Egg Distribution Patterns of Olive Psyllid Euphyllura phillyreae (Homoptera: Aphalaridae) on Phillyrea latifolia and Olea europaea in Northern Greece

Abstract

Egg distribution patterns of Euphyllura phillyreae Foerster among buds and inflorescences of olives and Phillyrea latifolia L. ( Phillyrea media L.), a perennial, bushy, evergreen plant that blooms from March to May, were quantified in the field and in the laboratory. In the field, the 1st eggs on olive were observed in early April in 1989 and 1990 on developed buds. Eggs became abundant only when the apical bud and the axillary buds started to swell. In May the eggs were observed on inflorescences. Eggs were deposited 8 wk earlier on P. latifolia than on olives, mostly on developing inflorescences. Preference for oviposition at different sites of the developing bud changed over the season on olive. Initially, the outer and the median pair of bud scales were preferred. Later in the season the eggs were uniformly distributed on all 3 pairs of scales of developed (expanding) buds. On inflorescences the petals of closed flowers were the most preferred site, followed by the sepals. On P. latifolia the most preferred site of developing inflorescences was the bracts, followed by the sepals. Young, actively growing tissue, such as developing buds or inflorescences, apparently were the preferred sites for oviposition on both olive and P. latifolia . In choice and no-choice laboratory tests, more eggs were laid on olive twigs bearing developing inflorescences, fewer eggs on twigs bearing only swollen terminal or axillary buds, and few eggs or no eggs at all were laid on the other plant parts.