Life Sciences Commons^™

Machine Learning-Based Soybean Yield Prediction And Optimizing Lidar-Mounted Uav Efficiency, Leticia Santos

LSU Master's Theses

The first chapter of this thesis explores the predictive capabilities of random forests algorithm on datasets obtained from field plot experiments on crop management systems in soybean. Furthermore, the chapter presents a complementary analysis of model performance according to dataset sizes and two techniques on how to impute and deal with missing data. Random forests are being compared with standard statistical techniques such as linear regression on a well-structured, information-rich agronomic experiment. The key findings of this chapter includes the best hyperparameters adjustment and the identification of the dataset threshold for optimal algorithms performance. The second chapter has a research …

Isolation Of The Toxic Principle Of Senecio Latifolius By Means Of The Sensory Receptors Of Sheep, Leendert D. Snyman

Poisonous Plant Research (PPR)

The aversive substance of Senecio latifolius was isolated by means of the sensory receptors of sheep averted to S. latifolius. Chemical fractions refused due to the presence of the aversive substance sensed by the sheep were fractionated until a purified substance had been isolated. Nuclear magnetic resonance (NMR) analysis of the purified substance showed it to be sceleratine nitrogen oxide, the toxic principle of S. latifolius.

Nitrogen Fertilization And Harvest Management Improve Forage And Crude Protein Content In Crabgrass, B. C. Pedreira, I. T. M. D. Barros, J. I. Yasuoka, D. Helwig, J. K. Farney, G. F. Sassenrath

IGC Proceedings (2001-2023)

Crabgrass (Digitaria spp.) is an annual summer grass that can provide high-quality forage, but optimal management strategies are unclear. Our objective was to compare the yield and quality of crabgrass (Mojo and Quick-N-Big) under different nitrogen rates and harvest management. The experimental design was a randomized complete block with five treatments and three replications for each crabgrass variety, totaling fifteen experimental units for both Mojo and Quick-N-Big, in adjacent sites. Treatments were nitrogen rates (0, 100, and 200 lb N/acre) and harvest management (cut once or twice per year) for two growing seasons (2020 and 2021). Total forage accumulation …

Chemical Composition And Microbial Diversity Of The Silage Of Forage Peanut Harvested At Two Regrowth Ages And Treated With Microbial Inoculants, A. J. S. Macêdo, O. G. Pereira, V. P. Da Silva, A. J. Dos Anjos, W. Alves, H. R. O. Santos, K. G. Ribeiro

IGC Proceedings (2001-2023)

The objective of this study was to evaluate the chemical composition and microbial diversity of the silage of forage peanut harvested at 40 and 80 days of regrowth and treated with microbial inoculants. The inoculants evaluated were commercial inoculant (CI) Sil-All 4×4 (Lallemand®, Brazil); the AV14.17, Lactiplantibacillus pentosus strain (ISO) isolated from alfalfa silage; and control (CTRL), without inoculant. A total of 500 g of forage was ensiled in nylon-polyethylene bags (25.40 × 35.56 cm). After 60 days of fermentation, the bags were opened and silages were analyzed for dry matter (DM), mineral matter (MM), organic matter (OM), crude protein …

Evapotranspiration Of Rewetted And Drained Fen Soils With Grass – Long Term Lysimeter Studies, M. Pesch, J. Hoysagk, F. Eulenstein, A. Behrendt

IGC Proceedings (2001-2023)

In the context of reducing greenhouse gas (GHG) emissions to combat climate change, rewetting of peatlands is of particular importance. High groundwater levels covering organic matter in the soil prevent its oxidation to CO₂. The amount of water needed to allow the rewetting of peatlands can be determined in lysimeter studies.

