Rust Mite Monitoring & Control.

FAQ: When should Rust Mite sprays be applied?

Rust Mite levels were seen to be significant in some vineyards last season. Rust mite are microscopic mites that enter into grapevine buds during early spring and affect the growth of early season shoots.

The significant level of Rust Mite’s last spring has made us re-think our recommendation regarding Rust Mite control. It is likely that a high percentage of vineyards monitored last season will benefit from a controlling sulphur spray.

We have been advising our clients regarding whether they should apply a controlling sulphur spray, or not for this season. If you would like specific advise please contact DJ’s.

Recommendations for prevention of Rust Mite symptoms are:

Did you see Rust Mite symptoms, as stunted an uneven shoot growth, in spring last season? Y/N

Suspected symptoms of stunted shoots from rust mite activity at bud burst.

Did you see Rust Mite symptoms, as bronzed leaves, in autumn last season? Y/N

Rust Mite Bronzing Symptoms in late summer. These symptoms generally appear in early February.

If you answered yes to these questions then look at a possible control measure below.

To limit the stunted & uneven shoot growth;

• Application of wettable sulphur @ 500g/100lt (include non ionic wetter at label rate if not adding oil).

• Water rates of 600 – 900 lt of water per hectare - do not use less than 500 lt/ha

• Increased water rate should be used if worried about coverage.

• Make sure coverage of the cordon and all spur wood is thorough.

• Inclusion of Canola oil or Mineral oil at 2% (2lt per 100 lt) may improve control (10-15%) but should only be applied if the variety being sprayed is fully dormant (eg. Cabernet). Need to be aware that some Canola oils may contain GMO’s.

• A period of 2-3 fine days and 15 degrees C or higher on the day of spraying is ideal.

• Chardonnay is the indicator variety for timing of spraying in each region. Spraying should be done on all varieties when Chardonnay reaches 10% green tip (i.e. most buds woolly bud).

Look for services like McLaren Vale & Langhorne Creek CropWatch to advise of this timing.

Based on previous seasons we have some rough dates for your planning.

McLaren Vale Wine Region - Valley Floor

Our feelings are that spraying should occur from the last week of August to the end of the second week of September on all varieties/blocks that require rust mite treatment.

Currency Creek Wine Region
Spraying should occur from the last week of August to the end of the second week of September on all varieties/blocks that require rust mite treatment.

McLaren Vale Wine Region - Blewitt Springs & Clarendon

Spraying should occur from the first week of September to the end of the third week of September on all varieties/blocks that require rust mite treatment.

Adelaide Hills Wine Region

Mid-September through to the end of September. To get ideal timing find a block of Chardonnay in within your mesoclimate for exact timing.

Eutypa Control - how to limit its spread at pruning time.

What you should know to inform your decisions?

When are pruning wounds susceptible to Euytpa lata infection?

• Does time of the year make a difference? Wounds are susceptible all through winter. SARDI trials* have showed susceptibility consistent from early to late during pruning season

• Most susceptible period is first two weeks after pruning.

• Does grapevine cultivar make a difference? Wound susceptibility during first two weeks similar for all cultivars evaluated*. SARDI McLaren Vale Trial.

Control of eutypa dieback can be achieved by protecting wounds from infection by the fungus, Eutypa lata or by physically removing infected wood. 

• Wounds can be protected with fungicides, paints, pastes and biological control agents. It is also important to time pruning in order to avoid rainfall events and to maintain good sanitation. Pruning in wet weather should be avoided and preferably delayed to dry periods.

• Controlling established infections is achieved by removing infected wood and retraining of watershoots from below infection. Removal of dead wood from grapevines and alternative hosts in and around the vineyard will reduce the potential inoculum level.

How to limit Eutypa by;

CULTURAL CONTROL

The level of infection may be reduced by double pruning, the practice where mechanically pre-pruning is used to leave long spurs in early winter followed by hand-pruning to short spurs in late winter.

Contamination of pruning tools is NOT a major means of spreading the disease (although viruses can be spread this way). Don’t expect by cleaning snips you will be limiting pruning wound disease.

