Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Citrus mussel scale (340)

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  • Worldwide distribution. Citrus species. Potentially severe scale, sucking sap, causing leaf drop, dieback, and unsightly fruit.
  • Mussel shaped, purplish-brown, pale at narrow end; eggs laid under a cover (or 'armour'); 'crawlers' (nymphs) hatch and disperse, settle, moult, and females grow up to 3 mm long. Males have wings, and short-lived.
  • Spread by crawlers that walk, or are carried by wind, vehicles, animals, birds, and clothes, and trade in plants.
  • Natural enemies: wasp parasitoid (Aphytis lepidosaphes).
  • Cultural control: check nursery stock free from scale; if present, prune, and spray with insecticide (see below); in field, use Gliricida windbreaks to reduce crawlers carried by wind; provide adequate nutrition.
  • Chemical control: use lime sulphur or wettable sulphur, leaving 30 days if also spraying oils (READ INSTRUCTIONS); alternatively, spot-spray infestations using soap, horticultural or white oils (see Fact Sheet no. 56); avoid malathion and synthetic pyrethroids - they will kill natural enemies.
Common Name

Citrus mussel scale; purple scale

Scientific Name

Lepidosaphes beckii

AUTHOR Grahame Jackson
1Information from Swaine G (1971) Agricultural Zoology in Fiji. Her Majesty's Stationery Office. London; and CABI (2008) Lepidosaphes beckii (purple scale). Crop Protection Compendium (; and from Citrus Research International Scales: Mussel Scales. ( Photo 1 United States National Collection of Scale Insects Photographs, USDA Agricultural Research Service, Photo 2 MAF Plant Health & Environment Laboratory (2011) Purple Scale (Lepidiosaphes beckii): PaDIL - (

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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