Quantifying Asian chestnut gall wasp (Dryokosmus kuriphilus Yasumatsu) impact on fruit yield and on tree growth using terrestrial LiDAR

Abstract

The Asian chestnut gall wasp is an invasive pest that causes ecological and economic losses in the management of the sweet chestnut (Castanea sativa Mill.). The pest therefore needs to be monitored in order to assess its impact on tree growth and fruit yield. As part of this work, we propose an infestation level classification based on the number of galls per branch. For two sweet chestnut orchards infested by the wasp, terrestrial light detection and ranging (LiDAR) data were used to calculate tree growth and fruit yield was quantified in terms of nuts and burrs. The tree growth and fruit yield variables were statistically analysed to determine the impact of different infestation levels on these variables, and differences between pairs of infestation levels were tested for significance. Negative correlations were found for the fruit yield variables with infestation indicators, while positive correlations were found for the tree growth variables. Significant differences were observed in fruit yield and tree growth variables associated with different infestation levels.