Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Zinnia > Discolored or spotted flowers
Zinnia > Flowers > Discolored or spotted flowers
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Bacterial Leaf Spot
Xanthomonas campestris pv. zinniae
- Small brown to black angular spots surrounded by yellow halos on leaves
- Spots on petals are reddish and circular
- Spots may merge together creating larger dead black areas that dry and crack
- Disease starts on lower leaves and progresses up the plant
- More information on Bacterial Leaf Spot (3.46 MB PDF)
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Alternaria Blight
Alternaria zinniae
- Reddish brown circular spots up to ½ inch in diameter appear on leaves and petals
- Centers of spots turn grayish white
- Center of an older spot may fall out giving the leaf a shot-hole appearance
- Severely infected leaves, stems, and flowers turn brown and die
- Dark brown sunken lesions (cankers) are common on the stem near the soil line
- Warm, wet or humid weather favors disease
- More information on Alternaria Blight (3.46 MB PDF)
