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Extension Master Gardener Volunteers (EMGVs) serve as critical educators in promoting research-based gardening practices such as integrated pest management (IPM), sustainable and environmentally responsible pest control methods. Despite the central role EMGVs play in public horticultural education, few studies have evaluated their actual IPM knowledge. This study assessed baseline IPM knowledge among EMGVs nationwide using a 12-question instrument developed through a modified Delphi process. A total of 887 valid responses were analyzed using descriptive statistics, χ2 tests, and regression modeling. Results revealed that although most respondents self-identified as “somewhat knowledgeable,” objective assessment scores revealed a higher level of competency, with 519 respondents (58.5%) scoring in the “very knowledgeable” range. Higher IPM knowledge scores were significantly associated with more years of education, younger age, male gender, and in-person or longer-format EMGV training programs. However, knowledge gaps were evident in questions related to pesticide classification, biological control, and organic labeling—terminology often misunderstood or conflated by both consumers and volunteers. These findings suggest that although EMGVs are generally well informed about IPM, targeted enhancements to training programs—particularly in areas such as pesticide usage, definitions, and biological controls—may enhance their ability to provide accurate research-based information to consumers. This study establishes a foundation for improved curriculum development and encourages continued research into EMGV competencies across other horticultural topics. This study represents the first national quantitative assessment of EMGV IPM knowledge in the United States and establishes a national baseline for future program evaluation.
EMGVs are trained to assist Extension agents in providing consumer horticulture education outreach to the community (Bobbitt 1997). Originally developed in the 1970s, the EMGV program was designed to meet rising public demand for horticultural information and extend the reach of land-grant universities (Gibby et al. 2003). Master Gardener Volunteers serve as critical conduits for disseminating research-based gardening practices, including IPM, a science-based approach to pest control that emphasizes sustainable methods and minimizes environmental impacts (Boyer et al. 2002). Previous research has primarily evaluated EMGV training outcomes, program outcomes, and self-reported confidence. Few studies have directly measured EMGV IPM knowledge, particularly using validated, multistate quantitative methods. This study addresses this gap by providing the first multistate quantitative evaluation of EMGV IPM knowledge (Boyer et al. 2002; Frank and Blevins-Wycoff 2024; Liere et al. 2020; Mayfield 2006; Meyer et al. 2010; Pottorff and Brown 1994).
Consumers have growing concerns over pesticide overuse, and they are seeking out alternative pest control methods, including learning about the utilization of a combination of chemical and nonchemical approaches such as IPM (Deguine et al. 2021; Jeffers et al. 2025). IPM adoption among home gardeners has been inconsistently documented, and several studies have indicated that, despite training, public awareness and the application of IPM principles remain low (Bruhn et al. 1992; Jeffers et al. 2023, 2025). Another consumer survey showed that consumers were somewhat knowledgeable about IPM (Jeffers et al. 2025). Given EMGVs’ public education responsibilities, their knowledge and confidence in promoting IPM strategies are vital for successful community-based pest management education (Sellmer et al. 2003, 2004). However, few empirical studies have rigorously assessed the baseline IPM knowledge of EMGVs or evaluated how effectively training programs impart these principles (Boyer et al. 2002; Jeffers et al. 2025; Sellmer et al. 2004).
Understanding the extent of EMGVs’ IPM knowledge is critical not only for curriculum improvement but also for broader programmatic outcomes related to environmental stewardship and public health (Rice and Steffey 2009). Previous research has suggested that training interventions can significantly enhance volunteer competency in complex topics such as IPM, provided that educational efforts are aligned with adult learning principles and supported by ongoing reinforcement (Meyer et al. 2010; Pinson 2015; Rice and Steffey 2009). Consequently, measuring current knowledge levels and identifying potential gaps will contribute to a more strategic, evidence-based approach to Master Gardener education and outreach.
