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Pollinator Fest

Saturday, June 23, 2018 - 10:00am to 2:00pm

Admission is FREE from 10:00am - 2:00pm on 6-23-2018 to celebrate National Pollinator Week at Reiman Gardens!

There will be many collaborators present to make sure this day is educational and plenty of fun! Collaborators include the Iowa State University Pollinator Working Group, the ISU Entomology Graduate Student Organization, the ISU Graduates in Evolutionary Biology and Ecology, Blank Park Zoo, and Ames High School.

FREE 4R Plus Field Day

Tuesday, July 31, 2018 - 9:30am

"On July 31, from 9:30 a.m. to 2:45 p.m. at ISU’s FEEL Farm near Boone, farmers, agronomists and other stakeholders will have the opportunity to hear from experts who will present ways to use the '4Rs,' plus conservation practices to achieve maximum profitability, yields and environmental stewardship. The day of learning is free, with lunch provided, and attendees participating the whole day can receive six continuing education (CEU) credits toward their certified crop adviser (CCA) certification."

Harrison County Pest Resistance Management Field Day

Wednesday, July 7, 2021 - 10:00am to 1:00pm

The Harrison County Pest Resistance Management Project team will hold a field day Wednesday, July 7.  The event, from 10:00 a.m. to 1:00 p.m., will include both herbicide and fungicide trials in soybeans at a farm southwest of Logan, operated by Larry Buss. This event is free and open to the public.

Producer Perception of Large-Scale Foliar Fungicide Adoption on Corn

A recently published study in the American Phytopathological Society’s (APS) Pathology Journal, “Perceptions of Midwestern Crop Advisors and Growers on Foliar Fungicide Adoption and Use in Maize” (Sept. 18), explains the various ideologies behind the exponential increase of foliar fungicide on corn crops from the year 2000-2010. The study surveys  certified crop advisors (CCAs) and corn growers across Iowa Wisconsin, Ohio and Illinois.

Fungicide use in the United States increased rapidly during the first decade of the new millennium, despite lack of intense pressure of fungal foliar diseases in corn. According to the study, fungicide use in corn production before the year 2000 in the U.S. was a rare practice; however, by 2007, nearly 10 percent of the country’s corn was being treated with fungicide. In 2010, a report by the Agricultural Resource Management Survey (ARMS), conducted by the U.S. Department of Agriculture (USDA) found that 22.5 percent of planted corn in Illinois had been sprayed with a fungicide.

For background information on the economical and agricultural technology landscape of the time periods being investigated, the report states that fungicides were commercially available to corn farmers since the 1980s. The Farm Crisis was occurring at this point in American history, and low commodity prices and low farm income continued until around 2000, when corn prices began to increase. In 2008, corn price topped out at approximately $6 per bushel. Foliar fungicide use remained a rare practice through 1998, at which point it was mainly used in the production of high value hybrid corn seed. According to the report, “at that time, extension and crop advisors predicted no appreciable change in fungicide use over the next five years, because crop rotation and hybrid resistance would continue providing economically acceptable levels of disease control.”

However, this prediction did not come true. At the turn of the millennium, the mass adoption of shorter crop rotations and reduced tillage increased residue-born disease presence. Gray leaf spot (incited by Cercospora zeae-maydis) in corn was propelled — as predicted by researchers, according to the study — from the “sideline to international status.” An uncertainty in being capable of predicting foliar disease outbreaks was also on the rise, as corn prices began to trend upward. Around this time also came the registration of quinone outside inhibitor (QoI) fungicides for corn. The mass marketing of these products to farmers was integral at this time, due to the mechanism of which QoI’s worked. These types of fungicides were able to last longer in direct sunlight, and had activity against  a broad spectrum of fungi Perhaps more intriguing than the aforementioned benefits were claims that this class of fungicides could boast plant health benefits, such as green leaf longevity and improved stalk strength.

The study sought to understand CCAs and corn growers’ perceptions on fungicide use during this time period, as well as measure the average perceived benefit and/or consequences of this increase in fungicide use. Increased fungicide use with no increase in disease pressure went against researchers’ observed behavior of corn farmers, whose decision making has been very much dependent on profitability. These findings also go against the practices of integrated pest management (IPM), which urges responsible pesticide use through information-based decision making and multiple other management tools for pest control. The report states that multiple university trials across the U.S. Corn Belt had shown inconsistent profitability under low foliar disease severity.

The survey was sent to 188 CCAs and 188 corn growers in each states, totaling 1,504 individuals. The survey response rate was 47.4 percent. From 2005 through 2009, 73 percent of all CCAs recommended the use of a foliar fungicide on corn. Just 35 percent of corn growers applied foliar fungicide. Of this total, 84 percent were applying a fungicide for the first time. 68 percent of CCAs who recommended spraying had done so for the first time. When it came to ranking threats to corn production, weeds were the number one concern (90 percent by CCAs and corn growers), followed by insects and then diseases. The perception on behalf of corn growers when it came to disease impacts on yield loss varied among the states evaluated, however the study did not examine the disease pressures and other circumstances in each state.

