to the incidence of the disease across the Corn Belt through a multistate survey conducted during the 2011 growing season. Of the 2,400 surveys distributed throughout nine states, 486 were returned with corn leaf samples, of which 70% tested positive for C. michiganensis subsp. nebraskensis using an enzyme-linked immunosorbent assay. The agronomic data associated with each field were analyzed using classification and regression tree and random forest analyses to identify the factors that contributed most to Goss's bacterial wilt and leaf blight development. A χ2 test of independence was also done to determine relationships between certain variables and disease incidence. The two best predictors of Goss's bacterial wilt and leaf blight were hybrid resistance to Goss's bacterial wilt and leaf blight, as indicated by the seed companies' score and a planting population density >67,500 plants ha-1. Other important predictors included longitude, planting date, crop rotation, percent residue, yield history, tillage, and growth stage. Relationships between glyphosate applications, foliar fungicide applications, and corn rootworm beetle with samples testing positive for C. michiganensis subsp. nebraskensis were also detected. These data contribute to our understanding of factors that increase the risk of Goss's bacterial wilt and leaf blight, and should enable more effective management practices to be adopted or developed.

Effects of corn treated with foliar fungicide on in situ corn silage degradability in Holstein cows

With increasing feed prices and decreasing profit margins livestock producers are constantly searching for ways to increase nutritive value of the feed in order to get more production per unit of feedstuff. The objective of this study was to assess the digestibility of corn silage made of corn plants treated with various foliar fungicide applications. Treatments were: control (CON), corn received no foliar fungicide application; 1X, corn received one application of pyraclostrobin foliar fungicide (PYR; Headline; BASF Corp.) at vegetative stage 5 (V5); 2X, corn received 2 applications of foliar fungicides, PYR at stage V5, and a mixture of pyraclostrobin and metconazole (PYR+MET; Headline AMP; BASF Corp.) at reproductive stage 1 (R1); and 3X, corn received 3 applications of foliar fungicides, PYR at stage V5, PYR+MET at stage R1, and PYR+MET at reproductive stage 3. Corn was harvested at the same time and ensiled for 7 months. Dried unground corn silage was put into 288 (3 per time points/treatment/cow) 10×20cm bags and incubated for 8 different time points (0, 2, 4, 8, 12, 48, 72, and 96h). A sample of unground dried corn silage was also placed into 20×40cm bag and incubated for 48h. Digestibility of corn silages was estimated using in situ procedure with 3 rumen-cannulated lactating multiparous Holstein cows. The degradable fraction of dry matter (DM) tended to be greater (P=0.08) for corn silages treated with fungicide when compared with CON. There was no treatment effect (P>0.05) on neutral detergent fiber (aNDF), acid detergent fiber (ADF), starch, and crude protein (CP). However, the soluble fraction of DM, aNDF, and ADF decreased (P<0.05) as fungicide applications increased. Effective degradability (ED) was greater (P<0.05) in CON than corn silages treated with fungicide mainly due to decreased ED in 3X compared with 1X and 2X. In situ digestibility for bigger and smaller bags was different. Degradability of DM, aNDF, and ADF was higher (P<0.05), while starch and CP degradability was lower (P<0.01) in the larger bags. Fungicide application to corn for silage lead to higher DM degradable fraction which seems to be the result of increased sugar and starch along with decreased aNDF and ADF.

Sensitivity of Phakopsora pachyrhizi Isolates to Fungicides and Reduction of Fungal Infection Based on Fungicide and Timing of Application.

Soybean rust (SBR), caused by Phakopsora pachyrhizi, is a damaging foliar fungal disease in many soybean-growing areas of the world. Strategies to manage SBR include the use of foliar fungicides. Fungicide types, the rate of product application, and the number and timing of applications are critical components for successful rust management. The objectives of this study were to determine i) the sensitivity of P. pachyrhizi isolates collected in the U.S. to a range of fungicides and ii) the reduction of fungal infection based on fungicide type and timing of applications on soybean. There were differences (P < 0.05) in effective concentration (EC50) values among the fungicides tested. Azoxystrobin had low EC50 values for both urediniospore germination and fungal sporulation on inoculated leaflets. There were differences (P < 0.05) in fungal sporulation for application times, fungicide treatments, and their interaction when the fungus was inoculated on plants. All application times and nearly all fungicide treatments reduced (α = 0.05) fungal infection compared with the nonfungicide control. Information on fungicide sensitivity of P. pachyrhizi isolates and the preventive and curative effects of different fungicides are important in the management of SBR.

