The Australian Wine Research Institute

27 October 2025

Under conditions favourable to disease development, downy mildew can lead to severe crop losses, especially when fungicide resistance develops. This eBulletin covers the key reasons resistance occurs, how to detect and confirm it, and strategies for effective management. 

 About downy mildew  

When conditions favour disease prevalence, Downy mildew is one of the most important diseases of grapevines in Australia. The disease is caused by the pathogen Plasmopara viticola, which affects green grapevine tissue. When the following set of conditions arise, downy mildew can become a problem:  

What is fungicide resistance in downy mildew and why does it matter? 

Downy mildew can develop resistance to fungicides when the pathogen Plasmopara viticola changes genetically over time, making fungicides less effective or even ineffective at controlling it.  

Fungicide resistance can have serious flow-on effects for winegrape production. As resistance builds, growers face fewer effective fungicide choices, sprays are applied more often, and input costs are higher. Fungicide resistance can also increase environmental concerns, attract negative public attention, reduce yields, and even lead to fruit rejection at the winery. 

Read more about how fungicide resistance occurs and how to avoid it here. 

 

How do you know if you have resistance to downy mildew fungicides? 

If you are applying fungicides each year and the incidence and severity of downy mildew in your vineyard seems to be getting worse, you may have fungicide resistance or reduced sensitivity. 

 

 Downy mildew fungicide resistance detections in Australian vineyards 

Recent research led by South Australian Research and Development Institute (SARDI), a research division of the Department of Primary Industries and Regions (PIRSA), has confirmed the detection of downy mildew fungicide resistance to several fungicide groups commonly used in vineyards.   

Active ingredient	Fungicide Activity Group	Resistance status
metalaxyl	4	Detected
pyraclostrobin	11	Detected
dimethomorph	40	Not detected
mandipropamid	40	Not detected

Source: South Australian Research and Development Institute (SARDI)

While only one representative formulation per active ingredient was evaluated as part of this research, a range of registered products for each of the above active ingredients can be found in Table 2 of the 2025/26 Agrochemicals registered for use in Australian viticulture, commonly known as the ‘Dog book’. A full list of detections from this research can be found on page 18 in the 2025/26 ‘Dog book’. 

 

How can you test for downy mildew resistance? 

If you suspect you may have fungicide resistance in downy mildew, a free national testing service to monitor fungicide resistance in downy mildew, powdery mildew and botrytis in winegrapes is available (until June 2027).  

Samples for downy mildew resistance testing can be submitted to the SARDI Horticulture Pathology Laboratory by following the detailed sampling instructions here.  Biosecurity considerations apply. Prior to sending samples to the laboratory, please contact ismail.ismail@sa.gov.au.  

This testing service is part of a research project led by SARDI in collaboration with Curtin University and the AWRI, and funded by Wine Australia, the Cooperative Research Centre for Solving Antimicrobial Resistance in Agribusiness, Food, and Environments (SAAFE CRC), SARDI and Curtin University.  

 

Importance of spray program management 

Overuse of the same fungicide groups as part of a spray program is a key contributor to the development of downy mildew fungicide resistance.  

One of the key information sources provided annually in the ‘Dog book’ to assist you in reducing downy mildew fungicide resistance is the CropLife Australia resistance management strategy on page 15.  

Before you order chemicals for the new season, review this strategy alongside your proposed spray program. Take note of: 

• the fungicide group associated with each product you plan to apply; 

• which fungicide groups must be applied as a protectant − Groups 11, 11+3, 21, 40, 45+40, 40+49 and 49, or can be applied after an infection event but before the first sign of oilspots – Group 4;  

• which fungicide groups must be applied as part of a co-formulation or tank-mixed with an alternative chemical activity group − Groups 4* and 49;  

• the suggested maximum number of times each fungicide group be applied in the season; and 

• whether the fungicide group can be applied as a consecutive spray in the program – Groups 4, 21, 40 and 45+40. 

Note that some fungicide groups and/or products are restricted or prohibited from use by some wineries or grape suppliers. Refer to Table 2 in the ‘Dog book’ and your winery/grape purchaser’s guidelines before you spray. 

In addition to reading the CropLife Australia resistance management strategies, always read chemical labels prior to spray application, to ensure you are applying the correct treatment rate. 

*As advised in the AWRI eBulletin on 25 August 2025, the APVMA registration of Group 4+M3 co-formulated downy mildew products Axiom MZ WG (mancozeb + metalaxyl-M) and Axiom MZ 720 (mancozeb + metalaxyl) was stopped on 01/07/2025. These fungicides are being replaced by Group 4 Axiom Flexi (metalaxyl-M) which must be tank-mixed with a product containing a different mode of action to avoid downy mildew fungicide resistance. 

