Phil Brannen
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I was at a muscadine meeting in Americus, GA earlier this week (Thursday), and I made comment on how I have never really observed significant crown gall on muscadine grapes in Georgia. I scheduled a muscadine grape visit with a producer near Ellijay, GA the next day, and I can now say that I have…
Posted in: Muscadine Grapes -
We have been receiving multiple grape samples with black rot in our diagnostic clinic. Only one or two infected grapes can provide a vast number of spores for secondary infections of clusters going forward. Prevalent rainfall has made control difficult. The disease cycle will slow as grapes mature, but fruit can still be infected till…
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We are starting to see diseases pop up on both European vinifera and hybrid grapes. For some of these, such as anthracnose and Phomopsis, much of the initial infection occurred much earlier. The goal now would be to prevent secondary spread — especially to developing clusters. Relative downy mildew, Sarah Campbell (UGA grad student) reported…
Posted in: Uncategorized -
Sarah Campbell, a graduate student in the Plant Pathology Department at the University of Georgia, has been reviewing our situation with downy mildew resistance to three fungicide classes utilized in Georgia. The maps in the document below show the counties which she has surveyed and whether resistance has been found in those counties. Of critical…
Posted in: Uncategorized -
Downy mildew was confirmed today in west Georgia (see below for photos from the producer). This is the first confirmed report this year, but as I said yesterday, it is likely out there in other locations as well. We will likely see more symptoms of downy mildew this week as the epidemic takes off. If…
Posted in: Uncategorized -
I think most producers are fully aware that recent rainfall events will increase disease levels in wine grapes. I am particularly concerned about fruit rots and downy mildew. In particular, more active materials for downy mildew are needed at this time. Though the contact materials such as Captan and Mancozeb are good materials, I think…
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We are now hitting peak bloom on many of our grape cultivars. Bloom is a critical time for disease management in grapes, and with the rainfall that has occurred this week, we are setting ourselves up for another active downy mildew and rot season. In addition, other diseases, such as powdery mildew, Phomopsis and Botrytis,…
Posted in: Bunch Grapes -
If you are really interested in learning about grapevine trunk diseases, this new journal article is for you (see link). It is a highly scientific article which covers the state of the art relative this topic. We mainly have issues with Botryosphaeria-type diseases, and I include Phomopsis in this category as well. However, we have…
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You may already be aware of this app, but I just found out about it today. The Vineyard Advisor App has been developed by Texas Tech, and it appears to largely be an IPM app. I don’t think it is that helpful in identification, so you have to largely know the organism already to find…
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Crown gall can sometimes be confused with either leaf roll virus or Pierce’s disease. In general, if a plant is a completely brilliant red, this is likely caused by crown gall or some trunk injury. Pierce’s disease and leaf roll viruses can also have reddened leaves or leaf margins, so this is a little confusing…