Powdery mildew is the main fungal disease that most grape growers
confront every seasons. Many grape growers struggled to keep powdery mildew under control in
vineyards, as once your vines are infected and the symptoms are
visible, the disease already is in an advance stage of development.
DJ's have specialist skills, based on experience, in detecting the disease early in the season. This week we have detected the following symptoms.
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| 1. A powdery mildew a flagshoot - A small amount of powdery mildew at this point in the season becomes a significant amount at harvest. McLaren Flat 22/10/2012. |
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| 2 & 3. Powdery mildew on the reverse side of the leaf. Willunga 23/10/2012. |
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| Leaf spots in an abandoned vineyard. Willunga 23/10/2012. |
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| 4. A powdery mildew flagshoot in Grenache. Note the upturned lower leaves covered in white fungal growth. |
Infections at this time of the season are very serious. One of the vineyards pictured above in Willunga has 4-6 powdery mildew infections per panel (2 & 3),
this will obviously turn into a ranging infection of the next four weeks if the
vineyard remains unsprayed.
Berries are extremely susceptible from the immediate capfall stage (EL-18) through fruit set (EL-30). This is the most critical time to keep powdery
mildew under control. Severe powdery mildew infections on the clusters
is usually a result of poor fungus control and canopy management
throughout this period.
Maintaining proper airflow and sunlight penetration
into the vine will ensure a “drier” micro climate inside the vine.
Direct contact with sunlight will also kill powdery mildew spores and
reduce the chances of crop loss. This can be achieved with good canopy
management.
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