Scale Insects

Scale Insects are a limpet like insect that feeds on plants by sucking their sap. This can include houseplants, ornamental plants, fruit and vegetables. There are more then 25 different species of Scale Insect in the UK. 

What do they do?

Scale insects weaken plants by feeding on the sap of the plant. They excrete a sticky substance (honeydew) on foliage, which then creates a black, sooty mould. This weakens the plant, causing it to grow incorrectly. Some species also produce white, waxy egg masses on stems and the undersides of leaves, this can be mistaken for mealybug or woolly aphids.


  • Scale insects can look like small bumps on the plant stems or leaves. 
  • Poor growth of plant
  • Some insects leave a sticky, clear substance (honeydew) on leaves, stems and fruit. 
  • Some insects create a white waxy fibre to deposit their eggs. 


How to treat

Non chemical 

  • Biological - Encourage natural enemies in the garden (parasitic wasps, the small black ladybird Chilocorus Nigrtus)


Many insecticides can be used to counter the effects of Scale Insects, always make sure you read the label before applying. Plants in flower should not be sprayed due to the danger to pollinating insects, such as bees. We recommend: