Posts

PEST & DISEASE LEVELS BEFORE BUDBURST

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EUTYPA LATA: Eutypa lata is a vascular pathogen of grapevines and other woody plants. This means it lives inside your grapevines and lives off the glucose-rich polymers that bind together the wood. Eutypa is actively spread during pruning time in during wet weather. Eutypa’s spores spread via rain and wind splash. It is recommended to only pruning vineyards with high levels during dry weather and close to budburst (EL-4-5). This may not be practical in many situations. Research shows that it is possible to stop Eutypa from infecting freshly made pruning cuts during wet weather. Creating a barrier either physically or with registered chemicals may be a practical solution. The fungicide Emblem is currently registered and available. The fungicidal paint GREENSEAL is a specially developed pruning wound dressing incorporating a tough, rubber like acrylic resin and a powerful fungicide with  disease control capabilities. GREENSEAL is easy to apply and dried quickly to seal off pruning wound…

Guildford Grass control in pasture.

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A question we get from time to time is how to control Onion or Guildford Grass (Romulea rosea) in pasture:

Note: this is not the same as Onion weed or Nut Grass (rarely seen in pasture, mainly undervine).  
Onion grass is a perennial herb with distinctive growth behavior. It looks like a grass, grows like an annual, and can spread rapidly . The plant not only produces abundant seed, but also corms underground to survive the hot and dry summers in Mediterranean environments of temperate Australia.
Originated from South Africa.Generally found in areas with low competition from other perennial plants due to low fertility, overgrazing, fire or poor seasonal conditions. 
Causes:The two main causes of onion grass infestation are autumn bare ground and lack of competition from desirable pasture species. Prevention involves managing pastures to maintain above 70 per cent ground cover and maximising growth during autumn and winter. 
Make sure you have a high proportion of desirable perennial specie…

Organic Compost.

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Compost contains organic carbon and nutrients whilst also adding soil moisture retention, structure and increasing root mass. It is added to vines after harvest to integrate into the soil over winter.

Organic matter is vital for good soil health and adding quality compost with organic carbon to the soil helps to improve soil condition. McLaren Vale soils are generally low in organic carbon. We record levels in vineyards between 0.5% to 3.0%.
Remember that value is not just about how much compost costs. While chicken manure is cheap per cubic meter, per tonne of nutrient it is expensive and can have side effects.

As the Willunga based composters Petes Soil say on their website, "Poorly or non-composted materials pose the risk of introducing pests and pathogens, weed seeds and may behave less predictably than material which has undergone the stabilising phase of the composting process. Non-composted manures may conceal a surprising amount of salt, contributing significant amount…

Shoot Growth Post Harvest - Is this a problem?

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The importance of the post-harvest period is largely determined by climate, variety, yield, and management prior to harvest. Vines will tolerate a season or two with limited post-harvest irrigation, but productivity will eventually be reduced if this continues over many seasons. In the same vain they are thought to tolerate excessive irrigation and fertiliser for one or two seasons before  the vine becomes unbalanced. 
Clearly in the picture below the rate of fertiliser and irrigation has been too high and the vines have re-shot.

For conventional vineyards DJ's also recommend using 'soft' fertiliser products instead of Urea which is straight Nitrogen. DJ's use techgrade MAP, NutriPHlow or a specialist fertiliser like KRISTALON which contain a combination of Nitrogen, Phosphorous and Potassium.
We recommend this because:
Like carbohydrates, grapevines require a supply of nutrients from stored reserves to support growth in early spring. Nitrogen in the roots and woo…

DJ’s Mediterranean Fescue and Medic - Establishment information

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Bud Dissection - Q&A

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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.




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 inflores…

Bud Dissection & Primary Bud Necrosis

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DJ's are specialists in grapevine bud dissection. Bud dissections are used for determining bud fertility to estimate yield potential. They can also show the health status of a vineyard by determining the level of  primary bud necrosis. This is when the primary bud is dead, whilst the secondary buds remained healthy. This phenomenon is known as primary bud necrosis (PBN).






30 bud samples.  The big question is can you really get insight into next seasons crop only taking 30x buds per position?
Yes you can. The most common fault with bud dissections is in many cases they tell growers information they already know. Their shoots for next season will have between 1.2 and 1.5 bunches on average and they will prune to spurs that have already been set over the last few pruning seasons.
Occasionally blocks will have problems with fruitfulness and have levels below 1 bunch per bud (inflorescence primordia per bud), or high levels of bud death. It is when you find blocks like thes…