Amaryllis with Anthracnose? Rare but Treatable
Hippeastrum vittatum
Anthracnose is a fungal disease caused by fungi in the genus Colletotrichum that affects many plants, including vegetables, fruits, and trees. The disease thrives in cool, wet conditions, causing dark, sunken lesions on leaves, stems, flowers, and fruits.
ð Symptoms
- âĒ Small irregular yellow or brown spots on leaves
- âĒ Dark sunken lesions on leaves, stems, flowers and fruits
- âĒ Water-soaked lesions that darken as they age
- âĒ Pink gelatinous masses of spores in lesion centers during warm, moist weather
- âĒ Spots that expand and may cover entire leaves
- âĒ Defoliation in advanced stages
â Possible Causes
- â Caused by fungi in the genus Colletotrichum
- â Cool wet weather promotes development
- â Optimum temperature between 75-85°F (24-29°C)
- â Foliage wet for extended periods of time
- â Fungi overwinter in seeds, soil and garden debris
- â Spores spread through water droplets
ð Treatment
Quick Fixes
Remove and discard all visibly infected parts
Remove and discard all visibly infected parts
Apply commercial systemic fungicide (azoxystrobin or mancozeb)
Apply commercial systemic fungicide (azoxystrobin or mancozeb)
Adjust irrigation to avoid wetting foliage
Adjust irrigation to avoid wetting foliage
Second application of systemic fungicide
Second application of systemic fungicide
Assess treatment effectiveness
Assess treatment effectiveness
Organic Treatment
Remove all infected plant parts and discard in plastic bag
Remove all infected plant parts and discard in plastic bag
Apply organic liquid copper spray to all plant surfaces
Apply organic liquid copper spray to all plant surfaces
Switch irrigation regime to drip, avoiding foliage wetting
Switch irrigation regime to drip, avoiding foliage wetting
Second application of copper fungicide or neem oil
Second application of copper fungicide or neem oil
Assess progress and remove any new lesions
Assess progress and remove any new lesions
Final organic fungicide application and ongoing monitoring
Final organic fungicide application and ongoing monitoring
ðĄïļ Prevention
- â Implement drip irrigation instead of overhead watering
- â Give plants enough room to breathe and reduce humidity
- â Remove infected plant material after harvest
- â Practice crop rotation between hosts and non-hosts
- â Choose resistant plant varieties when possible
- â Use western grown seeds not exposed to the disease
- â Avoid wetting foliage during watering
- â Ensure good air circulation around plants
ðą Care Guide: Amaryllis
ð§ How to Water
Water 2-3 times per week during flowering and active growth. Completely stop watering when leaves wilt to allow the necessary dormancy period. Avoid wetting the bulb directly to prevent rot.
âïļ Lighting
Prefers bright indirect light. Can tolerate morning sun but protect from intense midday sun. Rotate the pot occasionally for even growth.
ðŠī Ideal Soil
Use well-draining substrate composed of equal parts peat, soil, and sand. Plant the bulb leaving 1/3 exposed above the soil. Avoid waterlogging which can rot the bulb.