Submitted to: European Meeting in the IOBC/WPRS Working Group
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/1999
Publication Date: N/A
Technical Abstract: From 1990 through 1995, outbreaks of the gypsy moth (Lymantria dispar (L.); Lepidoptera: Lymantridae) occurred in 16 European countries, almost simultaneously. The occurrence of gypsy moth nuclear polyhedrosis virus (LdNPV) was mentioned and/or studied in 7 European countries where in most cases the virus presence led to epizootics with ensuing population collapse. As part of a search for natural enemies of the gypsy moth in France, virus-infected samples were found in an oak (Quercus robur L. and Quercus petraea (Matt.) Liebl.) forest around Pujaudran, 20 km west of Toulouse in a population that was increasing 5 years after a previous outbreak. Percent virus infection at the site was 31.7% and 50.1 on June 14 and 21 (1998), respectively. Polyhedra occlusion bodies were observed under light microscopy and purified occlusion bodies were examined using SEM. French LdNPV DNA cut with BamH1, EcoR1, Hind III, and Xba 1 revealed only minor fragment differences between North American, Asian, and European isolates. The dot blot of French viral DNA hybridized with labeled probes of the Korean strain of LdNPV and two North American strains, one being a recombinant construct (LdNPV-B-gal) and another a clone of the Abington geographical isolate (a624). However, no homology was observed using an Autographa californica nuclear polyhedrosis (AcMNPV) probe. Studies of strains from various origins, and subsequent bioassays to test their infectivity and potential impact on hosts, will help select the most effective viral material for biological control of the gypsy moth.