Disease
Aster Yellows
A phytoplasma disease spread by leafhoppers that distorts and yellows flowers and foliage, often causing a bushy witches-broom appearance in affected plants.
Symptoms to Look For
- Yellowing and stunting of foliage, often with a yellowed rosette of distorted leaves at the crown
- Flowers turning green and leafy instead of forming normal petals
- Bunchy, tufted new growth and side shoots giving a witches-broom appearance
Affected Plants
CarrotLettuceCeleryOnionStrawberryZinniaAster
Organic Solutions
Remove infected plants
Pull out and destroy all clearly infected plants immediately - there is no cure and they will continue to spread the disease via leafhopper vectors.
Control leafhoppers
Reduce the leafhopper population with reflective mulch, row covers, and insecticidal soap sprays to limit the vector that spreads the disease.
Prevention
- Use row covers from planting to exclude leafhopper vectors throughout the season
- Remove weeds around the garden perimeter which harbour both the phytoplasma and its leafhopper vectors
- Avoid planting susceptible crops adjacent to established perennial plantings where leafhoppers overwinter
Garden, by Willowbottom recommends only organic, wildlife-friendly solutions. No synthetic pesticides, no harmful chemicals - ever.