Increasing the impact of integrated pest management education with 3D printing

Abstract

Three-dimensional (3D) printing is a new tool in the extension educator’s toolbox. 3D printing allows users to print novel, cost-effective, and as-needed products to demonstrate key Integrated Pest Management concepts to stakeholders, such as plant damage patterns. 3D printing is underutilized in extension education but can have large impacts in the implementation and education of integrated pest management. Using 2 case studies, we demonstrate the broad impact of 3D printing in invasive species education and integrated pest management practice implementation. First, we developed 3D printed spotted lanternfly egg masses to train stakeholders to properly identify infestations. Second, a soybean defoliation tool was designed to showcase threshold estimations allowing stakeholders to visually calibrate the amount of leaf damage caused by soybean leaf defoliators. We assessed the impact of these tools on stakeholder education. In both cases, we found >15% increases in stakeholder knowledge and skill compared to pre-test values. Most stakeholders (~80%) stated that they enjoyed the inclusion of 3D printed products in the extension events. These case studies demonstrate the use and efficacy of utilizing 3D prints in extension education to improve IPM programming.

Three-dimensional (3D) printing provides a new opportunity to engage with stakeholders in the 21st century. Objects can be created from various Computer-Aided Design (CAD) programs using an additive process of printed layers. Printers are equipped to produce objects using a variety of substrates made from plastic, wood, or metal. The benefits of 3D printing include quick production time, low cost, and a high level of product customization (Shahrubudin et al. 2019). As a result, 3D printing has rapidly been adopted in many disciplines including educational fields (Ford and Minshall et al. 2019, Pinger et al. 2020). 3D printing provides a unique opportunity to create engaging and experiential opportunities for learners. While unexplored in extension education, previous studies from other educational fields have documented increased student performance using 3D printed products (Ford and Minshall 2019). Smith et al. (2018) reported a 14% increase in anatomy test scores when students were provided with 3D printed heart models. 3D printed models have also been used to visualize abstract concepts in fields like chemistry. When tested on their crystallography knowledge, students provided with crystallographic models scored 47% higher than the students who did not receive the models (Moeck et al. 2014). As in many of these fields, extension programming could also significantly benefit from 3D printed products. However, these applications are largely unexplored with a few exceptions (eg, Cornell Cooperative Extension Ulster County 2022).

Extension programs are often best received by stakeholders when accompanied with an active or experiential learning component (Rodgers 1993, Fell 1999, VanWinkle et al. 2005, Torock 2009, Strong et al. 2010, Baugher et al. 2017). Fell (1999) acknowledges that extension programs focused on adult learners should have activities that allow individuals to participate in and be stimulated by the program. Often, extension educators and stakeholders alike are calling for “hands-on” experiences that allow them to directly interact with material and have “face-to-face” contact with instructors (Strong et al. 2010, Lane et al. 2023). 3D printing offers a tangible product for learners to engage with, and the physical material lends itself to experiential learning. The practice of Integrated Pest Management (IPM) is often complex and require hands-on tools, especially in the case of scouting where insects or diseases may be difficult to identify. In some cases, invasive species training is nearly impossible without live specimens (which is logistically difficult and can be legally impossible outside of quarantine areas). Further, preserved invasives (pinned insects, specimens in vials, etc.) can be hard to obtain at early stages of the invasion and can be easily destroyed. 3D printing provides tangible, durable and highly specialized products that can improve an individual’s knowledge and skills. 3D prints can be rapidly reproduced through online makerspaces that allow easy download of preexisting prints (eg, Thingiverse.com, Yeggi.com). These tools could be widely applied in agricultural extension where stakeholders highly value hands-on, experiential opportunities. Many concepts in crop production can be challenging, but simplified models and decision aids may make the difference between adoption or rejection of a practice.

While 3D printing has numerous applications in pest management and related extension programs, its impact has not been fully assessed. Thus, we demonstrate 2 applications of 3D printing used to increase stakeholder knowledge and engagement, (i) learning how to identify spotted lanternfly (Lycorma delicatula, Hemiptera:Fulgoridae) egg masses in vulnerable agroecosystems and, (ii) increasing the accuracy of estimating soybean defoliation levels in soybean scouting. These early case studies showcase the potential positive effects of adding 3D printing to extension programming in pest management.

