Three pasture grasses are commonly planted in Florida: Pensacola bahiagrass (Paspalum notatum Flügge), Florona stargrass [Cynodon nlemfuensis Vanderyst (Bogdan)], and Floralta limpograss [Hemarthria altissima (Poir.) Stapf and C. E. Hubb]. Bahiagrass is a warm season perennial grass native to South America and is commonly grown in Florida pastures because it can tolerate a wide range of soil conditions, can produce moderate yields on infertile soils, and is easily started from seed. It is mainly planted for beef cattle pastures but may also be planted for seed production, hay, sod, and as an intermediate in crop rotation systems. Between the years 1996–1999, it was estimated that 300,000 acres of bahiagrass pastures were destroyed and the value of hay lost annually was around $6 million as a result of mole crickets in south-central Florida (Mossler 2008). Research with bahiagrass indicated that it was the most susceptible grass cultivar to mole cricket damage of the three commonly planted. The grass produces an underground rhizome capable of storing high starch concentrations that may serve as a large energy source for the mole crickets. Damage to bahiagrass is largely influenced by soil acidity and the amount of nitrogen fertilization which in combination can weaken the root–stolon system. Careful management practices to reduce overgrazing, reduce nitrogen fertilization, and maintain a near neutral soil pH can be helpful in reducing severe mole cricket damage.
Florona stargrass is a warm-season perennial grass that grows fast and spreads rapidly. It is mainly planted in Florida for forage production. The grass grows well in cool conditions, and mole crickets have not been observed as a considerable problem. Damage to the grass is apparently not largely influenced by nitrogen fertilization and soil acidity, as is the case with bahiagrass.
Floralta limpograss is native to southern Africa and is not extensively planted in the pastures of Africa. Limpograss was first introduced into Florida in 1964 as a forage grass, but an adapted strain, Floralta, may persist and provide good yields as a pasture grass under proper grazing management. Limpograss can grow in moderately acidic soils and is most productive under cooler conditions. Comparable to stargrass, damage to limpograss is not influenced by fertilization and soil acidity.
Controlling mole crickets with chemicals in pastures presents a problem to cattle farmers because using toxic insecticides may be harmful to the livestock. In order to reduce the use of insecticides it is essential to recognize mole cricket presence by detecting the galleries they produce and to focus control efforts on the intensely infested areas in hopes of reducing the spread of the mole crickets. Toxic baits can be used in the summer and early fall, but the local County Extension Service should be consulted before proceeding in order to obtain the most current information.
A common cultural practice to reduce the amount of mole cricket damage is to monitor the amount of the grass leaf remaining to prevent significant plant stress. Leaving a “stubble” of the grass leaf will allow for the plants to remain healthy and have a better chance at resisting mole cricket damage (Dr. Findlay Pate, personal communication). One agronomist claims damage to bahiagrass can be reduced by leaving a stubble of 4 inches, but this is very hard to achieve in dry spring months. When trying to reduce the damage by mole crickets on any pasture grass, overgrazing by livestock should be avoided at all costs to decrease the risk of severe or permanent damage. In addition, depending on the type of grass planted, overfertilization should be avoided, and methods to maintain a healthy soil acidity for the grass should be considered.
Chemical control lost its appeal when compared to using biological control agents to suppress mole crickets in pastures. Biological control provides permanent area-wide control once the organism is established, resulting in lower costs for the pasture manager and a reduction in the release of harmful pesticides into the environment.
In some parts of Florida, additional natural enemies of the pest mole crickets were released and became established. One is a parasitoid fly Ormia depleta, established everywhere south of Ocala. The other is a parasitoid wasp Larra bicolor, known to be established in at least 46 counties, including almost everywhere in north and central Florida. These two parasitoids, with a little help from deliberate plantings of the adult food source (nectar-producing plants) for the wasp, have shown much promise in Florida and may suppress pest mole cricket populations substantially in pasture grasses. The adult food source for the fly is inadequately investigated. The wasp is now distributed also in southern Georgia, and in coastal Alabama and Mississippi.