When asked to rank corn production factors from most to least important, approximately 23 percent of respondents ranked the use of foliar fungicide as being “very-extremely important”. The top four factors were maximizing profit, yield, commodity prices and plant population, followed by “other factors” (which includes trait resistance and Roundup Ready seed). Those who held disease as more important to impacting yield loss were more likely to perceive foliar fungicides as more important.

The breakdown of CCA recommendation of foliar fungicide use varied by the use of the end product: 98 percent recommended applications to grain, 35.7 percent to seed crops and 24.3 to silage. Of corn growers who applied fungicide, 94 percent applied fungicide to grain, 24.8 percent applied to seed crops and 27.7 percent applied to silage.

The impacts on crop yield, conditional on having sprayed a foliar fungicide were as follows: 94.4 percent of CCAs and 65.1 percent of corn growers saw a 5 to 9 bushel per acre increase (a 4.08 percent increase per year average); 47.4 percent of CCAs and 25.6 percent of corn growers saw a negative yield response of 1 to 4 bushels per acre.

The study also examined how much CCAs and corn growers were willing to spend on foliar fungicide, as a way to examine the economic decision making during this period. Approximately 20 percent of CCAs believed that their corn growers were willing to spend $25 or more per acre, while corn growers reported a willingness to spend between $16 and $38 per acre. The use of fungicide in previous crop production years had an influence on the amount that corn growers and CCAs were willing to spend. For those who had sprayed fungicides in the last 5 years, the odds of being willing to spend $25 or more per acre on fungicides compared with less were 5.2 times the odds for those who did not spray fungicides being willing to spend $25 or more per acre compared with less.

Upon reviewing the data collected in the study, researchers concluded that corn growers struggle with “balancing the conflicting roles of environmental stewardship and successful businessperson. In reality, short-term profit-making trumps the environmental stewardship role.”  Researchers further concluded that the use of fungicide in the absence of disease pressure, while disagreeing with IPM protocols, was seen as a form of insurance to protect yields with commodity prices spiking in the period examined. Since fungicides at this time covered a broad spectrum of fungi while also boosting plant health, the cost might have been worth the investment. The survey indicated that, on average, farmers observed yield responses above the break-even point. Though CCAs are influencers, and were more likely to recommend fungicide if they perceived disease to be important, corn growers were more skeptical, and viewed disease resistance as a seed trait/treatment to be more beneficial. Given the current state of commodity prices, it can be inferred that prices per bushel will influence growers’ attitudes toward using a fungicide.

Project Type: 
Duration: 
11/01/2018

Cropping System Diversification Reduces Severity and Incidence of Soybean Sudden Death Syndrome

A research study published in the American Phytopathological Society (APS) Plant Disease journal examined the effects of cropping system diversification on management of soybean sudden death syndrome (SDS), caused by Fusarium virguliforme, that provides some insight into preventing the disease for growers. SDS is a major disease that impacts North and South America. Estimates of annual yield losses in the United States due to SDS have ranged between 0.6 and 1.9 million metric tons during the years from 2006 to 2014, accounting for $200 to 750 million in monetary losses over the same time.

The study included a 2-year, 3-year, and 4-year crop rotation as well as a control. The rotations were as follows:

·      2-year: corn-soybean

·      3-year: corn-soybean-oat (with a red clover cover crop)

·      4-year: corn-soybean-oat-alfalfa

The study also examined differing crop practices, with manure application on the 3 and 4-year rotations and reduced rates of fertilizers, as well as weed management regimens. The study took place between 2010 and 2015.

Analysis shows cropping system diversification can be an effective strategy to manage SDS, especially when incorporating oat, clover and/or alfalfa into an annual crop rotation. Even in years when SDS disease pressure was low, the strategies’ effect was consistent over six years. SDS severity was 17 times higher in two-year cropping system plots, compared with extended and diversified systems, specifically four-year systems. F. virguliforme was isolated at higher frequency from roots from the 2-year system compared with the more diversified systems in 2012 and 2013.

Low levels of SDS in 2011 and 2012 may be explained by the amount of precipitation in those years. Development of SDS is highly dependent on soil moisture, and higher-than-average precipitation, especially during soybean reproductive stages, has been associated with SDS epidemic years. All 4 years of the study when severe SDS symptoms were observed had one or more months during the growing season where rainfall greatly exceeded the monthly average.

When it came to yield results, three and four-year systems showed 40 percent greater yields than in two-year systems. Between 50-87 percent of yield variance was explained by SDS incidence; SDS severity caused 30-70 percent variation in yields.

Extended and diversified cropping systems were correlated with lower F. virguliforme population densities. In both soybean and corn plots sampled in 2012 and 2013, the pathogen’s density in the soil was approximately fivefold greater in the two-year system, as compared to the four-year system. F. virguliforme can survive in soil for years as thick-walled chlamydospores and rotation with corn has been shown to be ineffective for reducing F. virguliforme soil populations or SDS symptoms.