 

Further information 

• AWRI Fungicide resistance fact sheet 

• AWRI Fungicide resistance information pack 

• AWRI Downy mildew information site 

• Agrochemicals registered for use in Australian viticulture, commonly known as the ‘Dog book’ 

• AWRI helpdesk – call 08 8313 6600, or email helpdesk@awri.com.au. 

 

Acknowledgements 

The fungicide resistance testing work has been supported by the SAAFE CRC whose activities are funded by the Australian Government’s Cooperative Research Centre Programme. 

The AWRI thanks Mark Sosnowski and Ismail Ismail from SARDI and Lincoln Harper and Fran Lopez Ruiz from Curtin University for their review. 

This eBulletin is supported by Wine Australia with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. AWRI is a member of the Wine Innovation Cluster in Adelaide, SA. 

24 October 2025

Fungicide resistance in powdery mildew puts both crop quality and costs at risk this season and beyond.

This eBulletin outlines why powdery mildew fungicide resistance is a problem, how to recognise, test for, and manage it.  

About powdery mildew  

Powdery mildew is one of the most important diseases of grapevines in Australia. The disease is caused by the fungus Erysiphe necator, which affects green grapevine tissue. When the following set of conditions arise, powdery mildew can become a problem:  

What is fungicide resistance in powdery mildew and why does it matter? 

Powdery mildew can develop resistance to fungicides when the fungus Erysiphe necator changes genetically over time, making fungicides less effective or even ineffective at controlling it.  

Fungicide resistance is a problem for winegrape growers because it can lead to:  

• fewer effective tools to manage the disease;  

• the need for more frequent or varied fungicide applications;  

• environmental issues; 

• negative public opinion; 

• higher production costs;  

• greater crop losses; and 

• possible fruit rejection. 

Read more about how fungicide resistance occurs and how to avoid it in this new fact sheet here. 

 How do you know if you have resistance to powdery mildew fungicides? 

If you are applying fungicides each year and the incidence and severity of powdery mildew in your vineyard seems to be getting worse, you may have fungicide resistance or reduced sensitivity. 

Powdery mildew fungicide resistance detections in Australian vineyards 

Recent research led by South Australian Research and Development Institute (SARDI), a research division of the Department of Primary Industries and Regions (PIRSA), has confirmed the detection of powdery mildew fungicide resistance to several fungicide groups commonly used in vineyards.   

Active ingredient	Fungicide Activity Group	Resistance status
difenoconazole	3	Not detected
penconazole	3	Detected
tetraconazole	3	Not detected
spiroxamine	5	Not detected
boscalid	7	Not detected
pydiflumetofen	7	Not detected
azoxystrobin	11	Detected
pyraclostrobin	11	Detected
proquinazid	13	Detected
quinoxyfen	13	Detected
pyriofenone	50 (U8)	Not detected

Source: South Australian Research and Development Institute (SARDI) 

While only one representative formulation per active ingredient was evaluated as part of this research, a range of registered products for each of the above active ingredients can be found in Table 2 of the 2025/26 Agrochemicals registered for use in Australian viticulture, commonly known as the ‘Dog book’. A full list of detections from this research can be found on page 18 in the 2025/26 ‘Dog book’. 

 How can you test for powdery mildew resistance? 

If you suspect you may have fungicide resistance in powdery mildew, a free national testing service to monitor fungicide resistance in powdery mildew, downy mildew and botrytis in winegrapes is available (until June 2027).  

Samples for powdery mildew resistance testing can be submitted to the SARDI Horticulture Pathology Laboratory by following the detailed sampling instructions here.  Biosecurity considerations apply. Prior to sending samples to the laboratory, please contact ismail.ismail@sa.gov.au.  

This testing service is part of a research project led by SARDI in collaboration with Curtin University and the AWRI, and funded by Wine Australia, the Cooperative Research Centre for Solving Antimicrobial Resistance in Agribusiness, Food, and Environments (SAAFE CRC), SARDI and Curtin University.  

Importance of spray program management 

Overuse of the same fungicide groups as part of a spray program is a key contributor to the development of powdery mildew fungicide resistance.  

One of the key information sources provided annually in the ‘Dog book’ to assist you in reducing powdery mildew fungicide resistance is the CropLife Australia resistance management strategy on page 17.  