The evapotranspiration in fens depends essentially on the groundwater table, the vegetation (transpirational active biomass) and the saturation deficit of the atmosphere. After rewetting, these factors can lead to an evapotranspiration of 1000 l m^-2 a^-1 and even 2000 l m^-2 a^-1 in …

Industrial Hemp Forage Potential, Swarup Podder, John H. Fike, B. Wilson

IGC Proceedings (2001-2023)

Hemp (Cannabis sativa L.) has been a valuable species for humans throughout history due to its adaptability and diverse uses. Farmers are interested in hemp as a forage and feedstuff due to its unique nutritional properties and fast summer production. Moreover, the presence of cannabinoids in leaf and bud tissues may provide pharmacological benefits to animal health, productivity, and product quality under different regulatory frameworks. This study examined two hemp cultivars, Grandi and Joey, solely as forage crops, and samples were taken at different growth stages in Blacksburg, VA, USA, in 2021. The highest biomass production of 1.41 tons per …

Differential Responses Of Yield And Shoot Traits Of Five Tropical Grasses To N And Distance To Trees In Silvopastoral Systems, L. S. Pontes, Emilio A. Laca

IGC Proceedings (2001-2023)

Light intensity and nitrogen (N) availability are important factors influencing the growth of C₄ forage species. Trade-offs may occur in the adaptive responses of species to shading and N inputs, and functional shoot traits can help to explain the consequences of these responses for species performance. Our objective was to gain understanding of the mechanisms between traits of five C₄ perennial grasses determining above-ground dry matter yield (DMY) when both resources, light and N, vary. Forage grasses were grown in six shading conditions (full sunlight vs. five positions between Eucalyptus dunnii rows) with two N levels (0 vs. …

Clovers Around The World: A Symposium In Memory And Honor Of Dr. Norman L. Taylor, Kenneth H. Quesenberry, D. Boone, B. M. Irish

IGC Proceedings (2001-2023)

Trifolium is arguably the largest and most diverse genera of herbaceous forage legumes (Zohary and Heller, 1984). Dr. Norman L. Taylor, Professor Emeritus, Department of Plant and Soil Science, University of Kentucky, deceased, was a pioneer and champion of collection and preservation of Trifolium species throughout his 57-year career. Dr. Taylor was a native of northern Kentucky, born near where this Conference is being held.

Estimating The Carrying Capacity For Habitat Of Urial Wild Sheep (Ovis Orientalis) In Tandoureh National Park, Iran, M. Rahimian, F. Tabatabaei Yazdi, Mansour Mesdaghi

IGC Proceedings (2001-2023)

In an attempt to estimate forage production and carrying capacity of wild ungulates in Tandoureh National Park of Iran, the Babanestan grassland was selected, as the typical habitat of about 200 Urial wild sheep. In order to estimate the carrying capacity of this habitat for foraging of Urial wild sheep, this habitat with an area of 132 hectares was classified as low flat (LF), high flat (HF), north aspect (NA), and south aspect (SA). Then, to estimate forage production, clipping method of comparative yield was used. In each land form, standing crop yield of five reference plots of 1-^{m2 …}

Development Of Novel Interspecific Fertile Cytotype (4x) Of Pennisetum Glaucum X Pennisetum Purpureum Utilizing Modified Ploidy Coupled With Embryo Rescue Technique, Maneet Rana, N. Kumar, R. Gajghate, S. Kumar, R. Kaldate, Kamini Gautam, R. P. Sah, R. Verma, H. A. Bhargavi, R. P. Saini, S. Ahmed, P. Kaushal, A. K. Roy, A. Chandra

IGC Proceedings (2001-2023)

Interspecific hybrids of genus Pennisetum (P. glaucum x P. purpureum) is the one of the most popular manmade hybrid. It combines the unique features of both P. glaucum (Pearl millet; Bajra) and P. purpureum (Napier; Elephant grass) species, which makes it more resilient to harsh environments with superior fodder quality. Due to ploidy level variation among the parents, these hybrids are sterile and propagated vegetatively only. To overcome this, attempts were made in the present study by exploring the feasibility of novel tetraploid pearl millet (2n=4x=28; Tetra 1; INGR 09047) developed at IGFRI, as a female parent in …

Integrating Grazing With 2,4-D And Florpyrauxifen To Control Broadleaf Weeds And Maintain Red Clover Productivity In Grass-Legume Pastures, M. J. Renz, G. M. Imhoff

IGC Proceedings (2001-2023)

In grass-legume pastures, 2,4-D-amine + florpyrauxifen-benzyl controls broadleaf weeds but red clover (Trifolium pratense L.) is eliminated. Grazing within a week prior to herbicide application is likely to reduce leaf surface area and may reduce red clover injury and maintain productivity. Experiments were conducted in 2020 and in 2021 to determine if red clover could be productive when 560 g ae ha-1 2,4-D-amine + 6.3 g ae ha^-1 of florpyrauxifen-benzyl with 1% v/v methylated seed oil applied in the spring was grazed before or after herbicide application. Grazing timings occurred 6, 4, or 2 days prior to herbicide …

Use Of Genuine Sources Of Ergot Resistance In Species Of The Dilatata Group Of Paspalum, R. Reyno, S. Murchio, C. Goñi, W. Iriarte, H. Oberti, Javier Do Canto, Walter Ayala, C. Rossi, M. Dalla-Rizza

IGC Proceedings (2001-2023)

Paspalum dilatatum Poir. (dallisgrass) is an excellent C4 forage for summer production, highly productive with a wide distribution within warm-temperate regions. P. dilatatum is native to South America with special relevance for milk and meat production since its forage quality is superior to that of other C4 forage grasses and it shows tolerance to frost and water stress. In situations of temperate and warm temperate climate, the presence of these species plays a key role in the ecological stability of the system due to the complementarity of the growth cycles between winter and summer grasses. Claviceps paspali (ergot) is a …

Fermentation Profile Of Signal Grass Silages Intercropped With Calopo Or Fertilized With Nitrogen And Treated With Microbial Inoculant, Karina G. Ribeiro, Tâmara Chagas De Silveira, João Paulo Santos Roseira, Albert José Dos Anjos, Wagner Souza Alvez, Danielle Nascimento Coutinho, Odilon G. Pereira

IGC Proceedings (2001-2023)

Tropical grasses have characteristics that allow the occurrence of undesirable fermentations resulting in low quality silage. Inoculants can improve silage quality. Fermentation profile and microbial population of signal grass silages under four management (M), with and without microbial inoculant, were evaluated. The experiment was carried out in a 4 × 2 factorial scheme, with silages of signal grass managed without N application (control, 0N), fertilized with 50 kg ha^-1 of N (50N), fertilized with 100 kg ha^-1 of N (100N), or signal grassintercropped with calopo (Calopogonium mucunoides D.) (LEG), with inoculant (I) andwithout inoculant (WI), in a …

Plant Breeding Perspectives For Alfalfa (Medicago Sativa L.) Success In Warm Climates, Esteban F. Rios, M. Murad Andrade, C. C. Fernandes Filho, P. Sipowicz, A. Biswas, R. Ulbricht, D. Basigalup, E. C. Brummer

IGC Proceedings (2001-2023)

Climate change can have major impacts on adaptation of forage species to agroecosystems around the world. The ability of breeders to select for traits that impart adaptability to climate resilience will be critical for the future of grasslands. Alfalfa (Medicago sativa L.) is the most important perennial forage legume in the world because of its relatively high yield and nutritional value. In Florida, nondormant cultivars were developed for improved adaptation to the state’s subtropical agroecosystem (‘Florida 66’, ‘Florida 77’, and ‘Florida 99’); however, these cultivars are not commercially available. Breeding efforts are underway to develop new nondormant alfalfa adapted …

Impact Of Fertilizer Type, Seed Coating, And Duration Of Exposure On The Germination Of Orchardgrass Seed, Edwin L. Ritchey, Christopher D. Teutsch

IGC Proceedings (2001-2023)

Cool-season grasses such as orchardgrass, are important components of forage systems in transition zone states like Kentucky. To maintain dense and vigorous sods, improved cool-season grass varieties are sometimes overseeded into existing stands in late-winter or early-spring. In many cases seed is mixed with fertilizer and top-dressed onto pastures. Little data are available on the impact of fertilizer type or duration of exposure on the germination of raw and coated grass seed. The objective of this study was to evaluate the impact of two fertilizer types, muriate of potash and a blended fertilizer (urea, diammonium phosphate, and muriate of potash), …

Accuracy And Precision Of Near Infra-Red Spectroscopy (Nirs) Versus Wet Chemistry In Forage Analysis, U. K. Saha, R. J. Kern-Lunbery

IGC Proceedings (2001-2023)

