Duration: 10/01/2011 to 09/30/2016

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Rationale and importance of work: Turfgrass areas including golf courses are a valuable and rapidly expanding component of urban and rural landscapes covering 12 million ha in the United States (Potter & Braman 1991). Over 16,000 golf courses in the U.S. provide green space in the urban environment; offer recreation for 36 million Americans; generate jobs, commerce, economic development, and tax revenues for communities; and contribute $62.2 billion worth of goods/services each year to the national economy (www.golf2020.com).

Annual bluegrass (Poa annua) is a highly invasive weed on short-mown golf course surfaces (fairways, tees, putting greens) where it often becomes the dominant species despite extensive attempts to suppress it. Superintendents often resort to managing it instead of more pest-tolerant bentgrasses (Agrostis spp.) (Miltner et al. 2004). P. annua can provide an acceptable playing surface for putting greens and fairways when properly maintained, but this requires extensive chemical inputs (Grant & Rossi 2005). It has high tiller density and tolerance of low cutting heights, shade and traffic, but is often maligned for its lack of stress tolerance, yellow-green color, prolific flowering habit, and susceptibility to many diseases and insect pests (Beard 1973).

Improved agronomic management practices are widening the possibilities for maintaining P annua in the turfscape. But some of these practices may enhance pest problems (Inguagiato et al. 2008). P. annua maintenance on golf courses in the Northeast and Mid-Atlantic has become increasingly complicated by two emergent pests. The annual bluegrass weevil (ABW) (Listronotus maculicollis) and anthracnose diseases (anthracnose basal rot = ABR) caused by the fungus Colletotrichum cereale have become in recent years the most severe pests of P. annua. Their control often depends almost entirely on chemical pesticides with multiple applications required throughout the growing season. However, the general public is increasingly concerned about the potential for pesticide exposure and long-term effects to humans and pets and the possibility of ground and surface water contamination. Extensive pesticides use to control these pests also reduces golf course profitability. In addition, insecticide resistant ABW populations and fungicide resistant C. cereale isolates are an increasing problem. There is an urgent need to refine our understanding of the biology, ecology, and pathogenesis of these pests, develop better IPM tools to assess and monitor their impact, discover and deploy more effective pest management practices, and gain a better understanding of the stresses that affect P. annua and how to mitigate them. To address this need, a regional project was initiated in 2005 (NE1025: Biology, Ecology, and Management of Emerging Pests of Annual Bluegrass on Golf Courses).

The ABW is a notorious and damaging pest of close-cut P. annua on golf courses and tennis courts in the northeastern U.S. ABW injury to turfgrass was first reported in CT in 1931 (Britton 1932) and until the last 20 years has been concentrated in the NY metropolitan area. Severe infestations are now reported from all other states of the Northeast and Mid-Atlantic, west into OH and Ontario and north into Quebec. Although not always present in turfgrass settings, the ABW has been reported from > 40 states, suggesting the potential exists for spread of impact across much of the U.S. and Canada.

In spring adult ABW move from off-course overwintering sites to the greens, tees, and fairways. As the insect completes 2-3 generations, the heavy damage inflicted by the stem-boring and crown-feeding larvae severely impacts the visual and functional quality of the turf. The problem is exacerbated because P. annua is least vigorous during the summer, which coincides with the peak of ABW feeding activity. In the proposal for NE1025 (in 2005), we stated that pyrethroid insecticides targeting adults were the only effective control option with superintendents making 2-5 applications per season putting ABW populations under strong selective pressure for developing resistance to this chemical class. Indeed, resistance has been confirmed (Ramoutar et al. 2009a) and seems to be on the rise. While the concerted efforts of NE1025 members has defined effective alternatives to pyrethroids (e.g., trichlorfon, spinosad, indoxacarb, chlorantraniliprole), ABW populations already resistant to pyrethroids seem to also be less susceptible to these alternatives (R.S. Cowles, pers. observation). Almost no presently available insecticides effectively control the most resistant ABW populations.

Anthracnose is the common name given to leaf diseases that occur throughout the world on almost all turfgrass species. They are particularly severe on P. annua and to a lesser extent on creeping bentgrass (Agrostis stolonifera). The anthracnose pathogen that attacks turfgrass had previously been identified as C. graminicola, a well-known pathogen of maize, but recent studies confirmed that pooid-infecting isolates differ substantially from the maize pathogen, prompting the resurrection of the original name, C. cereale (see below). C. cereale may cause a foliar blight or basal rot of leaf and sheath tissue (Smiley et al. 2005). In recent years incidence and severity of ABR on golf courses have increased throughout the U.S. (Dernoeden 2000, Landschoot & Hoyland 1995, Vermeulen 2003, Wong & Midland 2004) and Canada (Hsiang & Goodwin 1999). It has recently been shown that the increased frequency of ABR on putting greens is associated with the intensive management practices (e.g., low cutting heights, reduced nitrogen fertility, low soil water; Inguagiato et al. 2008, 2009b, Roberts et al. 2011) employed by superintendents to meet the ever-increasing expectations of the golfing public.

Superintendents often rely heavily on fungicides for disease suppression. But relying solely on fungicides is costly and has met with variable results, particularly when plants are under stress. Products are most effective when applied preventatively, but due to our incomplete knowledge of pathogen biology and fungicide timing, treatments are often ineffective. Because of the increasing use of fungicides to control ABR and the limited number of efficacious compounds, resistance to the benzimidazole and strobilurin fungicides has recently occurred on many golf courses in the U.S. (Avila-Adame et al. 2003). It is likely that fungicide resistance will become more widespread if current chemical and cultural control practices are not altered.

