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A I wuvr WA ,— M LL ‘ V‘LLLw LV ILIIVLIIIIIIIL'IIVLIIL THESIS Itifliil‘l’itWu]Iiifl'iiflimmimmifii 3 1293 01691 4503 This is to certify that the thesis entitled Effects of Maintenance and Cultural Practices on Ataenius spretulus Haldeman (Coleoptera: Scarabaeidae) and Their Natural Enemies on Golf Course Turf presented by Nikki Lynn Rothwell has been accepted towards fulfillment of the requirements for Master degree in Science Major professor {ll/4% Date December 19, 1997 0-7639 MS U i: an Affirmative Action/Equal Opportunity Institution LIBRARY Michigan State University PLACE 1N RETURN BOX to remove this checkout from your record. To AVOID FINES return on or before date due. DATE DUE DATE DUE DATE DUE sgifié’fz‘bo‘i 1/98 macros-mm“ EFFECTS OF MAINTENANCE AND CULTURAL PRACTICES ON ATAENI US SPRETULUS HALDEMAN (COLEOPI'ERA: SCARABAEIDAE) AND THEIR NATURAL ENEMIES ON GOLF COURSE TURF By Nikki Lynn Rothwell A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology 1997 ABSTRACT EFFECTS OF MAINTENANCE AND CULTURAL PRACTICES ON ATAENIUS SPRETULUS HALDEMAN (COLEOPI'ERA: SCARABAEIDAE) 0N GOLF COURSE TURF By Nikki Lynn Rothwell Field and laboratory studies were conducted to investigate why Ataenius spretulus Haldeman and Aphodius granarius (L.) infest golf course fairways in Michigan. A survey provided information on the distribution of A. spretulus and A. granarius on courses across the state as well as information on cultural practices. A follow-up sampling procedure for A. spretulus showed the larvae to be 4-fold more abundant in the fairway than the rough. A field experiment tested the affects of chlorothalonil on A. spretulus adults and larvae and predators. Chlorothalonil had no affect on the monitored insects or the Bacillus popilliae Dutky infection levels of A. spretulus larvae. A mowing study evaluated the effect of turf height on A. spretulus and its predators. In 1996, A. spretulus larvae were most prevalent in plots that were mowed to fairway height in 1995. In 1997, the highest populations of A. spretulus larvae were found in plots mowed to fairway height in 1996 and history had no affect on the location of larvae. In both years, staphylinids were most abundant in rough mowed turf. Twice as many A. spretulus larvae were infected with B. popilliae in the rough-mown turf compared with fairway-mown turf. This thesis is dedicated to my grandmother, Norma B. Rollet, a woman who always told me that I could do or be anything I dreamed, simply because I was me. iii ACKNOWLEDGMENTS I wish to express my appreciation to my advisor Dr. Dave Smitley, who always was willing to take the time for me throughout this sometimes seemingly impossible endeavor. My graduate committee, Drs. Edward Grafius, Deborah McCullough and Paul Rieke, who have provided me with immense assistance throughout my stay here at MSU. I would like to express my deepest regard for my whole committee not only as research scientists, but as incredible extension specialists. From seeing the differences you all have made in your respective commodities has inspired me to pursue a career involving extension. Thank you to the Michigan Turfgrass Foundation for the funding that made my whole project possible. Also, thanks to all of the superintendents around the state of Michigan who supported my entomological research. Doug Palm and Cattails Golf Club deserve a pat on the back for all of their help; you will always be remembered as the superintendent who let me mow his fairway THAT way. I thank Dr. Michael Klein for his help with the identification of Bacillus popilliae in Ataenius spretulus. Terry Davis for his statistical knowledge. To all of our students who began as our workers, but soon became my friends: Sarah, Mark, Rhonda, Molly, Shannon, Tracy, Pabitra, Gloria and Christy. I will always think of you all when it rains on Mondays. Mike Bernie, a thank you from all of our fingers who you saved by inventing the vial puller. Drs. Fred Stehr, George Bird, Trey Rogers for the exposure to great classes in which I have learned so much. Also, hats off to the office ladies for their outstanding work and friendly faces in the department. iv Thanks to the entomology graduate students, whose camaraderie at the Peanut Barrel was always appreciated, if not desperately needed. I am sure you will all think of me when you drive by at midnight and wonder if I am still there. To all of the fourth floor entomologists, especially John Wilterding, Jim Zablotny and Dr. WALT (water, air, light, temperature) Pett, thank you for answering my never ending 'rookie' entomologist questions with a smile. To the guys in the turf department, thank you for inviting a woman entomologist to join your group. Not only was I invited to join as a scientist, I was also welcomed as a friend. To JC Sorochan, a friend who never tired in helping me find the silver lining. To my friends outside of the department who have always been quick to call, e-mail or visit to lend a kind word of encouragement during this time, you will always be close to my heart no matter how far apart we are. To my dearest friend Rebecca, I can only offer a mere thank you in response to all of the encouragement and support you have Shown me over the past 2 years. No matter how hard I look, I will never find a friend as true as you. Lastly, but certainly not least, thank you to my family, who all have continually supported me in my endeavor. To my hermanito, Joshua, for continually making me laugh and for his never failing pride in his big sister. To my gramma, Big Norm, who always believed in me, even when I did not believe in myself. I will always be proud to be a 'little Norma'. To my dad, my #1 fan, for his belief that 'anything boys can do, girls can do better'. Also, for instilling in me the value of hard work and perseverance. To my mom, the most incredible woman I have ever met; from her generosity and openmindedness, she has inspired me to be who I am today. I can only hope that I can offer as much unselfish love and friendship to others as she has to me. All that I am or who I hope to be, I owe to my family. TABLE OF CONTENTS LIST OF TABLES .................................................................................. viii LIST OF FIGURES ................................................................................. ix INTRODUCTION .................................................................................... 1 Literature Cited ............................................................................... 6 CHAPTER] SURVEY OF MICHIGAN GOLF COURSE SUPERINTENDENTS FOR ATAENI US SPRETULUS AND APHODIUS GRANARIUS INFESTATIONS AND FOLLOW-UP FIELD SAMPLING OF SELECTED COURSES Abstract ...................................................................................... 10 Introduction ................................................................................. 12 Materials and Methods ..................................................................... 13 Results and Discussion .................................................................... 14 Literature Cited ............................................................................. 18 CHAPTER2 EFFECTS OF CHLOROTHALONIL ON ATAENI US SPRETULUS ADULTS, LARVAE, AND ON THEIR NATURAL ENEMIES Abstract ......................................................................... '. ............ 27 Introduction ................................................................................. 28 Materials and Methods ..................................................................... 29 Results and Discussion .................................................................... 31 Literature Cited ............................................................................. 34 CHAPTER3 IMPACT OF MOWING GOLF COURSE TURF ON ATAENI US SPRETULUS HALDEMAN AND ITS NATURAL ENEMIES Abstract ...................................................................................... 43 Introduction ................................................................................. 45 Materials and Methods ..................................................................... 47 Results and Discussion .................................................................... 49 Literature Cited ............................................................................. 56 CHAPTER4 LABORATORY AND GREENHOUSE EXPERIMENTS: l) OVIPOSITION CHOICE STUDY OF ATAENIUS SPRETULUS ON 4 DIFFERENT TYPES OF GRASSES Vl COMMONLY FOUND ON GOLF COURSES IN MICHIGAN AND 2) ADULT PHILONT HUS FEEDING TESTING ON A. SPRETULUS AND APHODI US GRANARI US ADULTS AND LARVAE IN SIMULATED TURF SYSTEM Abstract ...................................................................................... 72 Introduction ................................................................................. 74 Materials and Methods ..................................................................... 75 Results and Discussion .................................................................... 76 Literature Cited ............................................................................. 78 Introduction ................................................................................. 80 Materials and Methods ..................................................................... 80 Results and Discussion .................................................................... 82 Literature Cited ............................................................................. 83 CONCLUSIONS .................................................................................... 85 LIST OF REFERENCES .......................................................................... 88 APPENDD( Appendix 1: Record of Deposition of Voucher Specimens* ......................... 92 Appendix 2: 1995 Survey to 250 Golf Course Superintendents in Michigan ...... 94 vii LIST OF TABLES CHAPTER 1 Table 1 - Relationship of pesticide applications and cultural practices to the number of A. spretulus larvae found at 20 golf courses in Michigan in 1996 ................................ 20 CHAPTER 2 Table 1 - Two factor AN OVA of mowing height and chlorothalonil treatment in a field experiment testing the mean number of A. spretulus adults and larvae, staphylinid adults, . and carabid adults from pitfall traps and soil sampling methods of golf course plots ................................................................................................... 37 CHAPTER 3 Table 1 - Nitrate and ammonium soil concentrations in August of 1996 and in July and September of 1.997. All thatch was removed from soil samples. Sample depth varied between 5 - 15 mm .................................................................................. 60 Table 2 - Influence of the old fairway and rough before the mowing pattern was changed in April of 1996. Data are means i SE of nitrate and ammonium (ppm) in the old (1995) rough and fairway. All thatch was removed from samples. Sample depth varied between 5 - 15 mm ............................................................................................... 61 viii LIST OF FIGURES CHAPTER 1 Figure l - Percentages of different types of grasses found on the fairway of the surveyed golf courses in Michigan in 1996 .................................................................. 21 Figure 2 - Golf courses reporting on the presence of A. spretulus and A. granarius from a survey done in October 1995 in Michigan. 88 = A. spretulus, 02° = A. granarius, O = None, 38 93° = Both .................................................................................. 22 Figure 3 - Percentages of reported A. spretulus and A. granarius populations on surveyed golf courses in Michigan in 1995 .................................................................. 23 Figure 4 - Average number of fungicide, insecticide, and herbicide applications (per course) made to fairways (a), greens (b), and tees (c) on 49 surveyed golf courses in Michigan in 1995. Y error bars represent standard error (SE) ................................ 24 Figure 5 - Average mowing heights (cm) of golf course fairways (a) and roughs (b) on 49 surveyed golf courses in Michigan in 1995 ...................................................... 25 Figure 6 - Transect across fairway. Average number of A. spretulus larvae in the fairway and rough on 20 golf courses in Michigan in 1996. Y error bars represent standard error (SE) ................................................................................................... 26 CHAPTER 2 Figure 1 - Chlorothalonil study design along the rough/fairway interface on hole #17 at Cattails Golf Club in South Lyon, MI in 1996 .................................................. 