Cut off the infested blooms to break the cycle. If the central cones of your coneflowers appear black or muddy, sunflower moths (Homoeosoma electellum) might be the likely culprits. These silvery ...

However, coneflowers, like other garden plants ... It's typically noted by its dark brown and black spots surrounded by a halo of yellow that appears on leaves, directly impacting photosynthesis ...