Before you order your chemical products for the new season, review this strategy alongside your proposed spray program. In particular, take note: 

• of the fungicide group associated with each product you plan to apply; 

• that all powdery mildew fungicide groups must be applied preventatively before disease is present;  

• of which fungicide groups must be applied as part of a co-formulation or tank-mixed with an alternative fungicide group when applied consecutively – Groups 7 and 11;  

• that some fungicide groups (e.g., Group 11) exhibit cross-resistance among their members, meaning that changing the product or active ingredient within the same group does not contribute to effective resistance management; 

• of the suggested maximum number of times each fungicide group be applied in the season; and 

• of whether the fungicide group can be applied as a consecutive spray in the program – Groups 3, 5, 13, 19, 21, 50 (U8) and U6. 

Note that some fungicide groups and/or products are restricted or prohibited from use by some wineries or grape suppliers. Refer to Table 2 in the ‘Dog book’ and your winery/grape purchaser’s guidelines before you spray. 

In addition to reading the CropLife Australia resistance management strategies, always read chemical labels prior to spray application, to ensure you are applying the correct treatment rate. 

 Further information 

The AWRI is currently developing a new guide for powdery mildew management. Look out for it in an upcoming eBulletin.  

Currently available resources on powdery mildew and fungicide resistance include: 

• AWRI Fungicide resistance fact sheet 

• AWRI Fungicide resistance information pack 

• AWRI Powdery mildew information pack 

• Agrochemicals registered for use in Australian viticulture, the ‘Dog book’ 

• AWRI helpdesk – call 08 8313 6600, or email helpdesk@awri.com.au. 

 Acknowledgements 

The fungicide resistance testing work has been supported by the SAAFE CRC whose activities are funded by the Australian Government’s Cooperative Research Centre Programme. 

The AWRI thanks Mark Sosnowski and Ismail Ismail from SARDI and Lincoln Harper and Fran Lopez Ruiz from Curtin University for their review. 

This eBulletin is supported by Wine Australia with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. AWRI is a member of the Wine Innovation Cluster in Adelaide, SA. 

7 October 2025

Are you aiming to ‘rest’ your vineyard block this season by removing yield and reducing water, nutrition and spray inputs? Find out how, when and where you can apply Ethephon for best results and permit compliance.

What is ethephon and how does it work

Ethephon is a plant growth regulator. It can be sprayed on to grapevines in spring to significantly reduce grape yield. It does this by causing undeveloped berries to detach from the rachis.

Application details

Ethephon for bunch removal must be applied in strict accordance with APVMA Permit PER94008.

Timing
	Apply between E-L 25 (80% capfall) and E-L 27 (fruit set: young berries enlarging (>2 mm diameter), bunch at right angles to stem). The most effective fruit removal has been seen from application at E-L 27a. DO NOT apply unless the wind speed is between 3 and 20 kilometres per hour at the application site during the time of application. DO NOT apply in a manner that may cause contamination outside the application site from spray drift. DO NOT apply if heavy rains or storms are forecast within 3 days.
Number of applications
	Up to 2 applications permitted between E-L 25 and E-L 27, at least 7 days apart. It is unlikely that 2 applications will be needed in most circumstances.
Water rate
	Apply at a dilute spray rate to the point of run-off with a non-ionic wetting agent at label rate.
Product label rate
	According to the permit – for 900 g/L Ethephon products, apply at a label rate between 32-104 mL/100 L for 720 g/L Ethephon products, apply at a label rate between 40-130 mL/100 L for 480 g/L Ethephon products, apply at a label rate between 63-190 mL/100 L
Target zone
	Apply to the full canopy unless there is a defined bunch zone where spray application can be targeted to saturate the bunches.
Equipment
	Apply using an air-blast sprayer. Thoroughly clean spray unit after applying Ethephon to ensure all residue is removed before use on non-target vines.
Jurisdiction
	Under the permit, Ethephon may be applied in all Australian states and territories.
Grazing restriction
	Do not graze any vineyard block treated with Ethephon.
Carryover
	Minimal carryover effects on yield were found in the year following that in which one or two Ethephon applications were applied. Effects on other varieties were not measured a.

^a Results of research trials completed across the 2023 and 2025 vintages by the South Australian Research and Development Institute (SARDI) on one block of Shiraz in the Riverland.

More information

• APVMA Permit PER94008 is in force from 21 July 2025 to 31 July 2030.
• SARDI Fact sheet: ‘Resting Vineyards using Ethephon: A Cost-Saving Strategy when Grapes are in Oversupply’.
• AWRI Webinar delivered by Paul Petrie (SARDI): Vineyard Resting – Webinar 
• AWRI helpdesk – call 08 8313 6600, or email helpdesk@awri.com.au.

Acknowledgements
This eBulletin is supported by Wine Australia with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. AWRI is a member of the Wine Innovation Cluster in Adelaide, SA.

