DIAMOND

ZOYSIAGRASS

DALZ8502

Petition to Release

PLANT MATERIALS RELEASE PROPOSAL SUMMARY FORM

Date 9 April 1996

1. CROP Zoysiagrass Type of Release Varietal

2. Proposed name or identification: DIAMOND

3. Designation or name in development stages: DALZ8502

4. Primary features or advantages: Diamond is a Z. matrella which is vegetatively propagated and genetically stable and uniform. Diamond is distinguished from other zoysiagrass by it's fine texture, high rhizome and tiller density, superior salt tolerance, shade tolerance and rapid regrowth and recovery from damage. Diamond tolerate close frequent mowing as its potential commercial value include golf putting greens in the gulf coast states, and tee boxes in full sun and under moderate to heavy shade. Diamond generally lack sufficient winter hardiness to be used in open areas for turf north of the Red River between Oklahoma and Texas. Diamond is highly susceptible to the tropical sod web worm, tolerant to Rhizoctonia solani patch disease.

5. Plant Variety Protection - suggested action: Certification required, process for Plant Patent as this is a vegetatively propagated species.

6. Planting Stock -- amount available and date: Approximately 500 m² of breeder class sod which is under the USDA fire ant compliance program will be available for harvest approximately 1 June 1996. Planting stock is grown at Texas A&M Research and Extension Center - Dallas, TX.

7. Provisions to maintain breeder seed: Breeder stock will be maintained by the Texas Agricultural Experiment Station - Dallas.

8. Proposed seed stock distribution: Breeder planting stock should be made available directly to a licensee for further propagation and maintenance of foundation class sod. This variety is expected to have a limited market potential in comparison to other vegetatively propagated species and should be considered a speciality turf. We would recommend that a single entity be identified for national marketing and production. Potential exist for licensing for special targeted utility, i.e., sports fields with low light conditions, shaded tee boxes on golf courses, buffer surrounds for bentgrass greens, etc.

Submitted by:

Breeder and Scientists- Unit Head

M. C. Engelke Randy Upshaw

In cooperation with:

Drs. P. F. Colbaugh, J. A. Reinert, K. B. Marcum. R. H. White, B. A. Ruemmele and Ms. S. J. Morton

Diamond Zoysiagrass

M. C. Engelke, P. F. Colbaugh, J. A. Reinert, K. B. Marcum, R. H. White, B. A. Ruemmele and S. J. Morton.

'DALZ8502' ZOYSIAGRASS proposed name 'DIAMOND' is a fine textured vegetatively propagated clone of Zoysia matrella which is noted specifically for its excellent tolerance to low light conditions, salt tolerance and rapid recuperative ability. Diamond was developed and submitted for released by the Texas Agricultural Experiment Station in 1996. Diamond will be suitable for use as a warm-season turfgrass for putting greens and tee boxes on golf courses in the coastal regions of the southern United States where shade and salinity are a problem. Diamond is a fine textured highly rhizomatous vegetatively propagated zoysiagrass.

ORIGIN AND BREEDING HISTORY:

Diamond is a vegetatively propagated zoysiagrass which was identified in 1983 as an aberrant selection from among cultivated plant introductions and accessions planted in the fall of 1981. It was expected to be similar in texture to PI 231146 however all replications of the "parental" plant failed to survive the winter of 1981/82. This individual plant appears similar to the original PI however the surviving rhizomes apparently had better winter hardiness. Diamond was unique to the population differing primarily in rhizome density and leaf texture. The plant was removed and vegetatively increased to be included in a replicated turf trial at Texas Agricultural Experiment Station - Dallas in 1983 along with several other introductions and progeny to evaluate turf quality, and general performance in turf persistence. The trial was stripped with a sod harvester in 1985 and observations were made on regrowth and recovery. Several plants were selected from among the trials in 1985, this particular plant was designated as Diamond and has since be tested under that designation.

