Studies on the Frequency of Attack Produced by Obolodiplosis robiniae Haldeman in Black Locust Trees from Landscaped Spaces of Cluj-Napoca

Abstract

Obolodiplosis robiniae Haldeman (Diptera: Cecidomyiidae) is a monophagous species, the host plants being species of the genus Robinia. The species is native to the U.S.A., and in Europe, it was first reported in Italy, in 2003, from where it spread to all European countries. In Romania, it was reported in 2007. The attack of this species is produced by the larval stage and manifests leaves. After hatching, the endophytic and gregarious larvae cause changes in the parenchyma structure that lead to the appearance of characteristic galls located at the edge of the leaflet and rolled towards its lower part. In 2021, we monitored the frequency of attacked acacia leaves, the number of galls reported on a leaflet and the number of larvae in a gala in two locations in Cluj-Napoca: on the acacias in the Central Park of the city and on the acacias in some street alignments. In the case of acacias in Central Park, the frequency of attacked fruits was 15%, and in the case of acacias in the alignment, 7%. On the 50 attacked leaves taken from Central Park, there were 932 leaflets, of which 40% are with galls, and the leaves on the alignment had 1010 leaflets, of which 19.2% are with galls. The number of galas/leaflets was between 1 and 5 galas in Central Park, and on alignments between 1 and 4 galas. In both locations, most of the leaflets were with a single gala. The maximum larvae/gala was five specimens in Central Park and three larvae on the leaflets on the alignment.