Article of the Month - June 2002 - The Mole Cricket Nematode is Spreading Fast to Control Mole Crickets in South-Central Florida Pastures

South Florida Beef - Forage Program

"Article of the Month"
June 2002

The Mole Cricket Nematode is Spreading Fast to Control Mole Crickets in South-Central Florida Pastures

Martin B. Adjei (Ona), Herb Harbin (Osceola), Lockie Gary (Hardee), Jim Selph (DeSoto), Joe Walter (Brevard), Dennis Mudge (Orange), Travis Seawright (Manatee) and Gary Mikulecky (Highlands), UF/IFAS

We applied 22 billion beneficial nematodes to more than 20 ranches in south-central Florida to suppress damaging mole crickets and bring economic relief to livestock producers.

In September of 2000, nematodes were applied in strips to distribute 0, 1/8, 1/4, and 1/2 billion nematodes per acre to determine the rate of nematode spread within the mole crickets on a Polk City pasture. Number of mole crickets trapped were recorded weekly and samples of mole crickets were analyzed for nematode infection monthly. Mole crickets are very mobile and infected mole crickets spread the nematodes throughout that pasture within a few months. In the fall of 2001, the entire pasture got flooded for several days and the adult mole crickets relocated. However, results show that the nematodes persisted in the soil through the fall and subsequent winter months and have resumed breeding in adult mole crickets during spring 2002. For April 2002, percentage nematode infection at the Polk city site ranged from 30 to 50%. Mole cricket numbers have declined by 65-80% and pasture grass has recovered by 45-100%.

To promote widespread distribution of these mole cricket-killing nematodes, the Florida Legislature provided UF-IFAS Mole Cricket Task Force, through FDACS-DPI, $300,000 in 2001. The purpose of those funds was to reestablish a l research/demonstration Mole Cricket State Program and conduct an area-wide distribution of the nematodes in Florida.

In the first phase of the State Program, Nematac S donated by MicroBio, was applied in spring 2001 to seven ranches covering Hardee, DeSoto, Pasco and Polk Counties. Nematodes were applied with a slit-injector in strips at the 1/4 and 1/8 billion/A. We observed no differences between the effects of 1/8 and 1/4 billion rates of nematode application on infection level. The nematodes applied in spring 2001, persisted in the soil during summer, survived the winter and spread within the adult mole cricket population this spring. Percentage of trapped mole crickets infected with nematodes when averaged over March and April 2002 are as follows: H. Keller (Hardee) 50%; Peace River Ranch (Hardee) 75%; L. Bryant (Hardee) 25%; W. Wise (DeSoto) 20%; Al Bar (Pasco) 70%; M. Nutt (Pasco) 50%; and H. Combee (Polk) 20%.

In the second phase of the program, nematodes were applied to pasture and sod farms on 13 sites in south-central Florida. Nematac S product was applied in strips only at the 1/8 billion nematodes/A at all sites during fall 2001. The nematodes have spread on pasture from February to April, 2002. For the pasture sites, average March and April ratings for percentage trapped mole crickets infected with nematodes are: D. Barber (Osceola) 71%; Deseret (Orange) 20%; T. Kibler (Manatee) 35%; M. Taylor (Manatee) 45%; J. Payne (Highlands) 40%; Hollingsworth (DeSoto) 80%; B. Keating (Hardee) 65%; J.B. Starkey (Pasco) 30%; and Yates (Orange) 0%. Similar infection ratings for the sod farms are: Duda (Polk) 74%; Schrodder & Manatee (Manatee) 47%, Bethel (55%) and H & H (Osceola) 10% .

Conclusions
In all three studies, the percentage of trapped mole crickets infected with the nematodes increased steadily from winter through spring in 2002. Any mole cricket infected is expected to die within a few days. The nematodes have done a good job in breeding within the mole crickets and their offspring continue to attack other adult mole crickets in 19 of the 21 sites. Nematodes have persisted in the soil through flood and cold winter months. There has been dramatic recovery of pastures in most cases. We will continue to monitor the spread and grass recovery. Meanwhile, the nematodes became commercially available to ranchers and sod growers this spring and marketing information may be obtained from Becker Underwood‘s local representative, Gabe Diaz-Saavedra, at 941-358-9091. Information on application can be obtained from your local extension agent or from the Range Cattle REC at 863-735-1314 ext 211.

To responed to the "Article of the Month" -
The Mole Cricket Nematode is Spreading Fast to Control Mole Crickets in South-Central Florida Pastures

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