Weed Biocontrol Issue 83
In this issue
![Alistair Robertson releasing field horsetail weevils Alistair Robertson releasing field horsetail weevils](https://oldwww.landcareresearch.co.nz/__data/assets/image/0003/156909/varieties/thumb200.jpg)
First release of new agents
We are pleased to report the first field releases of two insect biocontrol agents – one for giant reed (Arundo donax) and another for field horsetail (Equisetum arvense).
![Zane McGrath Zane McGrath](https://oldwww.landcareresearch.co.nz/__data/assets/image/0008/156914/varieties/thumb200.jpg)
New faces
We would like to introduce some new staff who have joined us recently.
![Graeme Bourdôt with Californian thistle Graeme Bourdôt with Californian thistle](https://oldwww.landcareresearch.co.nz/__data/assets/image/0003/157647/varieties/thumb200.jpg)
What do weeds cost?
It is no secret that weeds cost the productive sector a huge amount of money each year, in terms of both control and lost production. But the size of this financial burden is not easily calculated.
![Darwin's barberry fruit infested with rust Darwin's barberry fruit infested with rust](https://oldwww.landcareresearch.co.nz/__data/assets/image/0006/156912/varieties/thumb200.jpg)
Darwin's barberry: playing the numbers game
Recently there have been some important breakthroughs in the Darwin’s barberry (Berberis darwinii) project, involving both the seed-feeding weevil (Berberidicola exaratus) and the rust fungus (Puccinia berberidis-darwinii) in what is really proving to be a numbers game.
![Adult field horsetail weevil Adult field horsetail weevil](https://oldwww.landcareresearch.co.nz/__data/assets/image/0010/156916/varieties/thumb200.jpg)
Choosing a good release site
A critical success factor for the successful establishment of new weed biocontrol agents is choosing good release sites.
![Hieracium gall midge damage Hieracium gall midge damage](https://oldwww.landcareresearch.co.nz/__data/assets/image/0004/157648/varieties/thumb200.jpg)
Autumn activities
There are a few things you might want to fit in before winter.