A PRACTICAL RESEARCH DIGEST FOR TURF MANAGERS

Volume 10, Issue 6 • June 2001

¡TURFGRASS CONTROL IN THIS ISSUE

• The changing of the The Changing of the guard in white grub Guard in White Grub control insecticides 1 Organophosphate/ Control Insecticides carbamate update New product information By Kevin Mathias Natural control influence of insecticides

combination of federal regulatory rulings and economic decisions by insecticide Multiple targeting manufacturers has dramatically changed the landscape of white grub insecticides A and control strategies. At the beginning of the 1990's white grub control insecti- • Site analysis for golf cides consisted mainly of organophosphate and carbamate based chemistries with only a course development 7 few biorational products available (Table 1). As a group, the organophosphate and car- Climate bamate insecticides, have a relatively short residual activity and are highly efficacious when used in curative control programs. Topography Optimum results are attained if the products are applied in mid to late August or into September, as white grub damage is first noticed and Drainage patterns when the grubs are young and relatively small. Optimum results are Water availability As we enter the new millennium many of the cura- attained if the tive control products have been replaced by a group of and geology products are applied new insecticides. These insecticides, Merit and Mach 2, offer greater applicator safety, have less adverse effect Environmental issues in mid to late August on the environment, provide a longer window of appli- Wetlands or into September, as cation due to their extended residual activities, have minimal impact on beneficial predators, and pro- Water quality white grub damage vide excellent control (+90%) of white grubs. is first noticed and Merit and Mach 2 affect the early instar stages of • Letters to the editor. 14 white grubs and are much more effective in preventa- • From the editor. 15 when the grubs are tive than in curative control programs. A review of field young and relatively evaluations for white grub control reported in Arthro- We'll miss you, Mike pod Management Tests from 1998 to 1999 demon- small strated that applications of Mach 2 or Merit applied within the early June to early August time period pro- vided excellent control (+90%), however, if these insecticide were applied from late August through September the average level of con- trol dropped to 80%. A recent survey conducted at the 2001 Maryland Turfgrass Conference illustrates how turfgrass managers have incorporated these new insecticides into their control pro- grams (Figure 1). Merit was used by 60% of the respondents, followed by Dylox at 28%, and then Mach 2 at 19% for white grub control. TURFGRASS TRENDS

Executive Editor Sue Gibson 440/891-2729; 440/891-2675 (fax) Dylox, an organophosphate, was product is Meridian (thiomethoxam) and sgibson@advanstar. com applied as a curative control for spot treat- white grub evaluation studies have shown Managing Editor ment to sites that had not been treated excellent efficacy when applied preventa- Curt Hurler with Merit or Mach 2. tively. Field evaluations of Meridian 440/238-4556; 440/238-4116 curt@curtharler. com demonstrated excellent control (97%)

On Line Editor Organophosphate I when applied within the June to early Lynne Brakeman carbamate update August period (Table 2). However, if

Senior Science Editor The ongoing review process mandated by applied in a curative manner, late August Dr. Karl Danneberger the Food Quality and Protection Act of through September, control levels Group Editor 1996 and under the direction of the Envi- dropped to 80% for Japanese , Vern Henry ronmental Protection Agency (EPA) has masked chafers, and oriental . Production Manager continued to affect product choices for European chafer control showed an Rene' Fall 218/723-9352; 218/723-9223 (fax) turf grass insect control. Dursban's (chlor- even greater drop when used as a preven- rfall@advanstar. com pyrifos) new turfgrass labeling removes the tative, 82% control, to 22% control when

