sponsored Research You Can Use Biology and Management of Nematodes on Turfgrass in Northern A variety of microscopic roundworms lurking just beneath the surface poses a challenge for putting surfaces. BY B. B. WESTERDAHL, M. A. HARlVANDi, AND L. R. COSTELLO ematode damage on Poa California. Following the survey, two annua putting greens has been golf courses were selected for biweekly N a recurring problem on monitoring of nematode populations. golf courses. Additionally, a trial comparing the Nematodes typically found causing effectiveness of six potential products as damage to turf include: root knot replacements for Nemacur was con- (Meloidogyne sp.), ring (Mesocriconema ducted on a green in sp.), dagger (Xiphinema sp.), lesion Northern California. (Pratylenchus sp.), stubby root (Tri- chodorus sp.), pin (Paratylenchus sp.), and SETTING UP THE TRIALS sting nematode (Belonolaimus longi- To survey for nematodes, one or more caudatus). In addition, we have recovered cores were taken with a cup cutter from Anguina pacificae lives within these galls visible large numbers of spiral nematode (Heli- at the base of the plant. at least one green on 14 golf courses in cotyknchus sp.) from problem turfgrass Monterey, , and San locations. stood. To further the development of Mateo counties (Table 1). Galls were In 1982, from San Francisco, San environmentally sensitive programs for individually removed from the cores Mateo, and Monterey counties of nematode management, a survey was and dissected. California, Anguina pacificae, a seed and conducted to determine the distribu- Following the survey, a single green leaf gall nematode, was first identified tion of A. pacificae and other nematodes was selected at the Olympic Club Golf from Poa annua galls located at the bases on coastal golf courses in Northern Course in San Mateo County and of stems. Since this finding, A. pacificae has been considered to be the primary Table 1 nematode causing problems on coastal Populations of various nematodes found on golf courses in Northern California. golf courses in Northern California. Nematodes Per Liter of Soil The organophosphate nematicide Golf Course Spiral Ring Root-Knot Nemacur (fenamiphos) has been used in the management of A. pacificae Bayonet 6,200 50 150 Cypress Point 22,500 4,200 300 and other nematodes on turfgrass in Del Monte 9,600 38,400 650 California (Winterlm et al, 1986). 13,260 10 0 Recently, the nematode problem has Monterey Peninsula 90,240 1 2,000 0 become increasingly more noticeable Northwood 5,760 9,120 1,450 both on courses that have used Nema- Olympic Club 6,857 1,600 29,400 Pacific Grove 3,600 1,800 0 cur and on those that have not. Nema- Pebble Beach 4,200 33,000 50 cur will be withdrawn from the market Poppy Hills 12,900 1,800 1,200 in the near future, and replacement Presidio 9,200 0 0 management techniques are needed. Quail Lodge 9,600 27,900 0 Up to this point, the life cycle of A. San Francisco 4,114 2,229 350 1,350 50 pacificae has not been completely under- Spyglass 600

SEPTEMBER-OCTOBER 2005 Table 2 Number of Anguina galls and nematode populations within galls following nematicide applications. Immature Total Total Treatment Rate/Acre Galls Females Males Adults Juveniles Eggs Adults Nematodes Untreated 13.0 13.3 8.5 19.0 105.5 1,745.3 40.8 146.3 Nemacur IOG 66.7 Ib/A 2.8 0.09 2.5 0.02 1.3 0.03 12.3 0.13 0.5 0.35 63.0 0.01 16.0 0.01 16.5 0.03 DiteraDF 100 Ib/A 17.3 0.77 14.0 0.68 8.8 0.98 8.0 0.34 12.5 0.74 1,422.3 0.01 30.8 0.64 43.3 0.55 A- 1641 20lb/IK 11.8 1.00 8.0 0.74 4.3 0.44 15.0 0.74 1.3 0.46 2,486.3 0.20 27.3 0.58 28.5 0.39 A- 1641 I5LB/IK 17.0 0.67 16.5 0.56 6.5 0.73 7.8 0.11 123.3 0.90 902.3 0.29 30.8 0.75 154.0 0.92 Quillaja35% 1.5 GPA 12.8 0.72 4.3 0.17 1.8 0.10 17.5 0.69 12.0 0.62 940.0 0.46 23.5 0.09 35.5 0.33 Quillaja35% 2.5 GPA 16.5 0.97 7.5 0.27 5.0 0.22 13.0 0.64 1.0 0.40 1,697.8 0.71 25.5 0.47 26.5 0.35 XRM 5053 3 GPA 14.5 0.78 15.0 0.66 3.8 0.25 10.8 0.08 124.0 0.89 2,554.5 0.99 29.5 0.70 153.5 0.92 Fore 28 liters 25.7 0.41 20.5 0.40 14.0 0.80 12.8 0.35 62.5 0.72 2,700.5 0.98 47.3 0.73 109.8 0.92 Fosthiazate 3 Ib AI/A 1.5 0.03 0.5 0.01 0.0 0.01 4.8 0.01 238.5 0.51 0.0 0.67 5.3 0.01 243.8 0.21

