My work involves biological control
of weeds, so that's using insects
to control weeds in Hawaiian forests.
So our targets include strawberry guava
and many other ecosystem altering weeds
in the Hawaiian Islands.
Some of our worst invasive weeds
in Hawaiian forests include strawberry guava (this tree),
miconia, clidemia.
This plant here, in the family Melastomataceae.
There are many serious invaders in that family.
This is very typical of the way strawberry guava invades
in thickets of small stems shooting up all over the place.
And so they're blocking out the light for the native understory.
So we get very little native regrowth
of native plants in the understory.
It's just all strawberry guava.
The young stems are slender and they fall over
and they will take root in the ground and send up new shoots
so you develop a very thick tangle of stems over time.
Essentially it becomes impenetrable.
So, our intent with the biocontrol is essentially
to restore the balance to the system
with a natural enemy for strawberry guava.
Here in Hawaii it has no natural enemies.
So, bringing in that specialized agent will help limit the
invasiveness of strawberry guava.
Some invasive species are valued in Hawaii and elsewhere.
For example, plants like strawberry guava create fruit
that some people eat, so there is concern
that biocontrol might wipe out strawberry guava
and eliminate that fruit source.
But, the biocontrol we developed for biocontrol
of strawberry guava is not going to kill these trees,
it's just going to limit their fruiting and limit their growth,
their availability to spread into native forests.
The biocontrol for strawberry guava is an insect that's native
to Brazil.
It forms galls on the new leaves so it would be feeding
on this part of the plant, and as the leaf grows,
the gall grows and that slows down the overall growth
and reproduction of the plant.
In Brazil, you don't see strawberry guava being invasive,
it's very limited in distribution.
It still produces fruit there and some people enjoy the fruit
but it remains a harmless native plant in its native range.
Our work involved is developing the biocontrol agent,
so that means doing the research to demonstrate the specificity
and impact they have on the plant, and then we turn
over that information to the state
and the regulatory agencies
who evaluate whether the biocontrol is suitable
for introduction.
If they decide it is okay to release it in the state,
then we help them with that process
and do the follow-up monitoring which is really critical
to understand whether the biocontrol is having the effect
we intend.
We are not in every case going to solve the problem.
A weed like strawberry guava is going to persist
in the areas it has already invaded, so it is going
to take other management approaches combined
with biocontrol to solve the problem.
For example, in a thicket of a forest like this,
these trees will not be killed by the biocontrol,
but their growth will be slowed and if resource managers do come
in and cut the trees, then their ability to respond
and regrow will be limited by the biocontrol.
Hopefully by combining these different strategies over time,
we will be able to actually restore forests
and really beat back the invaders,
so that's the long-term goal.