Managing Fungicide Resistance

With limited fungicide modes-of-action available to manage crop disease it is important to manage the risk of resistance developing. This post outlines strategies for managing fungicide resistance.

Introduction

Resistance is the heritable loss of sensitivity of disease to a fungicide, resulting in less efficacy in the field. Some fungicide modes-of-action are inherently more prone to resistance developing.

Strategies

To reduce the selection pressure on fungicides, it is recommended that growers use a spray program that incorporates a range of different mode-of-action fungicide groups and rotate between these different groups. Where permitted, mixtures of modes-of-action can also assist with resistance management.

CropLife Australia recommends growers follow a resistance strategy such as the following for managing Botrytis Grey Mould in pulse crops:

1. Do not apply more than two consecutive Group 1 sprays, including a seed treatment containing a Group 1 fungicide. Apply no more than two consecutive sprays of a Group 1 fungicide alone.
2. Do not apply more than two Group 1 treatments (including seed treatment) in a season.
3. Do not apply more than two Group 2 sprays in one season. Apply no more than two consecutive sprays of a Group 2 fungicide.
4. Do not apply more than two Group M3 treatments (including seed treatment) in a season. Apply no more than two consecutive sprays of a Group M3 fungicide alone.
5. It is advisable to rotate groups between seasons.

To see the fungicide MOA Group for each fungicide refer to Tables 2, 3 ,4 ,9 and 10 included in the ADAMA Foliar Fungicide Guide for Winter Pulses by clicking 'Download' below.

For pulse diseases where established resistance management guidelines do not exist, CropLife recommends the use of fungicides from any given activity group (excluding Group M) be limited to a maximum of one third of the total number of fungicide applications.

The use of consecutive applications of fungicides from the same activity group should also be limited by alternating between products from different activity groups.

The use of Group M fungicides is not included in this limitation as these fungicides carry an inherently low risk for fungicide resistance.

Latest advice from CropLife Australia

For the latest advice on fungicide resistance management strategies visit the Fungicide Resistance Management Strategies page of CropLife Australia.

Foliar Fungicide Guide for Winter Pulses

This post is extracted from the ADAMA Foliar Fungicide Guide for Winter Pulses. If you haven't already downloaded the guide, click 'Download' below for your copy.