Berling M. auteur aut IRD Blachère Lopez C. auteur aut IRD Soubabere O. auteur aut IRD Léry Xavier auteur aut IRD Bonhomme A. auteur aut IRD Sauphanor B. auteur aut IRD Lopez Ferber M. auteur aut IRD text journalArticle eng text/pdf born digital access Cydia pomonella granulovirus (CpGV) has been used for 15 years as a bioinsecticide in codling moth (Cydia pomonella) control. In 2004, some insect populations with low susceptibility to the virus were detected for the first time in southeast France. RGV, a laboratory colony of codling moths resistant to the CpGV-M isolate used in the field, was established with collection of resistant insects in the field followed by an introgression of the resistant trait into a susceptible colony (Sv). The resistance level (based on the 50% lethal concentrations [LC(50)s]) of the RGV colony to the CpGV-M isolate, the active ingredient in all commercial virus formulations in Europe, appeared to be over 60,000-fold compared to the Sv colony. The efficiency of CpGV isolates from various other regions was tested on RGV. Among them, two isolates (I12 and NPP-R1) presented an increased pathogenicity on RGV. I12 had already been identified as effective against a resistant C. pomonella colony in Germany and was observed to partially overcome the resistance in the RGV colony. The recently identified isolate NPP-R1 showed an even higher pathogenicity on RGV than other isolates, with an LC50 of 166 occlusion bodies (OBs)/mu l, compared to 1.36 x 10(6) OBs/mu l for CpGV-M. Genetic characterization showed that NPP-R1 is a mixture of at least two genotypes, one of which is similar to CpGV-M. The 2016-r4 isolate obtained from four successive passages of NPP-R1 in RGV larvae had a sharply reduced proportion of the CpGV-M-like genotype and an increased pathogenicity against insects from the RGV colony. specialized 084 75 4 925-930 2009 0099-2240 https://www.documentation.ird.fr/hor/fdi:010044252 10.1128/aem.01998-08 0099-2240 [F B010044252] https://www.documentation.ird.fr/hor/fdi:010044252 https://www.documentation.ird.fr/intranet/publi/2009/02/010044252.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2009-03-06 2023-07-26 fdi:010044252 fre