JACKSONVILLE JOURNAL 2019
CORPS’TINY WEAPON Winning the BIO CONTROL BATTLE Brigida Sanchez
Bathed in sunscreen and bug spray, a U.S. Army Corps of Engineers team sets out early in the morning with cloth nets, coolers and airboats hitched up to their pickuptrucks. Their mission is to collect the Corps’ tiniest weapon used to wage war on the prolific alligator weed. “In the 1900s alligator weed was introduced into the continental United States says Chelsea Bohaty, a biologist with the U.S. Army Corps of Engineers. “It caused a lot of problems in the waterways with plants blocking navigation channels and flood risk management problems.” Alligator weed kills native flora and fauna. The root system of the plant travels down into the water column, not allowing the water to receive the oxygen it needs to conserve its natural ecosystem. “In the ’60s the U.S. Army Corps of Engineers understood the impacts of the invasive species. We focused a lot of our treatment toward the alligator weed, and we spent a great deal of money on treating the plant. The alligator flea beetle was a game-changer,” explains Bohaty. The Corps would spend more than $1 million on managing the environmental impacts of the alligator weed in a given year. Invasive species cause economic losses of more than $138 billion in the U.S. annually. Utilizing a strategy called Integrated Pest Management (IPM), scientists employ a combination of biological, mechanical and chemical control measures to mitigate the impacts of the invasive plant species. Biocontrol agents such as the herbivorous alligator flea beetle go through years of rigorous research.
Biologists have to determine if the tiny agent will cause adverse impacts to plants and animals in the U.S. “The alligator flea beetle is a classic success story for aquatic weed biocontrol,“ says Nathan Harms, a research biologist at U.S. Army Engineering Research and Development Center (ERDC). “There are a couple of things that make it such a good agent. First, both the adults and the larvae feed on the plant. The adults can live a long time, for one to two months, and the female can lay thousands of eggs. So a couple of fecund (productive) females with a short developmental time in all life stages consuming the plant are effective.” This little beetle measures 5-7 millimeter in length as an adult. Its name, the flea beetle, is an attribution to its flea-like jumping capabilities. Under the right environmental conditions, the alligator flea beetle can make a significant impact. According to the University of Florida’s Entomology and Nematology Department, the alligator flea beetle once fully established can decimate an acre mat of the alligator weed. “The beetle has already established itself in Florida. They are doing their job out there right now,” says Bohaty, who coordinates and participates in the collection of the beetles. She is the lead biologist on the Corps Palatka team. On this particular morning, the collection takes place on Lake Woodruff with five airboats flying swiftly through the water to each mat of alligator weed. Each boat goes to a designated location where the vivacious beetles have been scouted out previously 29
