Mole cricket managementusing a soil fumigantLong used in agriculture, 1,3-0 is being tested for controlling molecrickets in turf.

J. Bryan Unruh, Ph.D., and Darin W. Lickfeldt, Ph.D.

Mole crickets have long been trou-blesome pests in turf-covered venues,particularly in the southeastern UnitedStates. Imported from South America inthe early 1900s, mole crickets damageturfgrass in several ways. They tunnelthrough the soil near the surface, loos-ening the soil and leaving the grassuprooted. As the soil dries, the rootsdesiccate and turf death ensues. Molecrickets also cause direct injury as theyfeed on grass roots, causing thinning ofthe turf and inevitably leading to baresoil. Indirect injury also occurs whenpredatory animals such as armadillosand opossums seek their nightly meal ofthese soil-borne insects.

Mole crickets are extremely prolific.Each spring, overwintered adultsemerge, fly around and mate and thendeposit eggs in chambers hollowed outin the soil. Most chambers are found inthe upper 6 inches of soil, but cool tem-peratures and/or dry soil result inchamber construction at greater depths.After hatch, the young nymphs escapefrom the egg chamber and burrow tothe soil surface in search of food. Theseyoung mole crickets begin feeding on

roots, organic material and other smallorganisms, including insects.

During warm weather, most molecricket feeding occurs at night afterrain showers or irrigation events.During the day mole crickets stay intheir permanent burrows and mayremain there for long periods when theweather is unfavorable. Adult molecrickets are strongly attracted to lightsduring their spring flights, and thereare reports of mole cricket sightings onwell-lit, offshore oil rigs.

Mole cricket controlControl of mole crickets has largely

been accomplished with syntheticinsecticides (5,6) and, more recently,with biological control agents such asthe entomopathogenic nematodeSteinernema scapterisci and theBrazilian red-eyed fly, Ormia depleta(4). Recently, however, severalresearchers have been evaluating 1,3-dichloropropene, a soil fumigant, for itsusefulness in controlling mole crickets.

l,3-dichloropropene (l,3-D) wasdeveloped in 1943 and was the firsteffective and inexpensive nematicide

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• Mole crickets kill turf byfeeding on roots and byuprooting grass throughtunneling.

• Long used in agriculture,the pesticide I ,3-dichloro-propene has recently beentested on turf under anExperimental Use Permit.

• In comparative tests withproducts used to controlmole crickets, I ,3-D's per-formance was similar tothat of the other products.

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for general field use (2). In turf, 1,3-Dwas tested for nematode control inbermudagrass turf in 1953 (1). Overthe years, researchers and practitionershave noted that 1,3-D (sold under theagricultural trade name, Telone II) pro-vided not only exceptional control ofnematodes, but also control of somesoil-borne insects (3). Therefore, DowAgroSciences has been in the process ofdeveloping turf use labels for 1,3-D.Tested under an experimental use per-mit, 1,3-D (turf trade name, Curfew)

Proper irrigation and fertilization promote healing of coulter injury incurredduring soil injection of 1,3-0 fumigant. Coulter injury is shown at threedays after treatment (top); the healed turf is shown at two weeks after treat-ment (bottom).

has been very effective when injectedinto the soil under a turfgrass sod fornematode management. However, tosubstantiate the claims of mole cricketand ancillary insect control, extensivetesting has been conducted since 1999.

Research projectsTrials have been conducted each

summer since 1999 to determine theefficacy of 1,3-D for insect control inFlorida. In all the studies, three or fourreplications of relatively large plots(~1,500 square feet) were used, and theapplications were made using a tractor-driven coulter/shank injection rig. 1,3-D was injected to a depth of at least 6inches and the coulters/ shanks werespaced 12 inches apart. Tests have beenconducted on golf course Tifwayberm udagrass fairways and drivingranges maintained at 0.5 inch. Becauseuse of 1,3-D requires a 24-hour re-entry interval and a lOa-foot setbackfrom an occupied structure (such as aschool, hospital, business or residence),care was given to assure compliancewith these regulations. Nitrogen ratevaries from location to location.

Sandestin Golf and Beach Resort - 1999Methods. A trial was conducted at

the Sandestin Golf and Beach Resort inDestin, Fla., in the Florida panhandle,in summer 1999 to determine the levelof turf injury that 1,3-D might causeversus the level of turf injury caused bythe application equipment. 1,3-D (9.4SL formulation: 94 percent 1,3-dichloropropene) was applied on July 7,at 5 gallons per acre, using the equip-ment described above. The fumigantwas injected at 4, 6 or 8 inches belowthe turf surface. To assess the turf injuryfrom the equipment alone, plots weretreated in a similar manner, withoutapplying the fumigant. An untreatedcontrol was also included.

