Friday, July 24, 2009

Glyphosate Resistant Ryegrass Pictures.

A block in Blewitt Springs where glyphosate resistant ryegrass regrowing after being sprayed with Glyphosate.

This grower will need to respray this vineyard with an alternative herbicide group to prevent this weed from smothering the vines. REMEMBER - the ryegrass is resistant and will not be controlled by glyphosate no matter what rate of product is used. Increasing the rate of glyphosate only makes the problem worse as you are selecting for resistant plants quicker.

Regrowth of glyphosate resistant Annual Ryegrass.

Tuesday, July 21, 2009

Introducing Greenseal paint for pruning wound protection.

We have been using a new pruning wound sealant as a precaution against the spread of eutypa lata, dead arm.

Independent trial work by SARDI of wound protectants including Greenseal™ paint, which are formulated with fungicides (tebuconazole), and acrylic paint (with and without fungicides) all prevented infection by E. lata (Figure 1).

Figure 1. Efficacy of pruning wound treatments applied 1 day before inoculation with E. lata.

Greenseal™ paint was registered in 2008 for control of eutypa dieback in Australia.

A treatment like Greenseal™, applied by hand, is strongly recommended for larger wounds, such as those made during reworking or remedial surgery.

The application of fungicide immediately after wounding and before application of a paint or paste minimises the risk of sealing a wound on which spores may already have landed and germinated, and of infection via cracks in the surface of the paint as it dries over time.

We are happy with its performance in the field, and because it is backed up with the independent trial work we think it is a good solution for your vineyard.

For more information and pricing contact - djs@djsgrowers.com.au or ring us 08 83238339

Saturday, July 11, 2009

Weather Report - Winter 2009

An average winter so far in 2009

Early July’s rainfall has helped increase the predicted amount of rainfall this season.

We have had an encouraging start to July with 27mm in the first three days and now a further 15mm in the up to Saturday the 11th. We have had 42mm already compared to July’s long term average, which from the Kay Brothers Diaries, is 74.96mm.

Click on the image for a larger sized table.

Kay Brothers Amery daily rainfall data stretching back to 1891 when Herbert and George Kay moved to the Amery property. The worst season for rainfall was 1914 where they only had less than 250mm for the year.

Thursday, July 9, 2009

Eutypa Dieback - Winter Identification Photos

There a three things to remember when dealing with Eutypa during pruning season.



Canker symptom.
1. Eutypa is often called Dead Arm because it slowly kills vines.

Symptoms start out low in young vineyards and increase over time as the vineyard ages.

Eutypa is caused by the fungus Eutypa lata. The fungus produces spores on old infected wood, called cankers, and these spores spread by rain splash and wind.

All winegrape varieties are susceptible to Eutypa Dieback but Grenache & Shiraz show the most severe symptoms. Many other plants including Almonds, pome fruit trees and willows are a source of disease.

A broken 'Dead Arm' caused by the fungus Eutypa lata. Note the cankers above the break.

2. When it rains Eutypa Dieback produces spores.

Note the the wedge shaped area of dead wood.
The spores are able to travel large distances and can infect unprotected wounds, such as those left by pruning cuts. Once inside the vine the fungus slowly grows spreading over a period of years along cordons and down to the trunk. Each spring the fungus releases chemical toxins that cause the stunted shoots and cupped leaves with tattered margins (shown in our Spring pictures).


3. Don't make large cuts during rain.

Cankered wood becomes distorted and twisted after a number of years.
Eutypa infection can be prevented by avoiding pruning cuts during wet weather.

Pruning cuts made in early winter remain susceptible to the disease for some weeks, while those made in early spring heal much quicker. If possible delay pruning until August for blocks with known Euytpa or at risk.

Should I spray chemicals to seal the cuts?

We think you shouldn't, in SARDI's independent testing, pruning wound dressings are just as effective and a lot safer for you to use. DJ's agronomists recommend 'Green Seal' wound dressing.

We don't recommend treating your pruning cuts with chemical protectants because some of the chemicals tested and used for pruning wound protection have question marks over their side effects eg. Carbendazim - Tradenames including Spin-flo ans Carbend. These have been removed for use from the 2009/2010 Guide to Agrochemicals (the Dogbook) onwards. 

For more information visit SARDI's research.