Black sooty moulds are a problem disease on Brussels Sprouts.
- The black sooty mould can be sticky and is the result of a whitefly attack.
- Cabbage whitefly overwinters on brussel sprouts as adult insects.
- Adult whitefly and their nymphs suck sap from the sprout plant and excrete a sugary substance (honeydew) onto the leaves.
- Sooty moulds then grow on this sugary substance – and can make a real mess of the sprout buttons.
- The warmer the weather the worse the problem is.
Black Sooty Mould is more of a problem in Brussels Sprouts after warm weather.