An association between the fungus Sphaeropsis sapinea and the cone bug Gastrodes grossipes in cones of Pinus nigra in Italy

Tip blight caused by Sphaeropsis sapinea is a well-known disease in pine plantations in Italy. Austrian pine Pinus nigra, which was largely used in afforestation programmes during past decades, has recently suffered great damage from this pathogen. The incidence of the fungus in third-year cones was investigated in four stands. The percentage of cones infected with the fungus varied from 17 to 62%. Infected cones were observed on trees lacking symptoms of the disease as well as on those showing tip blight. The possible association of S. sapinea with the cone bug Gastrodes grossipes, which inhabits mature and open cones of pines, was examined by log-linear analysis. The cone bug was found in up to 67% of cones. Results revealed that the presence of S. sapinea and G. grossipes in pine cones was not independent; thus, a role of the insect in disseminating the fungus is hypothesized.