The explanation for higher SDS severity and pathogen presence in the two-year system may be the result of the greater frequency of soybean planting, which creates inoculum build-up in the soil. Corn residue can support survival of the SDS pathogen, which could help explain increased SDS in two year rotations. It is possible alternating corn and soybean is more conducive to SDS than is interruption of that cycle with other crops.

Alfalfa and clover are susceptible to F. virguliforme infection, thus pathogen reduction in the extended rotation may be more closely attributed to the inclusion of oats. In addition, oat used in rotation or as a cover crop has been shown to suppress root rot diseases on certain crops because it produces avenacins, which are active saponin compounds that have antimicrobial activity against several fungal pathogens.

Diversified cropping systems, especially those integrated with livestock production, offer numerous potential environmental and agronomic benefits, including improved soil quality, greater nutrient cycling and retention, greater water-holding capacity, lower rates of soil erosion, and improved control of weeds, diseases, and insect pests. The loss of crop diversity in the Midwestern United States, due especially to reductions in small grain, hay, and pasture production, is linked with significant reductions in livestock production in the region, thus the reduction of manure application to fields. The study asserts that adoption of diversified systems will require growers to learn new practices and adapt to new farming equipment, which could serve to benefit growers financially in the long-run, by limiting yield loss.

Project Type: 
Duration: 
11/05/2018
Category: 

Inoculation Method Impacts Symptom Development Associated with Diaporthe

Soybean (Glycine max) is one of the most important crops in the United States. One production constraint includes the five diseases caused by species of Diaporthe, which can greatly affect yields. During 2014, approximately 1 million metric tons were lost in the U.S. and Canada from Diaporthe-associated diseases.

A research study used many inoculation techniques over five decades to study more than 150 Diaporthe isolates, that can be further separated into five types, from symptomatic soybean stem samples from Iowa and around the region. The researchers’ goal was to examine aggressiveness, disease severity, pathogen recovery and relative treatment effects of each of the five types of isolates to find the more effective ways to research the diseases, and ultimately combat them. Their study suggests different inoculation methods can have a significant impact on the study of symptom development in soybeans, with the toothpick and stem-wound inoculation methods being the most effective techniques on three of the five types to yield research data.

This study was published in 2019. To view the whole study, click here.

Project Type: 
Duration: 
03/04/2019
Category: 

Effect of Tillage and Cultivar on Plant Population, Sudden Death Syndrome, and Yield of Soybean in Iowa

Sudden death syndrome (SDS) affects soybeans around the world and accounts for millions of tons of yield loss in the United States and Canada, ranking it as one of the top 10 yield-reducing diseases of soybean for 16 years. Managing SDS has been difficult with the lack of effective foliar fungicides and completely resistant cultivars, environmental influences and inconsistent management practices.

The researchers in the study aimed to determine the impact conservation tillage had in relation to SDS. Conservation tillage practices have become common practice to preserve soil moisture and prevent erosion, and has shown results in reducing soybean cyst nematode (SCN) populations in the field. Both SCN and SDS have a linked severity, but SDS also has a positive correlation with the soil moisture content.

The field experiments took place in Iowa in a field with a history of SDS and were evaluated for five consecutive years. Data showed there were differences in root rot severity and foliar disease symptoms across the years among different cultivars, but this was not due to tillage. Although yields were different across the years, researchers write that this was not due to tillage and can be explained by seeding rates and sufficient rainfall. The study confirms using resistant cultivars is the best practice to fight SDS, and that seed treatment, SCN management and diversification in cropping systems can aid in disease resistance. In all, incidences of SDS were not dependent on tillage method, as the incidence of disease was consistent throughout the study. SDS resistant cultivars would make the most impact.  

This study was published in 2019. To view the whole study, click here.

Project Type: 
Duration: 
03/04/2019
Category: 

The Effects of ILeVO and VOTiVO on Root Penetration and Behavior of the Soybean Cyst Nematode

Soybean cyst nematode (H. glycines) is the most damaging pathogen of soybean in the United States and Canada. The main management strategy has been to rotate soybean crops with non host crops. However, this strategy has not proved always effective, leaving the need for more study and application of nematode-protectant seed treatments.

The goal of the study was to determine the effectiveness of two different seed treatments on soybeans: ILeVO (fluopyram) and VOTiVO (Bacillus firmus I-1582). These two seed treatments coat the soybean seeds in active ingredients (AI) to help the plants fight different pests and diseases, while also using a less amount of AIs as it’s applied directly to the seed and root area of the plants and not across an entire field.

The researchers grew soybeans and inoculated the roots of the treated and untreated soybeans with H.glycines at various soil depths. The data supports that ILeVO fights against H.Glycines, but gets less effective as the roots grow away from the treated seed. ILeVO also significantly reduced second-stage juvenile (J2) SCNs compared to the untreated soybean seeds. ILeVO treated seeds also significantly reduced the movement of J2 populations compared to the groups of non treated seeds and groups of just the J2 populations. VOTiVO had no effect on the measured parameters in the study.  

This study was published in 2019. For the whole study, click here.

Project Type: 
Duration: 
04/01/2019
Category: 

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