It sounds like your petunias have a fungal infection called powdery mildew. It is spread by pathogens on the wind but rarely leads to death. The best thing to is to remove the infected parts and water the plants all over to wash of the spores. The only preventative care is to maintain a healthy plant that can resist infection. But before you take action, I suggest you do some research into powdery mildew on petunias to double check what it is.
Petunias can get powdery mildew if they are kept too wet.
a petunia
Petunia.
Petunia is the correct spelling.
Petunia Petunia Pig.Petunia
petunia phlovera
The flower is a petunia.
Petunia axillaris (the large white or night-scented petunia) or Petunia integrifolia P. axillaris
Petunia flowers are an inch to 4 inch blossoms depending on the type of petunia.
The scientific name for the Mexican petunia is Ruellia simplex. It is a flowering plant with purple, tubular flowers that is native to Mexico.
Petunias are in the family of solanaceae which is also potatoes, tomatoes and nightshade. The petunia genus is Petunia Juss. The three species are Petunia x atkinslana D. Don ex Loudon, Petunia axillaris Lam. Britton, Sterns & Poggenb. (which is a large white petunia) and petunia intergrifolia (violet flower)Then there are four petunia groups: grandiflora, multiflora, milliflora, and groundcover petunia like 'Wave' and 'surfinia'.
Petunia was the girlfriend of Porky Pig.
Petunia Pig was created in 1937.