engleski

Collapse of an isolated outbreak population of Dendrolimus pini by a very high infestation of Beauveria bassiana

Pine-tree lappet moth, Dendrolimus pini is a pest known in some region in Europe (e.g. Germany, Poland) causing serious damage on pine trees by total defoliation of needles. However, in Croatia this pest is sometimes present in the continental part but not in high level abundance, so no damage have been reported up to now. In the Mediterranean region the presents of this pest was never recorded at all till autumn 2014, as an unexpected total defoliation occurred in several localities in the region around Skradin on Aleppo pine, Pinus halepensis. After larvae of this pest overwinter in the soil they climb in the spring to the tree crowns where they feed on needles but also on the bark of young shoots causing serious problems for pine trees including death. Therefore the pine forest has been inspected in the winter period for number of larvae on square meter on the soil surface. As on average more than 10 larvae per square meter were found which is considered as critical it was a surprise that almost no larvae survived, killed by Beauveria cf. bassiana. Unusual wheatear condition with high precipitation is probable the reason for the unusual D. pini occurrence on P. halepensis, but also apparently has create good condition for even more unusual high infestation of B. bassiana which broke the pest population in a manner known in Croatia only in Gypsy Moth (Lymantria dispar) outbreak collapse caused by nuclear polyhedrosis virus (NPV) or recently Entomophaga maimaiga.

Pinus halepensis ; Skradin ; total defoliation ; population decline

nije evidentirano