Aster Yellows

Candidatus Phytoplasma asteris

2 host plants · Phytoplasma

Last updated

Data Maturity Structured

This profile synthesizes data from multiple published sources. Expert field review is in progress.

Aster Yellows can show up on landscape plants, producing visible damage that ranges from leaf spots and discoloration to branch dieback depending on severity. Early detection gives you the best management options.

Start with sanitation: remove and dispose of affected material as you find it. Thin dense growth to improve air circulation, and redirect irrigation away from foliage. If the condition persists despite cultural adjustments, your local Extension office can help identify the pathogen and recommend targeted treatments.

Quick Reference

Agent Type
phytoplasma
Causal Agent
Candidatus Phytoplasma asteris
Host Plants
2
Spread
Exclusively vector-transmitted by the aster leafhopper (Macrosteles quadrilin...
Favorable Conditions
Warm temperatures favor both leafhopper vector activity and phytoplasma repli...

Management

Vulnerability Window

Growing season (April-October). Peak risk during warm months when leafhopper populations are highest and actively feeding. Young plants are more susceptible than mature plants. source: Extension guidelines

What Triggers Infection

Warm temperatures favor both leafhopper vector activity and phytoplasma replication within the plant. Disease severity and symptom expression increase with temperature. Leafhopper populations peak during warm months. Hot climates exacerbate symptoms; cooler climates may allow asymptomatic infections. source: PNW Plant Disease Management Handbook

Cultural Controls

  • Remove and destroy infected plants immediately to eliminate phytoplasma reservoirs. No cure exists for infected plants. source: PNW Plant Disease Management Handbook
  • Control weed hosts, especially in the Asteraceae family, near susceptible plantings to reduce alternative leafhopper feeding sites and phytoplasma reservoirs. source: IPM guidelines
  • Avoid planting susceptible crops adjacent to weedy areas or grain fields that support leafhopper populations. source: Extension recommendations
  • Use floating row covers on susceptible vegetable crops to exclude leafhopper vectors during peak activity. source: Extension recommendations
  • Use reflective mulches or yellow sticky traps to deter or monitor leafhopper populations. source: Extension recommendations
  • Plant resistant or tolerant varieties when available. source: General IPM
Regional Notes

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Host Plants (2)