Citrus Longhorn Beetle
Photo credit: GB Non-native Species Secretariat
Habitat: agricultural areas, natural forests, planted forests, ruderal/disturbed, scrub/shrublands, urban areas.
- Distinctive black longhorn beetle with variable white markings.
- A large beetle - 21 to 37 mm long.
- Antennae very long - 1.2 to 2 times body length.
- Antennae striped - black with white/light blue bands.
- Adult beetles most commonly found in July and August.
- Beetle exit holes (6 to 11 mm diameter) often near tree trunk base or exposed roots.
Origin and Distribution: Native to China, Japan and other countries in South East Asia. Citrus longhorn beetles have been moving around the world in ornamental trees from Asia. They pose a serious threat to horticulture, forestry and native trees.
Impacts: This species can kill many species of broadleaved trees, including maples (inc. sycamore), poplars, alders, willows, cherries, apples, horse chestnut, elm, mulberry, and boxelder.
The beetle completes most of its life cycle inside the host tree, with adults emerging in spring. Adult beetles feed on twigs, leaf petioles and primary leaf veins. Eggs are injected under the bark surface where they hatch into larvae. Larvae tunnel under the bark and destroy the tree’s vascular system which disrupts sap flow of infested trees. Older larvae tunnel into the heartwood where their feeding slowly destroys the structural integrity of trees. Trees are slowly killed over a 3-5 year period, although it may be longer.
How might it get here? Nursery trade, sea freight, in solid wood packing material such as pallets and containers. Citrus Longhorn Beetles may also be introduced in infected firewood.