UF/IFAS Mole Cricket Biological Control Program saves state millions

Howard Frank,left and Tom Walker check two-part trap that uses synthesized mole cricket calls to monitor both mole crickets and the beneficial flies that locate their hosts by sounds.

GAINESVILLE, Fla. — In a recent study, researchers with the University of Florida, Institute of Food and Agricultural Sciences in cooperation with Florida A&M University economists estimated that a 34-year program to control invasive pest mole crickets in the state has saved cattlemen approximately 13.6 million dollars a year. Over the long term, that figure balloons to 453 million dollars.

“The partnership with the State of Florida has been crucial to controlling the mole crickets,” said Norm Leppla, a UF/IFAS professor of entomology and nematology. “The Mole Cricket Biological Control Program has been worth every penny invested by the Florida Legislature and other stakeholders in the state.”

UF/IFAS researchers remember when the mole crickets reached outbreak levels in Florida during the mid-1900s and began wreaking hundreds of millions of dollars’ worth of damage to crops, pastures and turf. Cattlemen were beside themselves as they watched the tiny insects tear across their pastures like a biblical swarm of locusts. The effects were devastating, but not irreversible.

Mole crickets damage turfgrass in several ways. They not only feed on grass roots and blades at night, especially after rain or irrigation during warm weather, but also tunnel near the soil surface and dislodge plants or cause them to dry out, Leppla said.

With funding from the Florida Legislature through the Florida Department of Agriculture and Consumer Services, Division of Plant Industry, UF/IFAS researchers began searching for a way to stop the mole crickets in their tracks. Prior to the state funding in 1979, the insects were maintained under control with very toxic insecticides, such as chlordane that was phased out in the late 1970s, Leppla said. The replacement insecticides were less effective and too expensive for long-term use in pastures, he said.

“So, the state started the Mole Cricket Biological Control Program by investing in the UF/IFAS entomology and nematology department and at some of our research and education centers across the state,” Leppla explained. “The researchers went back to the pest’s origin in South America and looked for natural enemies of the mole crickets.”

Researchers found two primary insect natural enemies of the mole crickets, imported them and began testing them to make sure the parasites would not attack other organisms. The most useful was Larra bicolor, a wasp from Bolivia.

In 1985, researchers found and imported another parasite of the pest mole crickets. They discovered Steinernema scapterisci, a nematode, or insect parasitic worm, from Uruguay that was very effective, but had to be mass produced, Leppla said. “We got it into wide distribution across the state and saw a highly significant reduction of the mole crickets and their damage,” he said.

While the mole cricket problem has been greatly reduced, the pests have popped up in Duval, Alachua, Marion and Orange counties. The nematode is no longer available commercially but Leppla and his colleagues have created a manual that explains integrated pest management methods to mitigate the problem.

Find out more about mole crickets and how to stop them at http://edis.ifas.ufl.edu/topic_mole_crickets.

Cutline: Howard Frank,left and Tom Walker check two-part trap that uses synthesized mole cricket calls to monitor both mole crickets and the beneficial flies that locate their hosts by sounds./Marisol Amador

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By: Beverly James, 352-273-3566, beverlymjames@ufl.edu

Source: Norm Leppla, 352-273-3951, ncleppla@ufl.edu