Julie, It seems you may be reading a lot of Syd Singers info.... I was at many of the meeting he was at, and his take away was WAY different than most of the attendees...and he does have a following, along with his coqui sanctuary & such....
The main problem with Strawberry guava is that it has been increasing exponentially over the last century, and has gone fairly unchecked by anything...so 80 years ago there was so little of it that people fondly remember finding, 50 years ago it was one of those things you could find here & there, 20 years ago it was a common plant about, now it has developed the problem of choking out native plants in forest reserves & other "high quality" vegetation areas.
For over 20 years there have been calls for work crews to assist in the control of these plants in the native areas, but the control efforts could not even keep up with the reproduction rate (If more concerned people had gotten active, maybe the growth would not have been as drastic, but I was at some of the later control workdays & there were not enough volunteers to do much more than maintain a small area...
I also remember when the coqui & LFA were new & unique,just a few years ago, and there was a call to control, and how few people even showed up the the info meetings, much less the control efforts...& who was stating that these organisms should be allowed to stay...
Scientifically studied biocontrol has been successful on this island for quite a while (and no, the mongoose & cane toad were NOT scientific biocontrol, they were brought in by some cane growers as a whim...no research.... scientific research into biocontrol looks first at 'why not'....
One of the more interesting papers out on this is HOW a very few people have manipulated this one control, when all about there have been other biological controls uses, with no where near the public concern... the WHY is fairly interesting!
http://pus.sagepub.com/content/22/2/203.abstract
The Strawberry guava is from Brazil, and so the natural control was looked at from the native country.... E. ovatus has been studied for a fairly long time for this purpose:
http://link.springer.com/article/10.1007...3-3#page-1
http://www.invasive.org/publications/xsy...8pg659.pdf
This link is the Hawaii Conservation publication on this:
http://hawaiiconservation.org/resources/...erry_guava
edited cause I can not type!