Pine Weevil

Pine Weevil
Pissodes sp.
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 et al. 2016). Tiny circular feeding punctures on the stem or branches of young trees are characteristic symptoms of maturation feeding. Damage on young healthy trees may result in forking or branching of trees. In trees selected for breeding, it is common to see larvae, pupae and adults under the bark. In addition to these symptoms, 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 (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. The pupae, about the same size as the adults, are shiny white at first, darkening while maturing, with well-developed wings and legs. Adult weevils are rusty red to grey-brown, have long snouts and cylindrical and posteriorly tapered bodies about 6 mm long. 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). 

Remove dying and dead trees as these provide material for the population of the beetle to increase. Parasitoids are present but recorded levels of parasitism are low.

1942 (Webb 1974)
Eastern Cape, KwaZulu-Natal, Mpumalanga, Western Cape
Various pine species.
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

Pupal chambers
Larva of Pissodes
Adult of Pissodes
Larvae in growing tip of pine tree
Tip die-back caused by Pissodes

Gebeyehu S, Wingfield M, J. 2003. Pine weevil Pissodes nemorensis: threat to South African pine plantations and options for control. South African Journal of Science 99:531-536

Webb DvV. 1974. Forest and Timber Entomology in the Republic of South Africa. Entomology Memoir No. 24. Department of Agricultural Technical Services, Republic of South Africa,

Wondafrash M, Slippers B, Garnas J, Roux G, Foit J, Langor DW, Hurley BP. 2016. Identification and genetic diversity of two invasive Pissodes spp. Germar (Coleoptera: Curculionidae) in their introduced range in the southern hemisphere. Biological Invasions 18:2283.