Fungicide Resistance Action Committee

Introduction and General Information

A FRAC OSBPI Working Group was formed in 2015 to generate common resistance management recommendations for the fungicide oxathiapiprolin and fluoxapiprolin.

Go directly to FRAC-Recommendations for Resistance Management for OSBPI Fungicides.

OSBP fungicides are active against oomycete fungi and used for the control of Phytophthora and downy mildews of numerous crops. OSBPIs inhibit an oxysterol binding protein (OSBP) homologue. Oxysterol binding proteins are implicated in the movement of lipids between membranes, among other processes. Inhibiting OSBP may disrupt other processes in the fungal cell, such as signaling, maintaining cell membranes, and the formation of more complex lipids that are essential for the cell to survive.

Oxathiapiprolin and fluoxapiprolin are cross-resistant.

OSBPIs have been classified under the FRAC Code 49. The resistance risk is medium to high.

FRAC Code Target site and code Group name Chemical group Common name Comments
49 F9
lipid homeostasis and transfer/ storage  
OSBPI oxysterol binding protein homologue inhibition piperidinyl-thiazole-isoxazolines oxathiapiprolin

Resistance risk assumed to be medium to high (single site inhibitor). Resistance management required. 


Jean-Luc Genet

Corteva agriscience
82 rue de Wittelsheim
68700 Cernay, France