What is in this article?:
- Researchers are busy trying to find biocontrol options for invasive species that threaten native plants.
MELALEUCA, a prolific seed producer
“Working with all these groups, we normally do pre-screening before we ever bring the insects over to the U.S. Once we find an insect that shows promise — that proves to be a specialist on the target — we bring them here to the lab and study them in quarantine.
“In the past, all our quarantine work has been done in a small facility located at Gainesville, next to the University of Florida. But since 2005, we’ve had our own quarantine facility here at Fort Lauderdale. It’s a state-of-the-art facility and is designed to insure that insects can’t escape. This allows us to study them without having to work overseas.
“Once we have the agent tested, there is a long process to receive regulatory approval to release it. Once a permit is secured, we put it in the field and do studies to confirm that it is host-specific, effective, how well it disperses and other things.”
More on melaleuca…
“Melaleuca is an interesting plant that is really adapted to fire conditions. As a result, it produces seeds that are in persistent capsules that stay up in the canopy of the tree until something causes them to dry out. Then, they release the seeds en masse. One small tree can have 10 million seeds on it.
“In the past, to control it, they’ve used herbicides or cut the trees. That, in turn, causes the branches to desiccate and drop seeds. So, where once there was a single tree, all of a sudden there can be an acre of seedlings coming up. It’s a management nightmare.
“As part of our biocontrol strategy, we wanted to find agents that would reduce seed production. The biology of the plant is such that the seeds are produced on the growing tips. A shoot will grow, produce leaves and flowers, and continue that pattern over and over.
“The insects we brought in are very effective at attacking the tips of the branches and stopping the growth process. As a result, we’ve seen seed production drop by 90 percent to 95 percent.
“The first insect we released was a weevil, a top-feeder. The second was a psyllid, a small insect similar to an aphid that feeds mainly on the young foliage at the tips.
“The third insect — actually an insect/nematode combination — is gall-former. A gall causes an abnormal growth in a plant that is almost like a barnacle. The plant puts all of its resources into this gall, a gnarly, woody growth and then doesn’t have the materials needed to continue to grow.