Information Sources for Annual Bluegrass Management

Extension was ranked as the most helpful source of information most frequently (by 22% of the respondents) (Figure 2). Yet, this was closely followed by other turfgrass managers (19%), professional consultants/turf advisors (18%), and field representatives for local agricultural chemical distributors (16%). Extension was ranked in the top three most helpful information sources by 53% of the respondents, just behind field representative/local distributor source, at 54%. This also means that Extension was not ranked among the top three sources by 47% of respondents, illustrating that sports field managers’ views of helpful information sources for annual bluegrass were highly varied. Studies have found that urban populations traditionally have low awareness of Extension (Fox et al. Reference Fox, Ruemenapp, Proden and Gaolach2017; Henning et al. Reference Henning, Buchholz, Steele and Ramaswamy2014; Raison Reference Raison2014).

Figure 2. Top three sources of information for their helpfulness in managing annual bluegrass based upon survey of turfgrass sports field professional managers.

Adoption of Weed Management Practices Resulting from Extension Attendance

One respondent did not answer the question about Extension attendance. Whereas 6% of the respondents attended no Extension events in the previous 3 yr, 12% attended one, 20% attended two, 22% attended three, and 39% attended four or more events (Table 1). Respondents were asked if they adopted specific turfgrass management practices “as a result of attending and learning about topics at” Extension events. Respondents who did not attend Extension events did not answer questions about adoption “as a result of” attendance. Although responses ranged between zero and nine different practices, 52% of respondents adopted between two and four practices (Figure 3). The mode response was adopting three practices (21% of those answering). Of those attending an Extension turfgrass event in the previous 3 yr, 97% adopted one or more practice, 89% adopted two or more practices, and 76% adopted three or more. More than half of the attendees adopted four or more practices, and more than a third adopted five or more.

Figure 3. Total number of practices adopted as a result of attending Extension turfgrass events in the previous 3 yr.

The most adopted management practice was some form of improved cultural practice (i.e., mowing, cultivation, fertilization, irrigation, hand weeding, overseeding, resodding/replanting), with 65% of respondents adopting a cultural practice (Figure 4). This was followed by using a new herbicide (53%), adopting practices to improve soil physical/chemical properties (50%), varying herbicide MOA (i.e., using diverse MOAs within the year) (50%), rotating herbicide MOAs across years (49%), and site-specific or precision techniques (44%). Less frequently adopted practices included changing cultivars, changing plant growth regulators, and scouting and mapping plants that escaped control (27% or less).

Figure 4. Specific practices adopted as a result of attending Extension turfgrass event. MOA, mode of action.

Production inputs can be sold as products, allowing private firms to capture gains from technology transfer. Historically, a role of Extension has been to provide public goods–type information that the private sector may undersupply (Anderson and Feder Reference Anderson and Feder2007; Birkhaeuser et al. Reference Birkhaeuser, Evenson and Feder1991). The relatively higher rate of adoption of improved cultural practices could result from an Extension emphasis on such practices. Use of cultural practices may also be due to lack of new active ingredients and MOAs (Allen et al. Reference Allen, Ervin, Frisvold, Brosnan, McCurdy, Bowling, Patton, Elmore, Gannon, McCarty and McCullough2022; Elmore et al. Reference Elmore, Patton, Gannon and Brosnan2023; Hahn et al. Reference Hahn, Sallenave, Pornaro and Leinauer2020; McDougall Reference McDougall2016).

Respondents attending one Extension turfgrass event in the previous 3 yr adopted 2.9 management practices as a result of attendance (Figure 5). Average adoption increased with attendance: 3.1 practices for those attending two, 4.1 practices for three events, and 4.6 practices for four or more events.

Figure 5. Average number of management practices adopted for each level of Extension event attendance.

Factors Affecting Practice Adoption

Table 2 reports regression results determining factors affecting the total number of practices adopted as a result of attending Extension turfgrass events over the previous 3 yr. Only variables that were statistically significant (α ≤ 0.10) in the regression results are reported (Table 2). Relatively few variables capturing respondent personal or facility characteristics were significant. People operating facilities of more than 50 acres (20.2 hectares) adopted roughly one additional practice (OLS coefficient of 0.938) than others managing fewer hectares. Similarly, companies with 50 to 99 and 100 to 249 employees adopt almost one more practice than others (OLS coefficients of 0.863 and 0.972, respectively). Compared to the respondents with low education levels (i.e., high school or less), those with vocational/Extension certificate or graduate degrees adopted approximately one more practice. Other education levels (relative to the lowest) have positive, but statistically insignificant, effects.

