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| LBAM damage. |
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| Grafted vines. |
The
weather of the last week has been atypical for early summer in our
region. It has been humid, overcast with frequent light showers that produced
less than 1mm of rain.
Disease pressure is high and growers may need to adjust their strategies accordingly. Unseasonal rain and
high humidity has increased the disease pressure. Growers are advised
to adjust their spray programmes to ensure vineyards have good coverage.
DOWNY MILDEW
DOWNY MILDEW
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| Downy Mildew has sporulated - 9th/12th/2013. |
If you have Downy Mildew oilspots in your vineyard
they will multiply unless your leaves and bunches were protected with a
registered Downy fungicide in the last 7 days. The spread of Downy Mildew can
be stopped by an application of Metalxyl (tradenames including Axiomtm
and Ridomiltm) if this is applied within 5 days i.e the 14th
of December. Seek specific advice for your situation.
POWDERY MILDEW
Powdery Mildew pressure is currently very high.
Powdery is likely to have increased and spread in your vineyard if your
protective programme hasn’t been adequate. Leaf spotting has been seen in an
increasing amount of vineyards over the last 7 days confirm that the weather
has increased the speed of Powdery Mildew’s spread.
The first signs of Powdery Mildew
on grafted vines have been seen this week. Disease spores are transmitted by
wind from neighbouring vines onto new grafts. Also powdery can break out on the
watershoots that are left on the trunk.
Grafted vines are now growing very rapidly and have fresh, unprotected foliage that can be easily infected. Powdery infections this season lead to an increased risk in future season as grapevine buds on grafted vines are vulnerable. Once Powdery is inside a grape bud it survives winter to become a flagshoot next season. Growers are advised to keep protection on their grafted vines to prevent Powdery infections.
Grafted vines are now growing very rapidly and have fresh, unprotected foliage that can be easily infected. Powdery infections this season lead to an increased risk in future season as grapevine buds on grafted vines are vulnerable. Once Powdery is inside a grape bud it survives winter to become a flagshoot next season. Growers are advised to keep protection on their grafted vines to prevent Powdery infections.
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| Powdery Mildew. |
BOTRYTIS
BOTRYTIS
Berries Peasize (EL-31)
leads to Bunch Closure (EL-32) which is a key time in protecting fruit from
bunch botrytis. Rain during this period increases the risk of bunch botrytis in
tight bunched varieties.
Look for any ‘trash’ or old caps trapped inside your bunches. With humid and wet weather Botrytis can begin on this dead material and become a point of serious infection when grape berries start to ripen (8- 9oBe).
Look for any ‘trash’ or old caps trapped inside your bunches. With humid and wet weather Botrytis can begin on this dead material and become a point of serious infection when grape berries start to ripen (8- 9oBe).
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| Hail Damage Dec 2013 |
Where hail damage has occurred this has increased the risk
of Botrytis developing at harvest. Bunch Botrytis infections begin on damaged
plant material including old flower caps trapped in bunches, caterpillar damage
and other wounds. If Botrytis is present in your bunches now it is likely to
increase quickly if we have further wet weather after verasion (EL-35). Monitor
closely for bunch damage and if you find some prepare to treat this if wet weather
is forecast before harvest. Consult with your winery before any late season
sprays are applied.
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