Three new fungicides have been given Section 18 labels for use against Asian soybean rust in Iowa (Table 1—please note, this table is based on the latest information available as of May 2, 2005). They are:
- Headline® SBR, a co-pack of pyraclostrobinand tebuconazole;
- Orius™ 3.6F, which contains the active ingredient tebuconazole; and
- Quilt™, a premix of azoxystrobin and propiconazole.
In addition, a number of amendments have been made to existing Section 18 labels:
- The expiration date for all fungicides with Section 18 labels is November 10, 2007.
- A maximum of three total applications using approved Section 18 products collectively may be made under the soybean rust Section 18. This includes all products that have been approved or may be approved for use at a later date. However, no more than two applications may be made with any given active ingredient. So, for example, a grower cannot make two applications of Tilt® followed by one application of Stratego®, because both products contain propiconazole.
- The spray intervals for Folicur® and Stratego® have been changed to 10 to 21 days (the previous interval was 10 to 14 days).
- Products containing the active ingredient propiconazole (namely Tilt®, Bumper®, Propimax™, Quilt™, and Stratego®) may be applied no later than soybean growth stage R5.
- Products containing the active ingredient tebuconazole (namely Folicur®, Orius™, and Headline® SBR) have a preharvest interval (PHI) of 30 days (the previous PHI was 21 days).
- Spray adjuvants can now be used with Stratego® (previously spray adjuvants were not allowed).
Please visit http://soybeanrust.info for additional information about these fungicides. In particular, users should be familiar with personal protective equipment required, ground and surface water advisories, drift concerns relating to certain varieties of apples, and restrictions regarding the use of soybean hay and forage.
Table 1. Section 3 and Section 18 products for Asian soybean rust management (as of May 2, 2005). Click on the table below to view PDF version.
This article originally appeared on pages 60-61 of the IC-494 (8) -- May 2, 2005 issue.