Frac code

FRAC CODE LIST 2: Fungicides sorted by modes of action
INTRODUCTION
The following table lists commercial fungicides according to their mode of action and resistance risk. The most important bactericides are also included. The Table headings are defined as: MOA Code Different letters (A to I, with added numbers) were used to distinguish fungicide groups according to their general mode of action(MOA) in the biosynthetic processes of fungi. The grouping was made according to the processes in primary metabolism from nucleic acids synthesis (A) to secondary metabolism with melanin synthesis (I) at the end of the list, followed by host plant defence inducers (P), recent molecules with an unknown mode of action and unknown resistance risk (U, transient status, mostly not longer than 8 years,until information about mode of action and mechanism of resistance becomes available), and multi-site inhibitors (M). Target Site of Action If available the biochemical mode of action is given. In many cases the precise target site is not known. However, a grouping can be made due to cross resistance profiles within a group or in relation to other groups. Group Name The Group Names listed arewidely accepted in literature. They are based on different sources (mode of action, first important representative, chemical group). Chemical Group Sub-grouping due to chemical considerations. Common name Accepted (or proposed) common name for an individual active ingredient expected to appear on the product label as definition of the product. Comments on Resistance If field resistance is known to onemember of the Group, it is most likely but not exclusively valid that cross resistance to other Group members will be present. There is increasing evidence that cross resistance may not be clearly visible between Group 1

members and that the degree of the effect can differ both between group members and fungal species or even within species. For the latest information on resistance and crossresistance status of a particular fungus-fungicide complex, you are advised to contact your local FRAC representative, product manufacturer’s representative or crop protection advisor. The intrinsic risk for resistance evolution to a given fungicide group is estimated to be low, medium or high according to the principles described in FRAC Monographs 1, 2 and 3. Resistance management is driven bypathogen risk and agronomic risk (see FRAC pathogen risk list). Similar classification lists of fungicides have been published by T. Locke on behalf of FRAG–UK (Fungicide Resistance, August 2001), and by P. Leroux (Classification des fongicides agricoles et résistance, Phytoma, La Défense des Végétaux, No. 554, 43-51, November 2002). FRAC Code Numbers and letters are used to distinguish thefungicide groups according to their cross resistance behaviour. The numbers were assigned primarily according to the time of product introduction to the market. The letters refer to P = host plant defence inducers, M = multi-site inhibitors, and U = unknown mode of action and unknown resistance risk. Last update: December 2005 Next update: December 2006

2

MOA

TARGET SITE GROUP NAME AND CODECHEMICAL GROUP

COMMON NAME benalaxyl furalaxyl metalaxyl metalaxyl-M (=mefenoxam) oxadixyl ofurace bupirimate dimethirimol ethirimol

COMMENTS

FRAC CODE

A1:

acylalanines PA – fungicides (PhenylAmides)

Resistance and cross resistance well known in various Oomycetes but mechanism unknown. High risk. See FRAC Phenylamide Guidelines for resistance management Medium risk Resistance andcross resistance known in powdery mildews. Resistance management required. Resistance not known

4

A: nucleic acids synthesis

RNA polymerase I

oxazolidinones butyrolactones

A2:
adenosindeaminase

hydroxy(2-amino-) pyrimidines isoxazoles heteroaromatics isothiazolones

8

A3:
DNA/RNA synthesis (proposed)

hymexazole

32

octhilinone Bactericide. Resistance known. Risk...