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New Field Trials Planted in Northern California

On the first of August, new field trial plantings with vines using rootstocks modified with two different methods that give vines resistance to Pierce’s disease (PD) went into an isolated field trial research vineyard in Northern California.

A graphic showing how the modified vines work.

This builds on work that discovered five different genes that could impart resistance to PD into winegrapes. Initial field trials tested each method individually. Now they are stacking the different methods in combinations of two.

The field trials are being planted in common commercial plant and row spacing, with trellising, to see how the vines perform under standard vineyard conditions and the effect on yield.

During the field trials, the vines will periodically be inoculated with Xylella fastidiosa, the bacterium that causes PD.

The field trials are expected to last three to four years.

Winegrape Assessment Rate Unchanged for 2018

The PD/GWSS Board voted during its June 19 meeting to recommend the winegrape assessment for the 2018 harvest be set at $1.50 per $1,000 of value. Following the meeting, the recommendation was forwarded to and approved by CDFA Secretary

The 2018 rate is the same as the 2017 assessment, while over the 17-year life of the assessment, the rate has averaged $1.42 per $1,000 of value.

The assessment is used to fund research on Pierce’s disease and, beginning in 2010, can also be used to fund research and outreach on other pests and diseases of winegrapes. These pests and diseases are designated by the Board as posing serious threats to winegrapes. So far the European grapevine moth, mealybugs, brown marmorated stink bug, red blotch virus, fanleaf virus, and leafroll virus have been designated as serious threats to California’s winegrapes, and the Board has funded research on all of these. In addition to research, the assessment is also used to support related program activities.