Phil Brannen
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We have had pretty dry weather recently, but the rainfall of late and predictions for more storms next week will increase the likelihood of downy mildew onset — as well as other fungal diseases of wine grapes. We are still within a critical stage for cluster infections by downy mildew and other diseases. Scout aggressively…
Posted in: Uncategorized -
I have not personally observed this yet, but county agents and producers are now starting to observe limited downy mildew. Though it has been drier of late, dew is sufficient for infection, and we have had some rains over the last few weeks that may have initiated infections. Scout carefully for mildew, and if observed,…
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Bloom and post-bloom are critical times for disease management in grapes. Temperatures and rainfall are generally favorable for pathogen development at this time, though conditions are not as wet as those observed last year. This is particularly true for grapes that are susceptible to powdery/downy mildews and Botrytis. The fruit are generally more susceptible to…
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As we are at bud break, keep in mind the need to start sprays of mancozeb and sulfur as soon as green stem tissue shows to protect against Phomopsis and powdery/downy mildews. All require control on young tissues, but especially Phomopsis. A little bit of Phomopsis, downy mildew, or powdery mildew is never good, as…
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Hello to all. Captan is currently under review by EPA. For those of you with interest in this fungicide and its continued use for grapes, please respond with comments to EPA via the link below. Also, forward to other producers and other researchers outside Georgia and the Southeast who should respond to the need for…
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As the grape season wrapped up in 2018, county agents from Habersham, Lumpkin, Rabun, Towns and White Counties were busy collecting powdery mildew samples for a new multi-state USDA-SCRI grant, the “Fungicide Resistance Assessment, Mitigation and Extension Network for Wine, Table and Raisin Grapes,” also known as FRAME. This grant will study powdery mildew resistance…
Posted in: Bunch Grapes -
The school of hard knocks is tough, but lessons learned can be important and they tend to stick. I encountered an issue in one of our just-planted, on-farm research blocks yesterday. Vines were collapsing and dying, and symptomatic vines presented a combination of red leaves, and/or leaves with red to purple leaf veins arising from…
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This article (see link) reviews the state of grape downy mildew resistance in Georgia as of the close of the 2018 season. Field failures when using strobilurin (QoI) fungicides have been confirmed in Georgia for both research and multiple commercial vineyard sites. Of major import, efficacy of several downy mildew materials have been compared, and…
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Pierce’s disease (PD), caused by the bacterium Xylella fastidiosa, is quite prevalent in many locations this year. The cold winter this last year has not made up for the two previous warm winters, so the bacterium has survived and prospered over the last 2-3 years. Unfortunately, once vines are infected and symptomatic, the vines need…
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Some of you already tried sending Botrytis samples to Clemson for fungicide resistance testing — only to find out that the service was no longer offered. However, Dr. Guido Schnabel will be conducting studies with the PROFILE system in early September, so he is volunteering to take Botrytis samples at this time — all free.…
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