Current Articles
Browse Archives
Contact Us
AUF Home
ISA Seal
Get Acrobat Reader

Arboriculture & Urban Forestry Online
Volume 43, Issue 6 — November 2017

Relative Susceptibility Among Arborvitae Cultivars to Arborvitae Leafminer, Argyresthia thuiella (Lepidoptera: Argyresthiidae)    (View PDF)

Fredric Miller and Donna Danielson

Abstract: Eighteen Thuja species and cultivars were evaluated for ovipositional preference for, and relative susceptibility to, feeding by the arborvitae leafminer. Thuja occidentalis 'Hetz Midget' and 'Hoopesii' were least susceptible; T. occidentalis cultivars 'Gracilis', 'Holmstrup', 'Spiralis', and 'Techny', and T. plicata 'Fastigiata', were intermediate in susceptibility; Thuja occidentalis cultivars 'Aurea', 'Douglasii Aurea', 'Globosa', 'Hetz Wintergreen', 'Smaragd', 'Umbraculifera', 'Wagneri', 'Wareana,' and 'Waxen', and species T. occidentalis, and T. plicata, were highly susceptible to ALM feeding. Short trees suffered significantly less feeding compared to tall trees, with number of infested branch tips (IBTs) increasing with tree height. Short trees (<4 m) had significantly more feeding damage in the upper canopy zone and tall trees (>4 m) had greater damage in the lower and middle zones. Trees with very dense canopies had significantly fewer IBTs compared to trees with sparse, medium, and dense canopies, with IBTs decreasing as canopy density increased. There were no significant associations between number of IBTs and canopy aspect. Plant height, growth habit, and canopy zone and density appear to influence infestation levels and possibly ovipositional preference. These findings suggest some important ALM management guidelines for the nursery and landscape industries.

Keywords: Arborvitae; Arborvitae Leafminer; Argyresthia thuiella; Insect Ovipositional Preference; Susceptibility; Thuja.

Current Articles | Browse Archives | Search | AUF Home | ISA Home | Get Acrobat