The objectives of this study were to 1) establish baseline IPM knowledge among EMGVs across multiple states in the United States, 2) identify specific knowledge gaps in key IPM concepts, and 3) examine what, if any, demographic and training-related factors are associated with knowledge levels. It was hypothesized that EMGVs would perform better on objective IPM assessments than their self-reported confidence suggested, and that knowledge scores would be positively associated with education level, length of EMGV training course, and in-person course delivery.
To evaluate baseline knowledge of IPM among EMGVs, this study adapted a set of questions originally developed by Jeffers et al. (2025) to assess consumer IPM knowledge. The original instrument was developed using a modified Delphi process with input from nine academic and industry experts to ensure content validity, clarity, and relevance (Jeffers et al. 2025). Twelve questions from the validated instrument were selected to reflect foundational IPM concepts appropriate for a trained volunteer audience (Deguine et al. 2021; Jeffers et al. 2025). These items served as the basis for evaluating both general knowledge and specific misconceptions related to pesticide classification, biological control, and organic production (Deguine et al. 2021; Jeffers et al. 2025).
Surveys were sent to EMGV coordinators via the Extension Master Gardner (EMG) state coordinators’ emails listed on the EMG website in each of the 50 states in the United States. Coordinators were asked to encourage their EMGVs to complete the survey with a goal of at least 50 responses from each US state. Survey participants were asked to identify as: “certified and active,” “certified but inactive,” “intern (active but not yet certified),” or “not active and not certified.” Survey responses to the IPM questions were scored and categorized based on accuracy: participants scoring less than 50% were classified as “not knowledgeable,” scores between 50% and 75% as “somewhat knowledgeable,” and greater than 75% as “very knowledgeable,” following benchmarks established by Jeffers et al. (2023). Descriptive statistics and cross-tabulations were conducted using JMP (Version 18.0, 2025 JMP®. JMP Statistical Discovery LLC, Cary, NC.) to explore associations between IPM knowledge and demographic variables. An ordinary least squares regression was used to identify demographic predictors of IPM knowledge, with knowledge scores as the dependent variable.
The study protocol was approved by the university’s Institutional Review Board (IRB2025-0548). The survey was distributed through Qualtrics Panel Services (Qualtrics LLC, Provo, UT, USA) to US-based respondents via EMGV state coordinators to volunteers in their respective states. Respondents qualified for the survey if they indicated they were currently EMGV or if they were currently taking the EMGV training course. Demographic information collected included household composition, age, gender, race, education, state and region of residence, and self-reported income level. To simplify regression modeling, income and gardening hours were made into continuous variables by taking the median of the level. This approach aligns with best practices for treating ordinal categorical data in parametric models. For example, the “hours spent gardening” level of “7 to 12 h per week” was set to 9.5 (Behe et al. 1999).
A total of 1040 EMGVs attempted the survey, with a total of 887 useable completed surveys. The average age of the respondents was 67.9 years at the time of the survey. More than 600 respondents were women and spent an average of 10 h per week working in their home garden. Most respondents were from the southeastern United States, particularly South Carolina, North Carolina, Alabama, Florida, and Georgia. Most respondents were from suburban and rural areas with at least 16 years of education or higher (Table 1). More than 700 respondents were certified and active EMGVs with an average of 7.32 years of service (Table 2).
More than 600 respondents indicated that they were “somewhat knowledgeable” of IPM, with 139 indicating they were “very knowledgeable” of IPM. However, when tested by the IPM questionnaire, the respondents’ test scores showed a right-skewed distribution, indicating a larger proportion of high scores. The average score of the IPM questionnaire was 80.2% (Table 2). A total of 519 respondents scored well enough to be grouped into the “very knowledgeable” category, and 352 respondents scored in the “somewhat knowledgeable” category (Table 2).
Descriptive analysis of individual item responses revealed both strengths and notable gaps in EMGVs’ understanding of IPM principles. Although many respondents demonstrated a solid grasp of core IPM practices—such as identifying scouting as a key component (98%), recognizing herbicide use as chemical control (98%), and understanding that a yard cannot be completely pest-free (99%)—four questions had correct response rates below 80% (Table 3).
