Crown Gall

by Nanette Londeree, Master Rosarian

SIGNS

  • Rounded light green to light tan growths on roots or bud union
  • Irregularly shaped, rough, woody-looking dark-colored masses on stems near soil line or just below the surface

SYMPTOMS

  • Stunted growth – very small leaves with few flowers buds
  • Young plants with slow growth or that fail to grow at all

OPTIMAL CONDITIONS / HABITAT

  • Plants grown in infected soil
  • Warm, sunny weather; it is not active in cold weather
  • Can persist in the soil in a dormant state for years
  • Variety of other host plants including apples, raspberries, honeysuckle, euonymus and many vegetables

TREATMENT

Prevention:

  • Maintain good garden sanitation and cultural practices
  • Purchase plants from high quality suppliers
  • Inspect new plants thoroughly before adding to your garden
  • Avoid injury to canes and stems when planting or cultivating

Elimination:

  • Cut out galls using a sharp knife or pruning shears and destroy them; disinfect blades with a bleach solution after each cut
  • If heavily infected, remove and discard the plant
  • Replace soil where rose was growing with new soil, and don’t grow another rose or susceptible plant where the rose was removed
  • There is no known chemical treatment for this disease

GOOD GUY / BAD GUY?

Mostly a nuisance – generally not a big problem for most roses; though if a rose is infected it may cause the ultimate demise of the plant

Photos of Spring Dwarf are by Baldo Villegas from the extraordinary website: http://members.tripod.com/buggyrose/irosepests.htm

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