Tag Archives: Florida biological control

Bugs and more bugs — biological controls.


We’ve been given permission remove invasives on Womack Creek by Tate’s Hell State Forest providing we do it the proper way.  We have kept that creek clear of taro which infests Lake Talquin and the Ochlockonee river of which Womack Creek is a tributary.  Whenever we see a taro plant we dig it up then or soon after.

With Japanese climbing fern, however, the situation is different.  It requires more care to remove since the spores can fall into the water and be carried off to points downriver to sprout into some one else’s problem.  We GPS each new sighting during the year and in the dormant month set up a day to do exclusively that:  dig up the ferns.  It’s no easy thing what with that being a vine which goes every which-away trying to find light and where the roots get entangled with other roots of other plants trying to get maximum footing on the creek bank.   And we have to cover the plants up before rattling around the stems with our digging spade (a trowel won’t do it).

So when we saw in May this year a patch of alligator weed, just before we were leaving for cooler places for the summer, we noted that we’d have to clean that little patch out when we returned.  It didn’t matter that a little alligator had selected it as a private hiding place.  It was invasive and therefore had to go.

Imagine our dismay when we returned in October, after H. Michael,  to find that the whole creek had patches of that noxious weed.

We are in kayaks.  Kayaks are OK for carrying at least 2 bags of relatively light climbing fern or the occasional taro plant.  Kayaks are not OK for the alligator weed which mats in a thick cover, so thick no sunlight can get below it.  It is water sodden and heavy.

Our last  invasive weed pull was Coral Ardesia on Goat Island in Lake Talquin.  We had a crew of 8 paddlers but used a boat to ferry us with tools to handle that task.  And we were given permission to burn the invasives right there on the island — the numbers of bags we had to cart back and ensure it was deposited where it would be totally destroyed  was too daunting for the invasive species coordinator.  We  spent the whole day cutting, digging and burning and didn’t get the job finished.  We anticipated having to do the same for the alligator weed, a group effort.

When we returned last week, imagine our surprise.   Between late October  and early December, recent rainfalls had overflowed the banks and only one stand of alligator weed was there.  It happens to be the one which the now juvenile alligator likes.  With the air in the low 50’s, the juvenile alligator had enough sense to stay where it was warmer that day.

The leaves on that stand were non-existent.  Just like the alligator weed on Lake Talquin.   Alligator weed, water hyacinths and other invasives are choking the areas around the mouth of the upper Ochlockonee.  But in October on that lake we also spotted devastation of plant leaves by two bio-control agents, introduced to the USA in the 1960’s to control alligator weed.

Here in Womack, a tributary of the lower Ochlockonee, we saw the same depredation occurring.

We parked on the thick mat and starting opening up the stalks and few leaves which remained which were held together at the top by silken threads.   In several of  the stalks we found millipedes, in one stalk we found an adult alligatorweed flea beatle, on a cluster of leaves we found a pupa of the alligatorweed stem borer and on another the whitish thick larvae of that moth.  On one of the few intact spray of leaves we found a hungry alligatorweed flea beetle larvae eating its way up a leaf.

Photo 1 above is the designer designed alligatorweed flea beetle.   Photo 2 is a stem with a hole, either created by the beetle or the moth larvae we have yet to ascertain and above that section the spent stem section which interior had been eaten from the inside and vacated to dry up and die while the stem borer continued down the stalk, eating and vacating.  The last photo is of a pupa of the alligatorweed leaf borer.  We found the larvae of that species, too, but the photographs were too blurred to post.

We determined not to remove that patch in order to observe it over time to see how well the bio-control agents do their work.  And to understand better the life cycle of these two insects. Education over destruction.

On stands of alligator weed with these two agents in other waters, we have found small spiders and we have seen these spiders coming out out a larval case with a shrunken larvae within, like the nutrients and juices have been sucked up by the spider.  We have yet to get an ID for that spider.  We did not see any on that small patch of alligator weed.

The photo above is of a millipede — on a patch of alligator weeds, submerged in water.  Millipedes enjoy floating as much as we do.

In Hawaii, biocontrol agents did the job and then proceeded to become invasives themselves by expanding their appetites to native species, like native birds.  One would have  had to have slept through sciences classes from K through high school there not to have the dangers of insufficiently tested bio-control agents being  drummed into one’s subliminal zones.

We now don’t have to worry about logistics of removing the alligator weed.  We have a floating lab there.   Hopefully that alligator will find a better spot to bask as it gets larger.  We hate to have to scare it off to check on insects.