Results. Regardless of rating date, nosignificant differences were notedamong application depths or betweenplots treated with 1,3-D or equipmentonly (data not shown).

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Effect of 1,3-0 and chlorpyrifos on turf quality

Bars labeled with the some leiter indicate values that are not significantly different from one another. The trialwas conducted at Fort Walton Beach (Fla.) GC by J. Bryon Unruh, University of Florida, Joy.

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69

• Chlorpyrifos (2% a.i.)• Untreated

Days after treatment

39

Days after treatment

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39

• 1,3-0 5 gallons/acre• 1,3-0 10 gallons/acre

• 1,3-0 5 gallons/acre • Chlorpyrifos (2% a.i.)• 1,3-0 10 gallons/acre • Untreated

2

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Bars labeled with the some letter indicate values that are not significantly different from one another. The trial wasconducted at Fort Walton Beach (Fla.) GC by J. Bryon Unruh, University of Florida, Joy.

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Ft. Walton Beach Golf Club - 2000Methods. A trial was conducted at

the Ft. Walton Beach (Fla.) Golf Club inthe Florida panhandle in summer 2000to determine whether 1,3-D would pro-vide effective control of mole cricketswhen soil-injected on a golf course dri-ving range. Using the equipmentdescribed above, 1,3-D was applied at 5and 10 gallons per acre on June 22. As acomparative treatment, chlorpyrifos(Dursban Coated Granules, 2 percenta.i.) was applied at 200 pounds/acre.

Results. At 20 and 39 days after treat-ment (DAT), 1,3-D at both 5 and 10 gal-lons/acre provided mole cricket controlthat was not significantly different fromthe control provided by chlorpyrifos. By69 DAT,however, l,3-D control of molecrickets diminished to 57 percent for the5-gallon rate and 70 percent for the 10-gallon rate, while chlorpyrifos contin-ued to provide 85 percent control.

Some surprising observations werenoted with turfgrass quality, however.At 39 DAT, both rates of l,3-D hadunacceptable turf quality, attributedlargely to burn associated with thefumigant. By 69 DAT, turf quality inplots treated at the 5-gallon rate did notdiffer from turf quality in the untreatedplots. Turf quality in plots treated at thela-gallon rate was significantly belowthat of the untreated plots. The treatedarea was a driving range, and the turfhad received inadequate irrigation andonly minimal fertilizer application sothat it did not have the neededresources to recover from the applica-tion injury.

Bottom line. Results from this studyshowed that chloropyrifos and 1,3-Dcan control tawny mole crickets effec-tively. Results from this trial alsorevealed the importance of optimal

Bottom line. A minimal level ofinjury (necrosis or browning of theturf) occurred where the coulter cut theturf and the fumigant was injected .However, after two weeks, the brown"cut lines" were hardly noticeable andwere typically greener.

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Tawny mole cricket control in Winter Garden, Fla.

Bars labeled with the some letter indicate values that are not significantly different from one another. The trialwas conducted at Shoal River CC, Crestview, Fla., by J. Bryon Unruh, University of Florida, Joy.

Winter Garden, Fla. - 2001Methods. A trial was conducted at

Orange County National Golf Center inWinter Garden, Fla., to determinewhether soil-injected 1,3-D wouldeffectively control mole crickets on agolf course fairway. On May 15, 2001,1,3-D was applied at 5 gallons/acreusing the equipment described above.As a comparative treatment, chlorpyri-fos (2 percent a.i.) was applied at 200pounds/acre.

Results. As in the other studies, 1,3-Dprovided greater than 80 percent con-trol of mole crickets for up to 69 DAT,which was not significantly different

Shoal River Country Club - 2001Methods. A trial was conducted at

Shoal River Country Club in Crestview,Fla., in summer 2001 to determinewhether soil-injected 1,3-D would pro-vide effective control of mole cricketson a golf course fairway. Using theequipment described above, 1,3-D wasapplied at 5 and 10 gallons per acre onMay 29. As a comparative treatment,fipronil (Chipco Choice, 0.0125 G) wassurface broadcast at 12.5 pounds/acre.

Results. On all three rating dates (31,51 and 79 DAT), there were no signifi-cant differences in mole cricket controlamong all the treatments. In this studymole cricket control with 1,3-D wasmore variable than that achieved withfipronil, an industry standard.