Near Infra-red Spectroscopy (NIRS) is an attractive option for forage analysis. NIRS is less labor intensive, nondestructive, rapid, environmentally friendly and provides accurate and precise results. However, many nutritionists are quick to brush off NIRS, citing ‘poor accuracy’. We evaluated the accuracy and precision of dry matter (DM), crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) of 33 National Forage Testing Association (NFTA) proficiency test (PT) alfalfa hay samples analyzed by NIRS in 7 NIRS Forage and Feed Testing Consortium (NIRSC) member laboratories. The reference method averages (RMA), used to evaluate the NIRS results, were based …

Evaluation Of Different Genotypes Of Teosinte (Euchlaena Mexicana) For Herbage And Seed Production In Nepal, S. Sanjyal, John G. Hampton, P. Rolston, S. Marahatta

IGC Proceedings (2001-2023)

Teosinte is highly admired by the Nepalese farmers as a summer forage crop. It is also an important crop for milking animals in the tropical world where dairy husbandry is practiced. The only Sirsa cultivar of teosinte currently grown in Nepal takes 8 to 9 months from sowing to seed harvesting, which makes growing this crop difficult for farmers with small land holdings wanting to establish winter crops. Therefore, a diversity study on eighteen teosinte accessions was conducted in CRBD design. Seventeen teosinte accessions imported from CYMMIT Mexico and one locally grown Sirsa were evaluated in order to identify if …

Effects Of Insecticide And Tolerant Alfalfa Cultivars On Potato Leafhopper (Empoasca Fabae) Populations And Forage Yields In Quebec (Canada), Philippe Seguin, X. Shi, J. Saguez, Huguette Martel, A. Claessens

IGC Proceedings (2001-2023)

The potato leafhopper [PLH, Empoasca fabae (Harris)], which affects several crops including alfalfa (Medicago sativa L.), is a recurrent problem in several regions of Quebec. The objective was to evaluate alfalfa management tools in order to reduce yield losses caused by this pest. An experiment was conducted at two sites in Quebec over three field seasons to evaluate the impact of insecticide applications and the use of PLHtolerant cultivars on forage yield and PLH populations. Foliar insecticide applications in the seeding year reduced PLH populations but generally failed to impact alfalfa yields compared to untreated alfalfa. However, in one …

Addition Of Red Clover Or Birdsfoot Trefoil In Alfalfa-Based Mixtures To Improve The Forage Energy To Protein Balance, Philippe Seguin, Gaëtan F. Tremblay, M. Thériault, X. Godin, Shabtai Bittman, D. Hunt, J. Hakl, Gilles Bélanger, M.-N. Thivierge, Annick Bertrand, A. Claessens

IGC Proceedings (2001-2023)

The low ratio of sugars (S) to crude proteins (CP) in alfalfa (AL, Medicago sativa L.) leads to inefficient use of nitrogen by ruminants. The objective was to determine if adding red clover (RC, Trifolium pratense L.) or birdsfoot trefoil (BT, Lotus corniculatus L.) with or without a grass species to AL improved the forage S/CP ratio. Treatments were 100% AL (control) or AL-based mixtures with RC or BT in three proportions (75, 50, or 25% of seeded legumes) with either no grass or with timothy (Phleum pratense L.) or tall fescue (Schedonorus arundinaceus Schreb. Dumort.), resulting in …

Yield Potential Of Co4 Napier Hybrid Bajra (Pennisetum Perpureum Schumach.) Fodder Crop Under Irrigated Conditions In India, Om Singh, Ayushi Singh, Ananya Singh, Anita Singh

IGC Proceedings (2001-2023)

A field trial on Co₄ was conducted at ICAR-IVRI, Izatnagar during 2013-14 to 2017-18 to study the effect of harvesting season/time on green, dry matter yield and morphological parameters. Data shows that yield of Co₄ was increased from first year 2013-14 to third year 2015-16 and decreased in fourth year of plantation of crop. Regrowth of ratoon crop was good as it was in first year crop, it may be concluded that crop can be grown upto 5-6 years. The crop yield of first year and second year as par with fifth year. Maximum green fodder yield 307.7 …

Concentration And Bioactivity Of Condensed Tannins And Total Phenolics Of Lespedeza Species From A Germplasm Collection, Thomas H. Terrill, V. Smith, B. Morning, E. M. Courson, James P. Muir, N. M. Cherry, J. B. Morris

IGC Proceedings (2001-2023)