38 Figure 2 - Numbers of A. spretulus, staphylinid, and carabid adults caught in pitfall traps and number of A. spretulus larvae in soil cores in rough or fairway, with or without chlorothalonil treatment. Pitfall trap data are mean 3: SE of insects per 4 traps from May 5 to July 14, 1996 ..................................................................................... 39 Figure 3 - Regression showing the numbers of A. spretulus adults caught in pitfall traps compared to numbers of larvae from associated soil cores in rough and fairway plots on Cattails' golf course turf in 1996 (n = 64) ........................................................ 40 Figure 4 - Regression showing the numbers of A. spretulus adults caught in pitfall traps compared to numbers of larvae from associated soil cores in rough and fairway plots on Cattails' golf course turf in 1996 (n = 16) ........................................................ 41 1X Figure 5. Percentage of A. spretulus larvae infected with B. popilliae in the fairway and in the rough in perennial ryegrass plots in 1996 .................................................... 42 CHAPTER 3 Figure 1 - 1995, 1996, and 1997 mowing regime along rough/fairway interface on a perennial ryegrass golf course. Numbers 1-4 indicate the sites for pitfall traps and soil cores for 1996. We added 4 more soil cores in each plot in 1997 ............................ 62 Figure 2 - Mowing height treatments in 1995, 1996, and 1997 at Cattails Golf Course. Data are mean numbers of A. spretulus larvae per 4 soil core samples per 4 plots ................................................................................................... 63 Figure 3 - Effects of 1995, 1996, and 1997 fairway and rough turf mowing heights on numbers ofA. spretulus adults and larvae found per plot on a perennial ryegrass golf course ................................................................................................. 64 Figure 4 - Percentage of A. spretulus larvae infected with B. popilliae in the fairway and in the rough in perennial ryegrass plots in 1996 ........................................... 65 Figure 5 - Percentages of A. spretulus larvae infected with B. papilliae in the rough and fairway mowed turf on a perennial ryegrass golf course in 1997 ............................. 66 Figure 6 - Effects of 1995, 1996, and 1997 fairway and rough mowing heights on numbers of ants and carabids caught in pitfall traps. Numbers are insects per plot i SE..67 Figure 7 - Effects of 1995, 1996, and 1997 fairway and rough turf mowing heights on the most common species of staphylinds, P. cognatus and P. carbonarius, caught per pitfall trap, per plot on a perennial ryegrass golf course in 1996 and 1997 .......................... 68 Figure 8 - Regression showing the relationship between A. spretulus adults and Philonthus adults from pitfall traps from rough and fairway plots on golf course turf in 1997 ......... 69 Figure 9 - Effects of 1995, 1996, and 1997 fairway and rough turf mowing heights on Tetramon'um ants captured in tuna fish traps. Ant numbers are per plot on a perennial ryegrass golf course in 1997 ....................................................................... 70 Figure 10 - Regression showing the relationship between A. spretulus larvae taken from soil cores and nitrate soil samples taken from the respective plots in rough and fairway plots on golf course turf in 1996 .................................................................. 71 INTRODUCTION Ataenius spretulus Haldeman and Aphodius granarius (L.) were considered incidental pests of turfgrass prior to 1970 (Tashiro 1987). A. spretulus was first reported to damage golf course turf in Minnesota in 1932 (Hoffman 1935). In the last 25 years, this scarab has been causing damage on golf courses throughout the northeastern and midwestem portions of the United States and in Ontario, Canada (Cartwright 1974, Kawanishi et a1. 1974, Niemczyk and Dunbar 1976, Niemczyk and Dunbar 1979, Niemczyk and Dunbar 1981, Vittum 1995). A. spretulus has two generations per year in sectors below the southern part of Ohio and one generation per year in areas north of Ohio (Wegner and Niemczyk 1981, Vittum 1995). A. granarius is an introduced pest from Europe. It was first seen damaging golf course turf in 1976 in Toronto, Ontario (Sears 1979). It was reported again in 1978 on golf course fairways in Colorado and Michigan, after initially being mistaken for A. spretulus infestations (T ashiro 1987). This insect is now widespread across the United States and Canada (N iemczyk and Power 1978 and Woodruff 1973). It is unknown whether A. granarius has one or two generations per year. Two generations per year have been reported in Ontario, Canada and in Ohio, while only one generation has been documented in New Jersey (Sears 1979 and Wilson 1932). From what little is known of the biology of A. spretulus and A. granarius, they seem to behave in a similar manner. A. granarius begins to fly in late April and early May in Michigan. A. granarius lay their eggs in dung that has formed a hard crust on its surface (Wilson 1932) or in a turfgrass stand, apparently showing no preference for either. The larvae appear in early June and peak larval damage is seen in mid to late June. A. spretulus also emerge in April or May and we know that by the spring the majority of female beetles have already been inseminated (Wegner and Niemczyk 1981). They begin to lay their eggs 2 in mid to late June and peak larval densities are seen in late July to early August. A degree- day system for A. spretulus has been based on a flight activity temperature of 13° C. For northern states, eggs begin to appear after 100-150 degree days. In Michigan, A. granarius and A. spretulus life cycles seem to overlap only slightly in May when both adult beetles are flying. Because the life cycles are seperated by a few weeks, the larvae rarely compete for turfgrass roots A. spretulus and A. granarius are also very similar in appearance, both as adults and as larvae (Tashiro 1987). Both adults are small black beetles (2.5-5.1 mm), but A. granarius are broader and variegated with muted red or yellow unlike A. spretulus. The major distinguishing characteristic to decipher these beetles is the hind tibia. The hind leg of A. granarius has transverse carina on the tibia, while the tibia of A. sprctulus is smooth. The larvae are also both similar in size and appearance. However, the raster patterns of the larvae are distinctly different; A. granarius has a V-shaped palidium, while A. spretulus has no palidium on its last abdominal segment. Since these insects are new pests to turfgrass, little is known of their basic biology. overwintering, mating, oviposition and life histories of A. spretulus and A. granarius need to be more thoroughly examined. Golf course superintendents in Michigan have little knowledge of these insects and their life cycles, making it difficult to predict when they will cause damage on their courses. However, they are beginning to know the time of year when the damage from each type of larvae occurs. Presently, entomologists are offering help to golf course superintendents on how and when to sample for the larvae and how to spray if it is necessary. A. spretulus and A. granarius are found more often on golf course turf than on any other turfgrass areas (Vittum 1995). The high maintenance and cultural practices used on golf courses may create a more optimum environment for these insects. Michigan golf courses apply an average of 3-5 applications of fertilizer to fairways per growing season. 3 Potter et a1. ( 1985) showed an inverse relationship between nitrogen applications and earthworms in Kentucky bluegrass. Nitrogen fertilizers may also affect A. spretulus and A. granarius populations. However, fertilization had no affect on the New Zealand grass grub, Costelytra zelandica (White) (Presidge et a1. 1985). Mowing may also affect turfgrass pests. Masked chafer larvae produce smaller larvae in high-mown (20 cm) turf. High-mown turf also reduces numbers of these larvae by up to 55% (Potter et a1. 1996). Gyrisco et a1. (1954) found lower numbers of European chafers, Rhizotrogus majalis Razoumowsky, in turf plots that were maintained at a height of above 25 cm compared to plots that were mowed during the flight period of adult beetles. Smitley et a1. ( 1998) found more A. spretulus larvae in the shorter mowed fairway than in the longer rough turf. Much of the arthropod predatory complex of pests associated with turfgrass has only been observational (Terry et a1. 1993). Surveys performed in New Jersey, Florida and Kentucky revealed many species of ants, ground beetles, spiders, rove beetles, and hister beetles are present in a turfgrass ecosystem (Potter 1995). We believe that many of these groups feed upon the eggs and larvae of turfgrass pests, keeping pest populations to a minimum. However, pest resurgances have been documented in turfgrass when broadspectrum insecticides eliminated predators and parasites that naturally control these pests (Potter 1995). Insecticides used for white grub control disrupts the stability of predator communities (Strue 1973, Potter et al. 1989) and reduces the ability of predators to control turfgrass pests (Cockfield and Potter 1983, Potter et al. 1989 ). Other pesticides, such as fungicides and herbicides, are regularly applied to golf courses and these pesticides may also disrupt the natural enemy complexes associated with turfgrass. In another study, plots maintained on a fertilizer, herbicide, insecticide and fungicide schedule showed that predators were reduced by insecticide applications, but the other pesticide applications produced variable results (Arnold and Potter 1987). 4 However, little research has been done to demonstrate that arthropod predators actually reduce pest populations in turfgrass. Zenger (1997) showed that Solenopsis ants consume Japanese beetle, Popillia japonica Newman, eggs placed in the soil of a turfgrass setting. Cockfield and Potter (1984) demonstrated that predators removed up to 75% of sod webworm eggs placed on the surface within a 48 hour time period. But, when chlorpyifos was applied to the turf, predators of sod webworrns were suppressed. Turf plots treated with carbaryl or isazofos reduced predation on Japanese beetle eggs by as much as 70% (Terry et a1. 1993). Bacillus popilliae Dutky, B. lentimorbus Dutky and closely related Bacillus spp. known as milky spore disease pathogens, infect many species of the Scarabaeidae family. Scarab larvae injest the B. popilliae spores while feeding on the turf roots. The spores germinate in the gut of the larvae and move to the hemolymph where they reproduce and sporulate. The spores and parasporal bodies increase in the body of the larvae causing the larvae to die slowly, taking over 1 month (Klein 1995). The build-up of the spores and parasporal bodies results in the milky appearance of the larvae, hence the bacteria's name (Klein 1995). A key pathogen of A. spretulus is believed to be B. popilliae (Kawanashi et a1. 1974, Splittsotesser and Tashiro 1977, Tashiro 1987). B. popilliae found in A. spretulus is different in appearance from the milky disease found in Japanese beetle larvae. It also seems to be different with respect to infectiveness. The milky spore disease found in A. spretulus is not infective in Japanese beetle larvae (Kawanishi et a1. 1974), European chafer, Rhizotogus majalis Razoumowsky or May and June beetle (Phyllophaga sp.) larvae (Splittstoesser and Tashiro 1977). Therefore, B. popilliae found in A. spretulus is species specific. Three types of Bacillus sporangia have been identified from A. spretulus. All three are similar in appearance; spindle-shaped rods containing a single spore near the center of the sporangium, and lacking a distinct parasporal body (Splittsotesser and Tashiro 5 1977). B. popilliae appears in the majority of field collected A. spretulus larvae (Kawanishi et a1. 1974), but the ability of the disease to reduce A. spretulus populations is in question (Wegner and N iemcyk 1981). Chlorothalonil, a commonly sprayed fungicide on golf course turf, has been shown to reduce the infection capabilities of B. popilliae in the laboratory. Dingman (1994) showed that recommended rates of chlorothalonil reduces spore viability of B. popilliae. Even with reduced rates of chlorothalonil, it also inhibited vegetative growth of B. popilliae (Dingman 1994). Little is also known of how A. spretulus and A. granarius are distributed on golf courses. We know that both of these insects cause damage to greens, tees and fairways of golf courses (Niemczyk and Dunbar 1976, Tashiro 1987, Vittum 1995). However, Smitley et. a1 (1998) have shown that A. spretulus and A. granarius larvae are more abundant in fairways than in roughs of golf course turf. A. spretulus adults were also more abundant in the fairway, while A. granarius adults showed no preference between fairway and rough mowed turf. This research was designed to investigate why A. spretulus and A. granarius occur on golf course fairways. Objectives for this research include 1) a survey compiling information from golf course superintendents across the state of Michigan concerning maintenance and cultural practices as well as information on A. spretulus and A. granarius; 2) an examination to determine if the commonly sprayed golf course fungicide, chlorothalonil, inhibits predators or pathogens that naturally control populations of A. spretulus, 3) a field study designed to study the effects of mowing height on the populations of A. spretulus, and 4) laboratory experiments to study the affects of predatory arthropods on A. spretulus and A. granarius adults and larvae and an adult female A. spretulus oviposition test. 6 LITERATURE CITED Arnold, TB. and D.A. Potter. 