Exploring Systems Management of Insect Pests and Diseases on an Organic Vegetable Farm in Oregon

A goal of an organic farming system is to suppress insect pests and diseases through ecological and systems management. The goal of this project is to explore the strategies and outcomes of ecological and systems management on long term organic farms. This poster describes this effort for Persephone Farm, a 30-year-old diversified organic vegetable farm in the Willamette Valley of Oregon. Data sets utilized include farm data (field maps and 20-30 years of yield, cropping history, soil analysis, pest incidence, and input records), university personnel diagnostic and scouting data, and on-farm research data. The farm’s primary design and soil- and habitat-building strategies include 21 cropped acres amidst 30 additional acres of forest/riparian habitat; small farm fields bordered by native vegetation; a 4 year rotation including 3 years of vegetable crops and one year of pasture/cover crops; spatial rotation; a diverse crop mix; farm-scaping including beetle banks, aggregated in-crop insectary plantings, and a hedgerow; soil management including cover cropping, organic amendments, mulching, and liming; and a flock of pastured laying hens. Additional strategies include resistant varieties, irrigation management, staking, and row spacing/orientation. Insect pests and diseases that have been but are no longer a problem include cabbageworms (Pieris rapae, Plutella xylostella, Trichoplusia ni) most aphids (many species, especially Myzus persicae), Zucchini Yellow Mosaic Virus, and head rot (Pseudomonas spp.) and downy mildew (Peronospora parasitica) of broccoli. Clubroot (Plasmodiophora brassicae) has developed but is not a significant economic problem. Insect pests that are an economic problem but not increasing in importance (and likely suppressed to some degree) include brassica (Phyllotreta cruciferae) and tuber (Epitrix tuberis) flea beetles, cabbage aphids (Brevicoryne brassicae), cucumber beetles (Diabrotica undecimpunctata, Acalymma vittatum), thrips on onions (Thrips tabaci, Frankliniella occidentalis, and symphylans (Scutigerella immaculata). Diseases that are increasing in importance include cucurbit root rot/wilt (diagnosis underway) and spinach Fusarium wilt (Fusarium oxysporum f. sp. spinaciae). Onion downy mildew (Peronospora destructor), potato late blight (Phytophthora infestans) and winter squash storage diseases (Botrytis cinerea, Fusarium spp., Phoma spp., and Sclerotinia sclerotiorum)are important but not increasing. As possible, the project uses the available data to relate ecological and systems management practices to insect pest and disease outcomes, and examples will be provided. Project publications will be available at eXtension.org/organic_agriculture and should be useful learning materials for farmers, students, and researchers.