Hardwood injury and mortality associated with two shot hole borers, Euwallacea spp., in the invaded region of southern California, USA, and the native region of Southeast Asia

Table 4 Density of polyphagous shot hole borer (PSHB), Euwallacea whitfordiodendrus, and Kuroshio shot hole borer (KSHB), E. kuroshio, entrance holes (mean (±s.e.) per 232 cm²) on trees surveyed in southern California, USA, southwestern China, and northwestern Vietnam

Country	Factor		Number	Entrance hole density^a
USA	Forest type	Native trees	39	15.2 (±2.59)a
	Forest type	Ornamental trees	10	19.7 (±4.43)a
	Tree species	Boxelder maple, Acer negundo L.	5	45.1 (±5.91)a
		Bigleaf maple, Acer macrophyllum Pursh	4	24.1 (±7.42)b
		Coast live oak, Quercus agrifolia Née	1	19.5
		Castorbean, Ricinus communis L.	9	21.1 (±4.72)b
		Western sycamore, Platanus racemosa Nutt.	8	15.7 (±4.49)b
		Avocado, Persea americana Mill.	1	7.5
		White alder, Alnus rhombifolia Nutt.	2	11.5 (±11.5)bc
		Red willow, Salix laevigata Bebb	19	5.50 (±1.27)c
China	Tree species	Trident maple, Acer buergerianum Miq.	7	20.7 (±2.84)a
		Chinese banyan, Ficus microcarpa L.f.	1	20.0
		Oriental plane, Platanus orientalis L.	2	15.0 (±0.00)a
Vietnam	Tree species	Black wattle, Acacia mangium Willd.	8	10.6 (2.65)

Entrance holes were recorded at 1.37 and 0.3 m height along the tree stem in southern California and at 1.37 m only in China and Vietnam
^aMeans (± s.e.) followed by the same letters within each table sub-section are not significantly different

ISSN: 1297-966X