Sphaeropsis sapinea (Fr.) Dyko et Sutton causes different types of diseases on conifers: stunting of a new growth, browning of needles, shoot blight, twig and branch dieback, crown wilt, bark cankers, root disease, damping-off, root rot, and as saprophyte blue stain of sapwood of fallen or freshly cut timbers. The fungus is wide spread in the temperate and tropical regions all over the world (Browne 1968, Punithalingam & Waterston 1970, Swart & al. 1985, Chou & MacKenzie 1988). Among different hosts Pinus nigra Arnold, P. radiata Don. and P. sylvestris L. have been found as the most susceptible to the fungus attack (Punithalingam & Waterston 1970).
First report of fungus presence in Croatia as causal agent of pines dieback was by Böhm (1959). He reported one-year-old diseased Austrian pines in nursery near Karlovac. Till than there haven't been reports on damaging impact of S. sapinea. In 1992 it turned out as causal agent of pines dieback in Istria (Diminić 1994). In the December 1991 the local foresters noticed dieback symptoms in pine crowns in plantation on the eastern coast of the peninsula. First observation in that plantation and neighbour one have been made in April 1992 (Figure 1, research area No. 6). The observed symptoms were dieback of young and older shoots, branches and hole crowns of pine trees, mainly of P. nigra. Analyses showed that S. sapinea was the most frequent fungus on collected samples.
Since 1992 health condition inventory of pine plantations have been carried out, and further on observations revealed pines dieback on other localities in Croatia. To investigate where and with what influence S. sapinea is present on pines in Croatia, not only locations with dieback symptoms were observed, but also sites with no reports of dieback.