Responses of different geographic populations of two potato tuber moth species to genetic variants of P hthorimaea operculella granulovirus

P hthorimaea operculella granulovirus (Phop GV ) belongs to the genus B etabaculovirus of the arthropod‐infecting B aculoviridae. Phop GV is able to infect several gelechiid species. Among them are the potato tuber moths P hthorimaea operculella Z eller and T ecia solanivora P ovolny (both L epidoptera: G elechiidae). In various S outh A merican countries, Phop GV ‐based biopesticides are used to control either P . operculella or T . solanivora . Many trials have indicated that a particular viral isolate can exhibit very distinct pathogenicity when infecting different host species or different populations of one host species. In this study, we compared host–pathogen interactions using various Phop GV isolates and various populations of P . operculella and T . solanivora . Virus isolates from P . operculella were more pathogenic against their original host species than against T . solanivora . A Phop GV isolated from T . solanivora was less efficient against P . operculella . In addition, virus isolates differed in pathogenicity toward their hosts (i.e., lethal concentrations of isolates ranged from low to high). Unexpectedly, we also found that host populations of one species from distinct geographic origins did not differ significantly in susceptibility to the same Phop GV isolate. This was the case for both host species and for five Phop GV isolates. Comparative restriction fragment length polymorphism ( RFLP ) analyses of 11 isolates including those used in bio‐assays indicated three main regions of variation in the genome of Phop GV , corresponding to the regions of open reading frame Phop GV 046, gene Phop GV 129 ( egt ), and repeat 9 (located between open reading frames Phop GV 083 and Phop GV 084). Comparison of the nucleotide sequences of the insertions/deletions present in these regions were carried out for the most variable isolate, JLZ 9f. The results are discussed in the context of the production and use of Phop GV as a biological agent against these two pest species.