1439 Chemical composition and fermentation profile of corn silage ensiled for zero, thirty, ninety, or one hundred fifty days from corn treated with a foliar fungicide at different growing stages

1439 Chemical composition and fermentation profile of corn silage ensiled for zero, thirty, ninety, or one hundred fifty days from corn treated with a foliar fungicide at different growing stages

0745 Dry matter intake, milk yield, and milk composition of dairy cows fed corn silage from corn treated with various application times of foliar fungicide

0745 Dry matter intake, milk yield, and milk composition of dairy cows fed corn silage from corn treated with various application times of foliar fungicide

Plot size can influence yield benefits from fungicides on corn

Abstract Use of foliar fungicides on corn has increased over the last decade. Part of the reason for this increase is due to physiological benefits on plants from QoI (strobilurin) containing fungicides. However, there remains controversy over how significant yield and economic benefits are from strobilurin fungicides. A potential source of this controversy might be explained by experimental plot size. To better understand grower-relevant yield benefits from fungicides, three hundred and fourteen commercial-strip trials (8.1 ha fungicide treated and 8.1 ha untreated) were conducted on growers' farms across four years, and twenty-five small plot (37.2 m2 or less) trials were conducted across the corn belt in 2010. Yield benefits from fungicides were much greater in the commercial-strip trials than in the small plot trials. In 2011, twenty-six large plot trials (ranging from 557 to 1394 m2), were established with efforts made to reduce border and alley effects. Two corn hybrids were evaluated at each of the 26 trial locations, and the results indicated that corn yield benefits from Quadris® fungicide (a solo formulation containing 22.9% azoxystrobin) applied at the V4-V8 growth stage, Quilt Xcel® fungicide (a premix formulation containing 13.5% azoxystrobin and 11.7% propiconazole) applied at the R1 growth stage, or a combination of the two, provided yield benefits similar to those from the commercial-strip trials. The financial gain/loss from the use of fungicides was determined. Using the highest cost estimates for fungicide and applications, Quilt Xcel fungicide applied at the R1 growth stage provided estimated yield benefits of $105, $219, $241, and $278/ha ($19, $65, $74, and $89/A) over the untreated checks in the commercial-strip trials conducted in 2009, 2010, 2012, and 2013, respectively. The average economic benefit to growers over the four year period was $211 ± 37/ha ($62 ± $15/A). Variability in economic benefit not only includes costs associated with fungicides but also includes annual commodity price, disease pressure, and location effects. This study supports the hypothesis that plot size influences assessment of yield effects of fungicides. Yield responses from the small plot, large plot, and commercial-strip trials resulted in increases of 378 kg/Ha (6 Bu/A), 701 kg/Ha (11 Bu/A), and 1132 kg/Ha (18 Bu/A) over the untreated, respectively.

Stempedia: a weather-based model to explore and manage the risk of lentil Stemphylium blight disease

Lentil Stemphylium blight is a fungal disease threatening sustainable lentil-based cropping in South Asia including Bangladesh. A weather-based model ʻStempediaʼ was developed to understand the risk of the disease. Daily maximum temperature and sunshine hours are the two most important parameters of the model. When tested with field data from Bangladesh and Nepal, the model simulated the disease severity well both without (R 2 = 0.89, n = 17) and with (R 2 = 0.80, n = 18) fungicide application scenarios. As a result, Stempedia was subjected to experimentation to explore the risk and risk management options related to the disease under Bangladesh conditions. Taking Gazipur - a central regional district - as an example, the model identified that, predominantly, gradual reductions in sunshine hours (or, increased cloudiness) during the early part of the ‘disease susceptible window’ had increased the disease severity over the last 30 years. The model simulated Ishurdi, a north-western regional district, as more disease prone than Gazipur and Jessore, a south-eastern regional district. Stempedia simulated seasonal variability of the disease and predicted reduced severity with delayed sowing, the magnitude of which differed between regions. Stempedia also predicted financial returns with three foliar applications of an effective fungicide but this depended on the timing of application. The best financial return occurred with an early fungicide application, as soon as the disease appeared during initiation of flowering, followed by further application(s) if a disease-producing environment was expected. We conclude that the model has potential to assess regional and seasonal risks of this disease and to determine risk aversion by manipulating sowing time. This model can further be used to formulate the principle of foliar fungicide application to achieve financial gain.

Characterizing Soybean Yield and Quality Response to Multiple Prophylactic Inputs and Synergies

There is little peer‐reviewed information regarding prophylactic use of multiple inputs in soybean [Glycine max (L.) Merr.] production systems as a way to increase seed yield and profitability. Therefore, the objective of this study was to examine the effect of multiple inputs on soybean yield and quality in Wisconsin (WI). Two separate studies were established from 2011 to 2013. The inputs examined included: trait [first (RR1) and second (RR2Y) generation Roundup Ready traits], rhizobia inoculant, fungicide seed treatment, foliar fertilizer, foliar insecticide, and foliar fungicide. In the first experiment, main effects and up to three‐way interactions were evaluated; whereas in the second experiment, all inputs were combined in a high‐management (i.e., intensive) treatment. In the first experiment, soybean yield was not consistently increased due to the used inputs. Trait and foliar fungicide use were significant factors with variable effect on soybean seed yield in three and four of the nine location‐years, respectively. The foliar insecticide effect varied between traits in three location‐years. The (rhizobia inoculant + fungicide seed treatment) × foliar insecticide × foliar fungicide interaction was a significant factor in three of the nine location‐years. None of the examined factors significantly increased yield across all location–years. In the second experiment, high‐management, trait, and their interaction did not consistently increase soybean yield, nor improved seed quality characteristics. Overall, these results suggest that WI growers should continue to use university‐developed integrated pest management principles for making input decisions instead of relying on prophylactic input applications for maximizing soybean yield and profitability. No sole input or interaction consistently increased soybean yield across site‐years. Intensive management had inconsistent and minimal effect on soybean yield. Growers should not rely on prophylactic input applications to maximize soybean yield.