1987. Impact of a high-maintenance lawn-car program on nontarget invertebrates in Kentucky bluegrass turf. Environ. Ent. 16: 100-105. Cartwright, O.L. 1974. Ataenius, Aphoataenius and Psueoataenius of the United States and Canada (Coleoptera: Scarabaeidae: Aphodiinae). Smithsonian Contrib. Zool. 154: 1-106. Cockfield, S.D. and D.A. Potter. 1983. Short-term effects of insecticidal applications on predaceous arthropods and orbatid mites in Kentucky bluegrass turf. Environ. But. 12: 1260-1264. Cockfield, S.D. and D.A. Potter. 1984. Predation on sod webworm (Lepidoptera: Pyralidae) eggs as affected by chlorpyrifos application to Kentucky bluegrass turf. J. Econ. Entomol.. 77: 1542-1545. Dingman, D.W. 1994. Inhibatory effects of turf pesticides on Bacillus popilliae and the prevelance of milky disease. Appl. Envir. Micobiol.. 6: 2343-2349. Grysico, G.G., W.H. Whitcomb, R.H. Burrage, C. Logothetis and H. H. Schwardt. 1954. Biology of European chafer, Amphimallon majalis Razoumowsky (Scarabaeidae). Cornell University Agricultural Experiment Station Mem. 328. 7 Kawanishi, C.Y., C.M. Splittstoesser, H. Tashiro, and K.H. Steinkraus. 1974. Ataenius spretulus, a potentially important turf pest and its associated milky disease bacterium. Environ. Ent.. 3: 177-181. Klein, M.G. 1995. Microbial control of turfgrass insects. pp. 95-100. In R. L. Brandenburg and M. G. Villani [eds], Handbook of turfgrass insect pests. Entomological Society of America, Lanham, Maryland. Niemczyk, H.D. and D.M. Dunbar. 1976. Field observations, chemical control, and contact toxicity experiments on Ataenius spretulus, a grub pest of turf grass. J. Econ. Entomol.. 69: 345-348. Niemczyk, H.D. and K.T. Power. 1978. Another grub pest, similar to the black turfgrass ataenius found damaging fairways. p. 31. In Proceedings of Ohio Turfgrass Conference. Potter, D.A. 1995. Beneficial and innocuous invertebrates in turf. pp. 101-104. In R.L. Brandenburg and MG. Villani [eds.], Handbook of turfgrass insect pests. Entomological Society of America, Lanham, Maryland. Potter, D.A., B.L. Bridges and F.C. Gordon. 1985. Effect of N ferilization on earthworm and microarthropod populations in Kentucky bluegrass turf. Agron. J .. 77: 367-372. Potter, D.A., S.D. Cockfield, and T.A. Morris. 1989. Ecological side effects of pesticide and ferilizer use on turfgrass. In A. R. Leslie and R.L. Metcalf [eds], 8 Integrated pest management for turfgrass and omamentals. US-EPA, Washington, DC. Potter, D.A., A.J. Powell, P.G. Spicer, and D.W. Williams. 1996. Cultural practices affect root-feeding white grubs (Coleoptera: Scarabaeidae) in turfgrass. J. Econ. Entomol.. 89: 156-164. Prestige, R.A., S. Van der Zijpp and D. Badan. 1985. Effects of plant species and fertilizers on grass grub larvae, Costelytra zealandica. New Zealand J. Agric. Res. 28: 409-417. Sears, M.K. 1979. Damage to golf course fairways by Aphodius granarius (L.) (Coleoptera: Scarabaeidae). Proc. Entomol. Soc. Ont.. 109: 48. Smitley, D.R., T.W. Davis and N.L. Rothwell. 1998. Spatial distribution of Ataenius spretulus and Aphodius granarius (Coleoptera: Scarabaeidae) on golf courses. Environ. But. (in review). Splittstoesser, C.M. and H. Tashiro. 1977. Three milky disease bacilli from a scarabaeid,Ataenius spretulus. J. Inver. Pat. 30: 436-438. Strue, H.T. 1973. The turfgrass ecosystem: impact of pesticides. Bulletin of Entomol. Soc. Am. 19: 89-91. Tashiro, H. 1987. Turfgrass insects of the United States and Canada. Cornell University Press, Ithaca, New York. 39lpp. 9 Terry, L.A., D.A. Potter, and P.G. Spicer. 1993. Insecticides affect predatory arthropds and predation on Japanese beetle (Coleoptera: Scarabaeidae) eggs and fall armyworrn (Lepidoptera: Noctuidae) pupae in turfgrass. J. Econ. Entomol. 86: 871-878. Vittum, PJ. 1995. Black turfgrass ataenius, pp. 35-37. In R. L. Brandenburg and M. G. Villani [eds], Handbook of turfgrass insect pests. Entomol Soc. Am., Lanham, Maryland. Wegner, GS. and H.D. Niemczyk. 1979. The Ataenius of Ohio. Ohio J. Sci. 79: 249-255. Wegner, GS. and H.D. Niemczyk. 1981. Bionomics and phenology of Ataenius spretulus. Annuals of Entomol. Soc. Am. 74: 374-384. Wilson, J.W. 1932. Coleoptera and Diptera collected from a New Jersey sheep pasture. J. New York Entomol. Soc. 40: 77-93. Woodruff, RE. 1973. Arthropods of Florida and neighboring land areas, vol. 8. The scarab beetles of Florida. Florida Department of Agricultural Consumers Bureau, Entomological Contribution. No. 260. 220 pp. Chapter 1 SURVEY OF MICHIGAN GOLF COURSE SUPERINTENDENTS FOR ATAENIUS SPRETULUS AND APHODIUS GRANARIUS INFESTATIONS AND FOLLOW-UP FIELD SAMPLING OF SELECTED COURSES ABSTRACT In October of 1995, a survey was sent out to 250 golf course superintendents across the state of Michigan. The purpose of the survey was to aquire preliminary information of two recent pests to golf course turf, Ataenius spretulus Haldeman and Aphodius granarius (L.). The superintendents were asked to rate damage and distribution of A. spretulus and A. granan'us, report their pesticide usage and location of these pesticide applications on their course during the past growing season, theirmowing practices, and the grass types found on their course. The survey responses were broken down into three categories; tees, greens and fairways. The survey was succeeded by a follow-up sampling of 20 of the golf courses responding to the survey. The major type of grass reported on Michigan courses was creeping bentgrass, followed by annual bluegrass. Most golf courses superintendents claim to have observed only A. spretulus (39%) or neither A. spretulus or A. granarius (33%). Few courses had only A. granarius outbreaks (16%) or both A. spretulus and A. granarius (13%). Pesticide use data from the survey were compiled as the average number of applications of each pesticide to fairways, tees and greens per year. Fungicides were the most commonly used pesticides. Of the fungicides, chlorothalonil was most frequently applied (1.8 fairway applications per year), followed by propiconazole (0.6 fairway 10 l 1 applications per year, pentachloronitrobenzene (0.6 fairway applications per year), metalaxyl (0.4 fairway applications per year), ipriodione (0.3 fairway applications per year). Chlorpyrifos was the most commonly used insecticide on fairways (0.4 applications per year), greens (1.3 applications per year) and tees (0.6 applications per year). Irnidicloprid was used almost exclusively on fairways (0.2 applications per year). Herbicides were rarely used on greens and tees, but were occasionally applied to golf course fairways. Follow-up sampling was performed at 20 of the 49 golf courses that had returned the survey and indicated that A.spretulus larvae were present the previous year. One fairway at each course was sampled. A. spretulus larvae were found to be 4-fold more abundant in the fairway compared with irrigated rough. The density of larvae diminished quickly at the rough/fairway interface as we sampled across the fairway into the rough. No relationships were found between pesticide use and the reported incidence of A. spretulus or A. granarius or with the density of larvae in follow-up sampling. Also, no relationship was found between the reported severity of A. spretulus or A. granarius problems and the actual density of larvae in the follow-up sampling. 12 INTRODUCTION Reference to turfgrass has been found dating back to the Bible and other ancient literature. Since those times, the turfgrass industry has grown to over a 20 million acre commodity (Beard 1973). Turfgrass research began at Michigan State University around 1880 (Beard 1973). The United States Golf Association (USGA) Green Section was formed in 1920 for turfgrass research in Arlington, VA (Beard 1973). Eight years later the USGA Green Section had established 15 demonstration turfgrass areas on golf courses across the United States. The turfgrass industry parellels the history of the game of golf (Watson et a1. 1992). Golf course progress and maintenance have set the pace for the turfgrass industry's growth. Advances in technology in the industry are due to the construction, distribution, and maintainance of products used in association with golf courses (Watson et a1. 1992). The United States alone had 13,181 golf courses in 1986 and an average of 150-200 courses are added each year (Watson et a1. 1992). Therefore, the turf industry, more specifically golf courses, play a major role in the economy of the United States. This importance of the golf course itself stresses the need for turfgrass scientists to be able to grow healthy turf. Ataenius spretulus (Haldeman) and Aphodius granarius (L.) (Coleoptera: Scarabaeidae: Aphodiinae) are relatively new pests of golf course turf. A. spretulus is a native pest, while A. granarius was introduced from Europe. A. spretulus was first discovered infesting turfgrass in Minnesota in 1932 (Tashiro 1987). A. granarius, on the other hand, was found for the first time on golf course fairways in Toronto, Ontario in 1976 and 1977 (Tashiro 1987). Both larvae feed upon many different golf course turfgrasses. Little is known about the frequency and intensity of damage to golf courses caused by A. spretulus and A. granarius (Tashiro 1987, Villani and Brandenburg 1995). We attempted to define the distribution of A.spretulus and A. granarius in Michigan and explore the relationship between the incidence of infestation and pesticide and mowing 13 practices by surveying golf superintendents, and then visiting 20 of the surveyed golf courses to sample for A. spretulus larvae. METHODS AND MATERIALS Survey In October 1995, we sent out a survey to 250 golf courses across the state of Michigan. We selected the golf courses by random, but made sure that both private and public courses were adequately represented when the final list was compiled. The major difference between public and private courses is the size of the budgets. Private courses are able to apply pesticides as needed to cure turf diseases and insect problems, while public courses may not have the budget to do so. Also, private courses are able mow more frequently due to a larger crew and the necessary equipment. The survey asked superintendents if they had A. spretulus or A. granarius and if they had damage on their course caused by these larvae. The survey included an option of a 'not sure catergory', if superintendents did not know which insect, either A. spretulus or A. granarius, was on their course. The number of A. spretulus and A. granarius larvae on the golf course was based on a ranking system of 0 to 4, where O is no larvae and no damage and 4 is a high population and visible damage from larval feeding. There were also questions inquiring if the superintendents had needed to apply insecticide because of A. spretulus or A. granarius damage. The survey included questions on the fungicide, herbicide, and insecticide applications made throughout the 1995 growing season. The superintendents were asked which products were used, the rates of those products and the frequency of their applications. We inquired to where on the golf course each pesticide was applied; greens, tees, fairways or collars. Information was also requested for grass types, mowing heights, and mowing frequencies of tees, greens and fairways. Forty-nine surveys were returned by December of 1995. l4 Follow-up Sampling In July of 1996, we sampled 20 of the 49 courses that responded to the survey for A. spretulus larvae. Golf courses were chosen if they had a history of A. spretulus damage. Courses were also chosen if we had done research in the past and/or if the superintendents were willing to participate in this follow-up sampling. The 20 courses were spread out over the state of Michigan. The courses were in the following counties: Ingharn, Jackson, Macomb, Washtenaw, Ottawa, Genesee, Antrim, St. Clair, Wayne, Kalamazoo, Ogemaw, Calhoun, Allegan, Arenac and Oakland. At each golf course, the superintendent was asked to identify