If you notice fine black dust on the leaves of your plants indoors or in the garden, you could have an outbreak of Black Sooty Mould. This fungus feeds on honeydew secreted by Mealybug and other insects so the black soot usually means you have a bug problem.

There are a few steps needed to control the insect, get rid of the mould and prevent any recurrence.

Mealybug likes to burrow down into the plant and can be hard to find and treat.

• Inspect the leaves on your plants and look for fine black mould on the surface. It wipes off easily with soap and water. Remove the mould and any dust on the leaves as this layer cuts down the amount of light the plant can absorb and limits its ability to photosynthesize.
• Mealybug is a sucking insect that affects the growth and vigour of the plant. Look for signs of wilting and drooping, then try to find the cause.
• Look at the new growth on the plants. If it is distorted and there is a whitish, fluffy substance on the plant (especially around the base) Mealybug is probably present. Look closely at the white fluff and you may see the live insect.
• Look for ants climbing on the plant. They love the honeydew produced by Mealybug and will come to feed.
• Inspect indoor plants and those in the garden as Mealybug can occur inside and out. Any outbreak needs to be treated to bring it under control.
• Treat the affected plants with one of the following:

1. a low-toxicity soap-based insecticide, such as Natrasoap or Ecofend Insect and Mite Spray. The soap works by coating the insect and causing suffocation.
2. an organic insecticide such as Eco-Neem. It works by suppressing appetite and restricting insect growth.
3. a systemic and contact insecticide, such as Congard, that works on a broad range of pests including mealybug. It penetrates the plant tissue and the insect dies after eating the plant. The insecticide also works on direct contact with the insect.

You may have to use repeat applications of your selected treatment or need to try more than one method. Mealybug is very good at hiding in the plant and can be difficult to control. Regular inspections of plants and gardens, looking for the tell-tale signs of Black Sooty Mould and ants, will help to get the Mealybug under control before it does significant damage to your plants.

Always read the directions for use on any products used on plants.

Check out our range of solutions for Mealy Bug control. Shop Pest Solutions

This is intended as general information only. Please ask one of our qualified horticulturists for more specific advice for your situation.