Distribution and Survival of Eggs of Summerform Pear Psylla (Homoptera: Psyllidae) Affected by Leaf Midvein

Abstract

Distribution of pear psylla eggs on pear seedlings and cues affecting oviposition were monitored. Most eggs were deposited on the youngest foliage; few eggs were placed on the oldest, leathery leaves. Highest densities occurred adjacent to the midvein or in leaf serrations. Densities were very low on the leaf blade away from the midvein. Oviposition was induced in areas normally avoided (e.g., leaf blade) by providing strips of tape as artificial structures resembling midveins. Masking of particularly prominent midveins with strips of tape resulted in reduction of oviposition in these normally preferred sites. These results suggest that the midvein provided positive mechanical cues to ovipositing females. Effects of egg location on survival and development of eggs was quantified. Survival rates of eggs were higher for eggs deposited along the midvein than those deposited on the leaf blade. Survival decreased with increasing plant water stress. Development rates of eggs were not affected by location or stress.