Plant Protection - Pansy Root Rot
Host: Pansies (Viola spp.) and Vinca (Vinca spp.)
Disease common name: Pansy Root Rot
Disease scientific name: Thielaviopsis
Severity: Can destroy entire crop in the greenhouse; can be spread from plugs
Symptoms:
Specific:
Leaves -
Yellow bottom leaves; sometimes yellow new leaves
Roots -
Loss of root hairs in 2-4 days
Brown color on roots. No odor. Roots remain rigid
Black spores on roots (can be seen with hand lens)
Contributing factors:
Presence of pathogen in new plugs
Improper watering methods and unsanitary growing conditions
Control:
Inspect all new plugs as they arrive
Don't hold plugs any longer than necessary before transplanting
Transplant into new or sterile trays and media
Use preventative fungicide such as Banrot, Benlate or Cleary's 3336
Do not over-water plugs; avoid splashing water
Growing media should be pH 5.5 – 5.8 and well drained
Withhold fertilizer for 3 days, until roots grow out of root ball
When roots emerge, fertilize with 20-0-20 at the rate of 50-75 ppm N.
Keep soil temperature above 62 F
Remove infected plants immediately
As with nearly every disease, prevention is much easier than attempting a ‘cure' with fungicides. Inspect all incoming plants and keep the greenhouse clean.
READ AND FOLLOW ALL LABEL DIRECTIONS AS IMPROPER USE OF PESTICIDES MAY AFFECT ANIMAL AND HUMAN HEALTH.
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