Prevalence and Distribution of Pine Processionary Moth (Thaumetopoea pityocampa) in Shahat’s Aleppo Pine (Pinus halepensis) Plantations, Al-JabalAl-Akhdar, Libya

Abstract

The current study aims at investigating the spatial distribution of pine processionary moth (PPM) in parts of Al-Jabal Al-Akhdar region in Libya (in Shahat area). Two Pinus halepensis stands in the area (in Al-Mansurra and the ancient city of Cyrene) were chosen for field data collection. Growth parameters for pine trees including; tree height, crown height, diameter at breast height, stand density level, location within the stand, health condition, in addition to the observed number of PPM nests per tree were recorded. Pearson correlation coefficient analysis and variance analysis were applied to assess the relationship between obtained variables, and evaluate growth conditions for both stands. Results revealed relatively better growth conditions at Al-Mansurra site compared to Cyrene site. Moreover, PPM nests occurrence was positively correlated with trees growing isolated or on the stand edge (r = 0.54, P value <.001), and negatively correlated with tree height (r = - 0.4, P value <.001) emphasizing more dispersal rate among young pine trees. Crown height, dbh, and tree’s health condition showed no significant effect on PPM spread in the area. In-depth investigations of the population dynamics of PPM are highly recommended to provide insights into their spatial distribution in the region.