Australia to approve ISK’s Katana 250 WG Herbicide (containing flazasulfuron)

The Australian Pesticides and Veterinary Medicines Authority (APVMA) is considering an application for registration of Ishihara Sangyo Kaisha, Ltd’s new product Katana 250 WG Herbicide containing 250 g/L of the approved active constituent flazasulfuron, as a water dispersible granule formulation.

The active ingredient, flazasulfuron, inhibits acetolactate synthase (ALS), an enzyme which produces precursors for the synthesis of the branched chain amino acids, leucine, isoleucine, and valine in the treated weed. The Herbicide Resistance Action Committee (HRAC) has categorised flazasulfuron as a sulphonyl urea in group 2 for the purposes of herbicide resistance management.

Flazasulfuron was approved in November 2012 under the approval number 65347; however, no existing use patterns are approved for the active, nor has use in food-producing crops previously been considered.

The proposed product Katana 250 WG Herbicide is a 250 g/kg flazasulfuron water dispersible granule product for pre- and post-emergent control of various broad leaf and grass weeds in vineyards, olive groves, citrus orchards, and under electric power transmission lines and towers in stock exclusion zones on public land. The product is to be applied mechanically by boom sprayer at a rate of 150 to 200 g/ha (37.5 to 50 g a.c./ha) in all proposed use situations.

The APVMA Chemistry section has evaluated the chemistry of flazasulfuron and associated product Katana 250 WG Herbicide, including the manufacturing process, quality control procedures, stability, batch analysis results and analytical methods, and found them to be acceptable.

Based on a review of the chemistry and manufacturing details, the registration of Katana 250 WG Herbicide, containing the approved active constituent flazasulfuron, is supported from a chemistry perspective.

The APVMA invites comment from 1 November 2022 to 28 November 2022 on whether Katana 250 WG Herbicide should be registered.