Production of 3D Printed Extension Materials

3D printed extension materials were designed using Tinkercad, a free online CAD software, and saved to a stereolithography file format called STL. Then the STL file was converted into a machine language called geometric code or G-code file using a slicer software, called slicing. Sliced models were printed using a PRUSA i3 MK3S+ 3D printer (Prusa Research; Prague, Czech Republic) with a multimedia printing unit called MMU2S which has a printing capability of up to 5 colors (Fig. 1). Polylactic acid (PLA) filament (Micro Electronics, Inc., Hilliard, OH) was used to print the 3D models, due to its biodegradability, ease of use and availability of large selection of colors and finishes. This 3-step process of designing using a CAD software, slicing and mass production/printing is shown in Fig. 2. TinkerCAD software (Autodesk, Inc, San Francisco, California, USA) has a point-and-click interface and was used to produce designs of the desired prints. Once an optimal design was completed, it was sliced using PRUSA slicer software (Prusa Research; Prague, Czech Republic) and then printed. Designs were revised as needed to achieve an accurate and appropriate prototype. Once a final prototype was achieved, many copies of the sliced design were fitted to a build plate of the printer to accommodate for mass production of prototypes, thereby decreasing costs and the time of printing. This process was used for all the designs in this study.

Case Study #1: 3D Printed Spotted Lanternfly Egg Masses and Scavenger Hunt

Spotted Lanternfly (L. delicatula) is an invasive plant leafhopper originally detected in Pennsylvania in 2014 (Urban and Leach 2023). Spotted Lanternfly is a significant pest in grape production and a serious nuisance in residential areas (Urban 2020). Since its discovery in the northeastern United States, spotted lanternfly has rapidly moved across the country and has established populations as far west as Illinois. Stakeholder knowledge and identification of this pest are very important for early detection. Timely management can help slow the spread of spotted lanternfly and mitigate negative effects associated with infestations. In Ohio, spotted lanternfly infestations have been reported in >12 counties. However, populations are isolated to small areas in most of these counties, making stakeholder exposure and training difficult. We created 3D printed replicas of spotted lanternfly life stages paired with a scavenger hunt to improve stakeholder scouting of this new invasive pest. 3D printed spotted lanternfly egg masses and keychains were designed and printed to facilitate these activities.

3D Printed Spotted Lanternfly Egg Masses

Using the process described in 3D printing (Fig. 2), 3 versions of the spotted lanternfly egg mass were designed to mimic the natural variation: cracked, half-covered, and fully covered (Fig. 2A and B). Egg masses were also printed in different colors to showcase the effect of desiccation. Printed egg masses were used in the scavenger hunt activity and included on keychains.

Spotted Lanternfly Egg Mass Scavenger Hunt

Spotted lanternfly extension programs were conducted throughout Ohio in 2022 to 2024 to train stakeholders to scout for spotted lanternfly egg masses. Prior to the start of extension events, 3D printed egg masses (n = 30 egg masses per event) were placed randomly in an outdoor area to mimic the distribution of spotted lanternfly oviposition sites. To achieve this, 3D printed spotted lanternfly egg masses were affixed to vertical surfaces using reusable adhesive (“Blu-Tak”). Attendees were trained at the start of the program with a short presentation (10 to 15 min) on spotted lanternfly biology and identification. After the presentation, attendees were encouraged to scout for the 3D printed egg masses outside for 10 to 15 min and were instructed to find as many egg masses as possible. Attendees recorded each egg mass they found through a Qualtrics-linked survey that enabled smartphone photography. Once finished, attendees were also asked about their experience with the spotted lanternfly egg mass hunt. Participants were asked to assess the following questions using a Likert scale (strongly disagree, disagree, neither agree nor disagree, agree or strongly agree); “I learned new information during this program” and “I plan to use the information I learned during this program”. The survey also asked participants to describe their favorite part of the event.