Interest in ‘AU-Grazer’ sericea lespedeza (Lespedeza cuneata) as an anti-parasitic bioactive forage has been growing in the United States, but the concentration and bioactivity of tannins and other phenolics from additional accessions of L. cuneata, as well as other Lespedeza species, have not been evaluated. A study was completed to determine the concentration of extractable condensed tannins (ECT), total CT (TCT), total phenolics (TP), and protein-precipitable phenolics (PPP) of 32 accessions of L. cuneata and 16 additional Lespedeza species from a germplasm collection. The plants were established in small pots in a greenhouse and then transplanted into …

High Throughput Phenotyping: Field Based Triticale Breeding And Educational Resource Impact, Catherine Kay Mick

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Triticale (Triticosecale) is a multifunctional hybrid cereal crop that adopted the hardiness of rye and wheat's high-yielding and nutritional qualities. Plant breeding programs work to improve the quality and number of varieties available to producers through multiple rounds of evaluation and selection. However, traditional phenotyping methods are labor-intensive, time-consuming, and destructive, creating a phenotyping bottleneck. Remote sensing using unmanned aerial systems has the potential to alleviate this issue and change the evaluation of phenotypes in a breeding. Demand for educational resources to advance public awareness and prepare the workforce has increased with the utilization of more technology in …

A Global-Temporal Analysis On Phytophthora Sojae Resistance-Gene Efficacy, Austin G. Mccoy, Richard R. Belanger, Carl A. Bradley, Daniel G. Cerritos-Garcia, Vinicius C. Garnica, Loren Giesler, Pablo E. Grijalba, Eduardo Guillin, Maria A. Henriquez, Yong Min Kim, Dean K. Malvick, Rashelle L. Matthiesen, Santiago X. Mideros, Zachary A. Noel, Alison E. Robertson, Mitchell G. Roth, Clarice L. Schmidt, Damon L. Smith, Adam H. Sparks, Darcy E.P. Telenko, Vanessa Tremblay, Owen Wally, Martin I. Chilvers

Papers in Plant Pathology

Plant disease resistance genes are widely used in agriculture to reduce disease outbreaks and epidemics and ensure global food security. In soybean, Rps (Resistance to Phytophthora sojae) genes are used to manage Phytophthora sojae, a major oomycete pathogen that causes Phytophthora stem and root rot (PRR) worldwide. This study aims to identify temporal changes in P. sojae pathotype complexity, diversity, and Rps gene efficacy. Pathotype data was collected from 5121 isolates of P. sojae, derived from 29 surveys conducted between 1990 and 2019 across the United States, Argentina, Canada, and China. This systematic review shows a loss of efficacy of …

Mycorrhizal Feedbacks Influence Global Forest Structure And Diversity, Camille S. Delavaux, Joseph A. Lamanna, Jonathan A. Myers, Richard P. Phillips, Salomón Aguilar, David Allen, Alfonso Alonso, Kristina J. Anderson-Teixeira, Matthew E. Baker, Jennifer L. Baltzer, Pulchérie Bissiengou, Mariana Bonfim, Norman A. Bourg, Warren Y. Brockelman, David F.R.P. Burslem, Li Wan Chang, Yang Chen, Jyh Min Chiang, Chengjin Chu, Keith Clay, Susan Cordell, Mary Cortese, Jan Den Ouden, Christopher Dick, Sisira Ediriweera, Erle C. Ellis, Anna Feistner, Amy L. Freestone, Thomas Giambelluca, Christian P. Giardina, Gregory S. Gilbert, Fangliang He, Jan Holík, Robert W. Howe, Walter Huaraca Huasca, Stephen P. Hubbell, Faith Inman, Patrick A. Jansen, Daniel J. Johnson, Kamil Kral, Sabrina E. Russo, Et Al.

