Long term consequences of defoliation by the gypsy moth (Lymantria dispar L)

In 1993 an outbreak of the gypsy moth Lymantria dispar L. (Lepidoptera: Lymantriidae) caused a complete defoliation in many forests in southern Germany. The consequences of this defoliation on leaf quality and growth in young birch trees (Betula pendula Roth) were studied from 1993 to 1996. After defoliation and regrowth leaf length was reduced for two years, protein content increased for three years and phenol content increased for one year. Trees did not show a reduction of stem growth. Three years after defoliation larval and pupal weight of female gypsy moth larvae reared on leaves of trees from the outbreak area were reduced.