PERFORMANCE AND ADAPTATION:

Diamond has been evaluated in field, greenhouse and laboratory studies in conjunction with the USGA zoysiagrass improvement program since 1983 and was included in the 1991 National Turfgrass Evaluation Program (NTEP) along with 24 additional zoysiagrass varieties and cultivars. A major revelation supported by the results of the NTEP test over a 4-year period was the general lack of winter hardiness of this variety in northern climates, and the necessity to provide a higher level of management than is normally provided in such generalized trials. Diamond warrants release however due to its low dense growing habit, excellent shade tolerance, salinity tolerance and rapid regrowth potential. Details follow.

RHIZOME PRODUCTION - RECUPERATIVE ABILITY: Field studies designed to compare the quality of zoysia sod and the rate of recovery following sod harvest were conducted in 1985 at the Texas A&M Research and Extension Center - Dallas. The turf plots were established in 1983 in a randomized complete block design with three replications for 38 different zoysia accessions. . Following establishment and quality evaluations the fully established plots were harvested using a walking Ryan sod harvester. Sod was harvested to a depth of 10 mm below the crown. Sections of sod were placed on a strengthening mechanism designed to determine the force required to separate the sod into individual sections. Sod strength was measured as Kg/cm² on only thirteen of the entries and reported in Table 1. Experimental line KLS 3, (an introduction from Korea), Diamond and FC13521 had the greatest sod strength as they required the greatest force to separate the sod. Emerald ranked seventh and Meyer tied for last place among the 12 entries evaluated.

The same areas of the zoysia plots were monitored following harvest to determine the rate of recovery and regrowth. Observations were made on the number of rhizome tillers per 0.1 m² at 19 and 42 days post-harvest and are presented in Table 2. Thirty-eight varieties were evaluated which included several experimental entries and three commercial cultivars; Emerald, Meyer and FC13521. By 19 days an experimental line designated as DALZ8501 produced twice as many rhizome tillers as any other variety in the study. By 42 days post-harvest however, Diamond was equivalent to DALZ8501 in regrowth and both were significantly better than any other variety tested. Compared to Meyer and Emerald, Diamond produced 8.5 and 3.1 times more plants than Meyer and Emerald, respectively. This is further reflected in the practical sod regrowth rates we observe under field conditions where the sod cycle from harvest to harvest averages a 4-month growth cycle which translates into three harvest in a 24 month time period for North Texas. Carrow (1992) in Georgia rated Diamond as one of the best rhizome producers 12 months following establishment.

Table 1. Sod strength of a 2-year old stand of selected zoysiagrass varieties grown at Texas Agricultural Experiment Station - Dallas. Plots established in 1983 and harvested in 1985. (Reference USGA annual report Nov 1985 - Table 13.)

* Means followed by the same letter in each column are not significantly different at the P=0.05 according to Waller-Duncan k-ratio t test (k-ratio=100)

Table 2. The number of rhizome tillers per 0.1 m² indicating rhizome regrowth of experimental and commercial zoysaigrass varieties at 19 and 42 days following sod harvest. (Reference USGA annual Report November 1986 -Table 5).

DAYS POST-HARVEST

* Means followed by the same letter in each column are not significantly different at the P=0.05 according to Waller-Duncan k-ratio t test (k-ratio=100).

Diamond is vegetatively propagated and spreads by both stolons and rhizomes. It is considered strongly rhizomatous which accounts for its relatively slow establishment rate, but excellent recovery rate. Diamond will require between 12 - 18 months to develop a fully established turf when planted by sprigs or plugs. Once established, however, its harvest cycle will average between 4 - 6 months (growing period) resulting in approximately three harvest in 2 years under environmental conditions similar to those found at Dallas, TX.

SHADE TOLERANCE:

Light, water and nutrition are key components of the environment required for plant growth and development. With adequate water and nutrition, light becomes the limiting factor. According to Dudeck and Peacock (1992) 20 - 25% of all existing turfs is maintained under some degree of shade from buildings, shrubs, or trees.

Diamond has demonstrated excellent shade tolerance in trials under natural shade at TAES-Dallas (Morton, S.J. et al. 1991, 1994a, 1994b), and artificial shade in Hawaii (Morton et al. 1994c) and when grown under greenhouse conditions with artificial shade (Riffell Sam, M. C. Engelke unpublished). Diamond is capable of tolerating less than 10% light transmission for prolonged periods of time.

