Robotrout,

I don't have the specific info you are looking for...but if you really want to look into this further, you could contact one of the main researchers behind the project:

http://www.agri.gov.il/en/people/875.aspx

The $.05 cost per plant does not mean that the unit cost is $.05...that is just the cost to buy proper coverage for one plant, even if that means that there is one sensor for every 100 plants.