Virginia Grape Disease Updates

Upcoming Vineyard Meetings a)    17-18 Feb      Central Virginia UvaSapians (fee) b)    19-21 Feb.     VVA Winter Technical (fee) c)    27 Feb.          VT/VCE Vineyard Pruning Workshop – Winchester, VA d)    10-12 March Eastern Wine Exposition – Lancaster PA (fee) e)    14 March      Pruning Competition  -Abingdon, VA f)     24 March      Interactive grape disease management planning workshop (in English) g)    25 March       VT/VCE Vineyard IPM workshop– Charlottesville, VA h)    26 March      Interactive grape disease management planning workshop (in Spanish) __________________________________________________________________ More Information a)    17-18 Feb      Central Virginia UvaSapians (fee) Hosted by the Monticello Wine Trai...

Happy New Year! I hope we will have a nice 2020 season. Here are slides from a Private Pesticide Certification course that was held on 17 December 2019 at Loudoun County. The link will open a pdf file in Google Drive.

Virginia Tech is looking for an Assistant Professor - Tree Fruits/Specialty Crop Pathology Virginia Tech’s College of Agriculture and Life Sciences is seeking applicants for a tenure track position in Tree Fruits/Specialty Crop Pathology ( Job No. 511904 ) as part of its SmartFarm Innovation Network faculty cluster hire. The cluster hire of 13 new faculty positions will be filled over multiple years within several academic units and Agricultural Research and Extension Centers. Collaborations of cluster hires and existing faculty will enhance interdisciplinary flagship programs at the nexus of digital, biological, social, and physical sciences and engineering with application to agriculture, food, and natural resources. This ambitious vision will create a statewide network of interconnected faculty, partners, and resources for scientific discovery and developing and deploying new technologies. The goal is to increase overall efficiency, resiliency, sustainability, and economic value o...

I heard from many that their fruits are ~2 weeks ahead of "average" season, and some early cultivars are already harvested in the southern VA. I should have posted this earlier, but it probably is still applicable to many of us, so, here is a list of fungicides with PHI (Pre-Harvest Interval) equal or shorter than 7 days.   (the list is the same as in 2018, I did not see any additional material with PHI >= 7 days. If I missed any, please let me know.) I cannot cover every single fungicide out there, but I tried to cover common ones. Winemaking considerations can influence fungicide uses close to the harvest too. Make sure to communicate with your winemaker(s) if they have a preference on the use of fungicides, especially copper, sulfur, and captan (I listed several copper materials because they have different PHI or REI.) For fungicides to be used on cultivars that have more than a month to go, please refer to my previous post. Please make sure to rotate mode of action...

Our Chardonnay clusters are getting larger and berries are starting to touch each other. It feels a bit early, but here are grape disease management reminders at berry touch/cluster closure stage. Botrytis gray mold: The best management practice is canopy management. Botrytis pathogen likes high humidity, thus, the poorly managed canopy that traps humidity will help them to thrive. This pathogen also needs wounds to develop spores, thus, grape berry moth and other insects plus birds need to be managed too. There is a number of Botrytis materials such as Rovral and Meteor (FRAC 2), Elevate (FRAC 17), Vanguard and Scala (FRAC 9), Luna Experience (FRAC 7 plus 3), Kenja (FRAC 7), Miravis Prime (FRAC 7 plus 12), Switch (FRAC 9 plus 12), etc. Botrytis pathogen is well known for its ability to develop fungicide resistance, so, please rotate FRAC codes!! QoI fungicides (FRAC 11) are no longer the effective material for us due to the development of QoI-resistant Botrytis isolates thro...

My colleagues and I are seeking information on sour rot so that we can develop research priorities (and hopefully obtain grants). Many of us suffer from sour rot (remember the last season?), and we need to get our heads together. If you could fill in this short survey, we really appreciate. It should not take more than a few minutes to complete. It is not just for Virginia, so, please feel free to complete the survey if you grow grapes outside of Virginia. Sour rot survey (will open a new window) Thank you!!

Of course, once I mentioned the lack of rainfall, we  (i.e., northern VA)   were hit by a series of rain. To make things more complicated, we had at least three consecutive nights of warm and humid (RH > 90%) condition prior to the rains. Humid nights encourage downy mildew pathogen to produce spores, and rains will splash spores to healthy tissues. Thus, the risk of downy mildew during recent rain events was very high. ( Note : Central VA also had two humid nights in 7/5-7/6 at the Charlottesville airport, but the chance of rain is not high until this Thursday.) There are a number of materials can be used for protection: captan (FRAC = M4), mancozeb, ziram (FRAC = M3), Revus, Forum (FRAC = 40), Zampro (FRAC = 40 plus 45), Ranman (FRAC = 21)). Mancozeb products have the 66-day PHI, but ziram's PHI is 21 days.  Another good option is a copper (FRAC = M1) material, which is more economical than other materials. Copper has good efficacy against downy mildew, and ten...