Every garden contains a huge variety of fungi in the soil and on plants. Some fungi are visible, while others play an unseen role in the soil decomposing organic matter. Some plants have a symbiotic -- mutually beneficial -- relationship with certain species of fungi. But parasitic fungi, including many types of mould, can infect a plant, weakening and sometimes killing it. Fungicides are problematic as they kill nearly all the fungi they contact, including the useful varieties. Vinegar is an alternative treatment for mould on your plants and seems to destroy the white powdery mould often seen on plants, especially roses.
Make a weak dilution of 1 part vinegar to 20 parts water in the spray bottle.
Spray the afflicted plants thoroughly, covering the tops and bottoms of the leaves.
Repeat every four to five days until the mould appears to be gone.
Alternating the vinegar treatment with other natural sprays -- ones based on baking soda or vegetable oil, for example -- may be more effective than one remedy alone. If the mould is resilient, you could also try slightly stronger vinegar and water solutions.