A replicated study was initiated on May 15, 1995 in the greenhouse on sand-profile-over-plastic with 5 year-old sod of Diamond and artificial shade conditions imposed on the turf. The objective of this study was to determine the critical light level under which Diamond will continue to produce an acceptable quality turf. The photosynthetic active radiation (PAR) of the polyethylene covered greenhouse was 63% of natural sunlight. Shade cloth rated at 47%, 73% and 95% were used to further imposed additional light restriction on the turf. The four light levels evaluated were: level 1 = 37% (normal greenhouse conditions), level 2 = 67% shade (using 47% shade cloth), level 3 = 83% shade (using 73% shade cloth), and level 4 = 97% shade (using 95% shade cloth). The area was subjected to three traffic events weekly imposed by a 34 Kg tile roller measuring 22 cm wide and 10 cm diam. Tables 3a-e represent the information generated as a result of this test. Color retention rated on a 1-9 scale, where 9 is the most favorable color was consistently higher at the 83% shading. After 28 days of continuous treatment, color was rapidly declining at the 97% shade and was totally unacceptable at 69 days (Table 3a). Turf quality (1-9, where 9 is best) (Table 3b), and Turf uniformity (1-9, 9 best) declined at the 97% shade within 28 days, with no significant differences noted across other shading levels after 69 days. Vertical growth (1-9, where 9 represented the most vertical growth) (Table 3d) was significantly impacted and linear in response at all shade levels throughout the course of the study. The higher the level of shading, the greater the degree of vertical growth which is predictable. The critical level however is defined by the combination of traits measured including density of stand (Table 3e). Although some loss of density was noted at 83% shade after 69 days, the persistent response of acceptable turf (threshold = 5 and above) would indicate that Diamond can tolerate 83% shade under traffic, and that a 97% shading level is too severe based on the observed declines in density, quality and acceptability. In order to further define the threshold above 83% and below 97%, additional studies are being conducted in combination with the impact of maintaining optimum soil temperature. These studies are suggesting this light/soil temperature limit may approach 90-92% shade with soil temperatures are maintained near 20 - 28 ^oC. At lower soil temperatures the rate of root development is greatly compromised. Normally, shaded areas will have cooler soils as well.

Table3a. Color retention of Diamond under four light intensities provided by shade fabric .

Chicopee Shade Fabric place 10 cm above the turf canopy.

^¶Rated on a scale of 1-9, where 9 is the best.

* Means followed by the same letter in each column are not significantly different at the P=0.05 according to Waller-Duncan k-ratio t test (k-ratio=100).

Table 3b. Turf quality^¶ of Diamond under four light intensities provided by shade fabric .

Chicopee Shade Fabric place 10 cm above the turf canopy.

^¶ Rating scale for quality 1-9, where 9 is highest quality.

* Means followed by the same letter in each column are not significantly different at the P=0.05 according to Waller-Duncan k-ratio t test (k-ratio=100).

Table 3c. Uniformity ratings^¶ of Diamond under four light intensities provided by shade fabric .

Chicopee Shade Fabric place 10 cm above the turf canopy.

^¶ Uniformity rating scale 1 to 9, where 9 = most uniform.

* Means followed by the same letter in each column are not significantly different at the P=0.05 according to Waller-Duncan k-ratio t test (k-ratio=100).

Table 3d. Vertical growth^¶ ratings of Diamond under four light intensities provided by shade fabric .

Chicopee Shade Fabric place 10 cm above the turf canopy.

^¶Rating scale of 1-9, where 9 is the greatest growth

* Means followed by the same letter in each column are not significantly different at the P=0.05 according to Waller-Duncan k-ratio t test (k-ratio=100).

Table 3e. Density ratings^¶ of Diamond under four light intensities provided by shade fabric .

Chicopee Shade Fabric place 10 cm above the turf canopy.

^¶Density rating scale of 1 to 9, where 9 is the highest density.

* Means followed by the same letter in each column are not significantly different at the P=0.05 according to Waller-Duncan k-ratio t test (k-ratio=100).