Senior Graphic designer application of this product to residential applied in a curative manner (Table 2). Jeff Landis sites and restricts applications only to golf The proposed labeling for Meridian rec- 440/891-2702; 440/891-2675 (fax) jlandis@advanstar. com course and industrial sites. It also limits ommends an application window for maximum application rates of 1 lb. white grubs 45 days before adult flight Circulation Manager Cheryl Beeman A.I./acre per season. activity to second instar development with 218/723-9271 Though never a stellar white grub con- optimal timing at peak egg hatch. Addi- Group Publisher trol product due to its tendency to bind to tional for which Meridian will be John D. Payne 440/891-2786; 440/891-2675 (fax) organic matter, Dursban was effective at jpayne@advanstar. com the 2 lb. A.I./acre rate for adult control of the black turfgrass ataenius beetle. When Corporate & Editorial Office What we must do as 7500 Old Oak Blvd. applied in early spring prior to egg laying, Cleveland, OH 44130-3369 Dursban will control the adults thus pre- turfgrass managers and Mew Subscriptions venting or reducing egg laying. 888/527-7008 researchers is to continue to Various pyrethroid insecticides such as Abstracts: 800/466-8443 Talstar and DeltaGard are now replacing improve our abilities to Reprint: 440/891-2744 Dursban for this use. Permission: 440/891-2742 predict the likelihood of Single copy or back issues: Turcam (bendiocarb), a carbamate insec- Subscription/Customer Service ticide manufactured by Aventis, will no white grub damage. 888/527-7008; (fax) 218/723-9437 Web site address: longer be produced for turfgrass insect con- www. landscapemanagement. net trol in 2001. This was a voluntary decision by the manufacturer based on economic labeled for include billbug larvae and fire considerations. Current supplies can be sold control and suppression of chinch bugs until the existing inventory is depleted. and mole crickets. ÄDVANbTAR Diazinon is the most recent product to C OMMUNICATiONS see future regulations affect its use in the Natural control influence Chairman and market place. It will lose its labeling for all of insecticides Chief Executive Officer Robert L. Krakoff lawn and garden uses beginning in 2003 Our understanding of the important role (see TurfGrass TRENDS, February 2001, which the invertebrate community plays Vice Chairman James M. Alic Pg. 15). In the mean time annual produc- in the turfgrass habitat has just started to tion levels will be reduced for the 2001- be elicited by a number of researchers. This VP-Finance, CFO & Secretary David W. Montgomery 2002 seasons. With the impending cancella- invertebrate community consists of an

Executive Vice Presidents tion of Diazinon only one insecticide, Dylox array of predatory insects such as William J. Cooke (trichlorfon), will provide effective curative (Formicidae), ground beetles (Carabidae), Alexander S. DeBarr control of white grubs. Jean-Marc Levy and (Staphylinidae). Also Daniel M. Phillips predatory (Mesostigmatidae), spi-

Vice President & New product information ders (Araneida), and a host of decom- General Counsel A new insecticide from Syngenta is posers such as (Collembola), Eric 1. Lisman planned for introduction in 2001. The mites (Orbatidae) and (Lum- Treasurer and Controller Adele D. Hartwìck ORGAIUOPHOSPATES CARBAMATES BIORATIOIUALS 1990 • Dylox • Sevin • Milky disease • Oftanol • Turcam • Mainstay • Diazinon • Dursban • Triumph • Mocap

2001 • Dylox • Sevin • Milky disease nematodes Naturalis • Diazinon* • Merit • Mach 2 • Meridian**

