Nathan Kleczewski, Extension Specialist – Plant Pathology; nkleczew@udel.edu; @Delmarplantdoc
Our barley is starting to ripen and wheat finished flowering last week in Delaware and Maryland. Growers will want to check fields 18-24 days after flowering to assess fields that may have elevated risk levels for vomitoxin contamination. Fields with a high incidence of Fusarium Head Blight may be at risk for elevated vomitoxin. To assess Fusarium head blight (FHB), run multiple transects through a particular field. The number of transects should be sufficient to give you a fairly good overall representation of the field. When we run field level assessments for FHB a transect typically is 75-100 yards long. Fifty heads are picked during the course of walking the transect, with care taken to not look at the heads being sampled. This way you ensure that your sample is not biased, purposely or not, in favor of healthy or symptomatic heads. After you have collected all the heads from a transect, mark the total collected and the number with FHB symptoms (bleached florets or heads with pink at the base of the floret in many cases). If you have a high incidence of FHB you should try and do the following for that field:
- Harvest it as early as possible
- Dry grain to at least 15% moisture if you have the ability to do so
- Store the grain separate from fields without significant FHB issues
- Harvest with an increased fan speed, which helps removes lightweight, vomitoxin-rich tombstones from the heavier weight, higher quality grain.
Lightweight kernels called “tombstones (left) compared to healthy wheat grain.