SCAB FUNGICIDE APPLICATION
Many area wheat
fields are beginning to head. Growers should consider the use of a fungicide
for Fusarium head blight (scab) suppression because of the combination of high
grain yield potential, recent (and probably continued) wet weather, and
continued presence of leaf spot disease.
The optimum timing
of fungicide application for scab suppression is at early flowering for spring
wheat and durum, and at early full head emergence for barley. Early flowering
in wheat means 10-25% of the main stem heads are flowering. The fungicides and
timing of application also will provide good control of leaf spot diseases
including tan spot, Septoria leaf blotch, and leaf rust.
NDSU Extension
Service circular AE-1148 ‘Application of fungicides for suppression of Fusarium
head blight (scab)’ should be consulted to aid in effectively applying
fungicides. A summary of the recommendations include the following:
* For ground
application, angle spray toward grain heads, using forward and backward mounted
XR8001 nozzles or nozzles that have a two-directional spray, such as Twinjet
nozzles.
*When using XR
flat fan tips, use 40 psi with 9-10 gpa, and 90 psi with 18 gpa.
*Increase spray
volume for durum and barley to improve head coverage and disease control.
*Use a good
adjuvant.
*Use dew as
additional water.
*When using aerial
application, spray in evening or early morning to capture dew as extra water
volume, and use a small droplet size.
*Use NDSU’s
general guidelines for determining need for fungicide application based on
yield potential, crop price, disease presence, recent weather, and forecast for
upcoming weather. NDSU also has a disease forecasting system for scab and leaf
disease ().
SCLEROTINIA FUNGICIDES FOR CANOLA
Area canola fields
have started to flower at least two weeks ago. Recent rain and continued forecast
for more moisture will increase the likelihood of sclerotinia infection in
flowering canola.. General considerations to make a decision on fungicide
application for sclerotinia include: canola seed yield potential of at least
2000 lb/acre, wet weather in the past 1-2 weeks and forecast for more in the
future, and a history of sclerotinia in or near the current canola field.
Timing of
fungicide application is critical for satisfactory results and many area fields
may be soon past the stage for acceptable results with fungicide application.
The following is
general information on the two fungicides:
*Quadris: apply at
10 to 25% bloom (about 3-7 days after flowers are detected). Rate = 9.2 to 15.4
fl oz/acre (9.2 fl oz/acre is suggested at a cost of about $21-22/acre plus
application costs).
*Ronilan: apply at
20 to 50% bloom (about 4-8 days after flowering begins). Rate = 10.6 to 16
oz/acre (suggested rate is 12 oz/acre at a cost of about $16/acre plus
application costs).
Consult labels for
details before use!