Agriculture: Turfgrass Pest Management Guidelines

Stripe Smut

  • Ustilago striiformis
  • Description of the Disease

    Plants infected with stripe smut are often pale green and stunted with long, black stripes of spore pustules. Infected leaves curl, then die and become shredded. Fungal spores formed in the leaves can contaminate seed and infect seedlings and young tillers. The fungus survives in the grass plant.

    Susceptible Turfgrasses

    Bentgrasses, perennial ryegrass, fescues, and bluegrasses are susceptible to stripe smut.

    Conditions Favoring Disease

    Stripe smut is favored by moderate temperatures and is prevalent in spring and fall. Temperatures between 60° to 78°F are conducive to infection and symptom expression. Infected plants may die in hot, dry weather.

    Management

    Cultural Control

    Infected turf is generally under higher drought stress, so irrigate adequately based upon evapotranspiration needs, but avoid extended periods of prolonged leaf wetness. Avoid excessive nitrogen fertility during the summer months.

    Treatment Decisions

    Apply fungicides only if the disease is severe. Seed treated with a broad-spectrum fungicide like captan can possibly prevent initial infections of seedlings.

    Common name Amount to use Ag Use
    REI‡
    NonAg Use
    REI‡
    (Example trade name) (hours) (hours)
    Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least likely to cause resistance are at the top of the table. When choosing a pesticide, consider information relating to the pesticide's properties and application timing, honey bees, and environmental impact. Always read the label of the product being used.
     
    A. AZOXYSTROBIN
      (Heritage) 0.2–0.4 oz/1000 sq ft 4 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11)
     
    B. CAPTAN
      (Captan 4L or 50 WP) Label rates See label Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Multi-site contact (M4)
      COMMENTS: Seed treatment for susceptible cultivars.
     
    C. CHLOROTHALONIL
      (Daconil Action) Label rates 12 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Multi-site contact (M5)
     
    D. MANCOZEB
      (Fore 80WP, Dithane M-45) 4 oz/1000 sq ft 24 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Multi-site contact (M3)
      COMMENTS: Dithane M-45 registered for use on sod farms only.
     
    E. MYCLOBUTANIL
      (Eagle 20EW) 1.2 fl oz/1000 sq ft 24 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
     
    F. PROPICONAZOLE
      (Banner Maxx) 1–2 fl oz/1000 sq ft 12 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
     
    G. THIOPHANATE-METHYL
      (Fungo Flo) Label rates 12 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Methyl benzimidazole (1)
     
    H. TRIADIMEFON
      (Bayleton 50 Turf and Ornamental) Label rates 12 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
     
    I. TRIFLOXYSTROBIN
      (Compass) Label rates 12 Until dry
      MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11)
    1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of action. Fungicides with a different group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with mode-of-action group numbers 1, 4, 9, 11, or 17 before rotating to a fungicide with a different mode-of-action group number; for fungicides with other group numbers, make no more than two consecutive applications before rotating to a fungicide with a different mode-of-action group number.
    Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Agricultural use applies to sod farms and commercial seed production.
    Text Updated: 09/09
    Treatment Table Updated: 12/16