Eucalyptus cossid moth/Goat moth quince borer

Eucalyptus cossid moth/Goat moth quince borer
Coryphodema trisitis
Coryphodema capensis (Felder, 1874), Coryphodema punctulate (Walker, 1856), Phalaena (Noctua) tristis (Drury, 1782), Coryphodema capensis (Felder, 1874), Brachionycha punctulata (Walker, 1856), Cossus seineri (Grünberg, 1910), Cossus streineri (Dalla Torre, 1923)
Wood boring

Round holes penetrating the sapwood (A)

Trunk and branches of infested trees turn black (B)

Resin and sawdust appear on trunks and branches (B,C)

Extensive tunnelling of larvae is found in the sapwood and heartwood (D,E)

Pupal casings protrude from emergence holes or can be found on the forest floor (F)

Sawdust is found at the bases of trees (G)

 

Eggs. About 1mm long, oval in shape and dull cream coloured.

Larvae. About 30-40mm long when fully grown. Fully grown larvae have a brown head and the body is light yellowish in colour with reddish blotches. Three short pairs of legs are present behind the head. (A)

Pupae. Larvae pupate in woven silk and sawdust cocoons. Pupae are about 25-35mm long. Rows of spines present on abdomen and head terminates in spine. (B)

Adult. Rarely seen and short lived (about one week). Wingspan of 25-50mm. Body is greyish brown, front wings are mottled brown and hind wings are mottled light grey. (C,D)

 

Adult female cossid moths lay eggs on the bark of trees, usually in a sheltered place such as cracks in the bark. Upon emergence, larvae bore through bark and feed on the cambium. As the larvae grow, they bore into the wood, where they cause extensive tunneling. Pupation occurs in pupal cocoons constructed inside the larval tunnels. Just prior to adult emergence, the pupae cut themselves out of the cocoons and wriggle towards the tunnel openings until their bodies project halfway out the tree. In this position the adults emerge from the pupal cases, resulting in the shed pupal cases protruding half way out the tree or falling to the ground. The cossid moth is reported to have a two-year life cycle in the Western Cape, but the duration of the life cycle in the summer rainfall area is not yet known.

Larvae feeding in the cambium and the extensive tunneling in the sapwood and heartwood results in severe damage to trees, which often also die. Both the main trunks and branches are attacked. Trees from five to fourteen years old have been infested, but it is likely that the cossid will infest both younger and older trees, provided the diameters of the trunks/branches are sufficient to enable the larvae to feed. Associations with fungal pathogens seem likely given the black discolouration of the stems and members of the Tree Protection Cooperative Programme at FABI are currently studying this matter.

 

1872 (Drury 1872, Pettey 1917)
KwaZulu-Natal,Mpumalanga,Western Cape
South Africa and Botswana

Gallery

Figure 1: Symptoms of Coryphodema tristis in Eucalyptus nitens trees.
Figure 2: The juvenile larvae are cream coloured with two irregular red lines along the ventral side of the body with irregular red markings laterally (Pettey 1917) .
Biology and life cycle