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State
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"Do not expect Folicur to provide the same level of head blight/DON control as you have come to expect when fungicides are used to control other wheat diseases. The key is to think in terms of disease suppression, not control." Don Hershman, UK plant pathologist |
By Laura Skillman PRINCETON,
This
new fungicide tool, when used with other management tactics, will reduce the
risk of FHB and DON as long as weather conditions are not highly favorable to
FHB and DON during crop flowering and grain fill, said Don Hershman, University
of Kentucky Cooperative Extension Service plant pathologist. Management tactics
include using high quality seed with known high germination, planting moderately
resistant varieties, planting varieties with varying maturity dates, and using
crop rotation and tillage. Hershman
and Steve Isaacs, Hershman
cautioned that Folicur is not a "silver bullet" for managing head
blight and DON. A great deal of research suggests that about 30 percent
reduction in FHB symptoms and DON accumulation is a reasonable expectation for
winter wheat. Sixty percent control or more has been achieved in rare field
studies in the “In
other words, do not expect Folicur to provide the same level of head blight/DON
control as you have come to expect when fungicides are used to control other
wheat diseases,” he said. “The key is to think in terms of disease
suppression, not control.” Nevertheless,
Hershman said, a 30 percent reduction in head blight and DON could have a
significant economic impact locally, and statewide, if there is a moderate
amount in 2004. But he advised that significant losses are likely even where
Folicur has been applied if weather conditions favor severe head blight this
spring. The
Section 18 allows for a single ground or aerial application of four fluid ounces
per acre of Folicur 3.6 F to wheat at full head emergence to very early
flowering. Applications cannot be made before full heading or within 30 days of
harvest. The Folicur Section 18 applies only to wheat and is good for the period
April 20 to May 20, 2004. The
optimal time for application is 25 percent of primary heads, scouted at several
random sites in a field, showing anthers, Hershman said. Excellent
fungicide coverage on wheat heads is crucial to achieve the greatest possible
disease suppression. When spraying by ground using double swivel nozzles
provides the best coverage with twin jet nozzles providing acceptable coverage.
Ground speed should not exceed 8 miles per hour. For
aerial application, nozzles should be angled to direct spray 90 degrees to the
direction of travel. It is best to spray early in the morning or at other times
when heavy dew is present. This will facilitate fungicide coverage on heads. Many
wheat producers will have to decide whether to or not to use Folicur this
spring. Delaying application of Folicur to achieve head blight/DON suppression
could allow for excessive build-up of other fungal diseases. Conversely,
application of other labeled fungicides before full head emergence will control
other diseases, but will have no impact on either head blight or DON. Making
both applications, while legal, will be economically difficult to justify,
Hershman said. “In
this case, I would advise growers that foliar disease development should take
precedence since little is to be gained by suppressing head blight or DON if
serious losses are incurred by allowing fungal diseases to develop,” he said. For
more information on this Section 18 and wheat diseases, contact a
-30- Writer: Laura Skillman 270-365-7541 ext. 278 Source: Don Hershman, 270-365-7541 ext. 215 Return to Main News page. |