Crop & Pest Report

Accessibility


| Share

Late-Season Head Diseases of Wheat (07/30/15)

Harvesting of wheat and other small grains is starting to begin across the state, whereas some of the wheat has a few more weeks before full maturity.

Late-Season Head Diseases of Wheat

Harvesting of wheat and other small grains is starting to begin across the state, whereas some of the wheat has a few more weeks before full maturity. The relatively wide window of wheat maturity has stimulated questions on the identification and/or management of head diseases found in wheat.

Fusarium Head Blight (Scab):

Several reports of scab continue to be documented. The IPM survey scouts have reported low to moderate scab levels in most fields, with a few fields having high levels of scab (Figure 1). The ideal time to scout for scab is about a week after flowering until the heads begin to ripen. Look for prematurely bleached white florets on the head that are sometimes accompanied by an orange to salmon growth on the floret (mass of fungal spores). Stem discoloration may occur below the head as a result of the Fusarium pathogen colonizing stem tissue (Figure 2).

ppth.friskop.1.wheat scab 1 map

ppth.friskop.2.wheat scab 2 heads

Ergot:

Ergot is often one of the most recognizable head diseases of small grains. Hard, black to purple, irregular structures (sclerotia) are seen in place of wheat kernels (Figure 3). The ergot pathogen infects the plant at flowering when cool wet weather is present. The primary management of this disease includes crop rotation, tillage to bury sclerotia and using ergot free seed. Studies have shown that fungicides are inconsistent in managing this disease.

ppth.friskop.3.wheat ergot

Sooty Mold:

Sooty mold is a general name given to a variety dark green to black fungi found on dead or decaying wheat heads (Figure 4). Sooty molds are often seen on heads that have been damaged by wheat stem maggot, root rots or other sources of stress that cause wheat plants to die prematurely. The presence of sooty mold is higher in years when harvest is delayed or when frequent rain events occur at the end of the growing season.  Although sooty molds may discolor wheat kernels, management is not needed for this disease.

ppth.friskop.4.wheat sooty mold

Andrew Friskop

Extension Plant Pathology, Cereal Crops

 


This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

USDA logo

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.