USDA LTAR Common Experiment measurement: Cereal crop mycotoxin concentration
Brook J. Wilke, Martin I. Chilvers
Long-Term Agroecosystem Research
LTAR
Common Experiment
crops
crop quality
mycotoxin
deoxynivalenol
corn
small cereal grains
disease severity
Disclaimer
This research is a contribution from the Long-Term Agroecosystem Research (LTAR) network. LTAR is supported by the United States Department of Agriculture. The use of trade, firm, or corporation names in this publication is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the United States Department of Agriculture or the Agricultural Research Service of any product or service to the exclusion of others that may be suitable. USDA is an equal opportunity provider and employer.
Abstract
Crop pests and diseases can reduce crop yields, but they can also worsen crop quality via reduced grain density or accumulation of toxins produced by fungal diseases. Several mycotoxins are known to harm crop quality, with deoxynivalenol (a.k.a. Vomitoxin or DON) being one of the most common, especially in corn and cereal grains. Subsequently, deoxynivalenol concentration can be correlated with disease severity. This protocol describes a process for measuring DON in cereal grains harvested from LTAR plots and fields.
Steps
Sample collection, processing, and analysis
Collect a representative subsample of grain from each experimental unit in the study that contains grains produced by grass species possibly infected with DON, including plots and fields.
If using the whole plot/field harvest, combine multiple subsamples from each plot or field to accurately represent the entire plot or field.
Dry grain samples to a stable moisture content and then submit them to a laboratory for analysis of deoxynivalenol (a.k.a. Vomitoxin or DON).
Sites may choose to submit samples to a commercial laboratory or analyze them on-site.
Several devices are available for on-site DON testing. For on- site analysis, follow the protocol suggested by the manufacturer of your device .
Covariate metrics to be sampled concurrently
Other mycotoxins may be quantified at the same time, including aflatoxin, ochratoxin, zearalenone, fumonisin, or ergot alkaloid.
Analyze non-grass crops for other mycotoxins that are expected and specific to that crop.
Note observations of diseases and pests, including presence and abundance, by crop scouting
exercises. These data will be important covariates to consider when evaluating mycotoxin
concentrations.
Calculations
Determine mycotoxin levels as a concentration (e.g., ppm) and report them in the database using those units.
Quality assessment
Be sure to dry grain to stable moisture quickly after harvest and store at Room temperature until
analysis.
Representative subsamples are critical from each experimental unit analyzed.
Archiving
Grain samples should already be archived based on the crop productivity protocols.
Recommendations for data collection
Table 1. Summary of recommendations for measuring mycotoxins.
| A | B | C | D |
|---|---|---|---|
| Attribute | Preferred | Minimum | Comments |
| Spatial scale | Plot and field | Plot and field | Only measure specific mycotoxins for grain species commonly infected. For example, legume crops do not commonly have DON concentrations worth measuring. |
| Frequency | Once per harvest | Once per harvest | |
| Covariate metrics | Other mycotoxins (aflatoxin, ochratoxin, zearalenone, fumonisin, or ergot alkaloid). Pest and disease observations during the growing season. | Pest and disease observations during the growing season |
