Materials and methods

A non-probability sampling approach was employed to gather data from MGs in 11 north-central U.S. states. State MG coordinators used direct e-mail notification and announcements through websites and electronic newsletters to invite MGs to complete a 14-question survey relating to their confidence in making IPM recommendations and their use of IPM through SurveyMonkey software (SurveyMonkey, Portland, OR). The survey was available for a 6-week period from mid-April to late-May 2009.

An exploratory, multi-item approach was used to estimate confidence and engagement in IPM-related practices. Given the extant research and theory, IPM components were defined as prevention, monitoring, cultural control, and chemical awareness/control. MGs responded to the full set of questions on IPM practices for each of five kinds of plants: fruit, vegetables, flowers, trees, and lawns. As a result, data were explored to examine the fit of measurement models presuming that IPM practices are spread consistently across plant types, and for testing research questions about how experience and advanced training relate to these IPM practices among MGs.

Cronbach's alpha was employed to examine the internal consistency of these models. Alpha based on standardized items did not differ appreciably for any estimate, indicating that no variance assumptions were violated within the items, and is therefore not reported. Training analysis and group sample differences were compared. Given the large difference in group sizes across our advanced trained and no advanced trained groups, careful attention was paid to these assumptions. All distributions were roughly normal, regardless of comparison group. However, several times, Levene's test for homogeneity of variance assumption indicated that group variances were not equal. One remedy for this problem is to use a weighted means approach, or least squares computation (Harris, 1994). This computation was employed in all cases, using standard analysis of variance procedures in SPSS (version 17; SPSS, Chicago).

Slightly uneven sample totals appear within some of the analyses using these variables due in part to the fact that some respondents simply did not grow some of the plants we were asking them to consider. Our survey design, however, did not include a non-response option across every variable of interest, so erroneous non-responding was conflated with valid non-responding. Therefore, missing data totals cannot be estimated and the decision was made to treat missing responses as valid for all analyses.

The data file was split by advanced training to compare experience associations with IPM practices and confidence among those with and without advanced pest management training. Confidence intervals were drawn around these sets of correlations to examine whether they differed significantly.

Results and discussion

The survey was completed by 3842 MGs, or 16.7% of the 22,916 MGs in the north-central U.S. (Table 1). Roughly 41% of the final sample came from Michigan (25.8%) and Illinois (16.2%). Only 15% or 589 MGs reported they had completed advanced training in pest management within the past 5 years. Thus, the majority of MGs who participated in this survey, 85%, indicated they had no pest management training in the past 5 years (Table 1).

Table 1.

North-central U.S. Master Gardener (MG) state affiliation and advanced pest management training in the past 5 years.

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Nineteen percent or 749 participants were interns in their initial year of the program, 44% or 1670 had been an MG for 1 to 5 years, 25% indicated they had been in the program 6 to 10 years, 11% had 11 to 20 years, 40 or 1% had 21 to 30 years as an MG, and four participants indicated that they had more than 31 years experience in the MG program.

Almost all (99.7%) of the MGs indicated they grow flowers, followed by trees and shrubs 98%, lawn 95%, vegetables 82% and fruit 49%. Weeds were the pest category managed across plant types by the most respondents (62%), followed closely by diseases (52%), insects (47%), and wildlife (28%). Plant category had an influence: weeds were the most prevalent pest managed for flowers (86%), vegetables (83%), and lawns (84%), but disease was the most common pest (69%) for trees and shrubs. Respondents growing fruit indicated that they managed disease, insects, and weeds nearly equally (about 62%). While insects were not the main pest managed for any plant type, they were usually managed by at least 50% of respondents across all categories except lawns (36%), with the highest percentage of insects being managed for vegetables 73%. Wildlife was the least managed pest, with the lowest response for lawns, 13%, and highest for vegetables, 47%. MG pest management practices are shown in Table 2, and are the basis for IPM. Two practices were not widely used by MG: record keeping and rowcovers. Row covers were used infrequently (25%); they were used about four times more often on vegetables than other plant types (data not shown). Record keeping, a key component of IPM, is not being done by MGs according to this survey. Similar results for record keeping were found by Sellmer et al. (2003). Interestingly, these IPM pest management practice variables were all correlated substantially and positively with one another, indicating that MGs' engagement in IPM practices are often not just spread across plant types, but practice types as well (Table 3). The correlations between these variables were all highly significant and ranged from a low of r = 0.35 (between prevention and chemical awareness/control) and a high of r = 0.58 (between monitoring and cultural control).

