Spatial emergence patterns of the bronze birch borer, Agrilus anxius Gory, and associated parasite and woodpecker predation in European white birch, Betula pendula Roth, were examined. Beetle and total hole density (beetle + parasite + woodpecker) were significantly lower from stem bolts 6 m above ground, 0.1 to 5.0 cm in circumference, and with 0.1 to 1.5 mm bark thickness than bolts 1 to 3 m above ground, 5.1 to 60.0 cm circumference, and with 1.51 to 3.0 mm bark thickness. Significantly more emergence occurred from the southwestern quadrant of trees than from other quadrants. Beetle emergence and total hole densities were also significantly less from branches than from tree trunks.
Contributor Notes
2Salaries and research support provided by State and Federal funds appropriated to The Ohio State University, Ohio Agricultural Research and Development Center. Journal Article No. 200-85.
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