Abstract

One of the most important damaging insects on Turkish red pine (Pinus brutia Ten.) forests in the coastal Mediterranean Region of Turkey is pine processionary moth (PPM), Thaumetopoea wilkinsoni Tams. The larvae of PPM feed on needles of Turkish red pine and on some other Mediterranean conifers such as cedar. This study covers the impact of defoliation caused by PPM on growth of red pine. Three test sites were taken on different plantations in the coastal Mediterranean region of Turkey, near Antalya city. The heights and diameters at breast height (dbh) of individual trees both in the control group and the treatment groups were measured. The trees defoliated over 40% in the test sites were considered as the treatments. The results indicated that, compared to the control, the losses in defoliated trees in terms of dbh increment were 55, 50 and 35% in the three test sites, respectively. The corresponding losses in the three test sites in terms of volume increment were 44, 37 and 17%, respectively. Test results also showed that effects of defoliation and site on both diameter and volume increment were statistically significant at 0.000 probability level.

Key words: Turkish red pine (Pinus brutia Ten.), Thaumetopoea wilkinsoni, defoliation, growth loss.