Persistence of the biological effect of codling moth granulovirus in the orchard - preliminary field trials

Summary

In 2000 and 2001, in a field trial, the persistence of the biological effect of codling moth granulovirus (CpGV) was investigated. With a single treatment at full concentration of CpGV (MADEX 3, 100 ml/ha) a considerable reduction of CM population was achieved over the whole vegetation period. This may indicate that over a considerable period of time after a treatment a biological effect of CpGV sufficient for an increased mortality of the larvae was present in the orchard. However, the onset of mortality was not fast enough to protect the fruit from damage. Further research has to be done to gain more experience in handling this effect. It could be very important for the reduction of the number of treatments in organic apple growing.