Goldenrod (Solidago) Disease Management: Rust, Mildew, and Leaf Spot Control

Managing Diseases in Goldenrod Production

Goldenrod (Solidago) faces rust, powdery mildew, fungal and bacterial leaf spots, phytoplasma, crown gall, nematodes, and viral diseases. Cultivar resistance is available for some diseases, reducing management inputs.

Rust

Coleosporium, Puccinia, or Uromyces cause small bright orange/yellow/brown pustules on leaf undersides.

Management: Provide good air circulation. Clean up debris. Avoid overhead watering. 'Golden Fleece' and 'Fireworks' reported resistant. Apply fungicides.

Powdery Mildew

Golovinomyces, Erysiphe, Uncinula, Phyllactinia, Sphaerotheca cause white/gray powdery growth on upper leaf surfaces; leaves yellow/brown, curl, drop; new growth crinkled/distorted.

Management: Same as rust: good air circulation, avoid overhead watering. 'Golden Fleece' and 'Fireworks' resistant. Apply fungicides.

Fungal Leaf Spots

Multiple genera (Ascochyta, Asteroma, Cercospora, Colletotrichum, Macrophoma, Phyllosticta, Placosphaeria, Ramularia, Septoria) cause small dark spots on lower leaves first; heavily spotted leaves yellow, brown, wither.

Management: Avoid overhead watering. Space for rapid drying. Water early. Apply fungicides.

Bacterial Leaf Spot

Xanthomonas spp. cause dark brown/black leaf spots.

Management: Avoid overhead watering. Space for rapid drying. Water early.

Aster Yellows

Phytoplasma causes yellowed plants with poor flower color; tight leaf clusters.

Management: Remove/destroy infected plants. Apply insecticides for leafhopper suppression.

Crown Gall

Agrobacterium tumefaciens causes galls/swollen areas at soil line or higher at wounds.

Management: Start with gall-free plants. Remove/destroy infected plants.

Lesion Nematodes

Pratylenchus pratensis cause stubby roots with darkened areas.

Management: Remove/destroy infected plants. Replant with non-host species.

Viral Disease

Tomato spotted wilt virus (TSWV) causes yellow/brown rings or mottled yellowing; stunting.

Management: Remove/destroy infected plants. Suppress western flower thrips (vector) with insecticides.

Integrated Goldenrod Health Program

Key strategies: select resistant cultivars ('Golden Fleece', 'Fireworks') for rust and powdery mildew; avoid overhead irrigation; maintain good air circulation; early season leafhopper control; thrips suppression for TSWV; start with clean, gall-free plants; regular sanitation; and targeted fungicide applications. The availability of resistant cultivars significantly reduces disease management burden for the two most common foliar diseases.