The interaction of pine scale with pines in Attica, Greece

The pine scale (Marchalina hellenica) has been introduced to Attica and reached unprecedented population densities. Using a randomised transect-based sampling design in eight sites, we sampled the insect in random 10 cm squares on the trunk and main branches of pine trees. The insect did not show any clumping other than a micro-site preference for fissures and cracks. Canonical discriminant analysis and generalised multinomial logit regression modelling were used to determine the most important ecological variables which were the following: the population density of the insects; crown transparency; mean distance between trees; and the quality of the habitat. The site and the distance from the line transect were insignificant. The interaction of crown transparency with the abundance of the insect, the mean distance between trees and the quality of each site were important in configuring the level of damage sustained by the pine tree.