NE1025 members have have filled many gaps in our understanding of the biology, ecology, and impact of ABW and ABR; identified and tested new control options; developed improved IPM decision tools; and continuously updated best management practices (BMPs) based on the new information generated. But there are still many other aspects in the biology/ecology and management of ABW, ABR, and P. annua itself that require further regional efforts to develop optimal BMPs. Given the dominance of P. annua in many golf course fairways and greens and the absence of proven methods for its suppression, the continued optimization of BMPs for P. annua is a major goal of the proposed project. However, the recent advent of new herbicide chemistries for P. annua control (e.g., bispyribac sodium, amicarbazone, methiozolin) and modified use strategies of existing have enhanced the potential for the development of better methods to prevent its establishment and spread, and to transition to more sustainable turfgrass spp. The development of improved cultural techniques, either alone or in combination with biorationals and herbicides, to reduce/eliminate P. annua in favor of more desirable turfgrass species is a long term goal of the proposed project. Both goals should be pursued and coordinated to improve the overall sustainability of golf courses and to enhance the economic and environmental well being of this industry.

Need for project as indicated by stakeholders: In January 2001, a broad-based group of stakeholders interested in golf course IPM in the Northeast met at Rutgers University (NJ). This focus group included superintendents, university personnel, environmental and public health advocates, and representatives from the US Golf Association and the US EPA. Research and extension priorities cited by this group included (1) alternatives to current chemical pesticides, (2) forecast and sampling protocols for important golf turf pests, and (3) a comprehensive Web-based treatment of golf turf IPM. For a complete summary of the groups priorities see: http://northeastipm.org/ partners/priorities/ turf2001.html. Our proposed project will directly address these priorities as well as other gaps in knowledge and management practices associated with P. annua itself and its major pests, the ABW and anthracnose disease.

Consequences if it is not done: If the proposed research on management of P. annua and its major pests, ABW and ABR, and the suppression of P. annua/transition to more sustainable turfgrasses is not conducted, the consequences will likely be (1) further spread and intensification of pest resistance to several insecticide and fungicide chemistries, (2) increased economic and environmental costs associated with the application of chemical pesticides used to control these pests, (3) reduced likelihood that ABR -resistant grass varieties will be developed and marketed, (4) loss of revenue in the golf course industry due to widespread turf failure, and (5) lack of an integrated management system for intensely managed turf.

Technical feasibility: Most scientists involved with the ABW, ABR, and P annua management sections of this project have been collaboratively studying and publishing on these issues at least since the inception of NE1025 in 2005. New scientists on the project bring additional expertise, further enhancing collaborations and productivity of the team. Breeding programs in the region have extensive collections of P. annua (PA) and creeping bentgrass germplasm (NJ) that will continue to be shared in a coordinated fashion to determine the potential for genetic resistance to ABW and ABR. All scientists involved with the section on P. annua suppression/transition to more sustainable grasses already have experience working with this plant; the involved weed scientists already have studied the suppression of P. annua for several years. Combining their efforts will aid in the development of an effective suppression program. Many of the PIs currently have Cooperative Extension and outreach appointments and have extensive experience and successful track records in impact assessment and dissemination of research results to turfgrass practitioners throughout the U.S.

Advantages of a multistate effort: Turfgrass fungal and insect problems occur across state boundaries, so it is imperative to develop control strategies appropriate for the broadest geographic region possible. A multistate effort will increase the exchange of knowledge, experience, and techniques among scientists who would not otherwise have cooperated on these pest problems. A major practical goal of the multistate project is to coordinate breeding goals and control regimes such that time and money are not wasted. Standardized surveys/ questionnaires conducted at the conclusion of the current and proposed projects will be compared to provide a comprehensive evaluation of project impacts. Division of labor and collaboration according to the primary expertise of the involved labs will improve the quality of specific studies. Outcomes from the various labs will help other labs advance more quickly with their research/outreach efforts. This regional approach will allow us to conduct multisite studies across the Northeast and Mid-Atlantic. Bringing entomologists, pathologists, physiologists, weed scientists, management specialists, and plant breeders together will result in a better understanding of the biology and control/suppression of P. annua and its major pests, and will allow ABR. Finally, a multistate effort will allow scientists to develop a set of best management practices (BMPs) that will help practitioners successfully maintain or suppress, as needed, P. annua while reducing pesticide use. Project participants will relay detailed, relevant findings to practitioners through regional and national seminars, symposia, electronic newsletters, annual research field days, and multi-authored publications in a coordinated fashion.

Anticipated impacts: Our interdependent research strategy will lead to improved exchange of information among turfgrass management specialists, entomologists, weed scientists, breeders, pathologists, and physiologists throughout the U.S. A publication containing BMPs for P. annua, currently being developed by members of NE1025, will be updated/improved based on newly developed information. A publication containing BMPs for suppressing P. annua /transition to more sustainable turfgrass will be developed and disseminated to turfgrass managers in the region via this multistate effort. This and other applied publications developed through this project will be posted on the NIMSS website. The information will lead to improved management practices being adopted by golf course superintendents including the use of new biological, biorational, and chemical strategies, and new cultural and ecologically based control techniques. Adoption and implementation of this information by practitioners will result in improved management of P. annua and its major pests, or the transition of P. annua-dominated areas to more sustainable turfgrasses with reduced pesticide requirements, and ultimately enhanced economic and environmental health benefits across the region. Project impact will be measured with a survey conducted throughout the Northeast region in year 5 of the current project and year 4 of the proposed project.

