Julius-Kühn-Archiv (Feb 2014)
Control of ALS resistant volunteer oil seed rape and other dicotyledonous weeds with GF-145, a new cereal herbicide product containing isoxaben and florasulam
Abstract
GF-145 contains the active ingredients isoxaben (610 g ai/kg) and florasulam (40 g ai/kg) and is formulated as a Wettable Granule (WG). The active ingredients are found in commercial products such as Primus™2 (florasulam), Starane XL™ (fluroxypyr + florasulam), Ariane C™ (fluroxypyr + florasulam + clopyralid) or Flexidor™ (isoxaben). While florasulam has been widely used in cereal crops in recent years, isoxaben offers a new mode of action (MOA) for use in German cereal herbicides even when considering that Flexidor™ has had regulatory approval in 1988 to 1991. The MOA of isoxaben is inhibition of cellulose synthesis (HRAC class L), while florasulam inhibits Acetolactate Synthase (ALS) and is a representative of the HRAC class B. It is known that florasulam works through uptake by green leaves. Isoxaben is a herbicide with soil activity and with a very low activity when foliar applied, except on some species in the cruciferae family. GF-145 is intended to be applied in the autumn in cereals (wheat, barley, rye, triticale) for the control of ALS resistant volunteer oil seed rape and annual dicotyledonous weeds including Matricaria spp., Stellaria media, Papaver rhoeas, Capsella bursa-pastoris, Myosotis arvensis, Lamium spp., Galium aparine, Veronica spp. and others when applied at early post-emergence from BBCH 10 to 13 of the crop. The use rate in winter cereals is 95 g product/ha (58 g ai/ha isoxaben plus 3.75 g ai/ha florasulam). Field trials conducted in previous years confirmed excellent selectivity in all cereal crops and efficacy trials initiated in autumn 2012 show that GF-145 provides excellent and superior control to ALS resistant oil seed rape that was better than straight florasulam and other ALS active ingredients. GF-145 adds a new MOA to the cereal herbicide portfolio and controls volunteer oil seed rape, cruciferous weeds and broad-leaved weeds and is more robust than florasulam based products that do not contain isoxaben.
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