Pine Weevil

Pine Weevil
Pissodes spp.
Fusarium circinatum
Wood boring

Pissodes sp. prefers young healthy trees for maturation feeding and stressed or recently dead trees for breeding (Gebeyehu & Wingfield 2003; Wondafrash 2016). Tiny circular feeding punctures on the stem or branches of young trees are characteristic symptoms of maturation feeding (Figure 1). Damage on young healthy trees may results in forking or branching of trees. In trees selected as breeding habitat, it is common to see larvae, pupae and adults under the bark (Figure 2 and 3). In addition to these, the weevil leaves circular emergence holes on the bark of the main stem that do not penetrate deep into the wood. The exit holes start from oval-shaped pupal chambers or “chip cocoons” located between the bark and the wood (Figure 4 and 5) (Gebeyehu & Wingfield 2003). Emergence holes of the woodwasp, Sirex noctilio are similar to those of Pissodes, but Sirex holes continue into the wood and are usually larger than those of Pissodes weevil.

The eggs are pearly white, oblong, and equally rounded at both ends. The larvae are yellowish-white, cylindrical and legless grubs with a reddish brown head (Figure 6). The pupae, about the same size as the adults, are shiny white at first, darkening while maturing, with well-developed wings and legs (Figure 7). Adult weevils are rusty red to grey-brown, have long snouts and cylindrical and posteriorly tapered bodies about 6 mm long (Figure 8). They have ridged and roughened wings with patches of lighter brown or grey scales (Gebeyehu & Wingfield 2003).

Pissodes sp. undergoes complete metamorphosis. Males and females fly, undertake maturation feeding and mate. The female begins laying eggs soon after mating in feeding punctures on the bark. The newly hatched larvae bore into the inner bark, where they construct winding galleries and feed on the phloem. Pupation takes place between the bark and the wood in chambers excavated in the xylem and covered with wood fibers, commonly known as “chip cocoons”. The adult emerges leaving a circular emergence hole on the bark (Gebeyehu & Wingfield 2003). 

1942 (Webb 1974)
Eastern Cape,KwaZulu-Natal,Mpumalanga,Western Cape
North America is the possible origin of this weevil as it phylogenetically belongs to the North American Pissodes strobi species complex which comprises of four other cryptic species, namely, Pissodes strobi, P. nemorensis, P. terminalis and P. schwarzi (Wondafrash et al 2016).

Gallery

Pissodes
Larva
Pissodes
Oval-shaped pupal chambers between the bark and the wood.
Pissodes
Maturation feeding punctures on a young Pinus elliottii tree.
Pissodes
Adult
Pissodes
Pupa
Pissodes
Pupa and adult under the bark.
Pissodes
Exit holes starting from pupal chambers.
Pissodes
Larvae under the bark.