Related, Current and Previous Work

Critical review of the current turf regional project - NE1025. In a web-based survey of golf course superintendents in the U.S. and Canada (313 participants) conducted in year 2 of the current NE1025 project, 71 and 46% stated that they have had troubles with ABR or ABW, respectively. For ABR, participants estimated that they annually spent < $20,000 (48%), $20,000-40,000 (31%), or > $40,000 (18%) on fungicides specifically targeting ABR. The total cost of managing ABR on putting greens including fungicides and labor was estimated to be $5,100 to $28,000/year. Among superintendents aware of ABR research, 84% found information generated by NE1025 helpful in reducing ABR. ABW affected courses spent an estimated $5,000 to $9,000/year to control ABW. The most severe damage was observed along the of fairways edges and the turf surrounding collars and approaches of putting greens. Among superintendents aware of ABW research, 71% found information generated by NE1025 helpful in reducing damage.

ABW: Studies on ABW overwintering biology (Diaz & Peck 2007) showed that adults could overwinter 60 m from the fairway 10 m into the woods and were most abundant near the tree line; none were detected on the fairway. Abundance tended to be the highest in mixed tree litter followed by moss, high-cut grass, and pine litter. Pitfall trap captures showed a peak of activity in the spring; at one site this was directional toward the fairway. There was no directionality or increase in activity in the fall. It was proposed adults fly to defined tree lines in the fall. Defining this behavior should help target control tactics in space and time.

Overwintered adult ABW colonized fairways and moved within randomly, entering from the edges and deposited eggs over several weeks without any effects of host species (P. annua vs. creeping bentgrass) on adult or larval distribution (McGraw & Koppenhofer 2009a). The often higher larval densities along fairways edges may be generated by the preference of egg-laying females for short-mown grass first encountered along the edges. Prevalence of visual damage at fairways edges is not fully explained by insect load, host plant availability or drought stress, but may be linked to thatch accumulation and nitrogen availability (Seto et al., unpubl. data).

Population densities tended to be higher in the spring generation than in the summer generations (Diaz et al. 2008, McGraw & Koppenhofer 2009b). Observations by many NE1025 members indicated that unusual environmental conditions may change this pattern.

In numerous field trials by NE1025 members several newer reduced-risk synthetic insecticides were as effective as pyrethroids for ABW management (e.g., Cowles et al. 2008). Acelepryn (chlorantraniliprole) can target young larvae, Provaunt (indoxacarb) mid- to late-instar larvae, and Conserve (spinosad) all larval stages and adults.

Pyrethroid-resistance in ABW populations is an increasing problem (Ramoutar et al. 2009a) and is at least in part due to detoxification by up to three different systems (Ramoutar et al. 2009b). Due to the non-specific nature of the detoxification mechanisms, pyrethroid resistant ABW populations were also less susceptible to non-pyrethroid insecticides including indoxacarb, chlorantraniliprole, trichlorfon, and, in rare cases, even spinosad (R.S. Cowles, unpubl. data). Product mixtures containing a pyrethroid plus a neonicotinoid were often effective against larvae, even where adults are resistant to pyrethroids; but using mixtures containing pyrethroids against pyrethroid-resistant populations may have only short-lived benefits.

NE1025 members have attempted to integrate biological controls into an IPM approach for ABW. Endemic entomopathogenic nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophora) were common on insecticide-free fairways but cannot be relied upon to sufficiently reduce densities in a conservation biological control approach (McGraw & Koppenhofer 2009b). Despite promising larval control by S. carpocapsae, S. feltiae and H. bacteriophora under lab conditions (McGraw & Koppenhofer 2008), numerous field trials with multiple species, rates, and combinations showed variable performance and limited persistence; the overall best and most consistent species was S. carpocapsae (McGraw et al. 2010). The entomopathogenic fungus Metarhizium anisopliae showed promising results in the laboratory, but was ineffective in the field (Ramoutar et al. 2010).

Anecdotal evidence suggested that 50% of the emerging overwintered ABW adults occur when Forsythia spp. have lost half of their yellow petals (half green, half yellow stage). But adult emergence is not normally distributed, often demonstrating bimodality (Diaz et al. 2008, McGraw & Koppenhofer 2009a). Reliance on plant phenology rather than direct sampling of adults has created opportunities for mis-timing or misuse of insecticides. Improved degree-day models (Peck et al., unpubl. data) may improve prediction abilities.

Direct sampling of larvae using a jackknife, turf plugger, or standard golf course cup-cutter was the best method for predicting the need for and timing of management activities. But the probability of over- and underestimating population densities was great given the size and cryptic nature of stages and the patchy distribution of ABW populations (McGraw, unpubl. data). McGraw & Koppenhofer (2009c) examined the use of a reverse-leaf blower vacuum to obtain fast and reliable estimates of overwintered adult densities. Strong correlations were observed between adult and future larval densities. The procedure allows relatively quick population estimates and risk assessments. In mixed stands of P. annua and creeping bentgrass regression analyses suggested that damage may occur with as few as 10 larvae per 0.09 m2 in moderately mixed P. annua stands but not below 150 larvae per 0.09 m2 in pure creeping bentgrass plots McGraw & Koppenhofer (2009a). Hence, cultural controls for P. annua may be a means to reduce larval feeding damage but are unlikely to greatly reduce ABW populations.

