Month: March 2018

Western Bean Cutworm and Mycotoxin Screening – 2017 New York and Vermont Corn Silage Hybrid Trials

Joe Lawrence, Gary Bergstrom, Jaime Cummings, Elson Shields, Ken Wise, Mike Hunter

Mold and mycotoxin development in corn ears and the resulting corn silage continues to be a major concern for dairy producers. Mycotoxins can result in a range of problems for livestock throughout the year as they are ingested with the feed. The presence of mold does not always have a strong correlation to mycotoxin development but it does present the chance for incidence to occur.

A number of factors influence the prevalence of molds from year to year. Conducive weather conditions for mold and mycotoxin development are outside the control of management options. But hybrid characteristics and physical damage to the ears can be managed through the selection of hybrids and pest resistance traits in the hybrids.

The presence of Western Bean Cutworm (WBC) in NY corn fields continues to expand as shown in the WBC Pheromone Trap Network coordinated by the NYS IPM program, though the insect’s apparent population varies significantly across the state (Figure 1).

Where WBC populations are high, the corresponding ear damage from WBC feeding can leave wounded corn ears more susceptible to pathogen development, but a clear relationship between ear damage and mycotoxin development has not been documented. A number of mold species may develop on corn ears and a relatively few of these produce mycotoxins. Principal concern in New York is with the mycotoxins deoxynivalenol (DON or vomitoxin) and zearalenone, both produced by the fungus Fusarium graminearum.

While WBC damage to corn ears can be significant and may have detrimental effects on corn grain yield and quality, the economic impact on corn silage is less understood. For corn silage growers, understanding whether or not this pest significantly impacts the yield or quality of the forage is critical to their decision making for managing this pest.

Since the Cry1F protein, which has most commonly been utilized for protection against numerous corn insect pests, has been found to be ineffective against WBC, producers are left with limited management options. Currently the Vip3A trait in select corn hybrids in combination with a scout and spray program is the best option for WBC management in areas where the pest is prevalent.

The Commercial Corn Silage Testing program conducted by Cornell University in collaboration with the University of Vermont and the Northeast dairy industry offers a good opportunity to evaluate numerous hybrids for ear damage from WBC and mycotoxins. This was done in 2017 with support from both the New York Corn Growers Association and the Northern New York Agricultural Development Program.

In 2017, 49 hybrids were selected and planted in replicated plots at two locations in NY (Aurora and Madrid). Each plot was scouted prior to harvest for WBC feeding damage to the ears. Composite samples, of whole plant silage, for each hybrid were taken at harvest and submitted to the Dairy One forage laboratory for a mycotoxin screening package which included aflatoxins B1, B2, G1, G2, vomitoxin, 3-acetyl DON, 15-acetyl DON, zearalenone, and T2 toxin.

The results of the WBC and mycotoxin screening project revealed large differences in the number of hybrids damaged by WBC, but surprisingly few hybrids tested positive for measurable mycotoxins (Table 1).

The most prevalent species of mycotoxin-producing mold found in the screening was Fusarium graminearum which can also infect corn ears through the silk channels at the time of pollination during favorable weather conditions and result in contamination of the grain and silage with the mycotoxins DON, 3-ADON, 15-ADON, or zearalenone. A review of the 2017 weather data at both trial sites showed wet conditions conducive to this type of infection. As expected for New York, no aflatoxins were detected.

While there are numerous ways in which molds can establish themselves in forages, this study reflects a common challenge researchers face while attempting to document the conditions where mycotoxin development is likely. Recognizing that results are specific to the growing season experienced in 2017, which was conducive for silk channel infections. A different relationship between WBC damage and mycotoxin development may be found during a growing season less conducive to silk channel infections. These results from one year of data do not provide strong evidence that WBC damage is a significant concern for corn silage growers who are worried about mycotoxins in their silage. Multiyear studies, including years of varying weather conditions, are required for further evaluating these risks and providing recommendations. It is also important to note that these results do not reflect what may occur in corn harvested for grain as the time between silage harvest and grain harvest offers additional opportunities for infection and growth.

