Aggregative Infestation of Nine Bostrichidae Species on the Madagascar Almond Tree, Terminalia neotaliala Capuron (Myrtales: Combretaceae).

Abstract

Bostrichid beetles are well-known pests of wood and wood products in the world. The Madagascar almond tree, Terminalia neotaliala Capuron (Myrtales: Combretaceae), is uniquely layered and has been introduced and cultivated across several continents, where it is commonly used in urban landscape projects. To assess the damage caused by bostrichid beetles to T. neotaliala, the damage status of T. neotaliala, the classification of bostrichid beetles, and their vertical distribution on host plants were investigated. The primary site of infestation by bostrichid beetles on T. neotaliala living trees was the lateral branches in the fields with the damage symptoms, including unseasonable yellowed leaves, branch breakage, or eventual death of the entire lateral branch. The total percentage of attacked plants was 9.53%. Significant positive correlations existed between the percentage of attacked plants and the diameter at breast height and crown width, but not with the tree height. The percentage of damage by bostrichid beetles to T. neotaliala reached level I and level II over the 2-year observation. A total of nine species from four genera of Bostrichidae infested the T. neotaliala, i.e., Sinoxylon eucerum Lesne, S. flabrarius Lesne, S. japonicum Lesne, S. mangiferae Chûjô, S. pygmaeum Lesne, S. tignarium Lesne, Xylocis tortilicornis Lesne, Xylodectes ornatus (Lesne), and Xylopsocus capucinus (Fabricius). There were no distinct differences in the total number of Bostrichidae species on different crown layers of T. neotaliala, and no significant correlations between the total number of species and individuals, and the number of individuals of each species and the measurements of plants (i.e., diameter at breast height, crown width, and tree height). Our findings provide essential information for the development, implementation and monitoring of effective control strategies against bostrichid beetles on T. neotaliala.