* DIAZINON CANNOT BE APPLIED TO GOLF COURSE TURF OR SOD FARMS ** MERIDIAN IS EXPECTED TO OBTAIN EPA REGISTRATION IN 2001

bricidae) are part of this turf grass commu- a significant reduction of predators such as nity. spiders and rove beetles for a period of six All of these invertebrate play an integral weeks. Also, work by Vavrek and Niem- role whether it be in natural control, czyk (9) demonstrated how Oftanol enhancing soil tilth and productivity or caused significant reduction to mites, offering a stable food source for various springtails and rove beetles for periods predatory groups of . ranging from 13 to 43 weeks. Other Researchers at the University of Ken- researchers (1,3,5,11) have also reported tucky (8) were first to quantity the level of on the adverse affect organophosphate and in the turfgrass community. carbamate insecticides have on the inver- Predators such as spiders, ants, rove beetles tebrate community. and ground beetles were responsible for Rove beetles have been reported to be consuming up to 73% of one of the principal egg predators of the eggs. Zenger and Gibb (10) have reported black turfgrass ataenius beetle in Michi- egg predation by the thief ant and various gan( Smitely, personal communication). rove and ground beetles to reach mortali- Their populations seem to be relatively ty levels of 65%. stable in habitats which have an adequate The use of the older, broad spectrum food supply of springtails. However, if insecticides have been shown to have an populations decline, then rove adverse effect on a number of different beetle populations will also decrease thus predator groups and various decomposer resulting in lower predation of ataenius groups. Cockfield and Potter (2) reported eggs. Dursban and Oftanol applications caused The interrelationship of predator-prey relationships at a lower level provides species (4). This synergistic effect may be insight into the complexity of the turfgrass due to the way Merit alters the defensive habitat and in its natural control system behavior of white grubs to which can be easily altered by the appli- attack. No adverse effect was observed to cation of broad spectrum insecticides. the entomopathogenic nematode, Het- The new soil insecticides such as Mach erorhabditis marelatus, when Mach 2 was 2 and Merit are reported to have less applied (7). adverse effect on beneficial insects, mites, Since Mach 2 and Merit have been spiders, and earthworms when compared shown to have a minimal impact on the to the older curative control products such non target invertebrate community nat- as the organophosphate and carbamate ural control by way of predation and the insecticides. Kunkel et.al. (5) found that various other important roles which Mach 2 had no adverse effect on beneficial these beneficiáis play is not compro- invertebrates such as earthworms, spring- mised. , mites, and various insect predator groups. Multiple targeting Merit caused short-term reductions, The possibility of controlling more than though often slight, for earthworms, one turfgrass insect pest with these new springtails, hister beetles and larvae of insecticides is possible due to their long ground and rove beetles. Work by Zenger soil residual activities. For example an and Gibb (11) found that Merit and Mach application of Mach 2 if timed properly 2 did not adversely affect ants and in par- could control sod webworm or cutworm ticular the thief ant, , to larvae while also providing excellent prey upon Japanese beetle eggs. However, white grub control. However for this to when Oftanol and Diazinon were applied occur the turfgrass manager must be a reduction in ant populations occurred aware of the life histories of the major for a period of 4-8 weeks which resulted insect pests within their region. in lower white grub egg predation. At Maryland, black trapping has A synergistic effect has been reported been done at various golf courses since for Merit and the entomopathogenic 1996. A number of turfgrass insect pests nematode, Heterorhabditis bacteriophora, are collected and counted throughout the for controlling several masked chafer season and then posted on our home page (http ://iaa.umd.edu/umturf/umturf.html ). Adult scarab beetles such as masked 60 chafers, the black turfgrass ataenius beetle, the oriental beetle, June beetles, and the 50 asiatic garden beetle along with the Lepi- dopteran pests such as sod webworms and 40 black cutworms are monitored from May through August. 30 The light trap data can provide excel- lent insight into the proper timing to max- 20 imize control with the new preventative insecticides. Adult sod webworm and 10 masked chafer cumulative counts have been tabulated over the past four years 0 (Figure 2). If Mach 2 were to be used sev- Merit Dylox Mach 2 Sevin Dursban Turcam eral windows of application can be evalu- ated. For example if the major goal is to Figure 1. Survey results demonstrating the choice of white grub control white grubs then the timing of control used by turfgrass professionals in Maryland for the 2000 Mach 2 could occur between mid-June to season. The survey was conducted at the 2001 Maryland Turfgrass Conference. early August. MEAN % CONTROL MEAN % CONTROL WHITE GRUB SPECIES * PREVENTATIVE ** CURATIVE

i Japanese beetle 97% 80% i Masked chafers 97% 80% i Oriental beetle 97% i European chafer 82% 22%

* PREVENTATIVE CONTROL APPLICATIONS OCCURED BETWEEN MID-JUNE TO MID-AUGUST PERIOD ** CURATIVE CONTROL APPLICATIONS OCCURRED BEWTWEEN LATE AUGUST THROUGH SEPTEMBER

1800 1600 1400 1200 1000 800 600 400 200

0

5/18/99 6/1/99 6/15/99 6/29/99 7/13/99 7/27/99 8/10/99 8/24/99 9/7/99

Figure 3. Optimum timing for targeting of Mach 2 for sod webworm and masked chafer control based on light trap results from 1996 to 1999 at Westwood C.C.