Anthracnose: Based on molecular analyses using DNA sequence and RFLP markers from a diverse collection of C. cereale and other grass-associated Colletotrichum spp. collected from across the U.S. by NE1025 members, C. cereale affecting P. annua and other C3 species is a unique pathogen evolutionarily adapted to these hosts (Crouch et al. 2006, 2009a-d). The grass and monocot infecting species forming the genus Colletotrichum represent an extremely diverse pathogen group; those affecting C3 turf are unique from those affecting C4 turf. Seven new grass infecting Colletotrichum spp. were described in these studies. C. cereale groups affecting P. annua and other C3 species could be characterized into at least two distinct clades each with considerable genetic diversity, suggesting a complex evolution of the species as a specialized P. annua pathogen and that non-turf populations are unlikely reservoirs for disease inoculum.

Significant progress was made on the understanding of the sexual system of C. cereale and the potential role of sexual reproduction in the evolution, diversity and spread of the pathogen. The mating type gene cluster from C. cereale was characterized. Analysis of repeat-induced point (RIP) mutated transposons (Crouch et al. 2008a,b), in conjunction with multi-locus phylogenetic analysis of non-repetitive DNA sequence data, suggested that sexual recombination played an important role in C. cereale evolution. The role of sexual recombination in the development and overwintering of turfgrass ABR is still not understood.

Full genome sequencing and assembly of C. cereale in order to best understand the pathogen's genetics was not successful, even when using the genome assembly of the related fungus C. graminicola as a reference, further demonstrating that C. cereale is considerably different from C. graminicola.

Fungicide resistance to QoI and benzimidazole fungicides was found to be common in C. cereale. A few hundred isolates collected from across the U.S. were tested and QoI and benzimidazole resistance was found to be common (Mitkowski et al. 2009; Young et al. 2010a,b). Three types of mutations, E198K, E198A and F200Y were found in the beta tubulin gene associated with benzimidazole resistance. Both G143A and F129L mutations in cytochrome bc1 were found associated with QoI resistance. Results confirm that fungicide resistance is problematic and new chemistries or alternate controls are needed for the successful management of anthracnose on P. annua and other C3 turf species.

Numerous field trials by NE1025 members showed that many of the new demethylation inhibitor fungicides (metconazole, tebuconazole, triticonazole) were effective in reducing anthracnose severity, but could cause phytotoxicity when used repeatedly. Others such as polyoxin-D and fludioxonil were moderately effective and could be included as components in seasonal control programs. Chlorothalonil, although an older material and restricted to 82 kg/ha per year, remains a highly effective product. Some phosphonate and phosphite products provided some ABR suppression but often were not effective in controlling the disease on P. annua alone (but showed more activity when used on creeping bentgrass). Tank mixing of different fungicides (chlorothalonil, fosetyl-Al and pigment, and phosphites) with other systemic products provided good ABR control. None of the biorational products tested such as Bacillus based products provided acceptable control (Clarke et al. 2007).

Multi-year field studies were conducted examining the effect of fertility and cultural practices on the development of ABR. The effect of mower types on disease development (Rossi 2008), mowing and rolling practices (Inguagiato et al. 2009), and vertical mowing on ABR was examined. Results indicated that heavier weight, fixed head mowers increased ABR, and ABR was increased with lower mowing heights. Increasing height of cut by as little as 0.4 mm significantly reduced ABR development; increasing cutting frequency and the use of rolling could compensate for the increased height of cut and for maintaining ball roll speed on putting greens (Inguagiato et al. 2009). Both lightweight vibratory rollers and sidewinder rollers decreased ABR. Verticutting had little effect on ABR severity (Inguagiato 2008).

Tests examining the effect of nitrogen rate and application frequency (Roberts 2009) showed that light, weekly rates of nitrogen reduced disease by 25-73% as compared to monthly applications. Additional testing of foliar application of summer nitrogen showed that weekly amounts of N (9.8 kg/ha/wk) resulted in the lowest disease, as compared to higher rates of 19.6 and 24.5 kg/ha/wk. Granular nitrogen application in the spring provided greater disease suppression than in the fall, with increasing rates of granular N resulting in less disease.

The use of plant growth regulators was examined using both seedhead (mefluidide and ethephon) and vegetative growth (trinexapac-ethyl) suppressors (Inguagiato et al. 2009, 2010). Applications of both types of growth regulators did not enhance ABR, but occasionally and inconsistently reduced ABR severity. Mefluidide (ME) had little effect on ABR, but ethephon (EP) reduced ABR 3-22%. Trinexapac-ethyl (TE) applied every 7 or 14 days reduced ABR 4-29% and 4-16%, respectively. However, the effect of TE was greatest when used sequentially throughout the growing season after mefluidide or ethephon had been applied in the spring.

Sand topdressing reduced ABR severity (Inguagiato et al. 2009) but did so more effectively and consistently in summer than in spring. Lower topdressing rates (0.3 L/m2) initially increased ABR when applied at the onset of symptoms, while greater rates (0.6 L/m2) either had no effect or reduced ABR severity. Topdressing applied on a biweekly basis was more likely to reduce ABR severity than the single applications made after the initiation of ABR. Incorporation of sand by soft brushing, hard brushing, or vibratory rolling did not affect ABR severity. Sub-angular sand was more beneficial then round sand in reducing ABR on P. annua putting green turf.

The impact of irrigation practices was examined, and it was found that application of 40 and 100% evapotranspiration (ETo) caused more ABR than irrigation at 60 or 80% ETo. Hence both over and under irrigation can increase ABR severity (Roberts et al. 2009).

Host resistance studies to examine plant breeding strategies for reducing ABR had mixed success. Studies at Penn State showed that 65 P. annua accessions were identified with resistance to ABR. Additionally, some bentgrass lines and varieties were found to have consistent resistance to ABR (Bonos et al., 2009) and various other diseases.

