The onset of autumn brings cooler nights, dewy mornings and warm, sunny days. These are ideal conditions for fungal issues to form in your garden. Powdery mildew is particularly rampant, which can be identified by the appearance of a white/grey powdery substance forming on the foliage and sometimes on the stems. Also keep an eye out for black spot and rust. Treat these fungi as soon as they appear with spray-on fungicides such as lime sulphur or a fungicide product by a brand of your choice.