one fairway with a history of A. spretulus problems. One 10 cm diameter sample was taken starting 1.5 min from the rough/fairway interface and every 3 m across the fairway and 6 m into the rough, approximately 12 samples were taken at each golf course. Each soil core was torn apart and A. spretulus larvae counted. Statistical Analysis The surveys who had the highest rankings (3 or 4) of A. spretulus and A. granan’us were compared using a parametric regression analysis with fairway mowing height, the number of fungicide applications made to the fairway, and actual numbers of A. spretulus and A. granarius from the follow up survey (SuperANOVA® 1990). The relationship between the density of A. spretulus in the fairway and the mowing height was also tested by regression analysis. The same analysis was applied to the larvae in the rough and to the mowing heights of the rough. We also looked at the number of fungicide and insecticide applications made to the fairway and compared using a regression analysis with the number of larvae found in the fairway. RESULTS AND DISCUSSION Survey There are 7500 Species of grasses found around the world, but only 25 of these are used on golf courses and home lawns (Turgeon 1996). There are even fewer 15 turfgrass species that grow readily on golf courses in Michigan. The five most commonly reported grasses on fairways were Kentucky bluegrass (Poa pratensis L.), annual bluegrass (P. annua L.), creeping bentgrass (Agrostis palustris Hudson), perennial ryegrass (Lolium perenne L.), and fine fescue (F estuca rubra L.) (Figure 1). Annual bluegrass was the most common grass found on the 49 surveyed Michigan golf courses, followed by creeping bentgrass. A. spretulus and A. granarius were found throughout the state of Michigan, wherever golf courses were located (Figure 2). There seems to be a clustering of golf courses who had A. spretulus and A. granarius in the Detroit area (Macomb, Oakland, Wayne counties) simply due to the area having more golf courses and golf course superintendent involvement. A. granarius was not reported by superintendents in the northern part of the state. From the 49 golf courses who responded to the survey, there were 18 courses with only A. spretulus larvae, one with only A. granarius larvae, 6 with both and 18 with neither type of larvae (Figure 3). These data follow a similar trend seen by Smitley et a1. (1998). From their research on 5 golf courses, they found 3 courses had almost all A. spretulus, 1 course had almost solely A. granarius and 1 course had both A. spretulus and A. granarius. This distribution of A. spretulus and A. granarius indicates that both insects are widespread throughout the state, but most golf courses still do not have either type of larvae causing significant damage to their course. The survey information not only gave us some possible research sites for the following summer, it also provided us with the ability to correlate certain golf course maintenance practices with larval populations. These ideas were generated into hypotheses for future field research. We looked at the relationship between the rankings of A. spretulus larvae and the actual numbers of larvae at the golf courses from the follow-up sampling. There was no correlation between the reported larval numbers and the actual numbers from sampling (df 16 = l, 48; r2 = 0.09; F = 1.6; P = 0.22). There are many possible reasons for this. The larvae may simply not be there from one year to the next, which is typical of scarab behavior (Ng et al. 1983). Also, many times the perception of an insect problem on the golf course may be worse than the actual insect numbers. This demonstrates the need for superintendents to sample their courses to be accurate in assessing insect problems and the possible curative measures. The most commonly used pesticides on golf courses in Michigan in 1995 were fungicides (Figure 4). Propiconazole, chlorothalonil, metalaxyl, iprodione, and pentachloronitrobenzene (PCNB) were the most frequently applied fungicides at the surveyed golf courses. The fungicide most commonly used on fairways, greens, and tees was chlorothalonil (1.8 i 0.5, 4.4 i: 0.42, and 1.9 i 0.44 mean 1 SE, applications per season, respectively, Figure 4). Pentachloronitrobenzene was also applied in small amounts by 36 of the 49 golf courses surveyed. Among insecticides, chlorpyrifos was used most often on the fairways (0.39 i 0.56 applications per year), greens (1.1 :l: 0.12) and tees (0.68 i 0.24, Figure 4). Herbicides were used infrequently on greens and tees. 2,4—D, MCPP and Dicamba, herbicides, had 0.41 i 0.28 applications made to all fairways, while trichlopyr and chlopyralid were applied 0.11 :t 0.18 times (Figure 4). We also looked at the mowing height of the turfgrass in the fairway and in the rough (Figure 5). Vittum (1995) stated that A. spretulus larvae were found attacking greens, tees and fairways of golf courses. Smitley et al. (1998) found A. spretulus larvae mostly in the fairway with few larvae in the rough. The superintendents were asked to document the mowing heights of the fairway. One reason for asking the mowing heights of the fairways was to determine if mowing height affected the density of larvae found on fairways. Follow-Up Sampling From the 20 golf courses sampled in Michigan, we found more A. Spretulus larvae in the fairways than in the roughs (Figure 6). The density 17 of larvae declined sharply at the rough/fairway interface as we sampled across the fairway into the rough. The average number of A. spretulus larvae in the fairway was 1.5 i .25, mean i SE per 10 cm soil sample compared with only 0.33 i 0.14 in the rough. Most golf courses (72%) have different types of grass in the fairway than the rough. However, there were no correlations between grass types and A. spretulus larval populations. More testing needs to be done to determine if A. spretulus larvae prefers one type of turfgrass over another type. Another difference between the rough and fairway turf is the pesticide and fertilizer applications. From the surveyed courses we found that an average of 3.0 fungicide applications were made to the fairways and none to the rough. Dingman (1994) showed that chlorothalonil, the most common fungicide used on golf courses in Michigan according to the survey, suppressed Bacillus popilliae Dutky, a natural pathogen which may help keep A. spretulus and A. granarius larvae in check. Another possibility to why we have A. spretulus and A. granarius build up to damaging populations is that A. spretulus and A. granarius are resistant to the fungicides and insecticides that are applied to fairways while predaceous insects are not. Certain populations of A spretulus have built up in areas where chlordane was used, suggesting A. spretulus is tolerant of chlordane (Vittum 1995). Irrigation systems do not seem to be playing a large role in the location of A. spretulus and A. granarius populations. The irrigation system of most golf courses overlaps into the first 1-3 m of the rough from the fairway. Since all of the area we sampled was irrigated with similar amounts of water, it would not account for the abrupt drop in the number of A. spretulus larvae on the rough side of the fairway/rough interface. There seemed to be no relationship between the rankings of A. spretulus and A. granarius and the responses of fungcide, insecticide applications and mowing height of the turf from the survey. There was also no relationship between the A. spretulus larval numbers collected with the follow-up survey and the cultural practices given in the survey 18 (Table 1). Also, no relationship existed with actual A. spretulus populations and the insecticide and fungicide applications made to the fairways (Table 1). In conclusion, the survey presented many possible hypotheses as to why A. spretulus and A. granarius larvae are found on golf course fairways. Adjusting the mowing height in a field test would help verify if A. spretulus larvae prefer fairway length turf to rough length turf. Also, because chlorothalonil is the most heavily used fungicide, it should be tested on golf course turf to determine if it suppresses the predators or the pathogens of A. spretulus or A. granarius larvae. Larval feeding tests and adult female oviposition tests also should be done with different types of grass commonly found on golf courses to determine if A. spretulus or A. granarius has a preference for one type of turfgrass over another type. LITERATURE CITED Beard, J.B. 1973. Turfgrass Science and Culture. Prentice-Hall, Inc., NJ. Brandenburg, R.L. and M.G. Villani. 1995. Handbook of Turfgrass Insect Pests. Entomol. Soc. Am., Landham, MD. Dingman, D.W. 1994. Inhibatory effects of turf pesticides on Bacillus popilliae and the prevelance of milky disease. Appl. Envir. Microbiol. 6: 2343-2349. l9 Ng, Y.S., J.R. Trout and S. Ahmad. 1983. Sequential sampling plans for larval populations of the Japanese beetle (Coleoptera: Scarabaeidae) in turfgrass. J. Environ. Ent.. 76: 251-253. Smitley, D.R., T.W. Davis and N.L. Rothwell. 1998. Spatial distribution of Ataenius spretulus, Aphodius granarius (Coleoptera: Scarabaeidae), and predaceous insects across golf course fairways and roughs. Environ. Ent. (in press). SuperAnova. 1991. The accessible general linear modeling package. Abacus Concepts, Inc., Berkley, CA. Systat 5 for the Macintosh. 1990-1991. Systat Inc., Evanston, IL. Tashiro, H. 1987. Turfgrass insects of the United States and Canada. Cornell University Press, Ithaca, NY. Turgeon, A.J. 1996. Turfgrass Management. Prentice-Hall Inc., Upper Saddle River, New Jersey. 406 pp. Vittum, P.J. 1995. Black turfgrass ataenius, pp. 35-37. In R.L. Brandenburg and M.G. Villani [eds.], Handbook of turfgrass insect pests. Ent. Soc. America, Landham, Maryland. Watson, J.R., H.E. Kaerwer, D.P. Martin. 1992. The turfgrass industry. Turfgrass Agronomy Monograph. no. 32. 20 on + x35 u a 8d Bod 8d a ._ Sesame, 020835 SEE E 8E— “352% .< 2 + is n a mac Rd 36 M: ._ Sages Banana SEE E omE_ SNEEB. .< 3 - x: n A 86 2 2 .o M: ._ Ema: mazes swam £38 5 8E— .SNEES. .< ranger“ E 2 + x: u % So 3o 83. M: ._ Ema; S52: 3&3 EE_ SEES .< 3.82 0%; Salim cassava E .83 E 535:2 5 $558 how on am 658 omgfi “358% .< we beam: 05 8 moouoflm 33:3 98 mcouommmm oEoumom Co mEmeowfiom A 033. 21 Kentucky Bluegrass Annual Bluegrass Creeping Bentgrass Perennial Ryegrass EIIIEEE: Fine Fescue Figure l. Percentages of different types of grasses found on the fairway of the surveyed golf courses in Michigan in 1996. 22 x o o o x no» a: o a: at o o a: :90 a: 3:0“ 0 o 0 41L ‘9’" 8 o o x o a: at a: no ’5 o o .1 Figure 2. Golf courses reporting on the presence of A. spretulus and A. granarius from a survey done in October of 1995 in Michigan. 8 = A. spretulus, '3' = A. granarius, O = None, 38°: = Both 23 EDIE #WNN Figure 3. Percentages of reported A. spretulus and A. granarius populations on surveyed golf courses in Michigan in 1995. 24 £235 Eu: .93 uEEoEoaneE cote—goth. aceEeozo Eases? mZUm 2.28E_ :53»: Eng—«58°20 o_§eoo_mo.& cote—:05. 8:926 Ensues: mZUm 323?: .3302 Egg—.8020 Bongooaem 3:8qu .AEUE .Qéu note—not... 8:825 3322:: mZUm oeBeotE 13302 mac—«582:0 0.3302995 Figure 4. Average number of fungicide, insecticide, and herbicide applications (per course) made to fairways (a), greens (b), and tees (c) on 49 surveyed golf coursesin Michigan in 1995. Y error bars represent Standard error (SE). 25 20 ooooo none 15- ooooo I... 00000 O... 00000 O... ooooo one. ooooo .CII ccccc coo. ooooo 00000 I... ccccc I... 00000 ecu. 00000 CI.- ccccc coco cccccccccc O... O... 10‘ 0.0.0.... o.o.l.o.1 oooooooooo one. no 0 pppppppppp oooooooo ooooooooo ooooooo coco 00000 nnnnnnn oooooooooo ------- 00000 oooooooo nnnnnnnnnn cccccccc oooooooooo eeeeeeee uuuuuuuuuu oooooooo oooooooooo llllllll oooooooooo ........ ..... OOOOO I... 00000 O..- ..... I... IIIII OI.- 00000 I... I... 00000 IIIIIIII IIIIIIIIIIIIII 00000 I... Number of golf courses a... ooooo not. 00000 noo- nnnnnnnnnn 1.0 1.1 1.3 1.4 1.6 1.9 2.5 Fairway mowing heights (cm) 15 10" 'Itt'I'U'II U I'IIUUIUIOICIUII C.-ICOCOIUOIOIOIOIOCCOIICCOI. OI...IOOOOIOIOCOCIIOIIIOCOCOCO Number of golf courses I I'r'ii' 00...... 00...... OIIICCOC 3.6 3.8 4.1 4.6 4.8 5.1 5.8 6.4 Rough mowing heights (cm) Figure 5. Average mowing heights (cm) of golf course fairways (a) and roughs (b) on 49 surveyed golf courses in Michigan in 1995. 