A review of the research performed by NE1025 scientists from 2006 to 2008 was published as Best management practices for anthracnose on annual bluegrass turf in trade journals used as primary sources of research information by golf course superintendents in the U.S. and Canada (Murphy et al. 2008, 2008, 2009, 2010).

Outlook: The work conducted by NE1025 members over the last 6 years has greatly enhanced our understanding of ABW and ABR regarding (1) their significance and impact, (2) biology and ecology, (3) efficacy and optimal use of chemical, biological/biorational, and cultural management tools, and (4) IPM tools for sampling and predicting populations. Nonetheless, there is continued need for research on P. annua management. First, not all the objectives of NE1025 have been fully addressed due to unanticipated problems. For example, progress has been hampered by problems with the rearing of ABW, the development and spread of pyrethroid resistance in ABW populations, and the failure of new insecticides to adequately control pyrethroid-resistant ABW populations. Second, there are still many other aspects in the biology/ecology and management of ABW, ABR, and P. annua itself that require further regional efforts for the development of optimal BMPs and that are included in this proposal. Third, the recent advent of new chemistries for P. annua control along with the release of more competitive cultivars of Agrostis spp. has enhanced the potential for the development of better methods to suppress P. annua. Due to the many limitations of reducing/eliminating P. annua, both goals, better management of P. annua as well as its suppression/replacement by more sustainable grasses, should be pursued and coordinated to enhance the overall sustainability of golf courses and improve the economic and environmental well being of this industry.

Objectives

1. Develop improved options for the management of ABW on golf courses in the Northeast and Mid-Atlantic including (a) fill critical knowledge gaps in our understanding of ABW biology, ecology, and impact, (b) develop cultural, biological, chemical, and genetic control options, and (c) develop improved IPM decision making tools.
   
2. Develop improved options for the management of ABR associated with P. annua on golf courses in the Northeast and Mid-Atlantic including (a) fill critical knowledge gaps in our understanding of ABR biology, ecology, and pathogenesis, (b) develop cultural, biological, chemical, and genetic control options, and (c) develop improved tools for pathogen detection and quantification.
   
3. Develop a better understanding of stresses that affect P. annua and the cultural, chemical, and genetic methods to mitigate these stresses.
   
4. Develop cultural, chemical, biological, and genetic methods to suppress/eliminate P. annua and to transition P. annua-dominated areas to more sustainable turfgrass species.
   
5. Disseminate best management practices for P. annua and major pests and for P. annua suppression/transition to more sustainable turfgrasses and assess impact thereof.
   