15 September 2025

The 2025/26 Agrochemicals registered for use in Australian viticulture, commonly known as the ‘Dog book’ has been updated with several new active ingredients, changes to the downy mildew resistance management strategy and other important changes which may affect your planned spray program this season. These most recent changes are listed below and a running list of changes to the 2025/26 booklet can be found on the AWRI website here.

Key changes include:

1. New active constituents – mandipropamid + oxathiapiprolin to control downy mildew; and orange oil to control bud mite and powdery mildew, and to suppress mealybug, scale and botrytis
2. Expanded downy mildew resistance management strategy
3. Correction to categorisation of Trump spray oil
4. Change to winery restriction level of Katana 250 WG (active flazasulfuron)
5. Additional products added to existing active ingredients
6. Removal of products (see details below)
7. Product name changed from MethioSHIELD to Mesurol (active methiocarb)

For more information regarding these changes, read on below and download an updated Dog book (dated 15 September 2025),  available on the AWRI website.

1. New active constituents
The following new active constituents are now registered by the Australian Pesticides and Veterinary Medicines Authority (APVMA) for use in winegrape production and are included in the ‘Dog book’ for the first time:

MANDIPROPAMID + OXATHIAPIPROLIN

APVMA product number 92989: Keybri Ultra fungicide is a Syngenta product registered for control of Downy Mildew in winegrapes. It is an activity group 40 + 49 fungicide.

Recommended export harvest interval (withholding period): Use no later than E-L 29, berries peppercorn size (not greater than 4mm diameter).

Note: Affinity Labs is working to include oxathiapiprolin in the agrochemical residue screen for vintage 2026.

ORANGE OIL
APVMA product number 89248: Prev-Am fungicide, miticide and insecticide is distributed by Rovensa ANZ and is registered in winegrapes for the control of bud mite and powdery mildew, and for the suppression of mealybug, scale and botrytis. It is an unclassified activity group product.

Recommended export harvest interval (withholding period): Use no later than 30 days before harvest.

2. Expanded Downy Mildew resistance management strategy
The CropLife Downy Mildew resistance management strategy has been expanded to include instructions for Group 40 + 49 given registration of this new activity group combination.

3. Correction
Trump Spray Oil was incorrectly listed under petroleum oil as a control for Powdery Mildew on page 8 and in the fungicide section of Table 2. This product has now been correctly listed in both places under paraffinic oil.

4. Change to winery restriction level
The winery restriction level for herbicide Katana 250 WG (flazasulfuron) in TABLE 2: Agrochemicals registered for use in Australian viticulture has been changed to ‘Restricted for use by some wineries. Contact your winery or grape purchaser prior to use.’ Note: this product has a 77-day withholding period for grapes.

5. Additional products added to existing active ingredients (see details below)
The following products have been added for existing active ingredients:

• Caribou insecticide (APVMA product number 96001, active methoxyfenozide) for control of Lightbrown Apple Moth on grapevines
• Chicane insecticide (APVMA product number 84630/148297, active emamectin) for control of Lightbrown Apple Moth and Grapevine Moth in grapes, except grapes grown for dried fruit production.

6. Removal of products
The following products have been removed for existing active ingredients:

• Energise insecticide (APVMA product number 84630, active emamectin). Replaced by Chicane insecticide.
• Lepidex 500 insecticide (APVMA product number 33110, active trichlorfon). Product archived. Last use date was 30 June 2025, therefore existing stocks must be disposed of safely. The ChemClear program, managed by AgSafe, provides a safe disposal pathway for unused or obsolete agricultural chemicals. To participate, register your chemicals for disposal at a local collection point via this registration form or call 02 6206 6888 for more information.

7. Product name change
The following product name change has taken place:

• MethioSHIELD Snail & Slug bait (APVMA product number 92530, active methiocarb) has changed name to Mesurol Snail & Slug bait (APVMA product number 92530/148912).

About
The ‘Dog book’ is an annually published reference guide for Australian grape and wine industry and should not be interpreted as an endorsement of any product. It helps facilitate export market access, responsible application of chemical treatments and environmental stewardship.
For more resources relevant to agrochemical treatments, visit the dedicated Agrochemicals page on the AWRI website.

Acknowledgement 

This eBulletin is supported by Wine Australia with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. AWRI is a member of the Wine Innovation Cluster in Adelaide, SA. 

1 September 2025

The Australian Pesticides and Veterinary Medicines Authority (APVMA) recently handed down its final regulatory decision that the insecticide fenitrothion, used for the control of locusts and grasshoppers, is no longer supported and that a 12-month phase out period has commenced (APVMA Gazette,19 August 2025). This AWRI eBulletin provides a summary of implications of this decision for the wine industry.

