Scale Insects
Wide range of soft and hard scale species causing sap loss, honeydew and plant decline.
Scale insects (Coccoidea) include soft scales, hard scales and mealy-like variants. They feed on plant sap, causing chlorosis, weak growth and heavy honeydew deposits that encourage sooty mould. Crawlers are the mobile life stage and the key target for control. Biological solutions include parasitoid wasps (e.g., Metaphycus spp.), predatory beetles such as Cryptolaemus montrouzieri for soft scales, and various entomopathogenic fungi. Effective control requires targeting crawlers and removing heavily infested stems.
Biological Controls for Scale Insects
The species below are examples of beneficial organisms commonly used against scale insects. Recommendations are based on published biological control information and practical IPM experience. Always confirm suitability for your crop, growing system and local conditions before use.
Cryptolaemus montrouzieri
Environment: glasshouse
Temperature Range: 18.0 – 30.0°C
Rate: 2–10 beetles/m²
Frequency: Re-introduce if crawlers reappear
Cryptolaemus will feed on some soft scales; integrate with pruning and sanitation.
Further BioWiki Reading
For more background on pest biology, beneficial insects and environmental factors, use the BioWiki alongside this practical control guide.
Related Biological Solutions
Growers dealing with scale insects often also monitor these pests as part of a complete IPM programme: