Lethal yellows
Cause
Candidatus Phytoplasm australiense.
Symptoms
Infected plants show some inward rolling and purpling of older leaves, which flatten to the ground. Young leaves develop yellow margins and remain small with short leaf stalks, causing clusters of small, yellow-fringed leaves in the centre of the plant. Plants become stunted and usually die. Runners from infected plants also show symptoms.
How it spreads
Pathogens are transmitted to strawberry plants by leafhoppers after they have fed on infected alternative hosts. Symptoms develop 6 to 8 weeks after the strawberry plant is infected. This means lethal yellows symptoms appear after the runners are harvested and planted into fruit production beds. There is little transmission of the disease between strawberry plants.
Crops affected
Strawberry
Control
Remove infected plants and attached runners in runner beds. Plant runners from approved or certified runner schemes.
Control weeds around strawberry blocks. Use appropriate chemicals to control leafhoppers in runner production areas.
Chemical registrations and permits
Check the Australian Pesticides and Veterinary Medicines Authority database for chemicals registered or approved under permit to treat this pest on the target crop in your location. Always read the label and observe withholding periods.