From Gary Bergstrom, Extension Plant Pathologist, Cornell University
Winter wheat in New York is either beginning to flower now or will do so over the next week. The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and DON contamination when applied at flowering (emergence of anthers on heads). There is an application window of approximately 6 days from the beginning of flowering in which reasonable FHB suppression can be expected. Fungicide products containing strobilurins should not be applied to headed wheat or barley as they may result in increased levels of DON in grain. Caramba or Prosaro applied at flowering will also provide protection of flag leaves against stripe rust (see photo) – an imminent threat at this time. Based on the finding of severe stripe rust (photo courtesy of Mark Avery of Carovail) in some fields in northern Cayuga County this week and high levels of stripe rust in much of the north central, southern and eastern U.S. that could provide spores for aerial transport into New York, I am advising New York wheat growers to consider fungicidal protection of flag leaves against stripe rust infection at this time. The variants of stripe rust being found affect wheat but not barley.
Most winter malting barley fields experienced head emergence and flowering during the past several days and many had Prosaro or Caramba applied at full head emergence. For fields less than a week after head emergence, a triazole spray may still be warranted. Other disease being observed in winter malting barley include scald, powdery mildew, and seedborne loose smut in certain cultivars.
While the current risk of FHB epidemics is low over most of the state, that risk could increase. Check the Fusarium Risk Assessment Tool (http://www.wheatscab.psu.edu/) and your local weather forecast frequently as your crop approaches heading and flowering.
Receive FHB Alerts by Cell Phone:
I will be providing weekly New York commentaries on FHB risk through June. You can subscribe to receive FHB Alerts directly to your Cell Phone (http://scabusa.org/fhb_alert.php). You can select to receive alerts as 1) Text Message Alerts, 2) Email Alerts, or 3) both Text and Email Alerts. To receive alerts for New York, select the Northern Soft Winter Wheat option which provides alerts for MI, NY, WI and VT.