Table 2. Multiple regression of total turfgrass management practices adopted as a result of attending Extension turfgrass events. Regression coefficients and statistics are only reported for variables that are statistically significant at the ≤10% significance level. ^a

^a Default categories for categorical variables are working at an “other” facility type, with fewer than five employees, fewer than 3 acres (1.2 hectares), attending only one Extension turfgrass event in the previous 3 yr, aged ≤29 yr, with ≤5 yr experience, with a high school education or less, and male.

The most significant predictor of practice adoption was Extension event attendance over the previous 3 yr. Coefficients for attending three times and four or more times were highly significant. The OLS results can be interpreted as follows. The omitted, default variable is attending one event. The coefficient for attending twice was not statistically different from zero, implying no incremental effect of moving from attending one to two events. The coefficient for three events was 1.34, suggesting that moving from attending one to three events would increase the total number of practices adopted by slightly more than one on average. The coefficient for four or more events was 1.95, suggesting that moving from attending one to four events would increase the total number of practices adopted by roughly two practices.

The influence of Extension event attendance over the previous 3 yr and manager characteristics on the adoption of individual practices was considered via logistic regressions for each individual practice option from the survey (Table 3). Regressions included all the variables used in the total practice adoption equations (Table 1). However, we only reported variables where the odds ratio was significantly different from one at α ≤ 0.10. The adjusted count R² (ACR²) measures reduction in prediction error. For new herbicide use, ACR² = 0.238, meaning that the regression reduced prediction error (relative to the naive model) by 23.8%. For rotated herbicide, it reduced prediction error by 35%.

Table 3. Logistic regressions for adoption of individual turfgrass management practices (all variables in Table 1 were included in each regression; only results for variables with P values < 0.1 are reported here).

Based on odds ratios, attendance at four or more Extension turfgrass events increased the odds of adopting six different practices. For six practices, attendance at four or more events in the past 3 yr (compared to the reference case of one time) increased the odds of adoption 2.9 to 6 times (see odds ratios, Table 3), depending on practice. Attendance at three events increased the likelihood of adopting three practices (relative to attending once) 2.9 to 6.1 times (Table 3), depending on practice. Increasing attendance from one to two events (not shown) did not have a statistically significant effect on practice adoption.

There is some evidence for scale effects in adoption of some practices. Those operating larger acreages were associated with greater odds of rotating herbicides across years and with using herbicides with different MOAs, whereas those with more employees were associated with greater odds of changing cultivars and greater odds of using of plant growth regulators. There was not a clear pattern between education and adoption across practices. More years of work experience were associated with greater use of new herbicides. This may be because more new herbicides become available (or resistance to older herbicides develops) over greater spans of time. The time taken to register new products has risen above 11 yr in recent years (McDougall. Reference McDougall2016).

For the OLS and Poisson regressions of total practices adopted, only the Extension variables were jointly significant (Table 4). Extension variables were also jointly significant for six of eight individual practices. Coefficients for the type of facility were jointly significant for four practices (changed cultivars, changed plant growth regulators, changed practices to improve soil properties, and implemented site-specific/precision techniques). Age and experience coefficients were not jointly significant in any regression. To address possible collinearity between age and experience (as both tend to increase together), regressions were also run with age, but not experience variables, and vice versa. Results did not qualitatively change, however. The number of employees at a facility significantly affected the odds of changing cultivars or use of plant growth regulators. Education was a significant predictor for rotating herbicides and weed scouting/mapping. Hectares managed was a significant predictor for varying herbicide MOA.

Table 4. χ² tests of joint significance of grouped categorical variables in regressions of turfgrass practice adoption (e.g., null hypothesis is that regression coefficients for all education variables equal zero). ^a

^a Reported values are P values. Cells are blank for cases where the null hypothesis was not rejected (P > 0.10).

^b Abbreviation: MOA, mode of action.

Factors Affecting Extension Event Attendance

The responsiveness of practice adoption to Extension event attendance over the previous 3 yr begs the question, “what factors explain more frequent attendance?” Table 5 reports the results of the ordered logistic regression analysis. The dependent variable, the number of Extension turfgrass events attended in the past 3 yr, has reported values of 0, 2, 3, and ≥4. Most variables did not significantly influence the number of Extension events attended. However, those working at high schools and sports facilities were less likely to attend Extension events, whereas those with more years of experience (>5 yr) had an increased odds of attending more events.

