banned for agricultural and turfgrass uses in the USA (Ristaino and Thomas, 1997;Unruh, 1998). Dazomet (tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione)Dazomet is a granular soil fumigant that controls is a soil fumigant labeled for turfgrass renovation. Little is known about dazomet efficacy on annual bluegrass (Poa annua L.) seedling fungi, bacteria, nematodes, and weed seeds in soils (Haremergence, particularly when it is surface-applied. The objectives of ris, 1991;Fritsch and Huber, 1995). When incorporated this field study were to determine (i) the effects of rate and plastic into moist aerated soil, dazomet is degraded into several covering of surface-applied dazomet on annual bluegrass seedling volatile intermediate products including methylisothioemergence in turf; and (ii) effective creeping bentgrass seeding intercyanate (MITC). Methylisothiocyanate is toxic to many vals following surface applications of dazomet. All treatments were soilborne organisms, including weed seeds (Fritsch and applied to established turf during late summer in 2000 and 2001. , 1995;Mappes, 1995). Huber Covering dazomet treatments with plastic sheets resulted in fewerDazomet inhibits seed germination and emergence annual bluegrass seedlings than in noncovered treatments. All plasticof numerous weed species (Eitel, 1995;Mappes, 1995). covered dazomet treatments (388, 340, 291, and 194 kg ha Ϫ1 ) provided Efficacy varies with the rate of application and the greater than 98% reduction in annual bluegrass seedlings when compared with the plastic-covered controls during 2000 and 2001. When method of preventing escape of phytotoxic gases from not covered with plastic, the 388 kg ha Ϫ1 dazomet treatment provided soil. Eitel (1995) found improved control of seedling 97% fewer annual bluegrass seedlings in 2000 and 92% fewer seedlings emergence of Cyperus esculentus L., Galinsoga parin 2001 than the noncovered controls. Results of the seeding interval viflora Cav., Portulaca oleracea L., and Richardia braexperiment revealed that creeping bentgrass (Agrostis stolonifera L.) siliensis (Moq.) as rates of dazomet increased from 98 groundcover and yields were not inhibited when seeded 3 d after a to 392 kg ha Ϫ1 following incorporation into a sandy loam surface application of dazomet at 388 kg ha Ϫ1 .soil. When dazomet was incorporated into the same soil and covered with plastic sheets for 7 d, Eitel (1995) found improved control of the same four weed species

Kentucky bluegrass (Poa pratensis L.) is frequently established on sports fields that receive wear during one or more seasons. Differences exist among Kentucky bluegrass cultivars for seasonal performance characteristics such as spring green‐up and summer stress tolerance. The objective of this study was to determine whether the wear tolerance and recovery of Kentucky bluegrass cultivars were dependent on season. Twenty‐two Kentucky bluegrass cultivars, representing nine genetically diverse Kentucky bluegrass types, were established in September 2002 in North Brunswick, NJ on a loam. The effects of simulated wear were evaluated during spring, summer, and fall in 2004 and 2005. Generally, Kentucky bluegrass was more tolerant of wear during spring than summer or fall and recovery was more rapid after spring wear. The performance of many cultivars depended on season of wear; however, ‘Julia’ consistently exhibited the greatest wear tolerance as well as recovery. Compact‐Midnight Type cultivars (‘Midnight’, ‘Midnight II’, and ‘Liberator’) had good wear tolerance during fall wear, however were slow to recover after fall wear. ‘Cabernet’, ‘Lakeshore’, ‘Moon Shadow’, ‘Limousine’, and ‘Jefferson’ exhibited more rapid recovery from fall wear during the next spring. ‘Langara’, ‘Bedazzled’, and ‘Touchdown’ had poor wear tolerance and recovery during all seasons. The season(s) of play should be considered when selecting Kentucky bluegrass cultivars for sports fields.

Research is lacking on best establishment practices of fine fescues (Festuca spp.), such as optimal seeding timings, which are well known for other cool-season turfgrasses. Our objective was to document establishment and determine optimal seeding timings for mixed stand of fine fescue in multiple cool-season climate zones in the United States. From 2019 to 2020, an experiment was replicated across four locations in the northern United States to investigate nine monthly fine fescue mixture seeding timings from March through November. Fine fescue seedling emergence typically hastened as temperatures increased during the growing season, and emergence required 6.1-9.4 d when soil temperatures were within a range of 15-25 ˚C. Final grid count data across multiple sites indicated that seeding fine fescues in August, September, and at times, July, will likely produce the best establishment with the lowest weed infestation pressure, and there may be more flexibility in seeding timings in a Mediterranean climate, such as Oregon. Seeding fine fescues in the early-spring or late-autumn can be more unreliable because of greater likelihood of weed infestation, suboptimal growing conditions, and potential of a late-autumn seeding to act as an unintended dormant seeding. Results indicate the weed invasion pressure of specific weeds will vary depending life cycle of weed and seeding time of year. Overall, seeding a fine fescue mixture in August or September will increase likelihood of success in cool-season climate zones in the United States with a wider seeding window when planting in Mediterranean climates.

Glyphosate applied prior to perennial ryegrass (PRYE) seeding did not affect PRYE cover compared to seeding alone (nontreated).• Post-seeding herbicide regimens are necessary to maximize PYRE establishment where a significant annual bluegrass (ABG) soil seedbank exists.• Autumn applications of ethofumesate resulted in the greatest PRYE cover and ABG control by the following spring.• Mesotrione-based herbicide programs applied during autumn provided ABG control. There was no advantage of applying mesotrione + amicarbazone for postemergence ABG control prior to PRYE seeding. ABSTRACTAnnual bluegrass (ABG; Poa annua L.) is among the most problematic weeds in golf and sports turfs. Perennial ryegrass (PRYE; Lolium perenne L.) can be more effectively seeded into existing turfs compared with other cool-season turfgrasses due to its quick germination and seedling vigor. Herbicide programs are often used to suppress ABG encroachment into newly renovated turfs. The objective of this study was to assess the effectiveness of herbicide programs designed to suppress ABG in turf seeded with PRYE. Trials were initiated during September 2015 and 2016 on a mature stand of ABG in North Brunswick, NJ. Treatments consisted of 13 herbicide programs and a nontreated check. Programs involved applications of glyphosate, ethofumesate, mesotrione, and amicarbazone applied during September through December 2015 and 2016. Separate trial areas were core cultivated with soil reincorporated; 'Manhattan 5 GLR' PRYE was slit-seeded on 14 Sep. 2015 and 16 Sep. 2016. Glyphosate followed by (fb) seeding did not affect PRYE establishment compared to seeding alone (nontreated). Three autumn applications of ethofumesate resulted in the greatest PRYE cover and best ABG control by the following spring in both years. All mesotrione herbicide programs suppressed ABG encroachment. Applications of mesotrione + amicarbazone prior to PRYE seeding did not affect PRYE establishment compared to most mesotrione-only herbicide programs.