WOUND PROTECTION

Paints and pastes on the wound

The application of acrylic paints and Greenseal paste (containing tebuconazole) or Gelseal (also tebuconazole) are recommended as wound protectants, especially on large wounds. Other treatments such as and Garrison (cyproconazole + iodocarb) are also effective but are not yet registered for use on grapevines. There use is not recommended without winery permission.

Pic: https://wineanorak.com/2020/07/05/16-things-you-need-to-know-about-grape-vine-trunk-disease/

Fungicides sprayed onto wounds

Pruning wound protectant spray after pruning (photo by Dr. Doug Gubler, UCCE.)

Certain formulations of tebuconazole are registered for use on grapevines, and are the most effective fungicides tested as a spray on wound protectant available. Again consult with your winery if you have any concerns about their use. Use these fungicides at label rate. They can be applied efficiently to pruning wounds with commercial spray machines. It is important to direct nozzles to target the pruning wound zone and use high spray volumes (600 L/ha) to maximise coverage on wounds.

MORE INFORMATION from Wine Australia and the AWRI.

Bud Dissection Q&A

Hi, 

I am curious about looking at grapevine buds under the microscope. Could you also please let me know how many buds you can dissect in an hour, as I have a uni project to do on yield analysis and the number would be of assistance.

Many thanks, Andrew

Dear Andrew,

Almost anyone can learn to dissect buds, but not everyone has the patience to sit down and complete many samples. We use a compound microscope with to eye lenses that give a stereoscopic view of the inside of the bud. This allows us to assess the internal bud structure and look at the inflorescence primordia which are the structures that develop into grapevine flowers.

Bud Dissection speed.

We would average two to three buds a minute, therefore it takes us between one and one and half hours to complete a vineyard (30x; 5x bud canes). We would generally limit ourselves to three vineyards per day to keep our eyes fresh.

The time it takes to dissect buds under a microscope varies from variety to variety. Sauvignon Blanc has small buds and small inflorescences which make it the slowest variety to assess. Grenache has large buds and large inflorescences which are the quickest to assess.

Why do we dissect?

Essential we look to see how healthy the buds are for next season, and then make an assessment of how fruitful they are likely to be. We perform dissections to look for low fruitfulness and assess the level of primary bud necrosis

Bud health is relatively easy to assess. Low bud fruitfulness and high primary bud necrosis can be linked to vigorous vine shoot growth, excessive shading and other physiological factors.

A health primary grapevine bud with two inflorescence primordia visible.

If we find problems with fruitfulness eg. levels below 1 bunch per bud (inflorescence primordia per bud), or high levels of bud death from primary bud necrosis, we advise growers to change their pruning in the short term and look at their management in the long term.

It is when you find blocks like these bud dissections come into their own as a vineyard tool.

DJ's agronomist Matthew Wilson says,

"Vineyards with high levels of lateral shoot growth can show low levels of fruitfulness. Primary bud necrosis is often common in vigorous vines and this is contributing to low fruitfulness. If you can catch this before pruning you can take action to prevent correspondingly low yields at harvest.”

A primary bud that is beginning to turn necrotic.

Primary bud necrosis where the central (primary) bud has died (necrotic).

Veraison Tissue Testing for vineyards

Do you need to test your nutrition status before harvest?

DJ’s can perform a tissue test and advise on your results for you all you need to do is:

1: Collect a paper tissue testing bag from DJ's.

2: Collect about 50 leaf blades (aka. the leaf without the petiole leaf stalk). Pick the petiole opposite the first bunch on the shoot.

3: Drop in your samples in a paper bag labelled with your name, email to get the results back and the vineyard account name.

4: Tell us any relevant information to tailor the test to your needs. Are you an organic or biodynamic grower? Has your winery had trouble with fermentation?

Rust mite pest flare - is use of wettable sulfur fungicide the cause?

DJ’s are actively working on this issue. We are trialing no-sufur and minimal sulfur applications in vineyards to observe if by limiting sulfur use we limit Rust Mite symptoms in late summer.

