Sonoma County

Wines & Vines, Feb, 1991 by Rhonda J. Smith

Perhaps the most outstanding memory of the 1990 season was that all significant events, from bud break to harvest, occurred at "normal" times. The only disruption in an otherwise very uneventful year was late May rainfall. Occurring during bloom for some varieties, it significantly reduced fruit set in Cabernet Sauvignon and Sauvignon blanc in most growing regions by 50 % or more. Some late blooming Chardonnay in cooler areas along the Russian River also suffered crop losses due in part to Botrytis infections within the flower clusters. Overall crop levels, though down from 1989, were considered about normal for most varieties.

There was an excess labor supply available during harvest. This was attributed to well-spaced harvest dates. Also, the number of mechanized harvesters operating in the county increased.

More acres continued to decline due to phylloxera type B. Growers reacted by treating with Furadan and occasionally by implementing self-imposed restricted vehicular access in uninfected vineyards. The phylloxera threat increased the demand for other rootstocks such as 5C, 110R, 420A, 3309, 5BB and 101-14, although availability is still limited.

Insect and mite pest pressure was light. Western Grapeleaf Skeletonizer was located in the northeast part of the county. Traps will be placed throughout the county in 1991 by the Agricultural Commissioner's office. Powdery mildew incidence was higher than average in isolated areas throughout the county but could not be attributed to a specific cause.

The long-range outlook for viticulture in Sonoma County is quite good due to continued modest increases in demand for premium wine grapes. However, the industry is closely watching the increasing acres planted to these varieties in the northern San Joaquin Valley. To date, high yields in that area have not impacted local grape prices.