Feeding damage of Japanese beetle (Col.: Scarabaeidae) on 16 field‐grown birch (Betula L.) genotypes

Feeding damage by Japanese beetle (Popillia japonica Newman) was evaluated on 16 field-grown birch genotypes (Betula L.) under two irrigation regimes at Fayetteville, AR in 2003, 2004 and 2005. Percentage of total leaf area skeletonized by Japanese beetle was visually estimated, and leaf damage was rated as no damage, low damage, moderate or severe damage based on the percentage of leaf skeletonization. The average percentage of leaf skeletonization on all birch trees by Japanese beetles was 32% in 2003, 27% in 2004 and 25% in 2005. In 2005, well-watered trees had a higher percentage of leaf skeletonization than water-stressed trees. Betula utilis var. jacquemontii and Betula papyrifera 'Uenci', rated as severe damage in all 3 years, were estimated to have the highest percentage of leaf skeletonization followed by B. papyrifera, which was rated as moderate-to-severe damage. Betula maximowicziana, Betula nigra 'Cully', B. papyrifera 'Renci', and Betula platyphylla 'Fargo' were rated as low-to-moderate damage. Betula pendula 'Laciniata' had nearly no damage from Japanese beetle in all 3 years. The other birch genotypes were rated as low damage during the 3-year period.