INTEGRATED WEED MANAGEMENT FOR ORGANIC VINEYARDS

Authors: Baumgartner, Kendra; VEILLEUX, LISSA - 5306-15-00

Submitted to: Proceedings of the California Conference on Biological Control
Publication Type: Proceedings
Publication Acceptance Date: 7/1/2004
Publication Date: 7/15/2004
Citation: Baumgartner, K., Veilleux, L.M. 2004. Integrated weed management for organic vineyards. Proceedings of the California Conference on Biological Control.

Interpretive Summary: California winegrape growers are under increasing pressure from public regulatory agencies to decrease the use of herbicides that pollute our drinking water. Alternatives to herbicides are available, but their efficacy for controlling weeds is not well known. In this study, eight alternative weed control practices were evaluated. Research plots were established in a vineyard in Oakville, CA USA. The following practices were carried out: 1) Winter Roundup /Spring Roundup , 2) Fall Cultivation/Spring Cultivation, 3) Fall Cultivation/Spring Matran , 4) Fall Cultivation/Spring Roundup , 5) Winter Matran /Spring Matran 6) Cover Crop (Festuca idahoensis), 7) Natural Vegetation and 8) Spring Cultivation Only. Soil quality characteristics were sampled in each treatment plot before treatments were applied, and weed growth was assessed in spring. The most effective weed control treatment was Winter Roundup /Spring Roundup . Both Winter Roundup /Spring Roundup and Winter Matran /Spring Matran were equally effective at controlling the most problematic weeds. Although Matran did not control grasses well, the dominant grass weed was the cover crop (Zorro fescue), a short grass. Given that Matran controlled the more problematic broadleaves, this treatment was still successful

Technical Abstract: California winegrape growers are under increasing pressure to decrease the use of preemergence herbicides in order to achieve water quality standards established by various public regulatory agencies. Alternative weed control practices are available, but their effects on weed ecology are not known. In this study, eight alternatives to preemergence herbicides were evaluated for their effects on aboveground and seedbank weed communities. Research plots were established in a commercial vineyard in Oakville, CA USA in a randomized complete block design with 5 blocks. The following treatments were carried out in the vinerows: 1) Winter Roundup /Spring Roundup , 2) Fall Cultivation/Spring Cultivation, 3) Fall Cultivation/Spring Matran , 4) Fall Cultivation/Spring Roundup , 5) Winter Matran /Spring Matran 6) Cover Crop (Festuca idahoensis), 7) Natural Vegetation and 8) Spring Cultivation Only. Soil quality characteristics and weed seedbanks were sampled in each treatment plot before treatments were applied, and weed biomass and species composition were assessed at spring peak biomass. Based on total weed biomass, the most effective weed control treatment was Winter Roundup /Spring Roundup . However, based on broadleaf weed biomass, Winter Roundup /Spring Roundup and Winter Matran /Spring Matran were equally effective. Although Matran did not control grasses well, the dominant grass weed was the cover crop (Zorro fescue), a low stature grass. Given that Matran controlled the more problematic broadleaves, this treatment was still successful.