SALT TOLERANCE:

Diamond has excellent salt tolerance (Marcum et al. 1994). In studies conducted under greenhouse conditions using a salinity ramping procedure where 1575 ppm NaCl was added each day to a hydroponic solution of Hoagland's solution for a period of 12 weeks. The test included a total of 59 entries and additional results are provided in the reference. Selected data for the entries in the NTEP trials are included in Table 4. The excellent salt tolerance of Diamond further expands the utility of this grass as greater pressure is being placed on turfgrass managers and consumers to use alternate water supplies, supplies which often have compromised water quality. Continued use of poor quality water will lead to elevated and often toxic salt levels in the root zone of the turf. Grasses with the tolerance to salt as demonstrated by Diamond will find an important niche in low maintenance turf with marginal quality water resources.

Table 4*. Average percent shoot salt injury (average of 20 rating dates) on zoysiagrass entries in the 1991 NTEP^¤ Trials. (From Marcum et al. 1994 CPR-5244) .

^* Selected data set; complete data set includes 59 varieties and cultivars.

^¤ NTEP= National Turfgrass Evaluation Program.

^¥ Species identify.

^§ Means with the same letter were not significantly different, based on the Waller-Duncan k-ratio t-test (k-ratio=100)

^Seed propagated varieties.

COLOR RETENTION:

Color retention is a major issue with the zoysiagrasses in general. Meyer, the industry standard, is one of the first grasses to enter into winter dormancy. California, more than any other state demands strong winter color retention. A loner growing season with better fall/winter color retention would be desirable Diamond demonstrated fall and winter good color retention during the winter 1994-1995. (Table 5 ). This color response is consistent with the information obtained from Sacramento, CA (USGA annual report 1988). These finer textured varieties are of tropical origin (Z. matrella and Z. tenuifolia) and have a natural tendency to have better winter color retention. Diamond has been similar in response to Emerald (a fine leafed industry standard) with both rating a TPI= 6. The other grasses in the study are coarser textured (leaf width and leaf length) and generally demonstrate earlier winter dormancy.

Table 5. Green color retention (% of the turf that is green) during winter 1994-5 for the NTEP zoysiagrass trial planted at TAES-Dallas in August 1993.

¹ TPI is the turf performance index, or the number of times an entry was rated in the top statistical group.

² Seeded entry.

³ MSD is the minimum significant difference between entry means based on the Waller-Duncan k-ratio t-test (k-ratio = 100). Statistical tests were performed on transformed data, but means of untransformed data are listed. Means in the top statistical group are indicated by an 'a.

DENSITY:

Carrow (1992) rates Diamond among the most dense turfs and having good genetic color in studies in Georgia. Diamond has the finest texture rating among entries in the National Turfgrass Evaluation Program 1992-1995. The information reported in the NTEP annual reports is summarized (Table 6) in the form of turfgrass performance index for Texture over 3 years (1992-94).

Table 6. Turfgrass performance index (TPI) for density ratings of the National Turfgrass Evaluation program as summarized over a period of 3 years. (1992 - 1994)

¹ TPI is the turf performance index, or the number of times an entry was rated in the top statistical group.

INSECT RESISTANCE:

Fall armyworm and tropical sod webworm can annually be very damaging to warm season turfgrass in the southern U.S. and particularly in the Southeast. The tawny mole cricket is the number one most damaging insect problem to turfgrass in the southern U.S. The zoysiagrass mite is a relatively new introduction for the Pacific Rim area where it is one of their major pests, and has the potential to cause considerable damage to its host specific grass. Insect response of Diamond is summarized in Table 7. Diamond is moderately resistant to the fall armyworm (Reinert et al. 1994.), relatively susceptible to the tropical sod webworm (Reinert and Engelke 1992), and the zoysiagrass mite (Reinert et al. 1993). Diamond is moderately resistant to the tawny mole cricket as substantiated by researchers in Georgia. (Braman et al. 1994). In contrast, Meyer is susceptible to each of these pests. Although Meyer expressed resistance to neonate fall armyworm, it is susceptible to the later instars. Multiple insect resistance in Diamond may play a very important role in the success of zoysia as a turf species.

