Citrus long-horned beetle

Citrus long-horned beetle
Scientific Classification
Kingdom: Animalia Phylum: Arthropoda Subphylum: Atelocerata Class: Hexapoda Infraclass: Neoptera Subclass: Pterygota Order: Coleoptera Suborder: Polyphaga Infraorder: Cucujiformia Superfamily: Chtysomeloidea Family: Cerambycidae Subfamily: Lamiinae Genus: Anoplophora Species: A. chinenis
Binomial Name
Anoplophora chinensis
Image Description

Citrus long-horned beetles are an invasive species that destroy hardwood trees, making it very damaging to forests and urban trees. They damage the tree by cutting the bark with its mandibles and then inserting its eggs in the notch made. The egg then grows larger as it eats the inside of the tree, and eventually it grows into its Pupa it exits the tree leaving a hole and a large tunnel in the tree. They originally came from Asia and made their way to other places around the globe, normally through bonsai trees imported from Japan, Korea, or China mostly. This beetle is very similar to the Asian long-horned beetle and is easily confused. This invasive beetle is dangerous and it can destroy entire forests easily, for this reason any sightings that are reported are quickly investigated and eradicated before they have time to establish a large population. If you see this bug please report it to your local department of agriculture or pest control.

Body Design

The difference between Asian long-horned beetle (left) and Citrus long-horned beetle (right)

Adults are large and stout with the males smaller than the females and has a typical cerambycid beetle body shape. The beetle is a glossy black to blue-black and finely punctuated with a series of irregular white hair spots. They have 4 wings 2 hard wings and 2 membranous wings. Although very similar to the Asian long-horned beetle, the difference is the elytra base is granulated and the malasiaca form has blue-white markings on the pronotum.

The Females are about 35 mm (1.38 in.) in length, larger than the males. The males are about 25 mm (0.98 in.) in length. They have black shiny with numerous white spots. One way to tell the difference from male to female is by the antennae. All adults have 11 segments of antennae. The females have their antenna 1.2 times their body but are smaller than the males. The males have antenna 1.7-2 times their body length and have alternating black and white bands.

Life Cycle

Larvae

The females lay 200 eggs, and each egg is separately placed into the bark of a tree. When the beetle larvae hatch, they are 5mm (.20 in.), and creamy white with yellow, but their head is amber with black mouthparts. They burrow into the heartwood, feeding on the tree until they have killed it. Pupae are 27-38mm (1.06-1.5 in.) in length, and are an off-white color, but the forward top body segment (pronotum) is all black. Adults emerge from April to August. Adults are 2.5-3.8cm (1-1.5 in.) long and shiny black with white markings. They have a year-long life cycle, reproduce, then die.

The Citrus Long-Horned Beetle is known to emerge from April to August but is most abundant from May to July.Soon after emergence, they feed on leaves, twigs, and petioles of a preferred host choice. Most activity, including feeding and mating, occur during the daytime hours. Larvae hatch in one to three weeks, and usually feed on sappy portions of bark. Later, they make irregular tunnels into the bark and wait there till pupation. The pupal stage lasts for about four to six weeks until a pre-adult forms in it's final molt. This stage is inactive and is not mature for one to two weeks. Citrus Long-Horned Beetles take approximately one full year to complete development.

Ecology

The natural range of this beetle is China, Japan, and other countries in South East Asia (ex. China, Japan, South Korea, Vietnam Taiwan). This insect finds suitable host plants in forest, urban and fruit producing areas. The Citrus Longhorn Beetle is not exclusive to citrus orchards but may infest a great variety of fruit and nut trees. The Citrus Longhorn Beetle comes from Eastern Asia and is a serious pest of citrus and other ornamental and forest species in Japan, Korea and China. In lowland China the species is one of the most destructive cerambycid pests of fruit orchards, especially citrus; economic losses are substantial.

This insect has been recorded being seen on over 100 species of plants. The Citrus Longhorn Beetle damages different parts of plants during its lifetime. Adults feed on bark of small twigs and branches and sometimes on leaves, this causes young shoots and branches to die. The larvae feed and develop in the wood of the main roots and trunks, which they also excavate tunnels in; when larval density is great, infested trees can die or be felled.

Invasive Species

Damage done to a maple tree by the larval stage of the CLHB

Location and Method of Introduction Findings from the study of interceptions of alien insects in Europe from 1995 to 2004 showed the trade of bonsais played a huge role in moving these foreign insects throughout Europe. The bonsai trade is responsible for the introduction of at least one major tree pest in the countries of France, Italy and the United States of America in recent years, simply put, the Citrus Longhorned Beetle. The larvae and adult stages of the Citrus Longhorned Beetle have invaded Germany and the Netherlands on bonsai plants of Acer buergeranum (Trident Maple) , A. palmatum (Japanese Maple), Celastrus (Staff Vine) , Cydonia sinensis (Chinese Quince), Malus micromalus (Kaido Crabapple), and Sageretia (Bird Plum) from China and Japan.

Environmental Impact Adult feeding on twigs and foliage is considered minor except sometimes on fruit-bearing trees. Most damage results from larval tunneling in the cambial region and wood. After years of repeated attack, larval holes disrupt the tree’s vascular tissues and cause structural weakness, both of which can lead to tree death. They attack healthy and stressed trees , varying in size from small bonsai and potted trees to mature trees. Larval feeding also reduces wood quality .

Control Methods Like most issues with plants and forests, sanitation such as burning or chipping infested plant parts, reduce populations of immature stages of the citrus longhorned beetle. The use of wire netting or spiral guards at the trunk base can serve as a physical barrier for oviposition(egg laying). The pathogenic fungi Beauveria brongniartii is known to cause high adult mortality. In Japan, studies demonstrated adult mortality of 46% to 100% when sheets of polyurethane forms impregnated with Beauveria brongniartii were wrapped around the lower portion of the trunk or hung from the crotch.Systemic insecticides injected into base of a tree where it is then circulated to the branches, twigs and foliage is a way of chemical control that was tested and used by the eradication program in Asia.

Video

The Citrus longhorn beetle (Anoplophora chinensis), is a new threat with the potential to cause severe damage to a wide range of UK broadleaved trees and shrubs. Because it is not established it is classed as a quarantine pest for the European Union and is therefore subject to official controls. The natural range of the beetle includes China, Japan and other countries in South East Asia.