SPERIMENTAZIONE DI SOSTANZE AD EFFETTO REPELLENTE NELLA DIFESA E RECUPERO DELLE PINETE LITORANEE DELLA TOSCANA

Phytosanitary surveys were carried out in a pine forest located in a camping site on the coast of Tuscany, and in particular on 355 3m high stone pines about a year after their plantation. They had been planted in order to restore the pinewood landscape following phytosanitary cuts at the expense of maritime pines infested by harmful insects. Among these the most widespread and harmful species is the beetle Tomicus destruens (Wollaston), which for years has contributed to the decline of coastal pine forests. The conditions of the young pines appeared very critical in spring 2017, both due to the transplant crisis, and due to drought and in particular to the attack of the beetle. Overall, 152 plants died after transplantation due to all these adverse factors. More specifically, the bark beetle successfully attacked 25% of the pines used for the plant. Given the serious phytosanitary situation, it was considered appropriate to safeguard the remaining plants during the autumn of 2017, which corresponds, in the study area, to the period of greatest T. destruens activity. To this end, repellent substances were used in dispensers placed on the pines to be protected. From subsequent surveys on the progress of the attacks, it emerged that only one of the 203 treated plants was attacked and brought to death by the beetle. Another 8 protected pines died, not because of the attack on the Tomicus, but mainly because of the difficulties imposed by physiological stress. In our experience, the repellent substance has contributed in a promising way to protect pines susceptible to T. destruens oviposition. This protective barrier, although mild, proves to have a certain influence on the beetle, by hindering its search for pine suitable for colonization.