Incidence of Longhorn Beetles (Coleoptera: Cerambycidae) on Urban Trees in Hanoi and Dak Lak Province, Vietnam

Barringtonia acutangula (L.) Gaertner (Lecythidaceae), Cassia fistula L., Dalbergia cochinchinensis Pierre, Dalbergia oliveri Gamble ex Prain, Dalbergia tonkinenesis Prain, Pterocarpus indicus Willd., Pterocarpus macrocarpus Kurz (all Fabaceae), Tabebuia rosea (Bertol.) DC. (Bignoniaceae), and Terminalia neotaliala Capuron (Combretaceae) are widely planted in urban areas in Vietnam. However, trees in Dak Lak Province and Hanoi have been attacked by longhorn beetles (Coleoptera: Cerambycidae). We undertook this study to better understand the diversity and pest status of longhorn beetles on urban trees in Hanoi and Dak Lak Province. This work recorded Aristobia horridula (Hope) infesting D. cochinchinensis, D. oliveri, D. tonkinenesis, P. indicus, and P. macrocarpus; Aristobia approximator (Thomson) infesting C. fistula and T. neotaliala; Batocera rufomaculata (DeGeer) infesting B. acutangula; and Glenea mouhoti Thomson infesting T. rosea. Dalbergia cochinchinensis, D. tonkinenesis, and P. macrocarpus were seriously damaged by A. horridula, with damage incidence (P%) ranging between 79.2% and 88.7% and damage severity (R%) ranging between 68.3% and 75.4% among these three tree species. The P% and R% of T. rosea by G. mouhoti were 100% and 89.2%, respectively, and those of T. neotaliala by A. approximator were 80.0% and 76.5%, respectively. The following plants were identified as new hosts: D. oliveri and D. tonkinensis for A. horridula, T. neotaliala for A. approximator, and B. acutangula for B. rufomaculata. Tabebuia rosea is the first known larval host for G. mouhoti. Future research should focus on monitoring and identification of appropriate management solutions to effectively manage these four pestiferous longhorn beetle species.