Only 42% of respondents correctly identified horticultural oil as a chemical pesticide. Most misclassified it as a biological, physical, or cultural tactic, indicating widespread confusion regarding pesticide categorization. Similarly, just 52% of respondents were aware that certain pesticides are permitted in US Department of Agriculture (USDA)-certified organic production, with an additional 25% indicating uncertainty—highlighting a lack of clarity around organic labeling and regulatory standards. Furthermore, 76% of respondents correctly identified the definition of a pesticide, suggesting that nearly one in four lacked a clear understanding of this foundational term. Only 33% of respondents incorrectly answered that attracting beneficial insects is an example of biological control.
Cross-tabulations between self-reported and tested IPM knowledge and respondent demographics revealed several key trends (Table 4). EMGVs with higher income and more years of education generally scored higher on the IPM knowledge test, and their tested knowledge tended to exceed their self-rated knowledge. Course format also influenced knowledge scores. Respondents could indicate whether they completed their training in-person, online/virtual, or through a hybrid format. Those who completed in-person training scored much higher on the IPM questionnaire compared with hybrid participants, whereas online-only participants scored lowest. The length of the training course was another influential factor. Participants who reported training durations of 11 to 14 weeks demonstrated higher levels of IPM knowledge than those with shorter courses (10 weeks or less). Interestingly, knowledge levels appeared to decline when course length exceeded 14 weeks, with fewer respondents falling into the “some knowledge” or “very knowledgeable” categories.
The regression analysis identified several significant predictors of IPM knowledge (Table 5). Men scored higher than women on the IPM questionnaire (P < 0.05). Age was also found to be a significant factor. Specifically, as the respondent’s age increases, their IPM knowledge decreases (P < 0.05). The model yielded the finding that as years of education increased, the respondent’s IPM score also increased (P < 0.001).
Rather than comparing each US state in the model, a new variable was created by dividing the sample group into “South Carolina residents” and “non–South Carolina residents.” Being an EMGV in South Carolina reduced the potential IPM knowledge test score (P < 0.05) (Table 5).
The four knowledge areas with accuracy rates below 80% represent critical gaps that warrant targeted curriculum enhancements. The widespread misclassification of horticultural oil as a nonchemical control reflects fundamental confusion about pesticide categorization that could significantly impact public education efforts. IPM tactic categories can sometimes overlap, and it is possible that some EMGVs associated the concept of biodiversity with cultural control—an interpretation supported by previous research (Linstone and Turoff 1975; Sellmer et al. 2003, 2004). However, this confusion suggests a need for more explicit training on the scope and application of biological control strategies.
The lack of understanding regarding organic-approved pesticides is particularly concerning given consumers’ increasing interest in organic gardening methods. Nearly half of respondents were either incorrect or uncertain about pesticide use in organic production, suggesting that EMGVs may inadvertently provide inaccurate guidance to the public about organic pest management options.
Recent consumer research indicates growing interest in biological control products and related IPM services, such as scouting (Jeffers et al. 2023). EMGVs could play a pivotal role in educating the public on these tools, particularly as biological control options become more accessible to home gardeners.
The finding that men scored higher than women on the IPM questionnaire, and that younger EMGVs demonstrated greater knowledge, is consistent with previous consumer studies (Jeffers et al. 2025). Younger EMGVs may be more exposed to IPM strategies and tactics, as awareness of IPM has increased among the public in recent years (Jeffers et al. 2025). The positive association between education level and IPM knowledge aligns with adult learning theory, suggesting that volunteers with stronger educational backgrounds may be better equipped to master complex technical concepts.
The superior performance of in-person training participants compared with those in online-only or hybrid formats supports previous research indicating that face-to-face instruction enhances the retention of complex topics (Zimbroff 2023). This finding has practical implications for EMGV program delivery, particularly as many programs moved to virtual formats during recent years. The optimal training duration of 11 to 14 weeks suggests that abbreviated courses may not provide sufficient time for knowledge retention, whereas extended programs may experience diminishing returns or participant fatigue.
