06/19/2026
🌸 Seeing brown, dusty spots on the undersides of your snapdragon leaves? It could be snapdragon rust!
We recently diagnosed snapdragon rust in the Arkansas Plant Health Clinic. This fungal disease thrives during cool, humid conditions and can spread quickly when leaves stay wet for long periods.
The first signs of infection often appear as pale-yellow spots on the upper leaf surface. Turn the leaf over, and you’ll find the classic symptom—small brown, powdery pustules that contain spores capable of spreading the disease to other snapdragon plants. As the disease progresses, leaves may yellow, dry up, and drop prematurely.
To help reduce rust problems:
🌿 Clean up plant debris
💧 Avoid overhead watering and water at the base of plants when possible
🌬️ Space plants properly to improve air movement and help leaves dry more quickly
Snapdragon rust won’t usually kill your plants, but it can make them look much less attractive. Checking the undersides of leaves is key—those brown, dusty pustules are a dead giveaway!