3D Printed Spotted Lanternfly Keychain

3D printed keychains also featured variations of egg masses (Fig. 2E). The keychain was designed to educate stakeholders on appearance and was also designed with a beveled edge to use as a scraper for egg mass removal during scouting. A tag was also provided with the keychain that included a picture of the adult spotted lanternfly, and contacts (including a QR code) of the Ohio Department of Agriculture (ODA) to report spotted lanternfly sightings in Ohio. Keychains were distributed at trainings and events (eg, county fairs, grower meetings). Printing was scaled to distribute to as many county extension offices and events as possible.

Results

Spotted Lanternfly Egg Mass Scavenger Hunt

Scavenger hunts were replicated by Ohio State University Extension Educators at >10 events. However, data were taken from 3 events, reported here. On average, between 1 and 15 egg masses were found per person at each scavenger hunt (n = 3 events with 15 to 32 participants per event) with an average of 6.5 egg masses found per attendee. The spotted lanternfly scavenger hunt was well received, with 52% of participants indicated that the scavenger hunt was their favorite part of the training event (n = 85). Most stakeholders agreed or strongly agreed that they learned new information during the program (4.44/5.0 on a Likert scale) and planned to use the information they learned (4.84/5.0 on a Likert scale). Improvements in spotted lanternfly knowledge ranged from 15% to 45% from initial pretest surveys. Attendees (n = 85) accurately identified spotted lanternfly adults (96%), spotted lanternfly egg masses (90%), and the signs associated with heavy spotted lanternfly infestations including sooty mold and honeydew (82%), after attending the spotted lanternfly workshop.

Distribution of 3D Printed Spotted Lanternfly Keychain

Over 1,000 spotted lanternfly keychains were distributed from 2022 TO 2024. These keychains were widely distributed in areas where SLF has been detected or is expected, which included Metro Park systems, Regional Natural Resources Conservation Service offices, and extension offices in Ohio, Indiana, and Michigan. Keychains were only sent to personnel that expressed interest in the keychains, thus this wide distribution suggests a large interest in 3D prints aimed at invasive species education. In Ohio, 33% (29/88) of county offices received spotted lanternfly keychains for stakeholder distribution. Master gardener networks were also utilized to increase the distribution efforts of the 3D printed keychain. Nevertheless, the 3D prints are scalable and have been widely distributed during extension programming and community events in the Midwest.

Case Study #2: Soybean Defoliation

Soybean (Glycine max) is a highly valuable crop in the Midwest and occasionally suffers from arthropod-caused defoliation (eg, Musser et al. 2022). While defoliation is common in soybean production, it often does not warrant chemical intervention. Over-spraying can lead to insecticide resistance as well as a waste of resources and money for farmers. There are spray thresholds based on percent defoliation; however, percent defoliation is difficult to estimate with the naked eye. Overestimations of leaf defoliation and/or damage has been previously documented (Nutter and Schultz 1995; Nutter and Esker 2006). Most stakeholders tend to overestimate defoliation, which can lead to unnecessary sprays. The Ohio action thresholds to control damaging insects are: (i) 30% defoliation prior to bloom, (ii) 10% from pod development to pod fill, and (iii) 15% after full seed (Fig. 3) (Raudenbush et al. 2020). There are barriers to adoption of thresholds in soybean production including limited scouting confidence (Hoidal and Koch 2021). To address these barriers and improve estimation, other tools have been created to improve stakeholder estimation of soybean defoliation, including paper versions of soybean defoliation and defoliation quizzes (eg, Crop Protection Network, Sisson and Mueller 2023). However, these approaches have limitations, for example, they require the use of a computer (eg, online defoliation quiz) or degrade quickly with multiple uses (eg, paper version of soybean defoliation keys). Thus, we employed 3D printing to make soybean defoliation keychains that were more resilient than paper and used easily in the field. In total, the resource included three defoliated soybean leaves (at 10%, 15%, and 30% defoliation, respectively), assembled as a keychain, to improve stakeholder estimates of soybean defoliation.

