Pacific Northwest Plant Disease Management Handbook

Swiss Chard (Beta vulgaris subsp. cicla)-Damping-off

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Latest revision: 
March 2026

Cause Pythium/Globisporangium spp. and Rhizoctonia solani are soil-infesting microbes that can build up rapidly and attack young germinating seedlings when soil is moist.

Symptoms Stems are attacked as young plants emerge. Plants wilt, fall over, and die. Germinating seed also can be attacked, rotting plants before they reach the soil surface.

Cultural control

  • Manage the crop to promote rapid and vigorous seedling growth.
  • Do not overwater as wet soils promote Pythium/Globisporangium disease.

Chemical control

  • Use seed treatments.
    • Allegiance-FL Group 4) at 0.1 to 0.75 fl oz/100 lb seed plus a dye. Controls Pythium/Globisporangium spp. only. See label for reentry restrictions.
    • Captan 4F (Group M4) at 12 fl oz/100 lb seed plus a dye.
    • Dynasty (Group 11) at 0.1 to 0.38 fl oz/100 lb seed plus a dye. 4-hr reentry.
    • Maxim 4FS (Group 12) at 0.08 to 0.16 fl oz/100 lb seed plus a dye. Controls Fusarium and Rhizoctonia spp. See label for reentry restrictions.
    • MetaStar 2E AG (Group 4) at 4 to 8 pints/A as a preplant or at planting treatment. Controls Pythium/Globisporangium spp. 48-hr reentry.
    • 42-S Thiram (Group M3) at 8 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
  • Quadris Flowable (Group 11) at 0.4 to 0.8 fl oz/1000 row feet applied in a 7-inches or less band either in-furrow at planting or as a directed spray at cultivation for Rhizoctonia. 4-hr reentry.
  • Ridomil Gold SL (Group 4) at 1 to 2 pints/A as a soil spray (broadcast or banded) if Pythium/Globisporangium spp. are a problem. Incorporate 2-inches deep when used. 48-hr reentry.

Biological control

  • Actinovate AG at 3 to 12 oz/A as a soil drench at planting. 4-hr reentry. O
  • Bexfond at 7 to 14 fl oz/A. 4-hr reentry. O
  • Double Nickel LC at 1 to 2 quarts/A as a banded soil spray or drench on 4- to 6-week intervals or at 0.5 to 4.5 pints/A on 2- to 4-week intervals. 4-hr reentry. O
  • Rootshield WP at 3 to 8 oz/100 gal water for greenhouse soil drench and field chemigation or at 16 to 32 oz/A as an in-furrow spray. 4-hr reentry. O
  • SoilGard at 2 to 10 lb/A at 4-week intervals will suppress Pythium/Globisporangium and Rhizoctonia. See label for specific application types and timings. 4-hr reentry. O

Pscheidt, J.W., and Ocamb, C.M. (Senior Eds.). 2026 Pacific Northwest Plant Disease Management Handbook.
© Oregon State University.

Use pesticides safely!

  • Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
  • Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
  • Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.

Trade-name products and services are mentioned as illustrations only. This does not mean that the participating Extension Services endorse these products and services or that they intend to discriminate against products and services not mentioned.

H - Home garden packaging commonly available.     O - Acceptable in organic production.