Oviposition and feeding damage by Lymantria dispar L. (Lepidoptera) in an oak stand in 2017 and 2018
Frank Bohlander University of Applied Sciences Erfurt, Germany; Study of  Forestry 
Lymantria dispar (Gipsy moth) is an important pest to broad leave tress, especially oaks. The female deposits usually one egg mass on the bark. In 2017 and 2018 the deposition height of egg masses on survey trees, exposition and the total number per tree and feeding damage was accessed in a survey plot. 
The number of egg masses in the lower part of the trunk 10-100cm was much higher than in 110 to 200cm. The total number of egg masses is closely related to the total surface of the trunk. There is no evidence that Lymantria dispar can differentiate between tree species. As dominant species, oak had a much higher diameter in breast height (dbh) as other tree species, leading to a higher total amount of egg masses. Moreover, the female is able to differentiate between the exposition of the trunk. The sun exposed eastern, southern and western sector of the trunk showed higher numbers of egg masses in comparison to the shaded northern part. There was no relation between the number of egg masses and the feeding damage. Although the damage increased, no correlation could be found. A missing correlation between the number of egg masses and feeding damage might be due to the lack of complete defoliation. Viruses, parasitism and weather conditions might have killed a large number of larvae (we did not examine this), so we could not find a correlation.

Oviposition and feeding damage byLymantria dispar L. (Lepidoptera) in an oak stand in 2017 and 2018