DISEASE RESISTANCE:

Common disease of zoysiagrasses include two viral diseases; Zoysia dwarf and Zoysia mosaic found in Japan (Smiley et al. 1992) and of fungal diseases including Zoysia rust (Puccinia zoysiae), and the yellow patch disease (Rhizoctonia cerealis) that are widely distributed fungal diseases. Susceptibility of Z. japonica to Sclerotinia Dollar Spot has also been observed (Smith et al. 1989).

Inoculation studies were conducted with 18 experimental and six commercial zoysiagrasses at TAMU-Dallas to determine their relative susceptibility to Rhizoctonia blight. Field collected zoysiagrass plugs were inoculated in a walk-in growth chamber over a 7-day period. Rhizoctonia blight susceptibility differed significantly among the genotypes in the study (Metz et al, 1994, 1995). Diamond was among the most tolerant zoysiagrasses among the 24 accessions in the study. Diamond also ranked among the two zoysiagrasses with the fastest recuperability following R. solani inoculation. In a second inoculation study, 40 experimental and commercial zoysiagrasses were used to determine relatvie susceptibility to Pythium blight (Pythium aphanadermatum) which is a common foliar turfgrass pathogen in the southern growing zones. Results of this study indicated Diamond to be among the most moderately susceptible zoysiagrass genotypes. This group also include the commerical varieties Meyer, Emerald, Belair and El Toro (Colbaugh and Engelke 1993a, 1995).

The incidence and severity of naturally occurring Sclerotina dollar spot was determined on field planting blocks with 10 zoysiagrasses over a 2 year period. Zoysiagrasses with fine leaf texture and high leaf density were generally more dollar spot susceptible that turfgrasses with coarser leaves and lower leaf density (Colbaugh and Engelke, 1993b). Diamond exhibits only slight disease symptoms over the 2 year period and displayed disease tolerance compared to the fine leaved variety Emerald. These observations suggest DEALS has some tolerance to the dollar spot disease.

Diamond is among the most resistant varieties when inoculated with Rhizoctonia solani in studies conducted in 1993 (Metz et al. 1995) and only moderately susceptible to Pythium aphanidermatum blight in studies conducted in 1988 (Colbaugh and Engelke. 1995)

Diamond has multiple pest resistance as summarized in Table 7 but also appears to be susceptible to the Tropical Sod Webworm and the Zoysia mite. The tropical sod webworm could present an economic problem as in many of the climates which Diamond is adapted is also prone to tropical sod webworm infestation. An effective monitoring component will be necessary to achieve maximum performance of the grass in these areas.

Table 7. Summary of pest and disease resistance in selected zoysiagrasses.

R = resistant; M= moderately resistant; S = susceptible

PUTTING GREENS:

Diamond has been utilized through field testing on golf course tee boxes located in heavy shade at Banyan CC in Palm Beach, Florida and Colonial Country Club - Fort Worth, Texas, for chipping greens at Alvamar Country Club, Lawrence, Kansas (with the use of turf covers in the winter) and three putting greens have been established in the Dallas area on sand and native soils. (Figure 1.)

SPORTS FIELDS:

Studies were conducted at the University of California - Riverside to determine the potential use of zoysiagrasses for dome stadium sports fields. Diamond washed sod was sent to California in March 1995 for inclusion of the study. The study was conducted by Mr. Steven Cockerham, Director, Agricultural Operations, University of California - Riverside. Grasses used in the study included Manhattan II perennial ryegrass (Lolium perenne), Tifway (Tifton 419) bermudagrass (Cynodon dactylon x transvaalensis), DeAnza zoysiagrass (Zoysia japonica) and Diamond zoysaigrass (Z. matrella). Diamond sod was washed, shrink wrapped and shipped in a closed container over a 4 day road trip for inclusion in the study. The sod heated severely, resulting in the sod not establishing sufficiently for the onset of the study. Due to the set back, Diamond was not selected as the grass desired for inclusion in the Diamond Back Stadium - being constructed in Phoenix AZ. However in personal communications with Dr. Jim Watson, VP Toro Company, Mr. Don Follette (grounds manager, Sun Devil Stadium) and Mr. Steve Cockerham (UC-Riverside) Diamond has demonstrated the best shade tolerance and additional testing will be essential to determine its recuperative ability under actual playing conditions. Shade studies in the greenhouse and under heated soil conditions are targeted to provide additional data in this area. Additionally, several m² sod were sent to Sun Devil Stadium in August, 1995 at the request of Mr. George Toma, Dr. Jim Watson and Mr. Don Follette (grounds manager) to simultaneously evaluate DeAnza and Diamond in the south end-zone in heavy shade. Mr. Follette (personal communications) reports that Diamond was performing comparable to or better than DeAnza. Sun Devil Stadium has heat cables in the turf area to maintain adequate soil temperatures for continual growth of a warm season grass.

