Identifying and Treating Scale on Chrysanthemums

Diagnosing Scale Insects on Chrysanthemum Stems

Small, black raised bumps on chrysanthemum stems—especially when they appear irregularly and away from the soil line—often indicate a scale infestation. Unlike root sprouts from drought stress, these bumps don't follow a pattern and may affect only certain cultivars, as seen with dark red varieties while yellow and orange ones remain unaffected.

Effective Treatment Options

For scale control, a homemade solution of 1 part rubbing alcohol to 8 parts water with a few drops of dish soap works well as a weekly spray until the infestation clears. Alternatively, horticultural oils like Sun Spray Ultra Fine provide effective control. For definitive diagnosis, take an infected stem sample to your local County Extension Horticultural agent.

Prevention and Monitoring

• Inspect plants regularly for early detection
• Isolate affected plants to prevent spread
• Maintain plant health through proper watering and fertilization
• Consider cultivar resistance when selecting new plants

With prompt treatment and consistent monitoring, chrysanthemums can recover from scale infestations and return to healthy growth.