Though Florida has a long history of misguided imports — melaleuca to drain the Everglades, bufo toads to control sugar cane pests and blue tilapia to clear weeds in canals, to name a few — bio-controls today must clear a rigorous screening process involving multiple agencies that can take years, said Center, the lab’s research leader. The aim is to ensure imports won’t develop an appetite for unintended plants, including crops such as citrus and sugar cane.
In the last decade, scientists at the center, with support from state and counties agencies, have introduced dozens of imported insects. Not every bio-control has worked but some, such as the melaleuca snout beetle, have put a real dent in troublesome species.
Center stressed that bio-controls are not “silver bullets’’ capable of eradicating an invasive plant but they can promise cheaper, more environmentally friendly alternatives to chemical herbicides.
In a handful of initial tests this spring, the air potato leaf beetle has shown promise. Attractive as bugs go, its flame-colored wings standing out against a body as shiny as black patent leather, the beetle possesses a prodigious appetite, consuming by USDA estimates about 30 square feet of leaf in a three-month life span. It also reproduces rapidly, with females laying about 1,200 eggs each cycle. There aren’t enough beetles now to do much damage but Florida’s Department of Agriculture and Consumer Services will begin mass rearing them for wider release at three labs.
At the tropical forest in Davie, just 66 of the beetles have taken a visible bite out of a small test area, leaving air potato leaves looking like they’ve been peppered by repeated shotgun blasts. Ellen Lake, a USDA research entomologist, pointed out one native wild coffee plant, completely cloaked a few months ago, was now visible through the desiccated vine.
Though the beetles may not do enough damage to kill a vine outright, they could weaken the plant enough to limit its climbing or curb its output of bulbils. One key, Lake said, is how well the beetles survive the winter. It could take several years and wider releases to determine effectiveness.
Still, Center is optimistic the beetles could become a new and powerful tool against a supremely stubborn pest. He’s looking forward to next spring, when the bugs will emerge from the leaf litter and soil to find plenty of what they seem to crave most — tender new air potato shoots.
“We’ve very interested to see what will happen,’’ he said. “The hope is they’re going to devastate the foliage.’’