Red Blotch Disease and the Virus Status of CDFA-certified Grapevine Stock

August 25th, 2014
Red Blotch Disease and the Virus Status of CDFA-certified Grapevine Stock

The Discovery of Grapevine Red Blotch-associated Virus (GRBaV, Red Blotch) in 2012 focused the industry on Red Blotch disease—an unknown condition with recognizable symptoms that growers had been aware of for some time. GRBaV has been found in new planting materials as well as in established vineyards in California and several other winegrowing states in the U.S. During the past 18 months, in an effort to curb disease spread, key stakeholders…

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Late-season Mite Infestations and Management

August 18th, 2014
Late-season Mite Infestations and Management

Every year in Lodi there are a few vineyards that have a late-season infestation of spider mites, especially the Pacific spider mite. By late-season I mean late August or September. Typically the grower’s attention during that time period is shifting to harvest and there is the question of whether or not the mite infestation needs to be treated. One might think that the mite population will continue to increase throughout…

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How California Farms Measure Up in the 2012 Census of Agriculture: Smaller in Size with Higher Value of Production

August 11th, 2014
How California Farms Measure Up in the 2012 Census of Agriculture:  Smaller in Size with Higher Value of Production

The 2012 Census of Agriculture was released in early May 2014. Average farm size continues to grow in terms of acreage and market value of production. However, this trend is not universal across crop category or geographic region. For the crop category of Land Used for Vegetables, the average acreage allocation per farm reporting production in this category decreased, while certain counties in California experienced an increase in the average…

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Regulated Deficit Irrigation – Part II

August 4th, 2014
Regulated Deficit Irrigation – Part II

Part I of this series presented basic concepts of regulated deficit irrigation (RDI), early season soil moisture management, and the vine component of the soil-vine-atmosphere moisture continuum. In this posting, we will explore the other components of the continuum and regulated deficit irrigation after vines reach full canopy. The dryness of the atmosphere, the second component of the continuum, drives vineyard water use by drawing moisture from the soil and…

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Regulated Deficit Irrigation – Part I

July 28th, 2014
Regulated Deficit Irrigation – Part I

Deficit irrigation refers to the practice of applying less than the full amount of water a vineyard can use.  The objective of deficit irrigation is to induce and sustain moderate water stress that arrests shoot growth and limits fruit growth without impacting foliage health and sugar accumulation.  This is possible because shoot growth and berry growth are more sensitive to water stress than sugar accumulation.  Deficit irrigation reduces irrigation costs…

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In the Vineyard with Paul Verdegaal: A Dry Year and Pest Update

July 21st, 2014
In the Vineyard with Paul Verdegaal: A Dry Year and Pest Update

The official end of the rainfall year shows a total of 10.2 inches of rain for 2013-14 – the driest season in the last 12 years and only slightly ahead of the 1976-77 drought. Fortunately, the last significant rain occurred with perfect timing and in a heavy event that mitigated the very dry soil conditions for local vineyards. Enough rain fell just before budbreak to provide for good growth and…

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The Value of Powdery Mildew Resistance in Grapes: Evidence from California

July 15th, 2014
The Value of Powdery Mildew Resistance in Grapes: Evidence from California

Powdery mildew (PM) is a fungal disease that can damage many crops. On most plants, PM appears as white, powdery spots on leaves, shoots, flowers or fruit, which if untreated, can spread over large areas of the leaves and stems and cause reduced yields and lower fruit quality. Grape PM, Erisiphe necator, is the most prevalent leaf-infecting disease for California grapes. Across the state, it accounts for 74% of grape…

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Global Wine Market Update from the Ciatti Company

July 7th, 2014
Global Wine Market Update from the Ciatti Company

Updated reports are coming in on harvests around the world. The government projections in Argentina have changed dramatically over the past month. Earlier crop reports had projected a 30% decline in volume, but new reports now estimate only a 6% decline from the previous year. In Italy, an updated harvest report now shows that they had a much larger than previously reported crop in 2013, and now holds the title…

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Spider Mite Control in California Vineyards with Conventional and OMRI-approved Acaricides

June 30th, 2014
Spider Mite Control in California Vineyards with Conventional and OMRI-approved Acaricides

Spider mites are found in vineyards throughout most grape growing areas of the world. In California, the primary spider mite pests are the Pacific spider mite, Tetranychus pacificus, and the Willamette spider mite, Eoteranychus willamettei (Karban and Zalom, 1998). The Pacific mite can be a major problem in warmer grape-growing areas and in hot and dry years. Although it can cause damage early in the season, Pacific mites generally prefer…

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Lodi Acreage and Potential 2014 Crop Size

June 23rd, 2014
Lodi Acreage and Potential 2014 Crop Size

Here at Allied Grape Growers AGG, we recently combed through the 2013 Grape Acreage Report published by the California Ag Statistics Service.  As we have done over the years, we analyzed every corner of the report, identifying missing acres and creating a better understanding of the true winegrape acreage planted in the state, by district and variety.  Since the report is voluntary we know data will be missing, but fortunately…

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