Threats

Pine Wooly Aphid / Pineus pini

Pine Wooly Aphid / Pineus pini
Pineus pini (Macquart)

Anisophleba pini Koch

Aphis pini Gmelin

Kermaphis pini var. laevis Maskell

Kermes pini Macquart

Pineus boerneri Annand

Pineus havrylenkoi Blanchard

Pineus laevis (Maskell, 1885) Börner

Pineus pini (Macquart, 1819) Börner

Pineus simmondsi Yaseen & Ghani

Pineus sylvestris Annand

Sap sucking

Symptoms include dying branches and trees as well as discoloration of the foliage, distortion, reduced growth of plant stands and resinosis (Mailu et al. 1978; McClure 1982). Other signs include a shortening of the infected needles' length (Day et al. 2003). According to Mailu et al. (1982), measurements of needle lengths alone might be sufficient to determine the extent of an infestation because of a highly significant negative relationship between those two variables and the number of aphids. In warm, dry weather, tree damage is most severe (Mailu et al. 1978).

Pineus pini are small insects that have a reddish-brown body which is typically hidden by a mass of white wax threads. Adult females that do not have wings (apterous) range in length from 0.9 to 2.3 mm, with an ovoid to turbinate body shape.With ovoid bodies, dorsally segmentally arranged sclerotized plates embellished with wax glands and short legs and antennae hidden beneath the body, the adults resemble immature instars. The antennae are proportionately very short, with only 1-3 segments that are frequently partially or completely fused together, and the adult females each have an ovipositor, which is absent in the immature stages. In adults compared to immature P. pini, the dorsal plates fuse more frequently, particularly on the head and anterior parts of the thorax.

 

Winged adult female Pineus are similar to other winged aphids in that their bodies are clearly divided into head, thorax, and abdomen, and they have well-developed legs and antennae. The body length ranges from 1.0 to 1.9 mm. They are distinguished from other Aphididae by the presence of an ovipositor similar to that of the apterous female. There are five antennal segments. There are compound eyes present. 

All year, reproduction is asexual, with eggs produced parthenogenetically. Every year, there are at least three overlapping generations. There are significant differences between the hatching times of the first and last eggs laid because clutches of eggs are laid (one egg at a time) over a period of several weeks. Prior to the development of an adult, there are five immature instars. Hiemosistentes, which are heavily sclerotized adult females without wings, as well as second- and third-instar larvae, overwinter. The larvae transform into apterous progredientes, which are the summer form of the adult female and are lightly sclerotized, and alate (winged) females in the spring.

Sanitary practices and cultural control:

Stress can make pine trees more susceptible to P. pini attack (Madoffe & Austara 1993) and therefore, choosing suitable planting sites is paramount to avoiding P. pini infestation (Day et al., 2003).

Biological Control:

Pineus pini can be effectively controlled by predatory Leucopis species such as L. tapiae, L. obscura, and L. nigraluna (Culliney et al. 1988).

Host-Plant Resistance:

Alternatively, P. pini can be controlled by replanting with a less susceptible pine species, but this is a time-consuming and potentially costly procedure that may result in unintended costs such as lower yields and/or quality.

1978 (Zwolinski 1989).
Mpumalanga, Kwazulu-Natal midlands and Limpopo.
Pinus spp.
Western and Central Europe (Blackman & Eastop, 1994).

Gallery

Blackman, RL., Eastop, VF. 1994. Aphids on the world's trees: an identification and information guide. Wallingford, UK: CAB International.

Culliney, TW., Beardsley, JW Jr., Drea, JJ. 1988. Population regulation of the Eurasian pine adelgid (Homoptera: Adelgidae) in Hawaii. Journal of Economic Entomology 81, 142-147.

Day, RK., Kairo, MTK., Abraham, YJ., Kfir, R., Murphy, ST., Mutitu, KE., Chilima, CZ. 2003. Biological control of homopteran pests of conifers in Africa. Pineus boerneri. In: Neuenschwander P, Borgemeister C, Langewald J, eds. Biological Control in IPM Systems in Africa. Wallingford, UK: CABI Publishing, 104-106.

Mailu, AM., Khamala, CPM., Rose, DJW. 1982. Sampling techniques for populations of pine woolly aphid, Pineus pini (Gmelin) (Adelgidae). Kenya Journal of Science and Technology, (Biological Sciences) 3, 9-18.

Mailu, AM., Rose, DJW., Khamala CPM. 1978. Sequential surveys for the pine woolly aphid, Pineus pini (L.) Homoptera: Adelgidae in Kenya. East African Agricultural and Forestry Journal 43, 252-258.

McClure, MS. 1982. Distribution and damage of two Pineus species (Homoptera: Adelgidae) on red pine in New England. Annals of the Entomological Society of America 75, 150-157.

Zwolinski, JB. 1989. The Pine Woolly Aphid, Pineus pini (L.)—A Pest of Pines in South Africa, South African Forestry Journal 151, 52-57.