Impact of Needle Blight on Stone Pine Decline in Recently Planted Trees in Nallıhan District of Türkiye

Abstract

Stone pine (Pinus pinea L.) plantations have been encouraged by the General Directorate of Forestry of Türkiye because of their various uses and benefits. Recently, a distinctive growth retardation having intensive needle blight symptoms has been observed in a 5 ha area of 30 years old plantations in the Nallıhan district. Ten fungi have been recovered from 100 symptomatic needles collected from 20 different trees. The three fungi recovered; H. spartii, S. polyspora and V. sordida caused symptoms when inoculated onto healthy needles of P. pinea. The highest rate of needle necrosis was obtained when the three fungi were inoculated in combination. The fungi also produced necrosis when inoculated into bark tissues on the stems of 1–2-year-old stone pine saplings. The type of disease progression, appearing as a blight on the lower parts of the trees, resembled root-rot damage, yet no symptoms of rot were observed when the roots of three symptomatic trees were examined. It is concluded that the observed symptoms could have a detrimental impact on pine nut production.