Methods for Soybean Defoliation

3D Printed Soybean Defoliation Tool

Using the process and the materials described in the 3D printing process (Fig. 1), 3 soybean leaves were designed to feature 3 distinct levels of defoliation coinciding with critical management thresholds: 10%, 15%, and 30%. Since these 3D prints would be deployed on a large scale, we wanted to ensure their accuracy. After prototypes were developed, each leaf design was assessed against its expected percent defoliation rating with Photoshop, Leafbyte, and ImageJ (Abramoff et al. 2004, Getman-Pickering et al. 2020). A card describing each threshold level was also included with the 3D printed soybean leaves (Fig. 3). This tag also has a QR code that takes them to The Ohio State University website with more information on pests that cause defoliation.

Defoliation Survey Test

To test the change in stakeholder’s ability to estimate soybean defoliation pre/post exercises were conducted in 2022 and 2023 (n = replicated at 3 events with 19 to 78 participants per event). Participants were shown a series of 10 defoliated soybean leaves and asked to estimate the percent defoliation (0 to 100) for each leaf. Defoliated soybeans ranged from 5% to 50% defoliation. Defoliated leaves were evenly split between 5% and 50%, and there was no bias toward one rating and/or examples of lower versus higher defoliation. During the pretest, participants were not given any tools to help estimate defoliation. In the post-test participants were given a 3D printed soybean defoliation key. Once stakeholders completed the second test, answers were called out in order of presentation. Stakeholders were then able to compare their pre- and post-answers.

Statistical Analysis

Participant improvement in estimating defoliation was analyzed using a generalized linear mixed model, “lme4” (Bates et al. 2015). Participant improvement was assessed by comparing the actual defoliation score to the score provided before and after the participant was given the 3D printed key. A large score difference indicated poor estimation whereas a lower score indicated a better estimation. Scores were log-transformed to meet assumptions of normality. Participant and event were considered random effects and nested (Event: participant) while the presence of the 3D printed soybean tool was treated as a fixed effect. All data were anonymized, and no personal participant data were retained.

Results

Soybean Defoliation Estimates

Approximately 98% of participants improved their estimation of soybean defoliation (209/214 participants) with the use of the 3D printed defoliation keys (F = 71.64, df = 1, 213, P < 0.0001). The greatest gains in accuracy were observed in soybean leaves that were 20% to 30% defoliated, where stakeholders improved their accuracy by 4.1 to 7.7 points from the actual percentage of defoliation. Smaller improvements in accuracy were observed in leaves with lower levels of defoliation (5% and 10% defoliation), 0.5 to 1.6 points, respectively.

Discussion

3D printing is a tool that can potentially enrich extension programs. While 3D printed materials have been previously used in entomological research, mostly for refining research equipment (Domingue et al. 2014, Berry et al. 2016, Horton et al. 2019, Natola and Tousley 2022, Snyder et al. 2022, Gjonov and Hristozov 2024), there is limited documentation of 3D printing use in extension education. In our case studies, we showcase the application of 3D printed tools to increase stakeholder awareness and knowledge of spotted lanternfly and soybean defoliation thresholds. In both cases, we demonstrate benefits to utilizing these tools including positive stakeholder feedback, knowledge gain, increased pest awareness, and improved scouting accuracy. Further, these prints were scalable, allowing quick production of hundreds of prints for extension events. Online platforms including Thingiverse.com and Yeggi.com allow for fast distribution of design files among extension programs, which can increase the impact of these tools overall.

The implications of this study are that 3D printed materials can increase stakeholder awareness of invasive insects and encourage greater adherence to thresholds when managing agricultural pests. Training resources have been previously shown to increase the accuracy of scouting and remain a powerful tool to improve IPM implementation (eg, Bowers et al. 1999, Bock et al. 2016, 2021). Importantly, creative engagement with stakeholders can alter IPM adoption. These outcomes are similar to other extension-based studies documenting increases in stakeholder knowledge with experiential learning approaches (Rebek et al. 2013, Kondylis et al. 2017, Helmberger et al. 2022). Loomis and Thomas (2022) found that 63% of participants indicated they were likely to change their pest management strategies after playing the game. However, research should identify best practices with these hands-on programs to maximize impact. For example, in our soybean defoliation case study, an expected corollary outcome would be a decrease in insecticide use. Further, while stakeholders liked the addition of 3D prints to our spotted lanternfly extension programming, we did not test how stakeholders would feel without the 3D print. Thus, it is unknown whether the inclusion of the 3D printed materials would change stakeholder education or perception of our SLF programming. Thus, more data are needed to determine if 3D printed tools can change grower behavior.