Table 5. Ordered logistic regression of the number of Extension turfgrass events attended in the past 3 yr. Regression coefficients and statistics are only reported for variables that are statistically significant at the 10% significance level or lower.

Extension was ranked as the most helpful source of information for annual bluegrass management by only 22% of the respondents. However, this 22% was greater than for any other information source. Extension was ranked in the top three most helpful information sources by half of respondents, but not in the top three by half of respondents. Thus, Extension is an important, but not dominant, source of information for annual bluegrass management among sports field managers. Many respondents were not relying on Extension directly as an information source, yet they were not relying much on any other single alternative source either. Asmus and Schroeder (Reference Asmus and Schroeder2016) discuss similar results regarding Extension and weed management for agronomic crops, whereas Frisvold and Deva (Reference Frisvold and Deva2012) report similar results for Extension and irrigation management. The survey results suggest there is no “one-stop shopping” for annual bluegrass management information.

One reason Extension was not a dominant source of information for annual bluegrass management may be that not all states have a turfgrass Extension specialist. In a survey with 31 responding U.S. states, 26 reported having a turfgrass Extension specialist (Patton et al. Reference Patton, Trenholm and Waltz2013). Of those 26 states, only 14 had weed scientists with turfgrass Extension responsibilities. As such, the lack of Extension presence may diminish its impact. This lack of on-call expertise is one of several documented challenges to Extension delivery in urban settings (Collins and Gaolach Reference Collins and Gaolach2018; Fox et al. Reference Fox, Ruemenapp, Proden and Gaolach2017; Gaolach et al. Reference Gaolach, Kern and Sanders2017; Henning et al. Reference Henning, Buchholz, Steele and Ramaswamy2014; Raison Reference Raison2014).

Turfgrass managers were seeking out multiple and diverse sources of information to manage annual bluegrass. This raises two questions for future research and Extension programs. First, are these various sources providing consistent messages on herbicide resistance and other weed management topics? Earlier studies have emphasized the importance of consistent messaging for resistance management (Allen et al. Reference Allen, Ervin, Frisvold, Brosnan, McCurdy, Bowling, Patton, Elmore, Gannon, McCarty and McCullough2022; Johnson et al. Reference Johnson, Owen, Kruger, Young, Shaw, Wilson, Wilcut, Jordan and Weller2009; Shaw et al. Reference Shaw, Barrett, Schroeder, Asmus, Ervin, Jussaume and Coble2018) and for urban turfgrass management (Allen et al. Reference Allen, Ervin, Frisvold, Brosnan, McCurdy, Bowling, Patton, Elmore, Gannon, McCarty and McCullough2022; Borisova et al. Reference Borisova, Giacalone, Hanahan and Momo2011; Ervin et al. Reference Ervin, Dixon, Montry, Patton, Elmore, Gannon, Bowling, Kaminski, Kowalewski, McCurdy, McElroy, Unruh and Bagavathiannan2022). Second, how much are professional consultants, turfgrass advisors, and other information sources relying on Extension to get their information? Extension may be acting as a “wholesaler” rather than a “retailer” or direct provider of information (Stock et al. Reference Stock, Kowalewski, Gould and Jepson2020).

Among Extension event attendees, more frequent attendance over the previous 3 yr was significantly associated with adopting more weed management practices. Stock et al. (Reference Stock, Kowalewski, Gould and Jepson2020) found that practice adoption rates for school grounds managers were higher for those returning for additional Extension training than for those attending for the first time. This suggests that practice adoption could be enhanced by encouraging repeat attendance among past Extension event attendees. This might be attempted by maintaining lists of past attendees, then sending previous participants personalized follow-up invitations to new events. Personalized follow-up invitations could emphasize new topics or information to be covered, compared to previous events.

There was also some evidence of scale effects where managers working for larger operations (in terms of hectares or employees) were more likely to adopt certain practices. Elmore et al. (Reference Elmore, Patton, Gannon and Brosnan2023) note that employee turnover and finding skilled, knowledgeable labor are barriers to the adoption of integrated weed management practices. The turfgrass and landscape industry is known to have high employee turnover (Mathers et al. Reference Mathers, Acuna, Long, Behe, Hodges, Haydu, Schuch, Barton, Dennis, Maynard and Hall2010; Patton and Reicher Reference Patton and Reicher2011), and it may be that larger organizations are able to invest in training through attendance at Extension events to reduce the impact of employee turnover (Elmore et al. Reference Elmore, Patton, Gannon and Brosnan2023).