26 A. spretulus larvae per 0.1 m2 :1: SE Rough Figure 6. Transect across fairway. Average number of A. spretulus larvae in the fairway and rough on 20 golf courses in Michigan in 1996. Y error bars represent standard error (SE). Chapter 2 EFFECTS OF CHLOROTHALONIL ON ATAENIUS SPRETULUS ADULTS AND LARVAE, AND ON THEIR NATURAL ENEMIES ABSTRACT Chlorothalonil was applied 4 times to replicated plots in the fairway and rough of a golf course in southeastern Michigan, Oakland County. The golf course was planted entirely in Lolium perenne (L.), perennial ryegrass. Pitfall traps were used to monitor surface dwelling insects and soil cores were taken for sampling Ataenius spretulus Haldeman larvae. Treatment had no effect on the densities of A. spretulus adults or larvae. Staphylinid and carabid adults were also not effected by chlorothalonil. However, more A. spretulus adults (3-fold) and larvae (3-fold) were found in plots where the turf was mowed to fairway height compared with plots mowed to rough height, regardless of whether plots were sprayed with chlorothalonil or not. Staphylinids were found predominantly in the rough-mowed turf (45-50 per pitfall trap) compared to the shorter fairway turf (10-20 per pitfall trap). Carabids showed no preference between fairway and rough mowed turf. A. spretulus larvae were collected and dissected to determine if they were infected with Bacillus popilliae B. popilliae-infected larvae were found in the rough 50% more often than larvae found in the plots mowed to fairway height. 27 28 INTRODUCTION Ataenius spretulus Haldeman was first recognized as a turf pest in Minnesota in 1932 when patches of fairway infested with A. spretulus died (Hoffman 1935, Tashiro 1987). The insect remained an obscure pest until it began to appear again on golf courses in the late 1960's in Rochester, New York. This insect is now considered a serious pest of turfgrass throughout the United States (Cartwright 1974, Kawanishi et al. 1974, Niemczyk and Dunbar 1976, Wegner and N iemczyk 1979, Wegner and Niemczyk, 1981, Vittum 1995). Reasons for A. spretulus outbreaks on golf courses are not known. The most important natural enemy of A. spretulus is believed to be the bacterial pathogen, Bacillus popilliae Dutky (Kawanishi et a1. 1974, Splittstoesser and Tashiro 1977, Tashiro 1987), but the role of predators of A. spretulus has not been investigated. Bacillus popilliae, B. lentimorbus and closely related Bacillus spp. known as milky Spore disease pathogens, infect many species of the Scarabaeidae family. Endospores and Sporangia found in A. spretulus larvae have a slightly different shape than ones found in the B. popilliae of Japanese beetle, Popillia japonica Newman (Kawanishi et a1. 1974). Sporangia of B. popilliae recovered from P. japonica have a characteristic footprint shape formed by the enclosed spore and the smaller parasporal body (Klein 1980). Three types of Bacillus Sporangia have been identified from A. spretulus. All three are similar in appearance; spindle-shaped rods containing a single spore near the center of the sporangium, and lacking a distinct parasporal body. The first form of Bacillus found in A. spretulus has a particularly lenticular sporangium which contains an ellipsoidal spore, tilted at a slight angle from the line between the ends of the sporangium. The second type are the largest of the Bacillus spp. found in A. spretulus. The sporangia are believed to lyse immediately at maturity, after leaving only spores in the hemolymph of infected larvae. The third Bacillus type has spherical to elliptical spores surrounded by what appears to be two small, dark parasporal bodies (Kawanishi et a1. 1974). 29 Larvae ingest the spores of B. popilliae while feeding on roots of turfgrass. The bacteria enter the hemolymph and multiply. The milky white appearance of infected grubs is caused by a high density of Spores in the hemolymph. Infected larvae slowly die from the infection. Fungi cause nearly all of the major diseases of turfgrass, making fungicides the most commonly sprayed pesticides on golf courses. Dingman (1994) showed that recommended rates of chlorothalonil reduce spore viability of B. popilliae in the laboratory. Reduced rates of chlorothalonil also inhibit vegetative growth of B. popilliae (Dingman 1994). The purpose of this research was to evaluate the effects of chlorothalonil and mowing height on A. spretulus, B. popilliae infecting A. spretulus abundance, and the most abundant predators on a perennial ryegrass golf course in Michigan. METHODS AND MATERIALS The experimental arrangement, consisting of 8 rectangular plots, was located on the east side of hole #17 at Cattails Golf Club, South Lyon, Michigan. We chose Cattails Golf Club because it had perennial ryegrass in both the rough and the fairway, had very little fungicide use and no insecticide use. It was also a new course, only beginning its sixth season when we began doing research in 1996. Hole #17 was chosen based on a history of A. spretulus damage. The 9 m x 3 m plots were arranged along the rough/fairway interface such that half of the plots (3 m x 4.5 m) extended out into the fairway and half of the plots (3 m x 4.5 m) extended into the rough (Figure l). The plots were separated by a 3 m buffer. Plots 1, 4, 6, and 7 were sprayed once every 2 weeks from May 13, 1996 to July 14, 1997 with 4 kg/ha active ingredient, chlorothalonil. A hand held boom sprayer was used for all fungicide applications. The C02 powered backpack sprayer had 4 8008 30 flat fan nozzles that were set to 50 PSI. Two passes were made over each plot, slightly overlapping in the middle and leaving a 0.5 m border on either side of the sprayed plots. Spraying was done at 8:00 am when the winds were at a minimum. Pitfall Trap Sampling Surface insects were sampled in each plot with 4 pitfall traps made from 32 ml glass vials filled with 8 ml of ethylene glycol. Tops of the vials were flush with or just below the ground surface. The holes in the ground were made by a 19 mm-diameter soil probe. Vials were collected, capped, and replaced with fresh ones, once a week for 11 weeks beginning May 6, 1996. Ants and histerid beetles were identified to family level, while staphylinid and carabid beetles were identified to genus level. Staphylinid and carabid abundance for all plots was approximately 135 and 42 beetles, respectively. Ants and histerids had considerably less numbers. Larval Sampling Using a golf course cup-cutter (10 cm-diam. and 10 cm- depth), we collected A. spretulus larvae from 10 cm-deep soil cores on July 14, 1996. One soil core was taken to the left of each pitfall trap in all plots (4 per plot). Soil cores were torn apart and A. spretulus larvae were counted. Larvae were collected and frozen at 0° C for future dissection. Frozen larvae were removed from the freezer and allowed to thaw for 15 minutes. Each larva was punctured behind the head capsule with an insect pin and a drop of hemolymph was placed onto a microscope Slide and examined at 20x and 40x magnification to determine if B. popilliae was present. Statistical Analysis Numbers of adult A. spretulus, Carabidae, and Staphylinidae caught in pitfall traps were analyzed for treatment effects by a parametric 2- way analysis of variance with sprayed or unsprayed and rough or fairway as factors (SuperANOVA® 1990). Weekly counts from pitfall traps were averaged over all 11 weeks before analysis. The effect of fungicide application and height of mowed turf (fairway or rough) on the abundance of A. spretulus larvae were also determined by a 2-way analysis of variance. Numbers of adult A. spretulus were log (x +1) transformed before analysis to 31 minimize the tails of the distribution of the data. Because less than 3 A. spretulus larvae were found in some plots in the rough, the rate of Bacillus spp. infection could not be determined for every plot and therefore, a 2-way analysis of variance could not be done. Instead, B. popilliae data were analyzed using a chi-square contingency table for both the rough/fairway and the chlorothalonil Sprayed/unsprayed plots. Because there was no difference in Bacillus sp. infection due to chlorothalonil treatment, the 4 plots in the rough, where an adequate number of A. spretulus larvae (> 5) were recovered, were compared with the adjacent plots in the fairway using a chi-square test to determine if infection levels were different in the fairway and rough. Two of these pairs of plots were treated with chlorothalonil and three were not. Single regression analysis was used to determine the relationship between A. spretulus adults and larvae. Numbers of A. spretulus adults and larvae were log (x + 1) transformed before analysis. RESULTS AND DISCUSSION Mowing height of turf had a greater effect on the density of A. spretulus adults and larvae than did applications of chlorothalonil. Both A. spretulus adults and larvae were more abundant in plots mowed to fairway height (16 mm) compared to plots mowed at rough height (51 mm) (df = 1, 14; F = 9.7; P < 0.01 and (if = 1, 14; F = 10.5; P < 0.01 respectively, Figure 2). Five applications of chlorothalonil had no effect on the number of A. spretulus adults recovered in pitfall traps from treated plots (df = 1, 14; F = 0.26; P > 0.1) (Table 1). Control plots had twice as many A. spretulus larvae as the chlorothalonil sprayed plots. However, the means of these treatments were not significantly different because of variability among plots (df = 1, 14; F = 1.82; P = .20). Chlorothalonil had little effect on arthropod predators. There were no differences in the numbers of staphylinids and carabids found in chlorothalonil treated plots compared 32 with control plots. However, staphylinid beetles were more abundant in plots mowed to rough height than in plots mowed to fairway height (df 1, 14; F = 17.9; P < 0.01, Fig. 2). We do not know why staphylinids were consistently more abundant in the rough compared with the fairway; the same type of grass, perennial ryegrass, was present in the rough and the fairway, and the irrigation rate was the same. One hypothesis worth investigating is that the turf in the rough could support an abundant or diverse arthropod community, resulting in a better supply of food for staphylinids than turf in the fairway. It is also possible that 51 mm-tall turf creates a more suitable habitat for surface dwelling arthropods, like staphylinids than does 16 mm-tall turf. Similar numbers of carabid beetles were found in plots mowed at fairway height and rough height (df = 1, 14; F = 0.03; P > 0.1). In the fairway, similar numbers of carabids and staphylinids were trapped, but in the rough, staphylinids were 4-fold more abundant. Two regression analyses were run with A. spretulus adults against A. spretulus larvae to determine if the location of the adults influenced the density of larvae (Figure 3 and 4). Adults captured in 64 pitfall traps were compared with the density of larvae found in soil cores adjacent to each pitfall trap (y = 0.22x + 2.91; r2 = 0.10; F = 20.9; P = 0.0001). We ran a second regression with average of the 4 larval counts and 4 pitfall traps from each plot for a total of 16 data points (y = 0.4x + 5.0; r2 = 0.40; F = 13.5; P = 0.003). This experiment shows the variabilty in sampling for A. spretulus larvae. This study also demonstrates the difficulty of accurately predicting larval A. spretulus populations from adult trapping. Adult beetles could have laid eggs in certain plots, but desiccation, predators or disease could have prevented the eggs from developing into larvae. Also, the larvae may have not survived until our sampling date. Infection of A. spretulus larvae by B. popilliae was not affected by chlorothalonil in our field test. The proportion of A. spretulus larvae infected with B. popilliae was similar 33 in sprayed and control plots (df = l, 7; x2 = 6.6; P > 0.1). Our field test data does not uphold the findings of Dingman (1994), who reported that germination of B. papillae spores was inhibited by some fungicides, herbicides and insecticides. As a group, the fungicides had the detrimental effects on the vegetative growth and spore viability of B. popilliae. At concentrations of 1 ppm, chlorothalonil inhibited cell growth of B. popilliae up to 99%. We calculated the amount of chlorothalonil that would be found in 5 cm of water-saturated soil after a single application to be 12.5 ppm. This is a maximum concentration estimate and does not take volatility, binding and decomposition into consideration. The actual amount of chlorothalonil found in the soil after fungicide applications is probably much lower. Our field testing did not show any suppressive effect of chlorothalonil on B. popilliae infection of A. spretulus larvae in the fairway. We did not find enough A. spretulus larvae in the rough to determine if chlorothalonil had any effect on B. popilliae there. Mowing height of turf affected the B. popilliae infection rate of A. spretulus larvae (df = 1, 7; F = ; P < 0.5). B. popilliae was more active in the rough than in the fairway. In the turf mowed to rough height, infection (50%) of A. spretulus larvae was higher than turf mowed to fairway height (25%) (Figure 5). The soil beneath longer turfgrass may harbor the B. popilliae bacteria more efficiently or it may help the bacteria become more infective in scarab larvae. According to our data, both arthropod predators and B. popilliae bacteria, two potential natural controls of A. spretulus larvae, were more active in longer mowed turf, while A. spretulus larvae are more abundant in the shorter turf. This finding could prove to be very important for future maintenance recommendations for golf course management. Chlorothalonil did not affect A. spretulus adults and larvae, staphylinids, or larvae infected with B. popilliae. However, the mowing height of turf affected the abundance of the A. spretulus adults and larvae, staphylinid adults, and the percentage of larvae infected 34 with B. popilliae. One hypothesis worthy of further investigation is that shorter mowed turf is preferred by ovipositing female beetles. Maintenance practices in the fairway are also more intensive than practices in the rough: more pesticide and fertilizer applications are made to the fairway. At Cattails Golf Club, predators are more abundant and the pathogen B. popilliae are more active in the longer mowed turf. More research is needed to determine why more A. spretulus adults and larvae are found in the fairway compared with the rough and why predators and B. popilliae are more active in the roughs than the fairways of golf courses. LITERATURE CITED Beard, .1. B. 1973. Turfgrass science and culture. Prentice Hall Inc. Englewood Cliffs, NJ. Cartwright, O. L. 1974. Ataenius, Aphoataenius and Pseudoataenius of the United States and Canada (Coleoptera: Scarabaeidae: Aphodiinae). Smithsonian Contrib. 