Faculty Publications from the Center for Plant Science Innovation

One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles in proximity to conspecific adult plants. Although evidence shows that plant-specific soil pathogens can drive negative CDD, trees also form key mutualisms with mycorrhizal fungi, which may counteract these effects. Across 43 large-scale forest plots worldwide, we tested whether ectomycorrhizal tree species exhibit weaker negative CDD than arbuscular mycorrhizal tree species. We further tested for conmycorrhizal density dependence (CMDD) to test for benefit from shared mutualists. We found that the strength of CDD varies systematically with mycorrhizal …

Evaluation Of Vegetative Indices To Determine Canopy Ground Cover For Winter Survival And Hybrid Necrosis In Winter Wheat, Micheal Young

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The benefit of unmanned aircraft systems and image processing methods in agronomic research across numerous crops has been well documented as has the importance of wheat, Triticum aestivum L., on the global food supply. Hence there is great interest in digital solutions applied to aspects of wheat breeding. A major trait of importance to winter wheat breeders in higher latitudes is winter survival, which can result in poor yield and performance if lines do not survive extreme cold. Scoring winter survival is most commonly based on visual score of 0% to 100% with the higher percentage conveying higher winter survival …

Vulnerabilities Of Greater Prairie Chicken And Tier 1 At-Risk Species In Nebraska Caused By Grassland Transition To Woody Dominance, Robert Peterson

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Woody plant encroachment is a global threat and has been transitioning grasslands to woody dominance at a biome scale. This threat is present in the Great Plains grassland biome which is currently experiencing grassland biome collapse as the alternative woody biome advances northwest. Nebraska, which contains the most intact temperate grassland in the world, is currently at the front lines of this large-scale transition making this state’s management decisions vital for the remaining grasslands and the species which rely on these ecosystems. In this study, we assess the vulnerability of Greater Prairie Chicken and Tier 1 at-risk species in Nebraska …

Responses Of Maize To Different Irrigation Regimes In Semi-Arid Western Nebraska, Swathi Palle

Department of Biological Systems Engineering: Dissertations, Theses, and Student Research

As the “Cornhusker State”, Maize (Zea mays) is an important crop in Nebraska. However, farmers in the state are challenged by unstable supply of surface water and limited groundwater resources. A better understanding of maize's response to water stress that occurs at different growth stages can help implement the best irrigation practices that conserve water while maintaining yields. In this study, we conducted field experiments at the Panhandle Research, Extension, and Education Center to compare the responses of maize to eight irrigation treatments which included both limited and deficit irrigation regimes during 2022 and 2023 growing seasons. Specifically, …

Game-Theoretic Approaches To Optimal Resource Allocation And Defense Strategies In Herbaceous Plants, Molly R. Creagar

Department of Mathematics: Dissertations, Theses, and Student Research

Empirical evidence suggests that the attractiveness of a plant to herbivores can be affected by the investment in defense by neighboring plants, as well as investment in defense by the focal plant. Thus, allocation to defense may not only be influenced by the frequency and intensity of herbivory but also by defense strategies employed by other plants in the environment. We incorporate a neighborhood defense effect by applying spatial evolutionary game theory to optimal resource allocation in plants where cooperators are plants investing in defense and defectors are plants that do not. We use a stochastic dynamic programming model, along …

Unraveling The Tapestry Of Indigenous Maize In North America: A Case Study Of Pawnee Ancestral Maize, Kahheetah Barnoskie

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Studies on Indigenous ancestral landrace maize in North America has significant historical and scientific importance. Indigenous peoples, such as the Pawnee people, have been cultivating maize for thousands of years, resulting in diverse varieties adapted to their local environments. This study aims to deepen the knowledge of Indigenous maize by examining specific varieties from the Pawnee, including a comparative analysis of the genetic makeup through DNA sequencing. This study used Genotyping by Target Sequencing (GBTS) method to examine the genetic variation and characteristics among the multiple varieties the Pawnee people once grew historically, providing valuable information about the evolutionary history …

Human Dimensions Of Woody Encroachment Management In Nebraska, Emily Rowen

School of Natural Resources: Dissertations, Theses, and Student Research

Woody plant encroachment (WPE) is a social-ecological problem that will challenge conservation professionals and agricultural producers to adapt their management strategies. This research first examined WPE from the perspective of individual conservation professionals through an online survey. Conservation professionals’ attitudes about adaptation to vegetation transitions, such as WPE, were of interest because these attitudes are one measure of how prepared this group is to respond to WPE. Hypothesized predictors of adaptation attitude were tested through linear regression modeling. These predictors included ecological change, observation of WPE, or risk perception. It was found that risk perception was the strongest predictor of …