Figure 1. Home green of DIAMOND ZOYSIAGRASS on a modified sand root zone. Washed sod of DIAMOND was planted in June 1995.

Figure 2. Demonstrates shade tolerance of DIAMOND zoysiagrass following 69 days continuous exposure to limited light conditions with traffic imposed daily. Levels of light range from as little as 3% (97% shading) to as high as 63% (37% shading).

Figure 3. Field planting of DIAMOND zoysiagrass under heavy shade at Squaw Valley Country Club - Glenrose, TEXAS established April 1994.

REFERENCES

Dudeck, A. E. and C. H. Peacock. 1992. Shade and Turfgrass Culture. In D. V. Waddington, R. N. Carrow, and R. C. Shearman (eds.). Turfgrass Agron. Mono. No. 32: 269-284.

Braman, S. K., A. F. Pendley, R. N. Carrow and M. C. Engelke. 1994. Potential resistance in zoysiagrasses to the tawny mole crickets (Orthoptera:Gryllotalpidae) Fl. Entomol. 77(3): 301-305.

Carrow, R. N. 1991. Zoysiagrass performance, water use, and rooting as affected by traffic and nitrogen. USGA Annual Report, University of GA, Griffin, GA. 5p. 1 table

Carrow, R. N. 1992. Zoysiagrass performance, water use, and rooting as affected by traffic and nitrogen. USGA Annual Report, University of GA, Griffin, GA. 18 p. 11 tables

Colbaugh, P. F. and M. C. Engelke. 1992. Sclerotinia dollar spot on Inoculated zoysiagrasses. APS Biol. & Cult. Test Data 8: 126.

Colbaugh, P. F. and M. C. Engelke. 1993. Pythium Blight on Inoculated zoysiagrasses. APS Biol. & Cult. Test Data 8:125.

Colbaugh, P. F., S. P. Metz and M. C. Engelke. 1993. Pythium blight on inoculated zoysiagrasses. TX Turfgrass Res. - 1993, Consolidated Prog. Rep. PR 5131: 86-87.

Colbaugh, P. F., S. P. Metz and M. C. Engelke. 1993. Sclerotinia dollarspot incidence on zoysiagrass. TX Turfgrass Res. - 1993, Consolidated Prog. Rep. PR 5133: 89-90.

Colbaugh, P. F. and M. C. Engelke. 1993. Rhizoctonia Blight on Inoculated zoysiagrasses. APS BCT Test Data 8: 158.

Marcum, K. B., M. C. Engelke, S. J. Morton and C. Dayton. 1994. Salinity tolerances of selected bermudagrass and zoysiagrass genotypes. TX Turfgrass Res. - 1993, Consolidated Prog. Rep. PR 5140: 105-107.

Metz, S. P., P. F. Colbaugh and M. C. Engelke. 1994. Rhizoctonia Blight on Inoculated zoysiagrasses. APS BCT Test Data 9: 158.

Metz, S. P., P.F. Colbaugh and M. C. Engelke. 1993. Rhizoctonia blight susceptibility among commercial and experimental zoysiagrasses. TX Turfgrass Res. - 1993, Consolidated Prog. Rep. PR 5129: 82-83.

Morris, K. 1993. National zoysiagrass test - 1991, Progress report 1992. Nat. Turfgrass Eval. Prog. NTEP No. 93-4: 32p.

Morris, K. 1994. National zoysiagrass test - 1991, Progress report 1993. Nat. Turfgrass Eval. Prog. NTEP No. 94-5: 54p.

Morton, S. J., M. C. Engelke, and R. H. White. 1991. Performance of four warm-season turfgrass genera cultured in dense shade. TX Turfgrass Res. - 1991, Consolidated Prog Rep. PR-4894: 51-52.

