We have an interesting situation involving the use
of beneficial insects in Southern California.
We use a lot of Eugenia as an evergreen hedge. It
grows well in our climate and up to a few years ago,
it was essentially trouble-free. There are a number
of different species of Eugenia listed in Hortus and
I'm not sure which species is the one sold in most of
our nurseries - probably E. uniflora.
It then began to have problems with a psyllid. The
story is that Disneyland was also using a lot of Eugenia
and they worked at finding a solution to their psyllid
problem. They imported a predatory wasp from
Australia that feeds on this particular psyllid and for a
while it looked like they had solved the psyllid problem
for Southern California. The psyllid population dropped
off, I guess the predatory wasps then died of starvation,
and now, once again, we have a psyllid problem on our
Eugenias.
Do we have to go back to square one and wait for
Disneyland to import more wasps from Down-Under?