Methods

Objective 1. ABW biology/ecology and management (a) Fill critical knowledge gaps in our understanding of ABW biology, ecology, and impact Geographic distribution: All participants will continue to update current ABW distribution in golf course habitats within the Northeast and Mid-Atlantic states to monitor spread. Distribution data will be coalesced into a common database. Habitat and host plant associations: NJ will examine fine-scale spatial distribution of adults and larvae on fairways to study aggregation behavior and host plant association (e.g., P. annua vs. creeping bentgrass) using Spatial Analyses by Distance IndicEs (SADIE). Adult dispersal, population fluctuation, and phenology: NJ, RI, MA, and NH will continue observations on adult movement and population phenology. Reproductive biology: NJ will study aspects of ABW reproductive biology linked to population development and habitat exploitation such as pre-oviposition period, oviposition rate, lifetime fecundity, reproductive diapause, and oviposition behavior. These factors will be examined in tandem with host plant tolerance/resistance. Adult oviposition and larval feeding preferences. NJ will examine adult oviposition preferences and larval feeding preferences in tandem with host plant tolerance/resistance. (b) Develop cultural, biological, chemical, and genetic control options. Conservation biological control: CT will conduct studies to identify potential natural enemies of ABW and determine their effect on different ABW life stages and populations in laboratory and microplot field studies. If potentially important natural enemies are identified, we will examine the effect of different management options on their abundance to develop methods to conserve their populations and maximize their suppressing effect on ABW populations. Chemical/biorational/biological control: CT, MA, NJ, NH, and RI will continue to evaluate new chemical, biorational, and biological control products for the management of different ABW stages in field tests on golf courses. Insecticide resistance management and management of resistant populations: CT and RI will continue to evaluate resistant ABW populations with the goal of developing best management strategies for control of these worst case situations. Host plant tolerance/resistance: NJ will compare the tolerance/resistance to ABW of P. annua and several cvs. of creeping bentgrass, colonial bentgrass (A. capillaris), and velvet bentgrass (A. canina). Adult attraction, oviposition preferences, and larval development will be studied in no-choice and choice experiments in lab and micro-plot field experiments. (c) Develop improved IPM decision tools. Plant phenological indicators: While no reliable indicators exist for ABW larval development, our empirical observations suggest that Rhododendron catawbiense may be a good indicator thereof. We will conduct field studies to correlate ABW phenology with that of R. catawbiense to develop it as a reliable indicator for best timing of monitoring of and insecticide application against larvae. MA will correlate sexual maturity with degree day data. Validate a degree-day model for predicting ABW phenology: A degree-day model developed by NY and tested in 3 NY locations will be tested in locations throughout the Northeast. Thermal-based data (degree-days) will be compared to calendar-based data (date) and other environmental indicators to determine which best predicts ABW phenology and is robust enough to overcome differences between years and sites. Refine action thresholds: In conjunction with host plant tolerance/resistance studies, NJ will correlate adult and larval densities to damage expression in P. annua and several cvs. of creeping, colonial, and/or velvet bentgrass. Sampling techniques: To facilitate studies in most other ABW-related fields, NJ will refine existing sampling techniques for adults (vacuum and soapy water irritant) and larvae (turf plugger cores extracted with salt water or heat) to optimize extraction efficiency and/or labor. Sampling plans: RI will develop new/refine existing sampling plans for adults for preventive insecticide applications against adults and/or larvae. Rearing techniques: Efficient rearing techniques for different ABW stages would have greatly facilitated the progress in most ABW-related studies of NE1025. However, progress during the previous 5 years was very limited. Thus, NJ will continue to test different techniques including artificial diets and/or P. annua as a host for improved production of ABW stages. Objective 2. ABR biology/ecology and management (a) Critical knowledge gaps in understanding of ABR biology, ecology, and pathogenesis. Population biology and ecology: NJ and MD will continue to examione C. cereale population biology and ecology on golf courses and in natural settings to determine relationships among fungal strains from different regions in the U.S. and abroad. Two key areas currently limit our ability to effectively study the biology of C. cereale: (1) the limited number of high-quality molecular markers capable of providing a robust, genome wide sampling of diversity between different pathotypes; and (2) the requirement to establish the fungus in pure-culture before conducting analyses. We will address this through population genomics and the development of new molecular tools to allow us to conduct spatially structured, fine-scale population analyses necessary to begin studying C. cereale biology and epidemiology in different turfgrass ecosystems. Critical gaps in our understanding of C. cereale biology and ecology addressed include: (a) evaluation of epidemiological factors associated with disease development and the potential that different C. cereale genotypes are involved in early-season vs. summer outbreaks; (b) comparison of ecological factors associated with different C. cereale pathotypes; and (c) understanding the impact of host islands on pathogen population structure and disease progression. We will develop new genome resources and culture-independent molecular tools to better understand how populations and individuals of C. cereale have evolved in response to biotic and abiotic changes in their environment. Host Pathogen Interactions: Fungal isolates labeled with green fluorescent protein (GFP) have been made (NJ) and confirmed to be pathogenic. More transformed isolates (with GFP and Ds Red markers) will be produced allowing for direct visualization of the infection process by NJ. Pathogenicity and virulence of Colletotrichum isolates will be evaluated in the greenhouse and lab. Recent progress from genomic investigations of other Colletotrichum spp. (e.g., C. graminicola; Sukno et al. 2008; Vernard & Vaillancourt 2008) will aid this anthracnose work. (b) Develop cultural, biological, chemical, and genetic control options. Optimize Cultural Control: Research (NJ) has shown that N fertilization and topdressing have a strong effect on ABR severity. However, there is a broad range in the programmatic approach to using these practices on golf courses that remains undefined, and much still needs to be learned about how to utilize these factors to reduce ABR severity. NJ and CT will continue to develop and evaluate cultural practices to reduce ABR on P. annua, especially optimizing N-management (e.g., impact of application timing, N-source, critical N-levels in planta, cultivation, rate and seasonal effects of topdressing on disease severity) and elucidating the effect of plant growth regulators on disease development. Our goal is to improve current best management practices (BMPs) for the control of ABR on putting greens. NJ will evaluate programmatic aspects of N fertility, topdressing, and cultivation in factorial studies to examine the impact of: i) N source, ii) rate of summer N fertilization, iii) autumn and spring vs. summer topdressing, and iv) mid-season cultivation (grooming, verticutting, solid tining) on ABR development. Finding from these and other trials conducted by project members will be used to establish a large, factorial proof of concept study in NJ during 2013-2015 to show the effect of current BMPs on ABR severity, fungicide efficacy and playing quality of P. annua putting green turf. Alternatives to chemical control of anthracnose: CA, CT, NJ, and WI will develop and evaluate non-chemical alternatives (e.g., biological and biorational products) for ABR control. Improving chemical control: CA, CT, NJ, and WI will evaluate new fungicide chemistries and application strategies (rates, intervals, rotation/alternation strategies) to improve fungicide efficacy. Early season preventive applicatiosn will be tested as they have shown to improve control of dollar spot disease. Project participants will continue to collect and share ABR isolates from throughout North America for use in lab, greenhouse, and field experiments. NJ will maintain isolates for the project for epidemiological, population biology, and management studies. Fungicide resistance management and management of resistant pathotypes of C. cereale: CA and RI will evaluate management practices that delay or reduce the potential for the development of fungicide resistance. We will study mechanisms that confer fungicide resistance in C. cereale. CA will develop a screening procedure to assess fungicide resistance and share it with other project members to use in their fungicide resistance management studies. Pesticide combinations, timing regimes, and resistance management strategies will be assessed through the collaborative efforts of CA, CT, NJ, and PA. Isolates of the ABR pathogen will be collected from P. annua and bentgrass sites in the Northeast, Mid-Atlantic, and Western states where resistance is suspected and sent to CA to determine resistance frequency to the QoI, benzimidazole, and DMI chemistries. Molecular techniques (e.g., quantitative PCR) will be used to determine the frequency of fungicide resistance in populations of Colletotrichum from the field and to verify the mechanisms of resistance. Host plant tolerance/resistance: NJ will compare the tolerance/resistance of P. annua and cvs. of creeping, colonial, and velvet bentgrass to isolates of C. cereale collected from throughout the U.S. The extent of genetic resistance to ABR in commercially available creeping bentgrass cvs., P. annua selections, and existing germplasm collections from NJ and PA will be assessed and elite lines evaluated in the field by CT, MD, NJ, NY, PA, RI, and WI. (c) Develop improved tools for pathogen detection and quantification. Molecular tools (e.g. real-time PCR and array-based methods; see above) will be developed by CA, NJ, MD for pathogen detection, differentiation (fungicide resistant vs. susceptible strains) and quantification and be shared with other project members. Objective 3. P. annua stresses and mitigation thereof. Effects of abiotic stress on P. annua: CA, PA, NJ, an NY will seek to determine the effects of different abiotic stresses (winter injury, heat/drought, scald, mechanical wear, etc.) on P. annua physiology, performance and its impact on the turfs susceptibility to ABW and ABR. Cultural management to mitigate stress: NJ and VA will develop and assess programmatic practices to manage P. annua as a desirable turfgrass on putting greens. Focus will be on the interaction of various cultural and chemical practices (e.g., influence of macro and micronutrients, mowing regimes, aerification timing, chemical management practices such as PGRs, herbicides, and fungicides) and their influence on abiotic and biotic stress, and how this affects P. annua populations. Objective 4. Methods for P. annua suppression/transition to more sustainable turfgrasses. Industry survey: All participants will contribute to an initial survey (yr 1) of U.S. golf courses to determine what would currently constitute a successful transition/conversion process to confirm (or refute) specific foci of research for this objective. Cultural management to eliminate P. annua: NJ, PA, and VA will develop cultural techniques (e.g., overseeding species, timing, frequency, and rate; cultivation; soil fertility), alone or in combination with biocontrols and herbicides, to reduce/eliminate P. annua in favor of more desirable turfgrass species. Chemical control of P. annua: NJ will evaluate novel compounds (e.g., methizolin, amicarbazone) and existing chemistries (e.g., paclobutrazol, bispyribac sodium) for P. annua control in creeping bentgrass maintained at fairway and putting green heights. The influence of biostimulants, plant growth regulators, and other plant protection products on the efficacy of these compounds will also be assessed. NJ and VA will continue evaluation of bispyribac sodium for P. annua control on creeping bentgrass greens (e.g., application rate and regime). Optimum bentgrass species/cvs. for P. annua replacement: NJ will examine tolerance/ resistance of P. annua and bentgrass species/cvs. to ABW and ABR in lab and field studies. Objective 5. BMPs for P. annua and major pests and for P. annua suppression/transition to more sustainable turfgrasses: dissemination and impact thereof. All participants will disseminate and promote the most recent information on BMPs for ABW, ABR, and P. annua on golf course turf and on BMPs for P. annua suppression/transition to more desirable species on golf course turf to turf managers in the U.S. through their regular extension activities (e.g., oral presentations, publications in various printed and electronic outlets). Under the leadership of CA and NJ, all participants will collaborate to update a BMP publication developed by NE1025 for P. annua and its major pests based on our finding. Under the leadership of PA and NJ, all participants will collaborate to develop a BMP publication on P. annua suppression/transition to more sustainable turfgrass spp. based on our findings. At the beginning of the 5th project year, adoption and impact of project findings will be assessed through outreach programs and stakeholder surveys.