Morton, S. J. and M. C. Engelke. 1994. Performance of three warm-season turfgrass genera cultured in shade. III. Zoysia spp. TX Turfgrass Res. - 1993, Consolidated Prog Rep. PR 5139:102-104.

Morton, S. J., M. C. Engelke, and K. G. Porter. 1994a. Performance of three warm-season turfgrass genera cultured in shade. III. Zoysia spp. TX Turfgrass Res. - 1994, Consolidated Prog Rep. PR 5242: 27-29.

Morton, S. J., T. Stanton, and M. C. Engelke 1994b. Zoysiagrass shade tolerance. TX Turfgrass Res. - 1994, Consolidated Prog Rep. PR 5244: 30-32.

Reinert, J. A. and M. C. Engelke. 1992. Resistance in zoysiagrass (Zoysia spp.) To the tropical sod webworm (Herptegramma pheopteralis). TX Turfgrass Research-1992, Consolidated Prog. Rep. PR 4996: 55-57.

Reinert, J. A., M. C. Engelke, and S. J. Morton. 1993. Zoysiagrass resistance to the zoysiagrass mite, Eriophyes zoysiae (Acari:Eriopyidae) . Int. Turfgrass Soc. Res. J. 7: 349-352.

Reinert, J. A., M. C. Engelke, S. J. Morton, P.S. Graff, and B. R. Wiseman. 1994. Resistance in zoysiagrass (Zoysia spp) to the fall army worm (Spodoptera frugiperda). TX Turfgrass Research-1992. Consolidated Prog. Rep. PR 5248: 39-42.

Smiley, R. W., P. H. Dernoeden and B. B. Clarke. 1992. Compendium of Turf Diseases. A.P.S. Press: Minneapolis. 98p

Smith, J. D., N. Jackson and A. R. Woolhouse, 1989. Fungal disease of Anmenity Turfgrasses. E. & F.N. Spong: London. 401 p.

White, R. H. M. C. Engelke, S.J. Morton, and B.A. Ruemmele, 1993. Irrigation water requirement of zoysiagrass. In Int. Turfgrass Soc. Res. J. 7. R. N. Carrow et al. (Eds). Intertec Pub. Corp., Overland Park, KS. Chap. 83: 587-593.

USGA Semi-Annual and Annual Research Reports 1985 - 1995 . (Reports on file at TAES, Dallas and USGA, Far Hills NJ). All information can be provided as necessary. Data presented supports the primary features and merits of the grass.

AGRONOMIC MERITS OF DIAMOND

• EXCELLENT SALT TOLERANCE

• EXCELLENT SHADE TOLERANT

• HIGHLY RHIZOMATOUS

• EXCELLENT SOD STRENGTH

• LOW WATER REQUIREMENTS

• EARLY SPRING GREEN UP (GA 92)

• GOOD GENETIC COLOR (GA 91, 92)

• TAWNY MOLE CRICKET RESISTANCE (GA)

• EXCELLENT FALL COLOR RETENTION (CA)

• FINE TEXTURED

• HIGH SHOOT DENSITY (GA 92, 93)

• RHIZOCTONIA BLIGHT RESISTANCE

• FALL ARMYWORM RESISTANCE

Note: GA is data generated at GA Agr. Exp. Sta., Griffin, GA.

AGRONOMIC LIMITATIONS OF DIAMOND

• LACKS WINTER HARDINESS

• ADAPTED TROPICAL AND SUB-TROPICAL CLIMATES

• SUSCEPTIBLE TO THE TROPICAL SOD WEB WORM

• SUSCEPTIBLE TO ZOYSIAGRASS MITE

• TENDENCY TO THATCH AND SCALP UNDER IMPROPER MAINTENANCE

• WILL NOT TOLERATE OVERSEEDING WITH COOL SEASON GRASSES

• SLOW INITIAL ESTABLISHMENT FROM SPRIGS OR PLUGS (GA)

Copyright © 2000 Texas A&M University / M.C. Engelke & Sean Pease. All rights reserved.
Revised: May 22, 2003 .