Each figure is the mean of 4 replicates. Each mean is followed by the probability that it is statistically different from the untreated. Rate indicates amount of product applied for each of 3 applications at 4- to 6-week intervals. Galls indicates galls counted per inch of soil core. Other figures are total counts per 1 0 galls per replicate. Total adults is the sum of females plus males plus immature adults. Total nematodes is the sum of total adults plus juveniles. another at Poppy Hills Golf Course in 30, October 30, and December 12, tion, all courses surveyed had abundant Monterey County to monitor the 2003. Nematode samples were taken on populations of spiral nematode, 13 had population cycling of the four nema- January 20,2004. ring nematode, and 9 had root-knot todes found most commonly during Nematodes were extracted from soil nematode. Other nematodes found the survey. Three cup-cutter cores were around roots and the number of galls occasionally and in lower populations taken biweekly from each green. per inch of surface area was counted. were: needle (Longidorus sp.), pin Nematodes were extracted from soil Ten galls were individually removed (Paratylenchus sp.), stubby root (Tricho- around roots and were identified to from the cores and dissected under a dorus sp.), sheath (Hemicydiophora sp.), genus and counted under a dissecting dissecting microscope. From each dis- lesion (Pratylenchus sp.), and cyst (Hetero- microscope. sected gall, the number of adult males dera sp.).These findings indicate that For the management trial, a green and females, immature adults, juveniles, although A.padjicae is widespread in at the Olympic Club that was heavily and eggs was determined. coastal Northern California golf infested with A. padjicae, spiral nema- Turf quality was visually determined courses, there is potential for other tode, ring nematode, and root-knot by the golf course superintendent based nematodes to be causing problems nematode was selected. The treatments on standards acceptable for that location. as well. were: untreated, Nemacur IOG (Bayer), Digital photos were taken from a slope When sampled at 2- to 6-inch incre- DiTera DF (Valent), two rates of A-1641 overlooking the plot and a representa- ments, nematodes were abundant at all (mustard bran, Uniroyal/Crompton), tive photo in which all replicates were depths (data not shown).This indicates two rates of Quillaja 35% (Desert visible in full sun was selected for digital that although the galls of A.padjicae are King), XRM 5053 (1,3-dichloropropene analysis of turf quality. The digital located close to the surface, methods to plus emulsifier, DowAgro Sciences), and analysis was conducted with the histo- kill populations of other nematodes Fore (mancozeb, Dupont) (Table 2). gram function of Adobe Photoshop set will need to be effective to greater Applications were followed by 0.5 inch for RGB analysis. depths. Although they were not alive, of irrigation via overhead sprinklers. A.padjicae, spiral, and ring nematodes During the trial, the green was main- RESULTS AND DISCUSSION were recovered from a water sample tained by the course following standard A.padjicae was found on Poa annua taken from a pipe draining a green, cultural practices. greens in all golf courses (12) surveyed indicating the ability of nematodes to Each treatment was applied a total of in Monterey, San Francisco, and San move in drainage systems. three times at 4- to 6-week intervals. Mateo counties (Table 1). For two Two of the nematodes, A.padjicae Turf quality was evaluated and nema- additional courses with bentgrass greens and root-knot, monitored in the bi- tode samples were taken 6 weeks fol- (Lake Merced and Presidio), A.padjicae weekly survey are endoparasitic nema- lowing the final application. Applica- was not found on the greens but was todes. Juvenile nematodes penetrate tions were conducted on September present in surrounding areas. In addi- plant tissues, and the adults mature and

GREEN SECTION RECORD In the nematode management trial, Figure I OLYMPIC CLUB POPPY HILLS by visual observation, it was evident 10,000 000 that turfgrass quality in Nemacur- and fosthiazate-treated plots was superior to 9,000 all other treatments. Some improvement ANGUINA JUVENILES , 6,000 PER QUART OF SOIL { in quality was visible in the DiTera- 8,000 treated plots compared to the untreated,