Decision and implications for use
The APVMA has determined that the continued use of fenitrothion on grapes is NOT SUPPORTED. A number of registered chemical product labels have changed as a result of this decision; including removal of use on grapes against locust and grasshopper pests. In addition, Sumithion ULV premium grade insecticide (APVMA product number 50774) has been cancelled.

A 12-month phase-out period has now begun, during which time products bearing the previously approved labels may continue to be sold and used. After 14 August 2026 (“last use date”), it will be an offence to have possession or custody of fenitrothion products with old labels indicating permitted use on grapes.

As a result of this final decision, and in accordance with fenitrothion being listed in the Agrochemicals registered for use in Australian viticulture 25/26 (‘Dog book’) as “restricted for use by some wineries”, any vineyard owners considering application of this active prior to the “last use date” must do so in consultation with their winery/grape purchaser.

‘Dog book’
The current version of the ‘Dog book’ will remain unchanged as a result of the APVMA’s final decision on fenitrothion, given there is a one-year phase-out period applicable for use on grapevines. Changes will apply to the 2026/27 publication.

Managing custody of your de-registered agrochemicals
Safely manage storage of any fenitrothion products you hold in stock and fulfil requirements of certified membership of Sustainable Winegrowing Australia, by:

• Segregating the de-registered fenitrothion products from the remainder of your insecticides within your chemical shed.
• Making a note on your chemical inventory of the “last use date” of these fenitrothion products.  Registering any stock unused by this date with ChemClear  for collection.

Further information
For enquiries about the final decision on fenitrothion, please call (02) 6770 2400 or email chemicalreview@apvma.gov.au.

For further information on cancelled agrochemical products, refer to the AWRI website. For all other technical viticulture or winemaking enquiries, including those relating to Sustainable Winegrowing Australia, please contact the AWRI helpdesk on 08 8313 6600 or helpdesk@awri.com.au.

Acknowledgement 

This eBulletin is supported by Wine Australia with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. AWRI is a member of the Wine Innovation Cluster in Adelaide, SA. 

25 August 2025

With spring fast approaching and the spray season almost upon us, the AWRI encourages growers to review agrochemical stocks for use and safe disposal, based on the following:

1. Agrochemical active ingredients recently reviewed by the APVMA for which “last use date” falls in the early part of the current 2025/26 growing season.
   Diazinon – last permitted use date on grapevines is 10 September
   Chlorpyrifos – last permitted use date on grapevines is 30 September
2. Highlighted changes to APVMA registration status for selected agrochemical products.

The products in the table below held active registration with the APVMA for use in Australian viticulture during the 2024/25 growing season, however ceased registration with the APVMA on 1 July 2025. These products now have a “last use date” of 30 June 2026.

Product name	APVMA  status	Last use date	APVMA product number	Active ingredient(s)	Target(s)
Alpha C 100 EC	Stopped	30/06/2026	66052	alpha-cypermethrin	Pink cutworm, Apple weevil, Garden weevil
Axiom MZ WG	Stopped	30/06/2026	87679	mancozeb + metalaxyl-m	Downy mildew
Axiom MZ 720	Stopped	30/06/2026	51217	mancozeb + metalaxyl	Downy mildew
Custodia	Stopped	30/06/2026	66541	azoxystrobin + tebuconazole	Botrytis, Downy mildew, Powdery mildew
Downright	Stopped	30/06/2026	70040	dimethomorph	Downy mildew
Ethephon 720 SL (Ozcrop)	Stopped	30/06/2026	66352	ethephon	Plant growth regulator
Ozcrop Ethephon 720 SL (Rainbow)	Stopped	30/06/2026	64841	ethephon	Plant growth regulator
Getset	Stopped	30/06/2026	69716	chlormequat	Plant growth regulator
Thiragranz	Stopped	30/06/2026	48621	thiram	Black spot

Safe Disposal
The ChemClear program, managed by AgSafe, provides a safe disposal pathway for unused or obsolete agricultural chemicals. To participate, register your chemicals for disposal at a local collection point via this registration form or call 02 6206 6888 for more information.

Further information on cancelled products and last use date
The 2025/26 Agrochemicals Registered for Use in Australian Viticulture (the “Dog Book”) (released 1 June 2025) lists some cancelled products and final permitted use dates to assist growers to plan for the use and safe disposal of stock prior to the last permitted use date.

A comprehensive list of product registration status, including those in the above table, can be viewed on the AWRI website.

Acknowledgement 

This eBulletin is supported by Wine Australia with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. AWRI is a member of the Wine Innovation Cluster in Adelaide, SA.