Mildew is a common fungus that infects plants. Plant fungus is more easily controlled by using preventative measures. If your plants or vegetable crops have become infected with fungi, however, you can kill it with a fungicide.Common types of fungus seen on plants include powdery mildew, leaf spot, blight, root rot and white mold.Although some fungal infections do little damage to plants, others that are left untreated can lead to the death of the plant.For the best chances of success, treat your plants at the first signs infection.ildew is a common fungus that infects plants. Plant fungus is more easily controlled by using preventative measures. If your plants or vegetable crops have become infected with fungi, however, you can kill it with a fungicide.