The Plant Health Department said yesterday it is on the look-out for any symptoms of the citrus longhorn beetle (anoplophora cinensis) in order to take immediate action should the insect be introduced on the island.

The beetle is a pest of a range of trees and shrubs.

The natural range of the beetle includes China and Japan and other countries in South East Asia. But these beetles have extended their range through ornamental trees imported from Asia.

They are a threat to horticulture, forestry and to citrus production in the Mediterranean, the department added. Worth mentioning is the outbreak that occurred in Lombardy, Italy leading to the destruction of hundreds of mature trees.

Adults of the citrus longhorned beetle are 21 to 37 millimetres long and black with variable white markings. Their antennae are longer than their bodies and are black with white/light blue bands.

These beetles spend most of their life (ranging from one to two years in Asia) as larvae inside a trunk or root and, therefore, there can be little or no sign of their presence to anyone inspecting a host tree.

The most obvious symptoms of the damage caused are exit holes which are typically six to 11 millimetres in diameter generally found towards the base of trunks.

This pest is most likely to be seen in July and August but interceptions have occurred as early as May and as late as October.

The department is encouraging the public to immediately report any suspect presence of this pest and its symptoms.

Further details on the biology and symptoms of this insect can be found on the department's website www.planthealth.gov.mt.

Any suspects should be reported on 2590 4312 or 2339 7222/3.