While 3D printed products can offer many advantages to extension, it requires specialized skill to design or even print products. Thus, increased use of 3D printing in extension will require a time commitment by extension educators. This commitment will vary depending on the extension educator and the desired outcome. For example, learning how to download a predesigned product from an open-source website will likely require a small commitment, but learning how to design and execute a new prototype will be more challenging and time intensive. Further, 3D printers are not always widely available, especially for extension educators. While 3D printers are often housed within university campuses, they are rarely found in local extension offices and/or satellite campuses which will hinder access to 3D printed materials. Further, many of these printers produce specialized products (eg, biomedical supplies) and may not be suited to develop extension materials. Thus, resources are needed, both in materials and education, to increase the impact of 3D printing in extension and outreach.

3D printers vary widely in quality and cost, which can make them risky investments. Our case studies used an Original Prusa i3 MK3S+ printer which is relatively inexpensive (800 to 1,159 USD) and contains all parts needed to start printing. Other brands including Bambu and Creality produce similar machines that allow users to modify them to meet specialized needs. Importantly, these machines can be purchased for 300 to 800 USD making them feasible to buy with lower budgets. Similarly, printing materials can also vary and add cost to projects. In our study, we used PLA filaments, due to their ease of use, wide color assortment, and biodegradability (useful for objects that might be left behind outside) (Arockiam et al. 2022). However, PLA can become brittle over time and can cause stringing (eg, melted strands of plastic appear on the 3D printed product), which may make it an undesirable material depending on the application (Tümer and Erbil et al. 2021). Educators have also reported that the 3D printed tools, both the spotted lanternfly key chains and soybean defoliation keys, warp, and melt in the heat, which is a concern since many of these tools are stored in uncontrolled environments (eg, truck cabs, spray sheds). Further exploration and refinement of materials used in 3D printed extension products is needed, to best match the material with the desired outcome. In most cases, however, products for extension can be inexpensive to produce, similar to traditional paper-based information, allowing distribution on a wide scale.

Suggestions for Integration of 3D Printing into Extension Programming

3D printed materials may increase the quality of extension programs. We demonstrated through 2 case studies that specialized prints can increase stakeholder knowledge and awareness of IPM programs. However, prototype development and deployment are time intensive. This skill requires education and availability of more collaborative workspaces with 3D printers (eg, Makerspaces) for printing designs or refining 3D products. Further evaluation of 3D printed products is needed to assess the total impact of these products on IPM practices. While further investment in the tool is needed, 3D printing offers stakeholders an unparalleled hands-on experience in IPM knowledge and practice.

Acknowledgments

We thank all extension educators who have trialed or supported the development of these 3D printed tools.

Funding

This work was funded by North Central-IPM Center critical needs grant and Crop Protection and Pest Management Program grant, 2023-70006-40608.

Author contributions

Olivia Lang (Methodology [equal], Project administration [equal], Software [equal], Writing—review & editing [equal]), Suranga Basnagala (Data curation [equal], Methodology [equal], Software [equal], Writing—review & editing [equal]), Andy Michel (Conceptualization [equal], Funding acquisition [equal], Methodology [equal], Project administration [equal], Writing—review & editing [equal]), Kelley Tilmon (Conceptualization [equal], Funding acquisition [equal], Writing—review & editing [equal]), and Ashley Leach (Conceptualization [equal], Formal analysis [equal], Funding acquisition [equal], Project administration [equal], Writing—review & editing [equal])

Conflicts of interest. None declared.

References