The winter pine processionary moth has become an important pine pest in the last century, as a consequence of the spread of pine cultivation in the Mediterranean region. The pattern of genetic differentiation of this group, that includes two sibling species (Thaumetopoea pityocampa and Th. wilkinsoni), has been studied in nine populations using amplified fragment length polymorphism (AFLP) and single strand conformation polymorphism-sequence analysis (SSCP) of the mitochondrial cytochrome oxidase 1 (COI) and cytochrome oxydase 2 (COII). Results indicate the existence of strong genetic differentiation between the two species that became separated before the Quaternary ice ages. Moreover data indicate that Th. pityocampa has a strong geographical structure, particularly evident at the nuclear level, where all pairwise phiST resulted to be highly significant and individuals from the same population resulted to be strongly clustered when an individual tree was reconstructed. The estimates of the absolute number of migrants between populations (Nm), obtained from mitochondrial and nuclear DNA markers, suggest that gene flow is low and that a gender-related dispersal could occur in this species. The males appear to disperse more than females, contributing to the genetic diversity of populations on a relatively wide range, reducing the risks of inbreeding and the genetic loss associated with bottlenecks occurring in isolated populations.

Pine species were largely used for reforestation in Italy, especially since the beginning of this century. This fact has favoured a large spread of Thaumetopoea pityocampa, the pine rocessionary caterpillar.The main host plants of T. pityocampa are Pinus nigra, P. sylvestris, P. hal!-pensis and P. radiata. In some stands of P. nigru of the Eastern Alps the population cycles of T. pityocampa seem to be well correlated with the pattern of adult emergence, the sex ratio and the percentage of individuals which undergo a prolonged diapause. The knowledge of these parameters permits a satisfactory forecast of the outbreaks.In the case of P. nigra, it was possible to show a reaction of the host plant to defoliation: needles grown after a defoliation do not represent an adequate food for the larvae.The natural enemies have an irregular distribution and in general they are efficient in the control of T. pityocampa only during the years following the outbreak.The integrated control concerns: a) the sampling program, b) the tolerance level, c) the sylvicultural management, d) the control methods.

-Tomicus are among the most dangerous pine pests. In this paper we assess the genetic structure of some Italian Tomicus populations, and the possible sympatry of T. destruens and T. piniperda. A fragment 358 bp long of the mitochondrial DNA relative to the COI was investigated in eight populations by SSCP analyses and sequencing. In the sampled populations T. destruens and T. piniperda were not found to be sympatric. T. destruens populations of southern and central Italy strongly differ from a population of northern Italy. The phylogeographic analysis of T. destruens populations in Europe is geographically structured, probably due to the fragmentation of the host pine ranges. The populations of T. piniperda are polymorphic, with haplotypes occurring also in Europe and Asia. T. piniperda populations seem to be genetically unstructured because of both the continuous distribution area of its main host (Pinus sylvestris) and the international trade of pine timber. T. destruens montre une structuration géographique probablement liée à la distribution fragmentée des pins hôtes. Par contre, les populations de T. piniperda sont très polymorphes, sans doute à cause de la distribution continue de son principal hôte, le pin sylvestre, ainsi qu'au commerce international de bois.

1 Sexual pheromone traps are commonly used to monitor populations of the pine processionary moth, Thaumetopoea pityocampa, assuming that trapped males are representative of the breeding population. 2 For seven Italian populations, mitochondrial haplotypes (COI and COII) of adult males caught in traps were compared with those of larvae obtained from egg batches laid in the same year, to test whether the males trapped were representative of the local populations. 3 The distribution of haplotype frequencies revealed substantial homogeneity between adult males and larvae samples from the same population, except for Aosta Ruines Verres, a population recently expanding in the south-western Alps. In this case, the results suggested that trapped males were recruited over a wider area than local moths because haplotype diversity was higher than that of larvae. 4 A further analysis of this population using nuclear markers (AFLP) confirmed that adults, collected in pheromone traps, were genetically different from the larvae emerging in the same stand. 5 In conclusion, the assumption that trapped males are representative of breeding populations was confirmed for core populations, but has not been verified for the recently established population of Aosta Ruines Verres. This should encourage discussion with respect to the reliability of pheromone traps in monitoring programmes of the pest, especially at the range's edge

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