2001. 154: 1- 106. Dingman, D.W. 1994. Inhibatory effects of turf pesticides on Bacillus popilliae and the prevelance of milky disease. Appl. Envir. Microbiol. 6: 2343-2349. Hoffman, C. H. 1935. Biological notes on Ataenius cognatus (Lec.) a new pest of golf greens in Minnesota (Coleoptera: Scarabaeidae). J. of Econ. Entomol. 28: 666-667. 35 Kawanishi, C.Y., C.M. Splittstoesser, H. Tashiro, and K.H. Steinkraus. 1974. Ataenius spretulus, a potentially important turf pest and its associated milky disease bacterium. Environ. Ent.. 3: 177-181. Klein, M.G. 1980. Biological suppression of turf insects. p. 90-97. In H. D. Niemczyk and B. G. Joyner [eds.], Advances in turfgrass insects: a collection of papers presented at the symposium. Chemlawn, Columbus, Ohio. Niemczyk, H.D. and D.M. Dunbar. 1976. Field observations, chemical control, and contact toxicity experiments on Ataenius spretulus, a grub pest of turf grass. J. Econ. Entomol.. 69: 345-348. Smitley, D.R., T. W. Davis, and N.L. Rothwell. 1998. Spatial distribution of Ataenius spretulus and Aphodius granarius (Coleoptera: Scarabaeidae) on golf courses. Environ. Ent.. (in review). Splittstoesser, C.M. and H. Tashiro. 1977. Three milky disease bacilli from a scarabaeid,Ataenius spretulus. J. Inver. Pat. 30: 436—438. Tashiro, H. 1987. Turfgrass insects of the United States and Canada. Cornell University Press, Ithaca, New York. 39lpp. Vittum, P.J. 1995. Black turfgrass ataenius, pp. 35-37. In R. L. Brandenburg and M. G. Villani [eds.], Handbook of turfgrass insect pests. Entomological Society of America, Lanham, Maryland. 36 Wegner, G.S. and H.D. Niemczyk. 1979. The Ataenius of Ohio. Ohio J. Sci. 79: 249-255. Wegner, G.S. and H.D. Niemczyk. 1981. Bionomics and phenology of Ataenius spretulus. Ann. Entomol. Soc. Am.. 74: 374-384. 37 as 85 magnesia x E mass: :3 Sm anseozo m3 and swag €322 $386 93 Be #535an0 x E wage: ”so mad anseoao :55 EN swag mass: meansaasm 85 So. ansano an E wage: owe a: anseoao need one Emma: 9:302 323 @5533. .< MS was maoaseozo x E @502 3o 85 anseoao Sod Ea Ewan mesa: EBB scare .< 2627A 033$ 88mm 835 Boa 358 how we $5508 wcmqawm :8 can wash Emma Boa 316m Escudo use .333 Bananas; .832 new 333 “.5595“. .< mo confine :85 05 maumB “anatomic 20¢ a E Eugene“ 35358030 can Emma: mEBoE mo <>OZ< 88$ 95. .H 2an 38 Falnuay Rough/Fairway Interfaee * Four pitfall traps per plot 3.1m 3.1m 3.1m 3.1m Sprayed Plots Unsprayed Plots 3.1m 3.1m 3.1m Spray Border Plots Figure l. Chlorothalonil study design along the rough/ fairway interface on hole #17 at Cattails Golf Club in South Lyon, MI in 1996. Number of insects per plot :1: SE 39 100 Rough/ Sprayed I Rough! Unsprayed 75 “'4 D Fairway] Sprayed I Fairway/ Unsprayed 50 1 25 — A. spretulus A.spretulus Staphylinid Carabid adults . larvae adults adults Figure 2. Numbers of A. spretulus, staphylinid, and carabid adults caught in pitfall traps and number of A. spretulus larvae in soil cores in rough or fairway, with or without chlorothalonil treatment. Pitfall trap data are mean i SE of insects caught per 4 traps from May 5 to July 14, 1996. 4O 40 y = 0.22x + 2.91 r2 = 0.01 30- [J I: 20- 10- l 5} O 10 20 3O 4O 50 Number of A. spretulus larvae per x soil cores Number of A. spretulus adults per x pitfall traps Figure 3. Regression showing the numbers of A. spretulus adults caught in pitfall traps compared to numbers of larvae from associated soil cores in rough and fairway plots on Cattails' golf course turf in 1996 (n = 64). 41 80 y = 0.399x + 4.986 r2 = 0.404 U n O 50 160 150 Numbers of A. spretulus adults per x pitfall traps Numbers of A. spretulus larvae per x soil cores Figure 4. Regression showing the numbers of A. spretulus adults caught in pitfall traps compared to numbers of larvae from associated soil cores in rough and fairway plots on Cattails' golf course turf in 1996 (n = 16)‘ 42 Percentage of infected A. spretulus larvae :t SE 60 i T 0 °I;I;Z;I;I;I;Z;I;I;2;I;:;I;I;I;I;i zI:I3:3;255553221;3:2:1 Rough Fairway Figure 5. Percentage of A. spretulus larvae infected with B. popilliae in the fairway and in the rough in perennial ryegrass plots in 1996. Chapter 3 IMPACT OF MOWING GOLF COURSE TURF ON AT AENI US SPRETULUS HALDEMAN AND ITS NATURAL ENEMIES ABSTRACT The abundance of Ataenius spretulus Haldeman larvae in golf course turf mowed at typical heights for fairway and rough was evaluated. The rough-fairway interface of a perennial ryegrass golf course was replaced with a new mowing regime. The experiment contained 4 replications of 4 treatments: turf that was mowed to fairway height in 1995, 1996 and 1997, turf mowed to rough height 1995-97, turf that was fairway height in 1995, but was allowed to grow to rough height in 1996-97 and turf that was rough height in 1995 and we cut to fairway height in 1996-97. Glass vials were used as pitfall traps to monitor activity of surface-dwelling predators and adult A. spretulus. In 1996, the most A. spretulus adults were found in plots mowed as Fairway in 1995. However, A. spretulus larvae were found in the highest numbers in the areas where the turf was mowed to fairway height in 1995, regardless of how the turf was mowed in the present year. Adult Philonthus spp. (Coleoptera: Staphylinidae) were found in the highest numbers in the plots that were mowed to rough height, regardless of the turf height past years. In 1997, the highest populations of A. spretulus adults and larvae were found in plots mowed to fairway height in 1996 and in 1997, regardless of 1995 mowing height. Twice as many larvae were infected with the entomopathogen, Bacillus popilliae Dutky, in the rough compared to infection of larvae in turf mowed to fairway height. In plots 43 44 changed from rough to fairway in April of 1996, the number of ants caught in pitfall traps decreased from 1996 to 1997, while the number of ants increased in plots changed from fairway to rough at the same time. The most prevalent staphylinids, two species of Philonthus, were more abundant in the rough-mowed turf compared with fairway-mowed turf. In conclusion, A. spretulus larvae were found more prevalently in turf mowed at fairway height. Mowing height influenced distribution of A. spretulus adults and larvae the year following mowing. Mowing height again influenced the location of the larvae in 1997, but the previous mowing heights did not. Mowing height also affected the distribution of staphylinids and the infection rate of A. spretulus larvae of B. popilliae. 45 INTRODUCTION Ataenius spretulus Haldeman is a native scarab grub that was considered an incidental pest prior to the 1970's (Tashiro 1987). Turf damage by this insect is now regularly reported on golf courses throughout the northeast, midwest, and west coast of the United States (Cartwright 1974, Kawasnishi et al 1974, Niemczyk and Dunbar 1976, Wegner and Niemczyk 1979, Wegner and Niemczyk 1981, Vittum 1995). However, A. spretulus larvae rarely damage home lawns (Vittum 1995). A. spretulus larvae are also more abundant in golf course fairways than in the adjacent irrigated rough (Smitley et al.1998). Rough and home lawn turf are often similar in grass length and in pesticide and fertilization applications. The density of A. spretulus grubs decreases abruptly when crossing from the fairway into the rough. Three fundamental differences between fairway and irrigated rough on most golf courses are grass species, mowing height and pesticide use. Also, turf in a golf course rough can be up to 5 cm taller than in the fairway. A. spretulus adults are small black beetles (2.5-5.1 mm) with distinct striations on the elytra. One adult female can lay up to 15 cream colored eggs in clusters in the soil. The larvae are the characteristic C-shaped grubs; the most damaging stage is the third instar that appears 45 days after eggs are laid. Little is understood about the role of predators in stabilizing populations of scarab larvae. Most of what is known about predators in turfgrass is based on observational evidence (Terry et al. 1993). Broad spectrum insecticides used for white grub control are detrimental to the stability of predator communities (Strue 1973, Potter et al. 1989) and reduce the ability of predators to control turfgrass pests (Cockfield and Potter 1983, Potter et al. 1989 ). For example, isazofos (Novartis Corporation, Greensboro, NC) applied in mid-June reduces predatory arthropod populations and reduces predation on Japanese beetle (Popillia japonica Newman) eggs by as much as 70% (Terry et al. 1993). 46 Mowing height may influence female scarab oviposition preference. European chafer, Rhizotrogus majalis Razoumowsky, grubs are more common in pastures mowed during the female beetles' oviposition flights than in grass preserved at a constant height of greater than 25 cm (Gyrisco et al. 1954). Masked chafers, Cyclocephala spp. (Coleoptera: Scarabaeidae), are less abundant in turf that is not mowed from May to September compared with turf mowed to 7.6 cm (Potter et al. 1996). In the same study, the number of Japanese beetles did not differ between short and tall mowed turf, but the larvae from the taller-mowed plots developed slower than larvae from the short mowed turf in one year of the study and weighed less than in the short mowed turf another year. Bacillus popilliae Dutky, B. lentimorbus and closely related Bacillus sp. known as milky spore diseases infect many species of the Scarabaeidae family. Endospores and sporangia found in A. spretulus larvae have a slightly different shape than the B. popilliae in Japanese beetle (Kawanishi et al. 1974, Splittstoesser and Tashiro 1977, Tashiro 1987). B. popilliae has been found in over 70% of the A. spretulus larvae collected from some golf course fairways, and is believed to be an important pathogen of A. spretulus (Tashiro 1987). The purpose of this research was to evaluate the effect of fairway and rough mowing height on the abundance of A. spretulus larvae, arthropod predators and B. popilliae infection of A. spretulus on golf courses. We attempted to eliminate confounding effects of grass species and pesticide use by selecting a 6-yr old golf course with no history of insecticide use, minimal fungicide use, and perennial ryegrass, Lolium perenne (L.) in both the fairway and the rough. 