Primula Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of Primula diseases.
Primula Diseases - Articles

Updated: July 31, 2016

Primula Diseases
DiseaseSymptomsPathogen/CauseManagement
Aster YellowsPlants are stunted with excessive branching and yellow, strap-shaped leaves.PhytoplasmaDestroy infected plants. Maintain good insect and weed control in the greenhouse.
Botrytis BlightLeaves, especially those near the soil surface, rot and become covered with gray fungal growth as do fading flowers.Botrytis cinereaHeat and ventilate to maintain low humidity. Remove dead and dying tissue from the greenhouse. Apply a fungicide.
Damping-offSeedlings wilt and die.Pythium spp.Plant in pasteurized potting mix. Discard infected plants. Apply a fungicide.
Phytophthora Root RotRoots rot and plants wilt and die.Phytophthora primulaePlant in pasteurized potting mix. Discard infected plants. Apply a fungicide to protect healthy plants.
Rhizoctonia Crown Rot and Bud BlightRoots and stems brown. Plants wilt and die. Older plants may fail to flower or produce new leaves.Rhizoctonia solaniPlant in pasteurized potting mix. Discard infected plants. Apply a fungicide to protect healthy plants.
Thielaviopsis Root RotSmall black spots form on roots. Gradually, the entire root system browns. Old leaves die while younger leaves yellow.Thielaviopsis basicolaPlant in pasteurized potting mix. Discard infected plants. Apply a fungicide to protect healthy plants.
VirusesLeaves may be mottled, yellowed, or have dead spots or be curled. Plants are stunted. Flower color may break. Entire plants may die.Tobacco necrosis, primrose mosaic, cucumber mosaic, impatiens necrotic spot, tomato bushy stunt, alfalfa mosaic, or tobacco ringspot.Discard infected plants. Maintain good insect control, especially aphids and thrips.

Prepared by Gary W. Moorman, Professor of Plant Pathology