Releasing biological control agents
Collection and redistribution
The most cost effective way to establish new populations is to harvest from sites where the agent is already present and populations are expanding, and transferring to a new site. It is very unlikely that populations will have increased sufficiently for this to be possible within 2 years of first release, and it may take much longer before this method can be employed.
This method has been used extensively to distribute the clover root weevil parasitoid, Microctonus aethiopoides (Irish biotype) throughout pastures in New Zealand.
Other issues to consider