Eucalyptus snout beetle

Eucalyptus snout beetle
Gonipterus sp. 2
Leaf eating

Larvae of the Eucalyptus snout beetle feed on the new flush of Eucalyptus trees (Mally 1924, Tooke 1955). The first instar larvae feed on the epidermis of the leaves creating tracks on the leaf surface. The third and fourth instar larvae will consume the entire leaf. The adult Eucalyptus snout beetle feed on the older leaves of the Eucalyptus trees along the edges, creating a scalloped appearance (Mally 1924, Tooke 1955).

Adult: The adult beetles measure about 8-9 mm in length, smaller individuals may occur when infestation levels are high (Mally 1924, Tooke 1955). They vary in colour from rust brown to a dark brown appearance. There is a black X mark over the elytra with a white stripe on the scutellum. These markings may vary considerably from being prominent to very feint.

Larvae: The larvae are slug-like in appearance, green and covered in a sticky slime (Mally 1924, Tooke 1955). The fourth instar larvae measure 11 mm in length and 4 mm in width. The head is black and the body has a median dorsal line and a black lateral stripe. A black shield shaped dot is present on each segment of the larvae. The frass excrement of the larvae extends behind the body like a filament and often curls and sticks to the larvae.

The adult female will oviposit between 4 and 20 eggs on a leaf and cover them with a frass excrement (Mally 1924, Tooke 1955). The frass excrement hardens and protects the eggs. The larvae will go through four larval stages before reaching the pre-pupa phase (Mally 1926, Tooke 1955). During the pre-pupa stage the larvae will stop feeding, drop to the ground and burrow into the soil. They pupate in the soil and the adults emerge in search of a new host plant. The development time of the different stages of the life cycle is temperature dependant and it may take up to 90 days for the life cycle to complete. The female beetles will start to oviposit two – three weeks after mating. A single female can produce up to 270 eggs (Tooke 1955). The adult beetles can live up to 3 months. One and a half to two generations can occur in South Africa.

1916 (Mally, 1926)
Eastern Cape, Free State, Gauteng, KwaZulu-Natal, Limpopo, Mpumalanga, North West, Western Cape
Australiasia, Australia (Mapondera 2012)

Gallery

Gonipterus egg capsule
Gonipterus larva
Gonipterus> female ovipositing
Newly emerged larvae of Gonipterus