Additionally, there was no correlation between crop yield or starch content with WBC damage in this study. Growers should continue to scout for this pest and weigh the cost of control with the potential for damage.

An article addressing integrated pest management (IPM) practices for WBC has been generated by the NYS IPM team.

Integrated Pest Management for Western Bean Cutworm (Richia albicosta), https://blogs.cornell.edu/ipmwpr/

Anatomy of a Wet Year: Insights from New York Farmers

Shannan Sweet1, David Wolfe1, and Rebecca Benner2
1School of Integrative Plant Science, Horticulture Section, Cornell University
2The Nature Conservancy, New York State Office, Albany NY

Key Findings

  • The 2017 heavy rainfalls and flooding impacted farms across New York State
  • Crops grown on clayey soils suffered an estimated 53% loss in crop yield and crops grown on gravelly, sandy or siltier soils suffered estimated crop yield losses of 25% or less
  • In addition to yield losses, 95% of farmers said the quality of their crop was negatively impacted
  • 30% of farmers said they would have increased their drainage infrastructure, including adding tiling and drainage ditches, if they had known how wet 2017 would be

Background

A wet spring, followed by higher than average precipitation and heavy rainfall events (e.g. the heaviest 1% of all daily rainfall events) during the 2017 growing season (NRCC) led to saturated soils and flooding on many farms throughout New York State (NY). The frequency of heavy rainfall events have already increased by 71% in NY over the last half century (NCA 2014), and this trend is predicted to continue in the future (Wuebbles et al. 2014). Given this, and to get a sense of how farmers were affected by these conditions, as well as how they coped, we surveyed farmers across NY State throughout September of 2017. The survey was distributed online and in paper format with help from Cornell Cooperative Extension, The Farm Bureau, and New York State Department of Agriculture & Markets. A majority of the 45 farms in 24 counties were in areas of the state that experienced the heaviest rainfalls, and we had fewer responses from farms in the Adirondacks region and southeastern part of the state, where heavy rains and flooding were less prevalent (Fig. 1).

Fig. 1. New York State percent of normal precipitation for March through August of 2017 (map provided by the NRCC). Black dots indicate counties where farmers responded to our survey.

Heavy rainfall and flooding impact

Of the farmers surveyed, those with heavier clay soils estimated crop yield losses of 53%. More gravelly soils led to lesser yield losses (17%), and for crops grown on siltier or sandier soils farmers estimated yield losses of 22 to 25%. Vegetable, field, and fruit crops suffered estimated yield losses of 38%, 32%, and 24%, respectively (Fig. 2). Importantly, 95% of farmers said the quality of their crop was negatively impacted by issues related to the heavy rainfalls in 2017 (see Fig. 3 for list of ‘issues’).

Fig. 2. Percent crop yield loss by soil type (top) and crop type (bottom).

When asked what the economic impact of the heavy rainfalls was on their farm, 80% of farmers said it was either “moderate” or “severe”, 17% said it was “minor”, and 3% said the heavy rainfalls were merely a “nuisance” and had almost no economic impact. In rating the importance of various issues related to heavy rainfalls in 2017 in terms of economic impact on their farm, over half of the farmers rated saturated soils and field flooding, delays in or inability to plant or harvest, inability to use equipment, lack of field access, and crop disease as “extremely or very” important (Fig. 3).

Fig. 3. Response to the survey question “How important are these issues {listed on figure} related to heavy rainfalls in 2017 in terms of economic impact on your farm?”. Figure shows percent of farmers rating the issues as (a) extremely + very important, (b) fairly + somewhat important, and (c) not important.

Adaptive capacity

82% of farmers said they use drainage ditches or drainage tile to help deal with heavy rainfalls, yet over half of farmers said they did not have enough infrastructure and/or equipment to deal with heavy rainfalls. Further, 70% of farmers said the 2017 heavy rainfalls led to the recognition of weaknesses or limitations in the infrastructure on their farm, particularly in relation to manure management and drainage infrastructure. And when asked what they would have done differently if they had known how wet 2017 would be there was a variety of responses (Fig. 4). Nearly 1/3rd of farmers said they would have expanded their drainage capacity (e.g. more drainage tiles and ditches, etc.). Nineteen percent would have changed their fertilizer, herbicide, or pesticide application timing, and another 10% would have adopted better soil health practices, such as using cover crops, reducing tillage, and using composts or mulches.