The most common incidence of pest-flare that we see in the McLaren Vale Wine Region is a sudden build-up of Rust Mite (Calepitrimerus sp), which causes leaves to have a bronzed appearance. Vineyard scouting generally records the symptoms of bronzed leaves around the January 20, (CropWatch Vol. 17 Issue 26 - for example).

Rust mite leaf bronzing in a bio-dynamic vineyard. McLaren Vale Wine Region Vintage 2014.

Agrochemical use is often seen as a cause of Rust Mite pest flare. Conjecture has speculated that high rates of wettable sulfur may be responsible for interfering with predatory insects that naturally control Rust Mite.

Rust Mite symptoms are found in vines grown under minimal input regimes (above & below).

Close up picture of microscopic holes in leaves cause by Rust Mite feeding. Late Summer.

Note that in the McLaren Vale Wine Region, vines grown by different techniques including bio-dynamic, organic and conventional management show signs of bronzing. In biodynamic or organic vineyards (which don’t use Mancozeb or insecticides).

This anecdotal observation would support the theory that high rates of wettable sulphur, which we use for powdery mildew control, is a contributing factor to Rust Mite pest flare in late summer.

Herbicide spray drift ID photos

Herbicide spray drift is an occasional problem in vineyards..

For the vineyard pictured here the product Metsulphuron (tradenames Ally, Aim, Brush-off) is alleged to have drifted into a vineyard from a neighbouring property four weeks before the pictures were taken (early spring). A week after application the first symptoms were seen.

Herbicide drift shows as the ‘hormone’ shape, cupping and stunting of leaves (above and below) poor flowering and damage to the vine growing tips.

Disappointingly, herbicide spray drift is an ongoing issue in vineyards, and this is a timely reminder.

PIC: Spray drift affected vineyard. Poor shoot growth in spring.

Look out for your tribe

Since Winston Churchill used the phrase Black Dog to describe the bouts of sadness he experienced for much of his life, it has become the shorthand for the crippling disease we call depression.

Depression is a dog that can bite at anybody’s heels. These thoughts are to bring that hidden beast of a disease into the open.

Australian rural communities are losing too many people to this preventable sickness, and our beautiful district is never immune. Capable people are being laid low, or lost forever.

Every day a person loses to depression; is a loss to our whole community.

Since the economics of the wine industry have become depressed, all of us who work in it can feel alone and marginalised through the intense stress it brings. We are all under enormous pressure which can make our problems seem insurmountable.

Ordinarily happy folks suddenly become easy targets for the Black Dog.

Unfortunately I know this feeling, as do many of my friends and colleagues. There have been times in our lives where things have seemed too hard and the future looks too narrow. The feeling is like a crushing weight on your chest.

We must be very careful to look after each other, learn to watch out for symptoms, and stick together.

It's important to know that depression is a common illness which affects roughly 1 in every 5 people. Good treatments are available through your family doctor and, with treatment, sufferers should fully recover.

Beyond Blue is a good start for specific information. Its experts provide information especially tuned for people in rural and remote communities.

It's not always easy to help someone who may be experiencing depression. It can be hard to know what to say or do.

When you feel concern for a friend you think may be depressed, encourage them gently to talk about how they feel. Listen patiently: sometimes, when somebody needs to talk, they might not seek advice, but just feel like talking it through. Sometimes they may be vague about their concerns.

Gentle open-ended questions like "So tell me about...?", open the door for an answer bigger than 'yes' or 'no'. This is often a good way to start a conversation. If conversation becomes difficult or your friend gets angry, stay calm, be firm, fair and consistent and don't lose control.

Simply spending time with a depressed friend lets them know someone cares and understands them. Encourage them to seek professional help from their family doctor or at least get online and look at information themselves.

We need to watch out for the Black Dog now more than ever. Our tribe needs to stick together. As an industry, a community, and as individuals, we need to 'walk the walk.' Actions speak louder than words. So please look after your mates. Make a call. Go visit.

Website - Beyond Blue Website: The national depression initiative.

Hotline - 1300 22 46 36

https://www.lifeline.org.au/Get-Help/Facts---Information/Rural-Mental-Health/Rural-Mental-Health

Vintage 2020 - Ripening in pictures

Canopy of cv. Shiraz from January to March.