Measurement of Progress and Results

Outputs

• Development of BMP Publications including: (a) Updated publication of BMPs for P. annua on golf courses from previous (Murphy et al. 2008) MSRP (NE1025), including new biological, biorational, chemical, cultural and ecologically based techniques for the control of ABW and ABR; (b) BMPs for P. annua, currently being developed by members of NE1025; (c) BMPs for suppressing/transition of P. annua to more sustainable turfgrass. Publications will be disseminated to turf managers in the Northeast and Mid-Atlantic via industry publications (e.g., Golf Course Management), state turf organizations, and university websites, and will be placed on the project NIMSS website.
• Publication of results from practitioner surveys conducted throughout the Northeast and Mid-Atlantic in year 5 of project in trade journals, refereed publications, project and university websites, industry newsletters and websites. These publications will document geographic distribution of pests, management practices used, and impacts of the MSRP.
• Real-time interactive Web casts of project results reported in years 2-5 to golf course managers to national/international audiences through the Golf Course Superintendents Association of America (a 22,000 member international organization).
• Conduct regional and national seminars at turfgrass conferences in years 2-5 to inform turf managers about the latest projects results, as well as research updates at state field days and electronic newsletters.
• Release of new ABW and ABR resistant/tolerant P. annua cvs. and data on susceptibility of commercially available cvs.
• Release of new ABR resistant/tolerant bentgrass cvs. and data on susceptibility of currently available cvs. Improved sampling techniques and rearing procedures for ABW and new predictors of ABW phenology.

Outcomes or Projected Impacts

• Improved exchange of information among turfgrass management specialists, entomologists, weed scientists, breeders, pathologists, and physiologists throughout the U.S. and Canada.
• Increased knowledge base of practitioners and county extension agents for the control/management of ABW, ABR and P. annua.
• Improved management practices adopted by golf course superintendents including new biological, biorational, and chemical strategies, and new cultural and ecologically based control techniques. This will result in practitioners having: (a). a better understanding of the biology/ecology and management of P. annua and ABW and ABR; (b) better tools for assessing, monitoring and predicting injury from ABW and ABR on P. annua turf; (c) more effective control strategies for ABW and ABR that are more cost-effective and reduce reliance on chemical inputs; (d) optimal programs for P. annua maintenance, and (e) optimal methods for P. annua suppression, elimination, and transition to more desirable grasses.
• Adoption and implementation of this information by practitioners will result in reduced pesticide inputs, cost savings to the golf course industry, improved plant health and ultimately enhanced economic and environmental health benefits across the region.

