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Nonfungicide alternatives for control of brown patch (caused by Rhizoctonia solani Kuhn) and dollar spot (caused by Sclerotinia homoeocarpa F.T. Bennett) diseases are needed. Calcium silicate (CaSi[O.sub.3]) was applied as a topdressing (2440 or 4880 kg [ha.sup.-1]) to evaluate brown patch suppression in 'Bonsai 2000' and 'Tar Heel' tall rescue (Festuca arundinacea Schreb.) and 'L-93' creeping bentgrass (Agrostis palustris Huds.) in the field, or amended into soil at 7325 or 14650 kg [ha.sup.-1] to evaluate dollar spot on 'Peancross' creeping bentgrass in a growth chamber. The Chase silty day loam (fine, montmorillonitic, mesic Aquic Argiudoll) under tall rescue had a pH of 6.4, a high initial Si content (173 mg [kg.sup.-1]), and Si accumulation in leaves was minimal (one of five observations). Calcium silicate applied at 2440 kg [ha.sup.-1] increased the area under disease progress curves (AUDPC) for brown patch by 26% in 2002 and 30% (both rates) in 2003. Tall fescue leaf P and K concentrations were reduced by CaSi[O.sub.3] and were negatively correlated (r = -0.41 for P; -0.44 for K; P < 0.02) with brown patch. Calcium silicate topdressing increased Si in creeping bentgrass leaf tissue as well as the sand root zone, which initially contained

Irrigation management is generally assumed to have a significant effect on turfgrass pest management, yet little research has been done in this area. This field study was conducted on perennial ryegrass (Lolium perenne L.) maintained under golf course fairway conditions in 1995 and 19%. Objectives were to evaluate water savings afforded by monitoring turf ET and adjusting irrigation accordingly; to compare preventive and curative pesticide control measures for control efficacy and amounts required; and to evaluate effects of two irrigation regimes on turf quality, weed infestation, disease incidence, and pesticide requirements. Turf received either daily irrigation of 7.6 mm of water regardless of prevailing weather conditions or irrigation to replace approximately 80% of atmometer-estimated elk evapotranspiration (ET) on 3 d weekly. About 200% more water was applied to daily irrigated turf than to turf irrigated based on atmometer-estimated ET. Similar amounts of active ingredient were used on both fungicide schedules in 1995. In 19%, a curative fungicide schedule resulted in application of 64% less active ingredient than a preventive schedule. Daily irrigation suppressed brown patch (Rhizoctonia solani Kuhn) injury by 901, in 1995 and 2% in 1996 but resulted in more than twice as many dollar spot (Sclerotinia homoeocarpa F.T. Bennett) infection centers in 1996. Irrigation treatment had no effect on smooth crabgrass [Digitaria ischaemum (Schreb.) Muhl.] or dandelion (Taraxacum officinale Weber) incidence., Golf courses are often publicly scrutinized, in part, because of high summer water usage during peak demand periods in urban areas and fear of potential health and environmental problems posed [...]

Nonfungicide alternatives for control of brown patch (caused by Rhizoctonia solani Kühn) and dollar spot (caused by Sclerotinia homoeocarpa F.T. Bennett) diseases are needed. Calcium silicate (CaSiO3) was applied as a topdressing (2440 or 4880 kg ha-1) to evaluate brown patch suppression in ‘Bonsai 2000’ and ‘Tar Heel’ tall fescue (Festuca arundinacea Schreb.) and ‘L-93’ creeping bentgrass (Agrostis palustris Huds.) in the field, or amended into soil at 7325 or 14650 kg ha-1 to evaluate dollar spot on ‘Penncross’ creeping bent-grass in a growth chamber. The Chase silty clay loam (fine, montmorillonitic, mesic Aquic Argiudoll) under tall fescue had a pH of 6.4, a high initial Si content (173 mg kg-1), and Si accumulation in leaves was minimal (one of five observations). Calcium silicate applied at 2440 kg ha-1 increased the area under disease progress curves (AUDPC) for brown patch by 26% in 2002 and 30% (both rates) in 2003. Tall fescue leaf P and K concentrations were reduced by CaSiO3 and were negatively correlated (r = -0.41 for P; -0.44 for K; P < 0.02) with brown patch. Calcium silicate topdressing increased Si in creeping bentgrass leaf tissue as well as the sand root zone, which initially contained <12 mg kg-1 Si. A positive correlation (r = 0.81; P < 0.001) occurred between creeping bentgrass leaf Si concentration and brown patch severity in one of three years, which may have resulted from reduced leaf P and K after CaSiO3 application. The silty clay loam (170 mg kg-1 Si) amended with CaSiO3 before planting creeping bentgrass had no effect on leaf Si concentrations or dollar spot incidence. Thus, CaSiO3 application to soil containing adequate Si should not be recommended for control of brown patch on tall fescue, nor should CaSiO3 be recommended to control brown patch on creeping bentgrass grown on low Si soil or dollar spot on high Si soil. In fact, CaSiO3 application may exacerbate brown patch disease incidence possibly because of nutrient imbalances, particularly in tall fescue. [ABSTRACT FROM AUTHOR]