Table 2.

Integrated pest management (IPM) use by Master Gardeners in the north-central U.S. Participants were instructed to control which of the following pest management practices they typically used for each of five plant types: trees and shrubs, fruit, vegetables, lawns, and flowers. Each positive response was tallied and combined for the five plant types, thus, the four preventative practices across five plant types could result in a total maximum response of 20; three monitoring practices across five plants would yield a maximum of 15 responses; etc. The Cronbach's alpha, mean, and sd are shown for each of the four practice categories.

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Table 3.

Intercorrelations for integrated pest management (IPM) practices for Master Gardeners in 11 north-central U.S. states.

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MGs indicated their primary concerns for choosing pest management practices were (choosing no more than three): effectiveness at 79%, health and safety to family or pets at 79%, and environmental impact at 74%, and as opposed to cost of the management method at 20% or amount of time needed to use at 9%.

MGs indicated their preference for learning resources for pest management practices (Table 4). Time-sensitive extension pest management updates and tips (73%), face to face classes (72%), and online fact sheets (70%) had the highest responses. Web tools (63%) were viewed as “very helpful” resources, while self-paced or instructor-led online classes were ranked lower.

Table 4.

North-central U.S. Master Gardener preferences for learning pest management practices. Participants were instructed to control the single best answer for each learning method.

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To confidently make IPM recommendations, MGs indicated a need for more training in a number of topics, including identification of diseases at 81%, insects at 65%, and weeds at 54%, as well as using weather or climate data at 68%, organic pesticides at 64%, and biological controls at 57% (Table 5). Fewer responses for using adapted plants (26%) and cultural controls (25%) indicate that the MGs are more comfortable recommending these practices to others. This may indicate that they are less complex or that MG training has covered these topics more thoroughly.

Table 5.

North-central U.S. Master Gardener responses to the following question: “To be confident enough to make recommendations to other gardeners, I would need more training in the following pest management practices (check all that apply).”

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MGs with advanced training had significantly more confidence and used significantly more pest management practices and significantly more chemical controls than did MGs with no advanced pest management training in the past 5 years (Table 6). Years of experience as an active MG and confidence in knowing how to use IPM-related garden activities were correlated positively (r = 0.261), indicating there is a significant difference between experienced and inexperienced MGs (Table 7). Smaller, yet statistically significant, relationships between years of experience and prevention and monitoring pest management practices were also found (r = 0.06 and 0.09, respectively), indicating that MGs with more experience appear slightly more likely to engage in prevention and monitoring pest management practices than those with fewer years experience, although these correlations are very close to zero (Table 7).

Table 6.

Analysis of variance testing the role of advanced pest management training on confidence and implemented pest management practices of Master Gardeners in north-central U.S. states.

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Table 7.

Correlation between years of experience and confidence or integrated pest management practices when compared with advanced and no advanced training among north-central U.S. Master Gardeners.

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Advanced training appears to be more important than years of experience in disposing MGs to engage in IPM-related activities. MGs in north-central U.S. states are using most components of IPM, and the more advanced training they have, the more confident they feel in making recommendations involving IPM. A large majority of participants indicated a need for more training in disease and insect management. Implications for extension educators appear to be offering more classes, especially timely updates, followed by fact sheets and face-to-face classes in pest management for MGs.