Black spot is a fungus disease that affects a number of different plants, notably roses but also apples, pears, plums and quinces.

It causes dark spots on the leaves which wither and fall prematurely, rendering the plant unsightly. Extensive defoliation can eventually kill a young plant.

Black spot is usually worst when humidity is high or in tropical and subtropical regions.

Control:
Collect all fallen leaves. Cut off and destroy infected leaves. Spraying may also be necessary.

A number of fungicides are on the market. Ensure good air circulation by not overcrowding plants.