Resistance mechanisms in Pieris taxa (Ericaceae) to Stephanitis takeyai (Hemiptera: Tingidae).
This study examines some of the potential mechanisms of resistance in selected Pieris (Ericaceae) taxa to the Andromeda lace bug, Stephanitis takeyai Drake and Maa, based on differences in resistance to lace bug feeding, and the possible role of leaf parameters such as  leaf wax, toughness, nutrient composition, and stomatal characters in plant resistance. Experiments with extracts of leaf-surface lipids revealed that Pieris leaf wax did not have a role in resistance to lace bug feeding. Leaf wax extracts from a resistant species P. phillyreifolia  (Hook.) DC. applied to leaves of a susceptible cultivar P. japonica (Thunb.) D.Don ex G.Don 'Temple Bells' did not affect feeding, oviposition, or survival of S. takeyai; and neither the extracts from Temple Bells induce susceptibility in P. phillyreifolia.  Leaf penetrometer measurements indicated that significantly higher force was required to puncture P. phillyreifolia leaves, which also had higher fiber, lignin, and cellulose, and lower leaf moisture contents. Ultrastructural examination of leaves of Pieris taxa revealed significant  differences in the number and size of stomata. P. phillyreifolia leaves had the highest number of stomata per unit area but these were the smallest in size, whereas P. japonica (Thunb.) D.Don ex G.Don Temple Bells leaves had the fewest and largest stomata. Resistance in Pieris  taxa to S. takeyai may be attributed to a combination of different factors including leaf toughness, moisture, and stomatal characters. The type of resistance may be described as antixenosis combined with antibiosis, because reduced adult survival and reproduction were observed on the  taxa resistant to lace bug feeding.
Department of Entomology, University of Georgia, Griffin, GA 30223, USA.
Shakunthala
S
Nair
S Kristine
SK
Braman
D A
DA
Knauft
D000818:Animals; D029791:Ericaceae / Q000502:physiology*; D006430:Hemiptera; D060434:Herbivory; D018515:Plant Leaves / Q000737:chemistry / Q000502:physiology*; D014885:Waxes / Q000032:analysis
D014885:Waxes