Fig. 4. Response to the survey question “What might you have done differently if you had known how wet this summer would be?” The “other” responses included: plant more acres, plant in different location, and increase greenhouse infrastructure.

We also gave farmers a list of soil health practices and asked them to tell us if, for the ones they use on their farm, any of them lessened the impact of heavy rainfalls in 2017 (Fig. 5). Aside from “the use of mulches”, which 67% of farmers said did not help them, a vast majority said other soil health practices did help. Over 70% of farmers said that practices such as “use of winter cover crops”, “reduced tillage”, “use of composts or manure”, “leaving crop residues”, and/or “changing crop rotations” did lessen the impact of the very wet 2017 season. To learn more about soil health check out https://blogs.cornell.edu/soilhealthinitiative/.

Fig. 5. Response to the survey question “Did any soil health practices you have adopted on your farm lessen the impact of heavy rainfalls in 2017?”.

Insights for extension educators, researchers and policy makers

Over half of the farmers reported experiencing issues on their farm related to heavy rainfalls or flooding every 1 to 4 years. The other 46% reported this occurrence rarely or only every 5 to 6 years. While climate projections for NY indicate that we are likely to expect more heavy rainfall events, as well as more short-term summer droughts in the future (NCA 2014, Wuebbles et al. 2014, Sweet et al. 2017), our survey results suggest that, though farmers were concerned about the impacts of these events in the future, they are not as convinced that these events will occur more frequently in the future. For instance, 49% of farmers said they were “extremely or very” concerned that heavy rainfalls and flooding will negatively impact their farms in the future. Yet, only 38% said they were similarly concerned that such events may occur more frequently in the future (Fig. 6). Also, given the drought in 2016 (Sweet et al. 2017), we asked farmers a similar series of questions pertaining to drought. Though 31% of farmers were “extremely or very” concerned that drought may negatively impact their farm in the future, only 24% were concerned that drought may occur more frequently in the future.

Fig. 6. Level of concern by farmers of the frequency of occurrence and impact of (a) heavy rainfalls/flooding and (b) drought.

With climate change, NY farmers are likely to continue facing unique challenges related to both increased heavy rainfall events as well as short-term summer droughts. Resource managers and planners, engineers, researchers, extension agents, NGO’s and other farm-support organizations need to prepare to help farmers adapt to and become more resilient to an uncertain future.  Information collected from farmers about how they might adapt to future climatic events suggests there could be potentially dramatic consequences not only for farmer livelihoods and food production, but also for NY natural resources.  For example, certain adaptation practices could impact downstream water quality and availability.

Based on our survey results, here are some ideas farmers had on how the above mentioned organizations might help farmers better prepare for and cope with heavy rainfalls events in the future:

  • Low-cost loans or ‘in kind’ grants to help with costs of improving drainage (e.g. drainage ditches and tiles)
  • Continued education on nutrient management planning
  • Advice on how to increase soil organic matter for improved drainage capacity
  • Information about cropping options and strategies to cope with heavy rainfalls
  • Lower cost and better fungicides for wet years
  • Increased town drainage (e.g. more funding for ditch digging and for clearing debris out of ditches)

References:

NRCC – Northeast Regional Climate Center. URL: http://www.nrcc.cornell.edu/regional/monthly/monthly.html.
NCA – National Climate Assessment (2014). URL: https://nca2014.globalchange.gov/report/our-changing-climate/heavy-downpours-increasing#graphic-16693.
Sweet et al. (2017). URL: https://www.sciencedirect.com/science/article/pii/S0168192317302800
Wuebbles et al. (2014). URL: https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-12-00172.1

This project was funded by Cornell University’s Atkinson Center for a Sustainable Future and The Nature Conservancy. For more information, contact Shannan Sweet: 126 Plant Science Bldg., Ithaca, NY 14853; 607 255 8641, sks289@cornell.edu