Evaluating grower, landscape manager, and consumer perceptions of azalea lace bug (Heteroptera: Tingidae) feeding injury.

Abstract

A survey using modified azalea stems was used to establish a "tally threshold value" for assessing azalea lace bug, Stephanitis pyrioides (Scott), feeding injury to azalea shrubs. Consumers and green-industry professionals, represented by ornamental growers, landscape architects, and landscape managers, recognized azalea lace bug injury when injured leaf area exceeded 2%. Purchase and treatment decisions of professionals and consumers were evaluated by surveying responses to Rhododendron indica variety alba 'Delaware Valley White' azaleas representing a range of damage. Survey participants also provided a brief biographical background and answers to questions regarding pesticide use, ability to identify diseases, pests, and beneficial organisms, and willingness to consider pesticide alternatives. Professionals and consumers expressed a strong interest in limiting urban pesticide use. The 2 groups indicated a hypothetically acceptable level of 6-10% plant damage by arthropod pests. A 2% injury threshold was used to determine the level of proportional damage (the percentage of leaves displaying 2% or more lace bug leaf feeding injury) resulting in either the rejection of plant purchase or initiation of treatment. A nonlinear curve was fit to treatment and no-purchase responses of professionals and consumers using a modified 3-parameter Mitscherlich nonlinear growth function. Half of the surveyed professionals and consumers indicated that damage proportions >10% (1.03% actual injury) were sufficient to reject an azalea for purchase. Proportional damage levels >43% (3.3% actual injury) would be necessary to prompt 50% of the respondents to initiate treatment of damaged azaleas to control lace bugs.