However if one wanted to control 1 st Summary sod webworm larvae and masked chafer With the changing of the guard from the grubs then an application timed between older broad spectrum insecticides to the mid to late June would control both of newer more selective insecticides, turf- these turfgrass insect pests (Figure 2). grass professionals will now see improved Another possible multiple targeting exam- levels of control, greater applicator safety ple is the use of Merit to control billbug and less interference of natural control. larvae and white grubs by timing an appli- However, one major issue with the cation in mid to late May. application of these new insecticides is their use in preventative control programs. If we rely too heavily on these products Dr. Kevin Mathias has served since 1979 as the Turfgrass Lecturer and Advisor for the and apply them annually to large turfgrass Turfgrass and Golf Course Management sites without regards to the principles of Program at the Institute of Applied integrated pest management then the like- Agriculture at the University of Maryland. It is lihood of resistance and enhanced a two-year program offering certificates in biodegradation of these products will Golf Course and Turfgrass Management, occur. Horticulture, Equine Management and What we must do as turfgrass managers Agriculture Business. He received his Ph.D. in and researchers is to continue to improve 1988 from the Entomology Department at the University of Maryland. His major respon- our abilities to predict the likelihood of sibilities are in program development and white grub damage. teaching within the Institute of Applied Greater emphasis on record keeping as Agriculture, as well as in extension presenta- to where and when white grub damage tions, Web development of the Turf Online occurs, black light and trap- homepage, turfgrass insect monitoring and ping, and a better understanding of scarab as an advisor to the Maryland Turfgrass (white grub) behavior are needed. Only Council. then can we better identify high risk sites and apply judicious applications of these new insecticides.

REFERENCES Entomol. 91:618-623. tion on Japanese beetle (Coleoptera: ) eggs Braman, S. K., and A. F. Pendley. Kunkel, B.A., D.W. Held, and D. and fall armyworm (Lepidoptera: 1993. Relative and seasonal A. Potter. 1999. Impact of Noctuidae) pupae in turfgrass. J. abundance of beneficial arthro- halofenozide, imidadoprid, and Econ. Entomol. 86: 871-878. pods in centipedegrass as influ- bendiocarb on beneficial inverte- enced by management practices. brate and predatory activity in Vavrek, R. C. and H. D. Niemczyk. J. Econ. Entomol. 86:494-504. turfgrass. J. Econ. Entomol. 1990. Effect of isofenphos on 92:922-930. nontarget invertebrates in turf- Cockfield, S. D., and D. A. Potter. grass. Environ. Entomol. 1983. Short-term effects of insec- Lopez, R., and D. A. Potter. 2000. 19:1572-1577. ticidal applications on preda- Ant predation on eggs and ceous arthropods and oribatid larvae of the black cutworm Zenger, J.T. andT. G. Gibb. mites in Kentucky bluegrass turf. (Lepidoptera: Noctuidae) and Submitted for publication. Environ. Entomol. 12:1260-1264. Japanese beetle (Coleoptera: Identification and impact of egg Scarabaeidae) in Turfgrass. predators of lurida Cockfield, S. D. and D. A. Potter. Environ. Entomol. 29:116-125. Bland and Popillia japónica 1984. Predation on sod Newman (Coleoptera: webworm (Lepidoptera: Mannion, C. M.., H. E.Winkler, D. Scarabaeidae) in turfgrass. Pyralidae) eggs as affected by I. Shapiro, and T. Gibb. 2000. chlorpyrifos application to Interaction between halofenozide Zenger, J. T. and T. G. Gibb. Kentucky bluegrass turf. J. Econ. and the entomopathogenic Submitted for publication. Impact Entomol. 77:1542-1544. nematode Heterorhabditis mare- of four insecticides on Japanese latus for control of Japanese beetle (Coleoptera: Scarabaeidae) Koppenhofer, A. M., and H. K. beetle (Coleoptera: Scarabaeidae) egg predators and white grubs in Kaya. 1998. Synergism of imida- larvae. J. Econ. Entomol. 93:48- turfgrass. cloprid and an entomopatho- 53. genic nematode: a novel approach to white grub Terry, L. A., D. A. Potter, and P. G. (Coleoptera: Scarabaeidae) Spicer. 1993. Insecticides affect control in turfgrass. J. Econ. predatory arthropods and preda-