The ongoing project aims to evaluate habitat management strategies to create cost-effective biological control options for arthropod pests in California vineyards. Collaborating with ten commercial growers from 2008 to 2009, we assessed the conservation strategy Floral Resource Provisioning (FRP) using various flowering plants on soil quality and the dynamics of Erythroneura leafhoppers and Planococcus mealybugs in major wine regions. We studied five flowering plant species—Annual Buckwheat, Lacy Phacelia, Sweet Alyssum, Bishops Weed, and Wild Carrot—to enhance pest control in Napa, Sonoma, and Fresno counties, supporting new ecologically based pest management strategies that meet USDA organic standards.

In 2008 and 2009, we compared insect populations and soil quality between agroecologically managed vineyard blocks and typical farmer-managed plots. Wet weather negatively affected cover crop establishment in 2008, resulting in low pest densities, which hindered treatment effect isolation. However, reduced leafhopper populations were noted in treatment plots with good flowering cover.

Key findings include:

1. In 2009, lower leafhopper nymph densities were found in well-established treatment plots;

2. No significant differences in early-season Anagyrus sp. density were observed;

3. Leafhopper egg parasitism rates were similar between treatments;

4. Treatment plots had higher abundance and diversity of natural enemies;

5. Natural enemy diversity varied throughout the growing season;

6. Studies showed longer longevity of Anagyrus pseudococci and increased parasitism rates with FRP.

These findings support the idea that flowering cover crops in vineyards can enhance natural enemy populations and pest regulation while maintaining soil fertility. Further research in 2010 will provide additional long-term data on the effects of various flowering species on grapevine pest control.