47 MATERIALS AND METHODS Mowing Regime. Research on A. spretulus larvae was conducted on the east side of hole #14 at Cattails Golf Club, South Lyon, MI. We chose Cattails Golf Club because it had perennial ryegrass in both the rough and the fairway, had very little fungicide use and no insecticide use. It was also a new course, only beginning its sixth season when we began doing research. In 1996, the line between the fairway height (1.6 mm) and rough height (5.1 mm) was altered from the previous year by mowing a curved path back and forth across the old border (Figure 1). This mowing regime created plots that were fairway in 1995 and rough in 1996, rough in 1995 and fairway in 1996, rough both years, and fairway both years. The plots were 6 m long and 3 m wide from either side of the old interface. The fairway was maintained by mowing 4 times a week beginning in April. Irrigation and fertilization remained constant for all plots and no fungicides or insecticides were applied. In 1997, the mowing regime was the same as in 1996. A. spretulus Larval Sampling. Using a golf course cup-cutter (10 cm- diam.), we sampled A. spretulus larvae with 10 cm-deep soil cores at the time of peak larval activity (July 14, 1996 and on July 21, 1997). One soil core was taken to the left of each pitfall trap in all plots (4 per plot) in 1996. In 1997, two soil cores were taken next to each of the pitfall traps in all plots. A. spretulus larvae were counted then frozen at 0° C for storage. B. popilliae Methods. Frozen larvae were removed from the freezer and allowed to thaw for 15 min. Each larva was punctured behind the head capsule with an insect pin and a drop of hemolymph was placed onto a microscope slide. One slide from each larva was examined under a phase-contrast microscope at 20x and 40x magnification to determine if B. popilliae was present. The B. popilliae spores found in A. spretulus 48 larvae were slightly oblong in shape and lacked a sporangium. The spores in the hemolymph tilt elliptically when they move across the field of vision. Pitfall Trap Sampling. Each individual plot was sampled with 4 pitfall traps (32 ml, 1.5 cm—diam. vials with 8 ml of ethylene glycol). The vials were placed flush with or just below the ground surface in holes made by a 19 mm-diam. soil probe. We removed the vials with a t-shaped, copper vial remover (Smitley et al. 1998), capped them and replaced them with fresh vials, once a week for 11 weeks beginning May 6, 1996 and for 12 weeks starting on May 5 in 1997. Large Pitfall Trap Sampling. In 1997, we added 4 large pitfall traps in each of the 16 plots. The pitfall traps were 140 ml glass vials (4 cm—diarn.) placed 10 mm below the turf surface. The pitfall traps were covered with a 5 mm wire screen to prevent golf balls and surface insects from falling into the vials. These pitfall traps were intended to capture soil dwelling arthropods, especially staphylinid larvae. Ant Trap Sampling. Ants were also monitored in 1997 using tuna fish baited traps, a method previously shown to efficiently monitor subteranean ant activity in a turf ecosystem (Zenger 1997). Plastic centrifuge tubes (1.5 ml, 1 cm-diam.) with attached snap-on lids were filled half way with oil packed tuna fish. A string was tied around the piece of plastic that connected the lid to the tube. The strings were used as locators to find the tuna traps in the longer grass. The strings were also used to pull the tubes out from underneath the soil. In each plot, we used a screwdriver to make a hole beneath the turf. The tuna traps were placed down these tube-like holes in the soil approximately 5 mm below the surface of the turf. Each of the 16 plots contained 10 traps placed randomly within the plots. The traps were left for 5-8 hours before being collected and brought to the laboratory for ant identification (Bolton 1994). After identifying the ants in the laboratory, we were able to identify them in the field in future collections. 49 Soil Sampling. Five random soil cores (l9 mm—diam. x 20 cm deep) were taken from each plot on September 8, 1996 and on July 28 and September 5 in 1997. Thatch and grass were removed and the remaining soil was mixed in a paper bag. The soil samples were sent to the Soil Analysis Laboratory at Michigan State University and tested for pH, lime requirement, phosphorus, potassium, calcium, manganese, zinc, magnesium, copper, iron, nitrate, ammonium and particle size of the soil. Statistical Analyses. In 1996, weekly counts for adult A. spretulus, Staphylinidae, Carabidae and Forrnicidae were evaluated using 2-way analysis of variance, with rough or fairway in 1996 and rough or fairway in 1995 as the two factors (SuperANOVA® 1990). Weekly pitfall trap data were summed for each trap for the entire season before analysis. All data were log (x+1) transformed before analysis. Soil nitrate and ammonium levels were regressed against numbers of A. spretulus larvae in 1996 (Systat® 1991). Weekly counts for adult and larval A. spretulus, and Staphylinidae were analyzed by a 2-way analysis of variance, rough x fairway (SuperANOVA® 1990), with the two mowing height treatments in 1997. The 1997 data was also analde by a 2-way ANOVA to determine if there were any lingering effects of the 1995 mowing treatment. All data were log (x+1) transformed before analysis. Number of A. spretulus larvae and adults were regressed against averaged weekly counts of staphylinid and carabid adults. A chi- square test was applied to A. spretulus larvae to determine if larvae infected or not infected with B. popilliae were more commonly located in the rough or the fairway mowed turf. RESULTS AND DISCUSSION In 1996, May, June and July average daytime highs were 20° C, 23° C and 26° C, respectively. Heavy rains occured on May 9, May 19, and July 9 when we received 20 50 mm, 26 mm, and 23 mm, respectively. However, the rains did not affect pitfall counts in low lying areas on the days of May 9 and 20 and on July 9. Temperatures in 1997 were cooler in May, and warmer in June and July than 1996 temperatures; the average highs for May, June and July were 16° C, 26° C, and 28° C. The overall trap catches for A. spretulus adults and larvae were greater in 1996. The predators caught in pitfall traps, staphylinids, carabids and ants, all had higher numbers in 1997 than in 1996. A. spretulus Larval Sampling In 1996, A. spretulus larvae were found most commonly in the areas of turf that were mowed to fairway height in 1995, regardless of how we mowed the turf in 1996 (Figure 2). Turf height of 1995 seemed to play a larger role in the location of A. spretulus larvae ( df = 1, 1, 1, 12; F = 18.8; P = 0.001, 2-way ANOVA) than the 1996 mowing height (df = 1, 1, 1, 12; F = 0.05; P = 0.83, Figures 2 and 3). However, in 1997, more A. spretulus larvae were found in the fairway plots than in the rough plots (17.5 i 1.4 per plot per 8 cup-cutters and 7.7 :1: 0.9 per 8 cup-cutters, respectively, df = 1, 14; F = 7.9; P = .01) regardless of how the turf was mowed the previous year (Figure 2). Despite having lower A. spretulus numbers in 1997, the plots that were either rough both years or fairway both years had similar larval numbers in 1996 and in 1997 (7.4 i: 2.5 and 4.0 :1: 0.6 for larvae in the rough plots and 23.8 :1: 7.0 and 12.3 :1: 0.8 for the fairway plots). If all numbers were doubled, the plots that were rough in 1995 and were mowed to fairway height in 1996 and 1997 had twice as many A. spretulus larvae in 1997 as in 1996. Plots that were fairway in 1995 and were allowed to grow to rough height in 1996 and 1997 had half as many larvae in 1997 as in 1996. This demonstrates that A. spretulus larval populations will adjust to conform with the new mowing height treatments over a 2-year period after mowing height is changed. After 2 years, more A. spretulus larvae will again be found in the fairway height turf regardless of the original mowing height before the experiment. 51 B. popilliae. In 1996, mowing height of turf affected the proportion of A. spretulus larvae that became infected with B. popilliae (df = 1, 14; x2 = 6.6; P < 0.05). B. popilliae was more active in the rough than in the fairway. The turf mowed to rough height had a higher percentage of infection (50%) of A. spretulus larvae than turf mowed to fairway height (25%) (Figure 4). The 1997 season followed the same trend of having a larger proportion of A. spretulus beetles infected with B. popilliae located in the rough mowed turf (df = 1; df = 1, 14; x2 = 19.3; p < 0.05) . The percentage of larvae infected with B. popilliae in the rough was 67.7% compared to only 34.3% of the larvae being infected in the fairway (Figure 5). Of all of the larvae collected in 1997, 41.6% of them were infected with B. popilliae. Pitfall Trap Sampling. Similar species of Fonnicidae, Carabidae, and! Staphylinidae were caught in pitfall traps in 1996 and in 1997. Fewer ants were captured in pitfall traps in 199601 :1: 2.2) than ‘were caught in 1997 (16.8 :1: 10.2, Figure 6). Rough and fairway mowed turf determined the location of ants caught in pitfall traps. The turf plots that were fairway in 1995, but rough in 1996 and 1997, had an increase in the number of ants caught in pitfall traps. When the 1995 rough—mowed turf was mowed to fairway height, the ant numbers decreased. Plots that remained either all rough or all fairway over the 3 years had similar numbers of ants captured in pitfall traps from year to year. Bembidion sp. (Coleoptera: Carabidae) was the most common carabid genus in 1996 (0.4 :1: 0.1 per vial per week), followed by Amara sp. and Stenolophus sp. In 1997, Amara was the most frequently captured genus (2.8 i 6.4 beetles per vial per week) and Bembidion was the next most abundant carabid (2.2 i 4.8 beetles per vial per week). The mean numbers of ground beetles per treatment were too low for meaningful analysis in 1996. In 1997, the mean number of carabids was 2.25 :1: 2.6 beetles in the rough per week 52 and 3.4 i 2.6 beetles in the fairway per week (df = 1, 14; F = 0.73; P = 0.41, Figure 6). Histerids were uncommon in both years. Two species of the genus Philonthus (Coleoptera: Staphylinidae) were the most common predators found in plots. Philonthus cognatus Stephens were the most prevalent predators on the golf course, averaging 25.8 i 0.78 and 48 i 2.7 beetles per plot in treatments Rough 1995/ Rough 1996 and Fairway 1995/ Rough 1996 (Figure 7) in 1996. In 1997, turf mowed to rough height again contained the most of P. cognatus, 71.5 :1: 4 for the Rough 1995/ Rough 1996-97 and 81 i 5 for the Fairway 1995/ Rough 1996-97. Philonthus carbonarius (Gravenhorst)was the next most common staphylinid on the golf course, averaging 14.5 i 1.08 and 14.5 i: 1.07 beetles per plot in treatments Rough 1995/ Rough 1996 and Fairway 1995/ Rough 1996 in 1996. The following summer, the golf course had higher numbers of P. carbonarius 28.4 :1: 4.0 for beetles in the Rough 1995/ Rough 1996-97 plots and 52 i 2.6 beetles in the Fairway 1995/ Rough 1996-97 plots. A few Omaliinae and Aleocharinae species (less than 0.1 beetles per vial per plot for 11 weeks for each species) were also captured, but the numbers were minute compared with the 2 species of Philonthus in both years. In 1996, staphylinids were trapped most readily in the treatments of Rough 1995/ Rough 1996 and Fairway 1995/ Rough 1996. P. cognatus and P. carbonarius were most abundant in turf mowed at rough height ( df = l, 14; F = 10.3; P < 0.00075 and F = 67.9; df = 1, 14; P < 0.0001 respectively). In 1997, the location of rove beetle adults was also determined by mowing height, with most beetles being found in turf mowed at rough height (df = 1, 14; F = 27.7; P < .0001). Cockfield and Potter (1985) showed that Philonthus sp. as well as other predators were uncommon in high maintenance sites compared with low maintenance sites. High maintenance turf is defined as having a short mowing height, high pesticide and fertilizer use and regular irrigation. 53 In 1996, adult A. spretulus beetles were caught in highest numbers in the Fairway 1995/ Fairway 1996 treatment (49.6 :1: 10.1 beetles per plot) (Figure 3). The second highest pitfall catches for the A. spretulus adults were in Rough 1995/ Fairway 1996 plots (24.3 i 7.8 beetles per plot). In 1996, A. spretulus adults were affected by the mowing history of the previous year (df = 1, l, 1, 12; F = 13.2; P < 0.005). They were also affected by mowing height of the current year, with most beetles being found in the turf mowed at fairway height. However, in 1997, adult A. spretulus beetles were only located where the turf was mowed to fairway height in 1996 and remained fairway height in 1997. No effect remained from the 1995 mowing height. The two plots that were mowed to fairway height in 1996 and 1997 had the most adult beetles (18.75 :1: 3.6 and 26.8 :1: 0.48 beetles per week per plot) compared to the two plots mowed to rough height that had only 1.75 :1: 0.48 and 3.25 i 0.48 beetles per week per plot. A. spretulus adults were affected by the mowing height in 1997 and were not affected by the mowing history of the golf course as in 1996 (df= 1, 14; F = 62.4 ; P = 0.0001). We compared catches of staphylinids and carabids with the density of A. spretulus adults and larvae in the fairway and rough treatments using a regression analysis. There is an inverse relationship between staphylinids and A. spretulus adults (df = 1, 14; F = 30.5; r2 = 0.46; P < 0.0001, Figure 8). There was no relationship between the rove beetles and A. spretulus larvae or between carabids and A. spretulus larvae or adults. We do not know why staphylinids are consistently more abundant in the rough, while A. spretulus larvae are more common in the fairway. In our research plots, the same type of grass, perennial ryegrass, was present in the rough and the fairway, and the irrigation rate was similar. One hypothesis worth investigating is that the turf in the rough could support a more diverse arthropod community, resulting