Andy,
 
Thanks for that interesting article. The USDA has been proposing tighter controls on introducing organisms for biocontrol.  The last proposal I looked at went a little too far and it was dropped.  It'll be back in a modified form.  Many introduced weeds are serious pests of rangeland and many successful biocontrol programs have yielded great benefits.   In many cases they reduce or eliminate pesticide use.  Case in point: Eucalyptus psyllid.  Nurseries growing this cut green used to spray maximum strength chemical cocktails and get poor control.  The growers sent an entomologist to Australia.  He returned with a parasitic wasp that has reduced the pest populations below the economic threshold with no pesticide use. They do evaluate these organisms before introduction, probably much more than in the 60's.  
 
Of course one man's meat is another's poison.  To the beekeeper, yellow star thistle is a good forage plant but to the cattle rancher it destroys rangeland and draws blood from his horse's legs.  The native thistles probably don't do him much good either.  Other weevils are being spread at this time to control YST. 
 
Bob Roach