Bottom line. 1,3-D is a contact soilfumigant, killing biological organismsthat come into contact with it.Furthermore, environmental monitor-ing research has shown that there is lit-tle to no residual material left in the soil.Therefore, if 1,3-D is applied beforemole cricket spring mating flights andsubsequent egg laying, these insectsprobably will not be controlled becausethe fumigant will have dissipated.

pre- and post-application cultural prac-tices. Irrigation and nutrient manage-ment must be adequate to offset thelimited injury that can be observedwhen using 1,3-D.

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Bars labeled with the some letter indicate values that are not significantly different from one another. The trial wasconducted at Orange County Notional GC, Winter Gorden, Fla., by TotalTurf Consulting llC.

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60 GeM • February 2002

from the control shown by chlorpyrifosfor the duration of the trial. For 97DAT, turf quality in l,3-D-treatedplots was significantly greater thanthat in plots treated with chlorpyrifos,but no treatment differences werenoted in plots at 141 DAT (data notshown). These plots also contained asignificant number of sting nematodes(Belonolaimus longicaudatus) that werecontrolled by l,3-D (data not shown).

Bottom line. Trials conducted at geo-graphically different locations per-formed similarly. By using a broad-spectrum soil fumigant, golf coursesuperintendents can gain control ofseveral soil-borne pests.

ConclusionsThese research trials, which were

conducted across a large geographicregion, demonstrate that 1,3-D soilfumigant can be successfully usedto control soil-borne pests withoutcausing disruption to the turf. Oneshould expect a minimal level ofinjury where the coulters cut the turf,but after two weeks, this should nolonger be evident.

Optimal pre- and post-applicationcultural practices such as proper irriga-tion and nutrient management shouldbe performed to promote recoveryfrom injury by coulters. It is criticalthat irrigation or precipitation totalingYt to 1,0 inch of water occurs as soon aspossible following application. Thisallows 1,3-D soil fumigant to dissipatethrough the soil so that it comes intocontact with the soil-borne pests. Soilmoisture at the time of applicationshould be adequate to support goodturf growth and maintained at thatlevel for at least seven days. It is alsoadvisable to fertilize a week before the1,3-D application.

For the best level of mole cricketcontrol, application of 1,3-D shouldcoincide with peak egg hatch. Failureto do so will likely result in lessmole cricket suppression. Althoughthe active ingredient in the 1,3-D soilfumigant dissipates very quickly,

mole crickets usually avoid treatedareas for 60-90 days after application onsites treated under the experimentaluse permit. The mechanism of molecricket suppression is currently beinginvestigated .•

AcknowledgmentsThis research was supported by the Florida

Agricultural Experiment Station and in-kindfinancial support from Dow AgroSciences LLC.We thank Chris Hood and Clint White fortechnical assistance, and, for their assistance andsupport of the research, we thank golf coursesuperintendents George Kleinpeter, SandestinGolf and Beach Resort; David VonSchmittou,Fort Walton Beach GC; Radford Shirley, ShoalRiver CC; and Carl Benedict, Orange CountyNational Golf Center.

Literature cited1. Heald, C.M., and V.G. Perry. 1969. Nematodes

and other pests. p. 358-369. In: Turfgrass sci-ence. American Society of Agronomy,Madison, Wis.

2. Noling, J.w. 1996. Role of soil fumigants inFlorida agriculture. p. 14-24. In: J.N. Seiber,J.A. Knuteson, J.E. Woodrow, N.L. Wolfe, M.V.Yates and S.R. Yates (eds.). Fumigants:Environmental fate, exposure, and analysis.Proceeding of 1996 American ChemicalSociety Symposium, Chicago, Aug. 20-25.ACS, Washington, D.C.

3. Noling, J.w., and J.O. Becker. 1994. The chal-lenge of research and extension to define andimplement alternatives to methyl bromide.Journal of Nematology (Supplement)26( 4S):573-586.

4. Parkman, J.P., J.H. Frank, T.J. Walker and D.J.Schuster. 1996. Classical biological control ofScapteriscus spp. (Orthoptera: Gryllotalpidae)in Florida. Environmental Entomology25(6): 1415-1420.

5. Unruh, J.B. 2000. Mole cricket managementin fine turf. Florida Turf Digest 17(5):22-26.

6. Xia, Y., and R. Brandenburg. 2000. Treatyoung mole crickets for reliable insecticideresults. Golf Course Management 68(3 ):49-51.

J. Bryan Unruh, Ph.D. (e-mail: jbu@mail.ifas.ufl.edu), is an assistant professor at theUniversity of Florida's Institute of Food andAgricultural Sciences, West Florida Research andEducation Center near Jay, Fla. Darin Lickfeldt,Ph.D., is a field research biologist for DowAgroSciences LLC in Fayetteville, Ga.

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