Milestones

(2012): - Isolation and identification of C. cereale strains from North America (CA, CT, MD, NJ, PA, ON), ABWs, and ABW pathogens from the Northeast and Mid-Atlantic (CT, MA, NJ, NY, RI) for use in breeding programs, population studies, and management research. Website established by CT. - Develop fine-scale, multilocus markers (NJ, MD) to study the diversity of C. cereale and what role different populations of the fungus play in the anthracnose disease cycle. - Share real-time PCR methodology developed by NJ with other project members to further evaluate unique C. cereale isolates and genome-wide variation using the RAD-tagged database. - Initiate studies examining the effect of different abiotic stresses (winter injury, heat/drought, scald, mechanical wear, etc.) on P. annua physiology, performance and its impact on the turfs susceptibility to ABW and anthracnose. - Initiate cultural (e.g., overseeding spp., timing, frequency, and rate; cultivation; soil fertility) and chemical techniques to reduce/eliminate P. annua in favor of more desirable turfgrasses. - Develop improved rearing procedures (NJ, NY) to be shared and used by all project participants to more effectively screen biocontrol agents, biorational and chemical products and to evaluate turfgrass germplasm for ABW susceptibility. - Share field inoculation procedures (NJ, PA) and isolates of Colletotrichum with all project participants to standardize procedures for biological, cultural, and chemical studies and to screen P. annua and bentgrass germplasm (CA, CT, NJ, NY, ON, PA, RI, MD, WI). - Develop additional GFP- and DsRed-labeled isolates of C. cereale for use in direct visualization of the infection process (CT).

(2013): - Continued isolation and identification of Colletotrichum isolates, ABWs, and ABW pathogens for use in collaborative research studies. - Complete factorial studies in several states examining the impact of nitrogen, sand topdressing, and cultivation practices on ABR. - Initiate large factorial (proof of concept) studies in NJ and CT to show the effect of currently recommended BMPs developed from past research (from this and the prior MSRP) on ABR severity, fungicide efficacy, and playing quality of P. annua putting green turf. - Selections and cvs. of bentgrass from NJ with suspected resistance to ABR provided to CT, NJ, NY, PA, RI for greenhouse and field studies. - Expand collaborative genomics studies on C. cereale (MD, NJ, ON).

(2014): - Conclude studies involving infection processes of C. cereale using GFP-labeled isolates. - Continued cultural, chemical, biological, and genetic studies for the control of ABW, ABR and the maintenance or transition of P. annua.

(2015): - Follow up survey developed (CT, NJ, NY, PA, RI), conducted, and analyzed to ascertain impacts of ABW and ABR research on clientele. - Multi-year field evaluations of P. annua and bentgrass germplasm tolerance to ABR and ABW analyzed and summarized. - Complete studies examining the effect of different abiotic stresses (winter injury, heat/drought, scald, mechanical wear, etc.) on P. annua physiology, performance and its impact on the turfs susceptibility to ABW and ABR. - Conclude cultural (overseeding species, timing, frequency, rate; cultivation; soil fertility) and chemical techniques to reduce/eliminate P. annua in favor of more desirable turfgrass spp. - Complete attempts at assembly of the C. cereale genome, and publicly release the data.

(2016): - BMPs for P. annua developed and disseminated to turf managers in the Northeast and Mid-Atlantic. - Field report published for multi-year field evaluations of P. annua and bentgrass germplasm tolerance to ABR and ABW. - Evaluate progress of C. cereale genomics initiative and determine direction of research. - Symposium on biology, ecology, and control of ABW and ABR in P. annua organized for either the annual meeting of the American Phytopathological Society, Ento

Projected Participation

View Appendix E: Participation

Outreach Plan

The annual meeting of NE-temp1721 will serve as the mechanism to keep members and other interested parties abreast of research accomplishments related to the biology, ecology, and management of P. annua and its pests, in particular ABW and ABR, as well as related turfgrass activities (i.e., ancillary symposia, annual meetings, international exchanges). Information on this meeting and shared projects will be available on the NE-temp1721 Website. Project members will continue to make research results available through refereed and non-refereed scientific journals, extension bulletins, national/international conferences, and workshops. Information will be disseminated to the general public via publications in the popular press, magazines, oral and written presentations at workshops and at grower field days. A list of all publications developed by NE-temp1721 members will be updated annually and posted on the NE-temp1721 Website in NIMSS (www.lgu.umd.edu). The group will utilize national and international real-time, interactive web casts during the project (e.g., Golf Course Superintendents Assoc. of America, Turf Net, Inc and other stakeholder group web casts/webinars) to enhance information transfer to clientele groups. Project participants will utilize the final NE1025 wrap-up survey (spring 2011) of golf course superintendents in the Northeast and Mid-Atlantic states to further hone the direction of the project and refine priorities to be addressed during the NE-temp1721 project. These surveys will ensure an efficient evaluation of the achievements of both projects and the significance thereof to the clientele.

Organization/Governance

The organization of regional research project NE-temp1721 will be established in accordance with the format suggested in the Manual for Cooperative Regional Research. One person at each participating institution or agency will be designated, with approval of the institutions or agencys director, as the voting member of the Technical Committee. Other individuals and interested parties are encouraged to participate as non-voting committee members. Each year, members will elect a Secretary. The Secretary, whose duties begin the following year, becomes Chair-elect in year 2 and Chair in year 3.

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Attachments

Land Grant Participating States/Institutions

AL, CT, IN, MA, MN, MO, NC, NH, NJ, NY, PA, RI

Non Land Grant Participating States/Institutions

Beltsville Area, University of Guelph