Mildew comes in two types with respect to plants. It can be either downy mildew or powdery mildew, and each is a different disease. In appearance each appears as is a white, powdery fungal growth that can be found on plants.
Initially it will appear on the surface of a plant's leaves, then spreads to other parts of the plant.
Powdery mildew is both common and serious in its impact.
Signs of mildew on plants[edit | edit source]
Affected leaves turn yellow. They appear blotchy and may look distorted. After a time, the leaves drop off.
Asters and phlox are especially susceptible to mildew.
Causes[edit | edit source]
Mildew can impact plants that experience dry soil when they require moist soil or in humid conditions affecting the top growth of the plant.
If the weather has been continuously hot and dry, powdery mildew can take hold.
Cures[edit | edit source]
Remove leaves that have been worst affected. Dispose of properly. Do not compost such leaves.
Improve air ventilation around the plant(s).
Keep the soil sufficiently moist without waterlogging it.
Thin seedlings to prevent overcrowding.
Leaves can be dusted with sulphur but it's important to know which plants this is suitable for and to use the right amounts. A fungicide can be used but even with this, mildew can be hard to control once it strikes. Prevention is best.
Related problems[edit | edit source]
Similar to mildew are the diseases of botrytis or grey mould. These appear in the same manner but furrier in texture. These tend to spread over the whole plant and will even grow beyond the plant onto compost or organic matter surrounding it. The plants infected by these diseases often turn brown and wilt, eventually turning mushy.
