Apfelwickler-Granulovirus: Unterschiede in der Empfindlichkeit lokaler Apfelwickler-Populationen

Summary

This study is part of a BMELV (German Federal Ministry for, Food, Agriculture and Consumer Protection) project on prevention of codling moth damage by long-term population control on large areas. Local codling moth (CM) populations were collected in autumn 2003 from three different orchards in the South of Germany; two of them having been treated with granulovirus of codling moth for many years and one since two years. In autumn 2004, in addition to the three locations from the previous year, specimens from populations in four other orchards with serious CM problems were collected.
The susceptibility of the offsprings of the overwintering larvae to CpGV was investi-gated in the spring of the following year in bioassays on artificial diet and compared to a laboratory strain of the codling moth. The results indicated significant differences in sensitivity to the virus between the local codling moth populations. The LC50-values showed that two of the populations sampled in 2003 were more than thousand fold less susceptible than the third population and the laboratory strain. The results from the bioassays from the descendents of the diapausing larvae sampled in 2004 and 2005 confirmed the low susceptibility of two already in 2003 sampled populations and showed an up to thousand fold resistance also for the larvae from the new locations.
For the time being, the problem of reduced sensitivity to the virus seems to be limited to a few orchards in Germany, the majority of orchards being not affected.