A very common disease on roses. Black spots with yellow fringes spread quickly over the plant. Premature leaf fall may occur. Black Spot becomes visible July/August with heavy infections spreading to leaf buds and later to the stems which then die back. Premature leaf drop will occur.
Cultural measures: Remove and destroy fallen infected leaves. Encouraged by a shortage of potash and warm, wet summer weather. Feed with a plant food high in Potassium such as Toprose. Consider growing rose varieties that have been bred to show resistance to black spot.
Product solution: Spray with Systhane Fungus Fighter, Fungus Fighter Disease Control or Multirose Concentrate 2.