7,000 ; 5,000 while the remaining treatments could not be visibly distinguished from the 6,000 untreated. The digital photograph 4,000 analysis conducted using the histogram 5,000 function of Adobe Photoshop supported 3,000 the visual analysis (data not shown). The 4,000 red analysis indicated that Nemacur and 3,000 2,000 fosthiazate treatments were superior to the untreated. Of the products tested, 2,000 only Nemacur 10G, DiTera DF, and 1,000 Fore are currently registered for use on 1,000 turf in California. Several treatments reduced popula- 0 50 100 150 200 250 300 350 400 tions of A. pacificae (Table 2). Nemacur JAN MAR MAY JUL SEP NOV DEC reduced the number of males, females, lay eggs within the plant. The data reported are for populations of juveniles found within soil around roots. These are the populations most likely to be affected by nematicide applications. Spiral and ring nematodes are ectoparasites of turf, always being found outside of roots in the soil. Populations of all four nematodes fluctuated throughout the year. Pving nematode populations were consider- ably higher at the Olympic Club than at Poppy Hills. Populations at the Olympic Club were highest in September, and at Poppy Hills in November. As with ring nematodes, populations of root-knot nematodes were typically higher at the Olympic Club than at Poppy Hills, with peak populations occurring in April and September. Peak populations of root- knot nematodes at Poppy Hills were reached in September and November. Levels of spiral nematodes were similar at both locations, with the highest populations occurring at the Olympic Club in mid-August and at Poppy Hills in early November. Populations of A. pacificae peaked in June at Poppy Hills Population sampling for nematodes was conducted by Dr. Becky Westerdahl at several courses and in August at the Olympic Club. in the San Francisco and Monterey Bay areas.

SEPTEMBER-OCTOBER 2005 Damage to a Poa annua golf course green caused by the nematode Anguina padficae. eggs, total adults, and total nematodes. California Department of Food and Agriculture, Winterlin, W, F. Peterson, and L. R. Costello. Fosthiazate reduced the number of Division of Plant Industry. 1986. Nemacur residue in turfgrass. California Agriculture 40(1 & 2). galls, females, males, immature adults, Byrd, D.W.Jr., K. R. Barker, H. Ferris, C.J. and total adults. DiTera reduced the Nusbaum, W. E. Griffin, R. H. Small, and C. A. Stone. 1976. Two semi-automatic elutriators for ACKNOWLEDGMENTS: Funding was number of eggs. None of the treatments extracting nematodes and certain fungi from provided by the USGA, NCGA, several reduced populations of root-knot, soil. Journal of Nematology 8:206-212. Northern California golf courses, and the spiral, or ring nematodes (data not Cid del Prado Vera, I., and Maggenti, A. R. 1984. University of California Slosson shown). For several treatments, popula- A new gall-forming species of Anguina Scopoli, Foundation. The cooperation of the golf tions of spiral nematodes were signifi- 1777 (Nemata: Anguinidae) on bluegrass, Poa annua L., from the Coast of California Journal courses mentioned, the NCGA, and the cantly higher than for the untreated. of Nematology 16:386-392. USGA was essential to the success of this Increased nematode populations could RadewaldJ. D, and B. B. Westerdahl. 1988. research. occur if the treatments permitted the Nematode Diseases of Turfgrass. In Turfgrass development of a healthier root system Pests. University of California, Division of that could sustain higher populations of Agricultural Sciences Publication 4053. B. B. WESTERDAHL, Extension Nematolo- gist/Professor of Nematology, University of nematodes. This was also the case for Westerdahl, B. B., E. Caswell-Chen, and one treatment with ring nematodes. J. Hartin. 2000. Nematodes. In Turfgrass Pest California, Davis, Calif. M. A. HARIVANDI, Management Guidelines. In U.C. Pest Manage- University of California Cooperative Exten- ment Guidelines, IPM Education and Publica- sion, Alameda, Calif. L. R. COSTELLO, LITERATURE CITED tions (eds.). University of California, Agriculture Ayoub, S. M. 1977. Plant nematology: An and Natural Resources Publication 3339, University of California Cooperative agricultural training aid. Sacramento, Calif. Oakland, Calif. Extension, Half-Moon Bay, Calif.

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