The negative coefficient for South Carolina residents is concerning and may reflect regional variations in curriculum content, instructor preparation, or program implementation. This finding underscores the importance of standardizing core competencies across state programs while allowing for regional adaptation.
These findings suggest that survey respondents demonstrated moderate to high levels of IPM knowledge, consistent with the hypothesis that EMGVs would be more knowledgeable than everyday consumers, as in previous studies (Jeffers et al. 2025). However, the specific knowledge gaps identified—particularly in pesticide classification and biological control—mirror some of the same misconceptions found in consumer populations. Together, these findings point to persistent misconceptions related to pesticide classification, organic labeling, and biological control. Current training programs may not be fully effective in preparing volunteers for their roles. This possible inadequacy underscores the need to distinguish between volunteer development needs and broader public education objectives.
This study addresses a significant gap in the literature by providing the first multistate, quantitative assessment of EMGV IPM knowledge using validated instruments. Previous research has largely relied on self-reported confidence measures or single-state evaluations, limiting the ability to establish national baselines or identify systematic knowledge gaps. By demonstrating that objective knowledge often exceeds self-reported confidence, this research challenges assumptions about volunteer preparedness and highlights the importance of evidence-based program evaluation.
The identification of specific knowledge deficiencies provides actionable data for curriculum developers, moving beyond general recommendations to targeted improvements. This approach aligns with calls in the literature for more rigorous evaluation of Extension education outcomes and establishes a model for assessing volunteer competencies in other subject areas.
Several limitations should be acknowledged. State-level participation was uneven, with disproportionate representation from southeastern states. Because the official number of EMGVs is not known nationwide in the United States, the overall response rate cannot be accurately determined. The cross-sectional nature of the data precludes causal inference, and the reliance on self-selected respondents introduces the possibility of selection bias. Furthermore, although the Delphi process strengthened content validity of the survey instrument, psychometric validation beyond internal consistency was limited. The uneven state participation, self-selected volunteer sample, and predominance of older respondents necessitate caution when generalizing these results to the national EMGV population.
Cooperative Extension services could respond to these findings by incorporating supplemental pesticide-focused modules, pesticide literacy handouts, and reevaluating how pest management content is introduced and reinforced during EMGV training. Strengthening these aspects of the curriculum would help address these nuanced but critical knowledge gaps and better equip EMGVs as community educators in sustainable pest management.
The preference for in-person training formats suggests that programs should prioritize face-to-face instruction for complex topics while using online components for basic information delivery. The optimal training duration findings indicate that programs should aim for 11 to 14 week formats when possible, balancing comprehensive coverage with participant engagement.
This study provides the first multistate, quantitative assessment of IPM knowledge among EMGVs, establishing a national baseline that moves beyond single-state or self-reported evaluations. Although EMGVs demonstrated strong overall competency, notable gaps remain in pesticide classification, organic labeling, and biological control—areas essential for providing accurate, research-based guidance to the public. By linking knowledge outcomes to training format and demographics, these findings offer actionable direction for program development, including targeted modules on pesticide literacy and biological controls. More broadly, this approach establishes a framework for assessing volunteer knowledge across other horticultural topics and underscores the value of pairing self-assessment with objective testing. Strengthening these aspects of EMGV education will not only improve volunteer preparedness but also enhance Cooperative Extension’s ability to advance sustainable pest management and environmental stewardship in communities.
Contributor Notes
A.H.J. and S.T. are Horticulture Agents.
C.K. and B.F. are Urban Horticulture Agent/Master Gardener Coordinators.
S.S. is State Program Coordinator - Master Gardener Program.
B.S. is Area Extension Agent-Agricultural Engineer.
A.H.J. is the corresponding author. E-mail: ajeffe3@clemson.edu.
