Organic strawberry production in coastal California faces challenges from soil-borne diseases and high weed management costs. Verticillium wilt, caused by Verticillium dahliae, threatens strawberries, making long-term crop rotation necessary. However, even a seven-year rotation at the UC Santa Cruz organic farm hasn’t fully prevented outbreaks. Managing weeds can cost over $2,000 per acre.

To address these issues, we investigated anaerobic soil disinfestation (ASD), mustard cake (MC), and broccoli residue for their effects on V. dahliae and weeds in strawberries. Our objectives included:

1. Finding the best application rate for mustard cake regarding weed and V. dahliae suppression and fruit yield.
2. Demonstrating the combined effects of ASD, broccoli residue, and MC on V. dahliae, weeds, and strawberry yield at a working organic farm.
3. Sharing results with local organic strawberry growers via workshops and materials.

For Objective 1, we conducted a field experiment with various treatment combinations and monitored plant health and yields. Results showed that while high MC rates can hurt plants due to salinity, using MC at 1.5 t/A yielded good results. Weed emergence was minimal due to small planting holes, complicating evaluations.

In Objective 2, we tested different crop rotations and treatments at the UCSC farm. While some strawberry plants wilted, ASD treatment reduced wilt levels and increased marketable yields. No major differences were found between crop rotation treatments, but ASD maintained low levels of V. dahliae.

Our economic analysis indicated that ASD improved net returns significantly compared to control treatments.

For Objective 3, we set up a demonstration trial at ALBA in 2012, where strawberry plants again suffered from V. dahliae. Mortality and fruit yield varied across treatments, especially between broccoli and cauliflower plots.

A workshop was held to educate Latino growers, which received positive feedback. Data from the study has been shared at several outreach events.