ENTOMOPHAGA MAIMAIGA IN ROMANIA AND FUTURE POSSIBILITIES IN BIOLOGICAL CONTROL OF LYMANTRIA DISPAR POPULATIONS

Once the pathogen Entomophaga maimaiga was introduced in Bulgaria (1999), they were reported Lymantria dispar larvae high mortality in Romania during 2004-2006 outbreak which developed in wet mixed forests of oak (Q. petraea) and beech (F. sylvatica)in the South-West of the country in Baile Herculane, Orsova and Modova Noua Forest Districts. Larvae mortality were reported at the beginning of the 2013-2015 Lymantria dispar outbreak in several Turkey oak (Q.cerris)and Hungaryan oak (Q. frainetto) forests in Southern Romania (Ghimpati, Slavesti, Costesti)and in the years 2013 and 2014, the pathogen acted over a large area,causing significant mortality. The first field and laboratory experiments regarding the possibilities of biological control of Lymantria dispar populations using Entomophaga maimaiga were installed in 2014.Using cadavers of Lymantria dispar larvae with symptoms ofthe disease caused by Entomophaga maimaiga collected from forests in Costesti area,various experiments were installed in the field, pursuing the possibility of spreading and establishing the pathogen. There have been used a design with two influencing factors:A - the form of the dispersed material (powder -suspension);B – forest soil moisture (wet - dry). The spores were dispersed in the form of powder resulted from the grinding of dead larvae, and also in the form of water suspension, in wet soil and dry soil conditions.In the laboratory, experiments were performed on the persistence of spores in the soil and also in artificial growth on culture media of spores preserved in laboratory conditions. The results of the experiments are presented in the paper