Hi Fodder Followers! Is everyone safely afloat out there?  I've just finished totaling the current "hydro year" precipitation totals for our 7 (yes, we now have 7!) powdery mildew stations and 3 CIMIS stations.  (Note: The Amador Eagle station is awaiting an upgrade, so that station's data is not included.)

The "hydrological year", also called a "water year", is a term hydrologists and water resource managers use to describe the period from Oct. 1 of a given year to Sept.30 of the following year.  Thus, the hydro year is meant to include fall rainfall with dormant season rains that may impact the soil water holding capacity and total rainfall for crops emerging the following spring.

The stations are located across El Dorado, Amador, and Calaveras counties and give us a good picture of the rainfall totals across the region.  And the winner is....the Lava Cap station located in Camino has recorded the highest rainfall amount to date, 54.04 inches; closely followed by our newest addition to the network, the West Point station at 53.78 inches!

 

Greetings Fodder Folks! I'm often asked if winter is a slow time for me.  Even though the vines and trees are taking a much needed rest, fall and winter is the time for us UCCE Advisors to assess the previous season, prepare reports and presentations, and plan for next year's projects. Sort of like making sure the silo is full and the feed hasn't gone bad so you can produce a higher yield next season (my Wisconsin roots, don't you know...).

With a growing amount of knowledge needed to be an effective extension resource, that means attending informational meetings, such as the annual "Current Issues in Vineyard Health" and the Foundation Plant Services (FPS) annual "Grape Advisory Committee" meetings, both held in Davis last week.  

At those meetings, Dr. Maher Al Rwahnih, Director of the Diagnostics and Research Lab at FPS at

UC Davis, presented his work on a recently discovered virus named Grapevine Pinot Gris Virus (GPGV).  First identified in 2012 by researchers in Trentino, Italy, Maher is studying the virus presence in California.  He has found the virus in asymptomatic and symptomatic vines. In all symptomatic, GPGV positive vines, Grapevine Fanleaf virus was also present.  So far, the symptoms appear similar to those of fanleaf: chlorotic mottling, leaf deformation, and shoot stunting.  

 Maher, working with UCCE Farm Advisors, has tested samples from 10 grape growing counties and, so far, has only identified the virus from Napa.  In Napa, GPGV has been isolated from Chardonnay, Pinot Noir, Zinfandel, Malbec, Merlot, Cabernet Sauvignon, as well as other varieties.  

It appears an eriophyid mite may be a vector of GPGV.  Eriophyids are tiny, tiny mites, and there are several "strains" of eriophyid mites affecting grapes.  One of these strains infects grape leaf hairs, producing blisters on the top of the leaf and a distorted mat of fibrous leaf hairs on the leaf bottom. I have seen eriophyid mite damage here in the foothills, particularly in home vineyards where no sulfur has been used.  Sulfur effectively controls 

the mite.

Unlike Red blotch and leafroll virus, the best time to sample for GPGV is in the spring. I will be surveying foothill vineyards and sending samples for testing to Maher in spring. If you think you might have Pinot Gris virus, and would like your vineyard tested, please contact me! All results will be kept confidential. This is not a quarantined pest so the testing and information is only to improve our understanding of the disease.

Until next time...and thanks for sticking with me!

Hello Fodder Folks! The visit I coordinated by Professor Vittorino Novello, University of Turin, Italy, to our foothill region to tour Italian winegrape varieties and interact with local grape growers and industry was a huge success!  This was due in no small part to the hosting vineyard managers and winemakers who made the El Dorado and Amador vineyard tours a hit!

And wow, what an incredibly knowledgeable and gracious scholar.  Vittorino was

able to address the growing and culture of varieties Aglianico to Vermentino (OK, there wasn't any Zanello on the tour!).  Of course, since one of Vittorino's research projects right now is coordinating a national database of Italian varieties, with over 800 varieties described so far, he had no trouble at all addressing the questions we had about the 10 varieties we toured.  I think everyone who had a chance to participate came away with some insight for these mostly vigorous and challenging vines.

Sheila Bush discusses Nebbiolo culture in the shade at Sumu Kaw vineyard, El Dorado county.

Nebbiolo, we learned, like many Italian varieties, is difficult to grow but will reward those who handle it correctly (always cane prune, beware of frost damage during early budbreak). Sheila Bush, grower-Sumu Kaw vineyard, said she fell in love with Nebbiolo during a research trip to Italy in the early 90's but then thought often of pulling it out once she planted it in 1997 and had to deal with vigorous vines, frost damage, and highly tannic wine.  But then Sheila's brother in-law, Madroña vineyards winemaker Paul Bush, created a lovely Nebbiolo rosé and she thought, wait a minute. Ryan Wright, assistant winemaker for Madroña, filled in for Paul on the tour and described years of experimenting with Nebbiolo during the winemaking process to "soften the tannins but not lose the fruit". Adding just a drop of Barbera, and letting the Nebbiolo age, helped to soften the tannins to produce a lovely red wine, great with food (especially garlic!).

Vittorino commented that all of Sheila's observations as to the difficulty of growing Nebbiolo-the vigor, the need to cane prune, curbing yields to 3-4 tons to try to try to increase color, the highly tannic wines, were true to the variety.  The name

"Nebbiolo" is due to two things: the wax on the berry and the "nebbia" or 14th of November, as a late harvest date.  Nebbiolo buds early, but harvests late.  Nebbiolo, Vittorino said, "marks the soil"; which means it needs a special place to grow and only grows in a few regions in Italy.  There, Italian winemakers used to blend Nebbiolo with Barbera to solve the color instability problem, but no longer. There is no blending allowed for Barolo wines-the high quality DOCG Nebbiolo wine produced in Northern Piemonte.  Instead, they practice long maceration and age in very large barrels (100 hectoliters) to reduce the oak.  

I'll cover more on the Vittorino tours in my future blogs. To take a look at my recap of the tours, and Vittorino's evening seminars, go to the postings on my webpage here. 

Hello Fodder Followers! Are you still out there? I know the trough has been empty for awhile now, but I, like many of you, have been making hay while the sun shines! Rest assured, I've got your backs and have alot in store for you so listen up!

First off, powdery mildew has been a problem for many of you this year-and I've been answering a few farm calls related to this. All of the rains we had made for great canopy growth, making it more difficult for spray to reach the target. Leafing and shoot removal can really pay off when that is the case. That, plus ideal spring temperatures of 70-85° (remember those cool days we had? seems a long time ago now...) made it a mildew year. Calaveras Wine Alliance just funded a 7th mildew station (Yeah!) with a Ca. Specialty Crop Grant.  That station is located in West Point and it's weather data is currently up and posted at UCIPM.  The mildew model will begin running next year at this location. 

If you are interested in the latest mildew fungicide work, Doug Gubler will hold his annual powdery mildew field day this year at 10 a.m. on Aug. 3 at Rio Viento vineyards in Walnut Grove. RSVP to Trang Nguyen at xinguyen@ucdavis.edu if you plan to attend. 

After I presented my ET slope work and heard other researchers present their research at the annual ASEV conference in Monterey, I spent a week in Prosser, WA receiving spray application training from Prof. Emilio Gil from Spain.  Funded partly by a Western Sustainable Agriculture Research and Education (WSARE) grant, I was fortunate to be the only California participant in a week long, hands-on training that enhanced my ability to deliver spray tech training to all

of you. Gil currently works as the European Commission's TOPPS (Train Operators to Promote best management Practices & Sustainability) Director.  The program includes mandatory sprayer inspections with education for growers on how to best reduce drift and off site movement of pesticides. I'll be delivering this information in future workshops-so stay tuned for those.