|Pounders Jr, Cecil|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2008
Publication Date: 12/1/2008
Citation: Kirker, G.T., Boyd, D.W., Sampson, B.J., Pounders Jr, C.T., Spiers, J.M. 2008. The Effects of Stomatal Size on Feeding Preference of Azalea Lace Bug, Stephanitis pyrioides (Hemiptera:Tingidae), on Selected Cultivars of Evergreen Azalea. HortScience pg 2098-2103. Interpretive Summary: Feeding preference of azalea lace bug, Stephanitis pyrioides, was evaluated in choice and no-choice laboratory tests using 33 commercially available cultivars of azalea, Rhododendron spp. Stomatal length and area of cultivars were measured to correlate to feeding preference data. Measures of ALB preference were wignificantly different between cultivars and mean stomatal length and area were different between cultivars, but varied responses were seen between different cultivars. We found no correlation between mean feces, mean eggs, mean stomatal lenth, or mean stomatal area. We conclude that mean stomatal length and area are not accurate predictors of ALB feeding preference on azalea.
Technical Abstract: Azalea lace bug (ALB), Stephanitis pyrioides (Scott), is an important economic pest of azaleas in the southeastern United States. In this study, 33 commercially available cultivars of evergreen azalea, Rhododendron spp., were evaluated for S. pyrioides feeding preference in both choice and no-choice feeding bioassays. Mean stomatal length and area, which were hypothesized to affect ALB feeding preference, were also measured for each of 33 cultivars and results were correlated with indices of ALB feeding (mean feces)and fecundity (mean eggs). An azalea cultivar, Fourth of July, was least preferred by ALB in both no-choice and choice tests, whereas ‘Watchet’ was most preferred. Cultivars Fourth of July and Delaware Valley White had the smallest mean stomatal areas despite their disparate susceptibilities to ALB feeding. Although stomates through which ALB insert their proboscides vary in size among azalea cultivars, they confer no obvious resistance to ALB feeding preference. Therefore, the mechanism for lace bug resistance in azalea remains elusive.