in a better supply of food for staphylinids than turf in the fairway. More research needs to be done to determine if the turf in the rough has a higher food source for staphylinids and other turf predators than the 54 turf in the adjacent fairway. More research also needs to be done to explain the benefits of longer turf for all surface dwelling arthropods. Large Pitfall Trap Sampling. The small glass pitfall traps used were adequate for catching adult Philonthus beetles, but are not likely to be efficient for capturing Philonthus larvae. The small pitfall traps we used are better equipped to trap surface dwelling insects. Larval Philonthus are soil dwelling arthropods which would require pitfall traps to be placed further down below the ground surface. By using these large glass pitfall traps placed 10 mm below the turf surface, we believed we could monitor the presence of staphylinid larvae. These traps, however, did not capture the larvae as was anticipated. The traps were left out for 6 weeks and not one staphylinid larvae was caught. We believe that Philonthus larvae may be important predators in a turf ecosystem. Nekulisianu et al. (1987) states larval Philonthus sp. adapt quickly to new conditions and they play a large role in the population control of pests. Heessen et al. (1982) also showed that larval Philonthus spp. are polyphagous predators. However, better trapping methods need to be developed for capturing staphylinid larvae before we can determine their abundance and importance in the turf environment. Ant Trap Sampling In 1997, we attempted to measure the density of subsurface ants by using tuna fish baited traps placed in the soil. The main type of ants we captured in these traps were pavement ants in the genus Tetramorium (Figure 9). The mowing height of the present year (1997) or the past mowing height of 1995 did not seem to have an effect on the subsoil dwelling ants (df= l, 1, 1, 12; F = 3.0; P = 0.11 and df= 1, 14; F = 0.04; P = 0.85, respectively). The golf course had a very small population of Solenopsis, having an average of one trap filled with thief ants in only one of the plots per week. Our data is inconsistant with Zenger (1997). They found large numbers of Solenopsis in their turf plots and they seem to be effective predators against Japanese beetle eggs. 55 Soil Sampling Ammonium (NH4) soil concentrations did not differ significantly between mowing heights of 1995 and 1996 (Table 1). Ammonium levels were highest in Rough 1995/ Rough 1996 plots (4.4 i 0.1 ppm). The nitrate levels were highest in treatments Rough 1995/ Fairway 1996, Rough 1995/ Fairway 1996, and Fairway 1995/ Rough 1996 (35.6 :1: 6.3 ppm, 34.7 i 8.7 ppm, and 35.6 i 6.3 ppm, Table 1). Prestige et al. (1985) found that fertilization did not affect the New Zealand grass grub (Costelytra zealandica White). Nitrate concentrations and the numbers of A. spretulus larvae were significantly correlated (r2 = 0.32; df =1, 14; F = 6.5; P < 0.05, Figure 10). The mowing history does not seem to affect the ammonium or nitrate in the soil, but the mowing height of the current year does seem to affect the levels (Table 2). There was no relationship between the other soil nutrients and mowing height of the turf or A. spretulus adults or larvae. In 1997, there was no relationship between phosphorous, potassium, calcium and magnesium and rough and fairway mowing heights in either of the two soil samples. Nitrogen fertilizers, nitrate and ammonium, did not differ significantly with the first sample taken in July (df = 1, 14; F = 0.014; P = 0.90 and df = 1, 14; F = 0.23; P = 0.63, respectively, Table 1). However, both of the nitrogen samples taken in September were significantly different with rough and fairway mowing height (df = 1, 14; F = 8.7; P = 0.011 for nitrate and df = l, 14; F = 6.98; P = 0.019 for ammonium). A. spretulus larvae were compared with a regression analysis with both nitrogen fertilizer samples taken in September, but neither were correlated (r2 = 0.033; df = 1, 14; F = 0.48; P = 0.50 for nitrate and r2 = 0.19; df = 1, 14; F = 3.3; P = 0.09 for ammonium). In conclusion, A. spretulus larvae were more commonly found in golf course plots that were mowed to fairway height. Current mowing height did not affect the numbers of A. spretulus larvae in 1996 as much as the mowing height in the previous year (1995), but it did influence numbers of A. spretulus larvae in 1997 and Philonthus adults in both 1996 56 and 1997. Although Philonthus adults were strongly correlated with A. spretulus adults, they may or may not be predators of them, and we have not found an effective way to sample for Philonthus larvae in the soil. From this research, it appears that the length of the turf determines the location of A. spretulus adult and larval populations. The length of turf also determines infection rates of larvae with B. popilliae. Fairway-mowed turf supports a higher community of adult and larval A. spretulus, while rough-mowed turf maintains increased populations of surface predators and the bacteria B. popilliae. Ovipositing females may have a preference for shorter mowed turf or A. spretulus larvae may simply prefer to feed on the roots of fairway turf because they are smaller and more succulent than roots in the rough (Turgeon 1996). Our research suggests that future investigations should focus on predators of A. spretulus, female oviposition sites, and B. popilliae infection levels in order to explain why A. spretulus larvae are more prevalent in golf course fairways than in the rough. LITERATURE CITED Bolton, B. 1994. Identification guide to the ant genera of the world. Harvard University Press. Cambridge, MA. Beard, J.B. 1982. Turf managemnet for golf courses. Macmillan Publishing Co., New York, NY. Cartwright, O.L. 1974. Ataenius, Aphotaenius and Psuedataenius of the United States and Canada (Coleoptera: Scarabaeidae: Aphodiinae) Smithsonian Contrib. Zoo]. 154: 1-106. 57 Cockfield, S.D. and D.A. Potter. 1983. Short-term effects of insecticidal applications on predaceous arthropods and orbatid mites in Kentucky bluegrass turf. Environ. Ent.. 12: 1260-1264. Grysico, G.G, W.H. Whitcomb, R.H. Burrage, C. Logothetis, and H.H. Schwardt. 1954. Biology of European Chafer Rhizotrogus majalis Razoumowsky (Scarabaeidae). Cornell Ag. Exp.. 328. Heessen, H.J. L., M.A. Wildschut, and A.M.H. Brunsting. 1982. Duration of the developmental stages and timing of the end of the reproductive season of Pterostiches oblongopunctatus (Fabricius). (Coleoptera: Carabaidae) and Philonthus decorus (Gravenhorst) (Coleoptera: Staphylinidae). Netherlands J. Zool. 32: 49-62. Kawanishi, C.Y., C.M. Splittstoesser, H. Tashiro and K.H. Steinkraus. 1974. Ataenius spretulus, a potentially important turf pest, and its associated milky disease bacterium. Environ. Ent.. 3: 177-181. Klein, M.G. 1980. Biological Suppression of turf insects. p. 90-97. In H. D. Niemczyk and B. G. Joyner [eds.], Advances in turfgrass insects: a collection of papers presented at the symposium. Chemlawn, Columbus, Ohio. Nekulisianu, Z.Z., V,G. Ostafichuk, and A.F. Tsygankova. 1987. Biological peculiarities of some rove beetle species of the genus Philonthus Curt. (Coleoptera: Staphylinidae) of Moldivia. Entomol. Obozr.. 3: 511-518. 58 Niemczyk, H.D. and D.M. Dunbar. 1976. Field observations, chemical control, and contact toxicity experiments on Ataenius spretulus, a grub pest of turf grass. J. Econ. Entomol.. 69: 345-348. Potter, D.A., S.D. Cockfield, and T.A. Morris. 1989.Ecological side effects of pesticide and ferilizer use on turfgrass. In A. R. Leslie and R.L. Metcalf (eds), Integrated pest management for turfgrass and omamentals. US-EPA, Washington, DC. Potter, D.A., A.J. Powell, P.G. Spicer, and D.W. Williams. 1996. Cultural practices affect root-feeding white grubs (Coleoptera: Scarabaeidae) in turfgrass. J. Econ. Entomol.. 89: 156-164. Prestidge, R.A., S. Van der Zijpp, and D. Badan. 1985. Effects of plant species on grass grub larvae, Costelytra zealandica. New Zealand J. Agric. Res. 28: 409-417. Strue, H.T. 1973. The turfgrass ecosystem: impact of pesticides. Bull. Entomol. Soc. Am.. 19: 89-91. SuperAnova. 1991. The accessible general linear modeling package. Abacus Concepts, Inc., Berkley, CA. Systat 5 for the Macintosh. 1990-1991. Systat Inc., Evanston, IL. 59 Terry, L.A., D.A. Potter, and P.G. Spicer. 1993. Insecticides affect predatory arthropds and predation on Japanese beetle (Coleoptera: Scarabaeidae) eggs and fall arrnyworm (Lepidoptera: Noctuidae) pupae in turfgrass. J. Econ. Entomol. 86: 871-878. Tashiro, H. 1987. Turfgrass insects of the United States and Canada. Cornell University Press, Ithaca, NY. Turgeon, A.J. 1996. Turfgrass Management. Prentice-Hall Inc., Upper Saddle River, New Jersey. 406 pp. Vittum, P.J. 1995. Black turfgrass ataenius, pp. 35—37. In R.L. Brandenburg and M.G. Villani [eds.], Handbook of turfgrass insect pests. Ent. Soc. America, Lanham, Maryland. Wegner, G.S. and H.D. Niemczyk. 1979. The Ataenius of Ohio. Ohio J. Sci. 79: 249-255. Wegner, G.S. and H.D. Niemczyk. 1981. Bionomics and phenology of Ataenius spretulus. Ann. Entomol. Soc. Am.. 74: 374-384. Zenger, J. 1997. Egg predation and integrated pest management of white grubs (Coleoptera: Scarabaeidae) in turfgrass and maize. PhD. Dissertation, Purdue University, West Lafeyette, IN. 60 mod n A He “schemata xugomfiawwm Be 338 35 882?: H... _ 3.3 H 3 :5. H a: swam :3 H mm :3 H 3N SEE 32 canaucaom .2 H 5. Ha H a: swam be H 3. 3 H v.2 53am 82 .23 we H mm B H SN :32 no H 3 on H EN saga 82 Haws< mm H mm H $328: fine sz 8:858... fiae c6 32:2 Ewe: 3%: 93 23% .88 2 - m 5053 BE? Snow 295m .3383 :8 Bet @3082 we? :89: 3.. .33 Ho HopEeEom new b3 E use 83 Ho awn—wag. 5 meoumbeooeoo :8 8:30:83 98 Bfizz A 033.. 61 3 H E S. 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E:— 53 Eoibn Hanna—a Eon“ 3:“???th Fem—Avg a: 9 52.2.3»— Qnmwwmm no.» 85%. 2.5.7on ab Fame—8 avg m2. can: gum E:— 8: 2:8 nun—u ~62. can 13. <acb uumum cwwficuuz unu a“ camoauv you mcosfiuunm vuumafl u>onm onu vu>fiuuum Hamchom cc»; Hxxfiz m .nmma .oz nunuao> Avuahuv Amvosmz m.uoumwaumu>cH Ahuommuuoc ma ouuucm Hoseauuvvo omav 93 APPENDIX 1.1 Vbucher Specimen Data Page J of 1 Pages Michigan State University of South Lyon Ataenlus spretulus Aphodius granarius Philonthus sp. 29 20 Michigan Oakland Co. T1N, R7E, SEC 34 2.5 miles E. Museum where depos- ited euufimoaov van cum: Ho vuuuuHHou aoxmu Honuo no muauoam mauEHuuam you «one Huang Other Adults 0" Adults 9 Pupae Nymphs Larvae Eggs "mo uuofinz APPENDD( 2 Appendix 2. 1995 Survey to 250 Golf Course Superintendents in Michigan. Michigan State University Ataenius and Aphodius Survey QeneLaL—lnmmatinn 1. What kind of grub problem do you have, if any: Ataenius Aphodius Both . Not sure, but one or the other . Another type of white grub capo-g» 2. Have you identified Ataenius or Aphodius on your golfcourse (if no, please go to 3. Ify Adults: Grubs: question #9)? If yes, for 1995, did you find (Check one): Few (1-2 per cup cutter) Many, but no damage ( 5+ per cup cutter) Many, but little damage (5+ per cup cutter) Many, severe damage (5+ per cup cutter) 9.09:9» ou did find them, where were they located and how many in each location (Check all that apply)? None Few Many None Few Many Tees Greens Fairways 94 95 Rough 4. Did you specifically spray for Ataenius or Aphodius? 5. If you have Ataenius or Aphodius, is it widespread or spotty? 6. When did you find Ataenius grubs? (Circle all that apply) June July August September 7. When did you find Aphodius grubs? (Circle all that apply) June July August September 8. Does the population shift to different locations from year to year? Yes No 9. What fungicides(s) did you use in 1995. at what rate, how many applications and the location (Abbreviate locations as: Greens (G), Tees (T), Rough (R), Fairways (F))? Eunsisids Bats. LQLAnnliealiQns Location 10. If you used a snow mold in 1994 and it is not listed above, please list below. EH! Rate “[5].. 1‘. 96 11. What insecticide(s) did you use in 1995, at what rate, how many applications, and the location (G, T, R, F)? 1"] m #Ell" I . 12. What herbicide(s) did you use in 1995, at what rate, how many applications, and the location (G, T, R, F)? IIl"l Rats l!f!l’° I . 97 Mus—[um 13. What are your dominant grasses in the fairways (Check all that apply)? Creeping Bentgrass Kentucky Bluegrass Annual Bluegrass Rough Bluegrass (P. Ifixialis.) 14. What is the average cutting height of your fairways? 15. What is the average cutting height of your rough? 16. How many acres of woodlots are on the golf course? 17. How often do you mow? Max Lens. Lilli AW 5291mm a. the fairways: b. the rough: c. the greens: (1. the tees: Location (confidential information: Superintendant's name and golf course name will not be printed in reports) 18. Superindentdant: 19. Golf course: 20. County: 21. Township: