Since the 1970s Integrated Pest Management (IPM) has been promoted as an alternative to the singular reliance on pesticides to control agricultural pests. IPM involves the combination of chemical and non-chemical pest management practices to minimize pest damage to crops and reduce overall pesticide use. Although IPM has been promoted in both industrialized and Third World countries to reduce environmental and human health problems associated with pesticide use, it has not been widely adopted, particularly among small-scale farmers in the Third World. An important technical constraint to the adoption of IPM is the lack of simple, effective IPM techniques that farmers can easily incorporate into their existing farming systems. However, numerous non-technical constraints discourage farmers from adopting those IPM practices that have already been shown to be effective. Non-technical constraints to the adoption of IPM are the external political-economic forces and location-specific environmental, social and economic factors that may create obstacles to the adoption of IPM practices at the farm level. This thesis will use a political ecology approach to identify and examine the non-technical constraints to the adoption of IPM in the community of Denbigh Kraal in Jamaica. / Master of Science

While a more concentrated effort has been made in the last decade to understand the complex household behavior patterns and structures of Mali’s crop production systems and incorporate them into the prevailing research paradigms, information is still lagging in terms of knowledge related to the impacts of gender in agricultural production. This study examines the effects of resource allocation and production decisions on the attainment of food security and net revenue maximization for farmers located in the Koulikoro region of rural Mali. A linear programming model is used to determine how gender-differentiated constraints, size of the household, and potential integrated pest management (IPM) technologies could influence specific nutrient deficiencies and the ability to achieve household food security. The results suggest that IPM has the greatest potential to enhance the ability of farmers to attain higher food self-sufficiency levels by targeting women’s crop production systems. Increasing the probability of successful adoption and sustainability of natural resource management practices through IPM should positively influence food security through improved resource allocation, higher crop yields, and prevented pesticide dependency. A more thorough understanding of intra-household and community gender relations in Mali is needed so that gender-differentiated constraints can be recognized as obstacles to overcome rather than barriers to IPM adoption. / Master of Science

The twospotted spider mite, Tetranychus urticae Koch, is a serious pest of many ornamental plants (Johnson and Lyon, 1991). Pesticide resistance, the high cost of pesticides and loss of production time have raised interest by growers to introduce predatory phytoseiid mites to manage twospotted spider mites and reduce their need for acaricide applications (Sabelis, 1981). The predatory mite Phytoseiulus persimilis Athias-Henriot has been used successfully in integrated pest management programs for T. urticae suppression. Despite the success of P. persimilis in reducing populations of T. urticae, acaricide applications may still necessary due to limitations associated with the effectiveness of P. persimilis introductions. The objectives of this study were to; 1. Measure the effects of acaricides on the density and age structure of T. urticae populations. 2. Determine the compatibility of acaricides in an IPM program by measuring the toxicity of residues to P. persimilis and T. urticae adults. 3. Study the feeding behavior of P. persimilis on T. urticae. 4. Measure the effects of combinations of acaricides followed by release of P. persimilis on T. urticae populations using greenhouse trials. The effects of ten acaricides on T. urticae populations were measured on infested Buddleia x davidii 'White Profusion' cuttings. Acaricides did not alter age structure in predictable manner. Initial analysis of results demonstrates that cuttings treated with acaricides had age structures that were different from control treatments. However, these differences were not distinguishable from natural fluctuations in the age structure. Chlorfenapyr may have changed the age structure of T. urticae. Azadirachtin, pyridaben and spinosad did not suppress T. urticae populations at the rates and formulations tested in this trial. Abamectin, bifenthrin, chlorfenapyr, Gowan 1725,oil and neem oil suppressed T. urticae populations. Hexythiazox suppressed T. urticae populations but these results were not seen until two weeks after application. The effects of acaricide residues were tested on adult P. persimilis and T. urticae 1, 3, 7, and 14 days after application using a leaf disk system. Abamectin, Gowan 1725, hexythiazox, horticultural oil, neem oil, pyridaben and spionsad were not toxic to P. persimilis adults while bifenthrin and chlorfenapyr residues were toxic to P. persimilis. Tetranychus urticae mortality from chlorfenapyr residues was significantly greater than the control 1,3,7 and 14 days after application. Tetranychus urticae mortality from bifenthrin and abamectin residues was significantly greater than the control 3, 7, and 14 days after application. Tetranychus urticae mortality caused by Gowan 1725, horticultural oil, and neem oil residues was significantly greater than the control 1 day after application, while mortality from hexythiazox and spinosad residues was not significantly greater than the control at any of the times tested in this study. Phytoseiulus persimilis feeding behavior studies examining life stage preference tests and functional response studies were conducted on bean leaf disks. We found P. persimilis functional response to be a type II response for both eggs and adults with handling times of 0.079 hours for eggs and 3.399 hours for adults. The effects of a combination of acaricides followed by release of P. persimilis on T. urticae populations was tested using greenhouse studies conducted on infested Buddleia plants. In the first trial, severe plant damage occurred despite a reduction in the mean number of mites per leaf in treatments with oil+ predator treatments 7 days after release. Results from the second greenhouse trial produced plants with less visual damage compared to those in the first greenhouse trial. Treatments with predators alone and predators + acaricides produced similar results. However, treatments with predators had a mean numbers of mites per leaf that were significantly less than treatments with acaricides alone. The results demonstrate that the acaricides tested in the second greenhouse trial allowed the predators to provide suppression of T. urticae populations. A high release rate was used in the second greenhouse trial and lower release rates as well as different acaricide predator combinations need be tested to explore the possibility of new management techniques. Our results suggest that the number of pest mites present in the crop may be the most important factor affecting the success of biological control with predators. Combinations of oil applications followed by introduction of P. persimlis 3 days after release provided suppression of T. urticae populations in a meaningful time frame. I was not able to shape the age structure of T. urticae populations in a predictable manner with acaricide applications. Phytoseiulus persimilis does not have a prey-stage preference when feeding on T.urticae, but the shorter handling time for eggs may indicate that they are better able to suppress populations with higher proportions of eggs. However, we cannot determine if P. persimilis can keep T. urticae populations composed of predominately of eggs below threshold levels because our greenhouse trials did not test this hypothesis. Phytoseiulus persimilis feeding on adult T. urticae may suppress T. urticae populations below threshold levels because a reduction in the number of adults will lead to a reduction in the number of T. urticae eggs deposited on a plant. Our research suggests that abamectin and oil are two acaricides that would be less detrimental to the survival of P. persimilis. Additional greenhouse trials with compatible acaricides should be conducted as well as research on the threshold density of T. urticae that will allow P. persimilis to provide adequate control. / Master of Science

Integrated Pest Management (IPM) technologies have proven to be effective at increasing agricultural productivity and have been credited for providing economic, health, and environmental benefits in many developing countries. In South Asia, population growth and the increasing demand for nutritious foods have put pressure on farmers to produce more food with a relatively inelastic supply of land. Productivity enhancing practices, like IPM, have helped some farmers to meet this demand; however, with over 50 million farmers in Bangladesh and Nepal it is difficult to reach them with information about new agricultural technologies. This study evaluates the current IPM dissemination strategy being implemented by the Bangladesh Department of Agricultural Extension (DAE) and uses a linear programming (LP) model to propose alternative strategies that may extend the total benefits from IPM technologies. Additionally, using data from a household survey, a bivariate probit model and a two-step endogenous participation model are used to identify factors that may influence both knowledge and adoption of IPM practices in three regions of Nepal. The results from the LP model suggest that more farmers could be effectively reached by reallocating funding that is currently used for interpersonal communications (i.e. extension agent visits and farmer field schools) to more widespread methods such as mass media and field days. The model also suggests that a dynamic dissemination strategy is necessary to encourage adoption of IPM technologies with differing characteristics and levels of complexity. The econometric analysis suggests that farmers with "network linkages" to agricultural information and inputs, such as membership in a farmer organization, are more likely to be aware of IPM and to adopt IPM practices. The survey data also suggest that farmers who are members of Marketing Planning Committees (MPC) may be more likely to adopt more IPM practices when compared to non-members. Overall, the study suggests that strategically disseminating IPM information is vital to promote the adoption of these technologies in South Asia. / Master of Science

This dissertation is composed of three essays examining adoption of agricultural technologies in Ecuador and intergenerational mobility in the United States. The first essay entitled 'Does IPM Have Staying Power? Revisiting a Potato-producing Area Years After Formal Training Ended' examines (Integrated Pest Management) IPM spread and adoption several years after formal intensive IPM outreach efforts ceased in a potato-producing region in Ecuador. It describes adoption patterns and sources of IPM knowledge in 2012 and compares them with patterns that existed when outreach ceased in 2003. Results show that IPM adoption continues in the area but with a lower proportion of farmers adopting all practices and a higher proportion adopting low to moderate levels compared to 2003. Farmer-to-farmer spread has supplanted formal training and outreach mechanisms. IPM adoption significantly lowers pesticide use and saves production costs for adopters. The second essay entitled 'Can Text Messages Improve Agricultural Outreach in Ecuador?' seeks to understand how receipt of text messages complements training from a farmer field day. It measures the effect of text message receipt on adoption of (Integrated Crop Management) ICM technologies and knowledge about these technologies. In the first part of the paper, we present a theory of behavioral change and its application to adoption of agricultural technologies. In the second part, we use intention to treat (ITT) and an improved-ITT analyses to measure the impact of the intervention. The results of this essay suggest that as providers of information, text messages have some knowledge building effect leading to the adoption of IPM practices. As reminders, text messages effectively increase adoption of IPM practices, in particular recommended pesticides. The third essay entitled 'Determinants of Absolute Upward Income Mobility: The Hidden Cost of Commuting' focuses on commuting times as a determinant of upward income mobility in the United States. We provide an explanation of the channel through which the effect of commuting times on upward income mobility operates. Additionally, it evaluates empirically the effect of commuting on upward income mobility. The empirical results confirm the theoretical model predictions that commuting times affect negatively upward income mobility. / Ph. D.

This thesis analyzes factors affecting adoption of integrated pest management (IPM) techniques by Kenyan vegetable farmers, including the role of their risk preferences. It also analyzes factors affecting their pesticide applications and expenditures. A survey was administered to 450 Kenyan vegetable growers to identify their pest management practices, and a behavioral experiment was run to elicit their risk preferences utilizing. Cumulative Prospect Theory. Loss aversion was found to be correlated with higher likelihood of IPM adoption while risk aversion was associated with higher pesticide application rates and expenditures. The influence of IPM adoption on pesticide use differed by IPM technique. / Master of Science / Integrated Pest Management (IPM) techniques can improve small holder farmers' livelihoods by lowering production costs and decreasing dependence on chemical pesticides. Even though some IPM techniques have been available to Kenyan vegetable farmers since the 1990's, IPM adoption remains relatively low while chemical pesticide use remains high. A farm-household survey and behavioral experiment were conducted to identify factors that influence farmer decisions to adopt IPM and to apply pesticides. Factors that influence IPM adoption were found to differ from those that influence pesticide decisions. Furthermore, IPM adoption by Kenyan farmers does not decrease use of chemical pesticides for all IPM techniques.

Harlequin bugs are orange and black aggregation pheromone emitting stink bug pests, specifically of cole crops such as kale, broccoli and collards. This nearly loyal crop preference makes an interesting challenge for trapping them and helping farmers predict pest severity. Harlequin bugs can be found in much of North America, and are a serious problem in the southeastern United States. Presumably their persistence into northern regions is limited by extreme winters. In 2014 and 2015 the arctic polar vortex extended into mid-latitudes bringing a blanket of sustained sub-freezing temperatures to much of the United States. We used these events to determine effects of extreme winter weather on harlequin bug survival. In both years we observed nearly identical low temperatures of -15oC and this linked to high (80-96%) harlequin bug mortality. In the lab we measured exact lethal freezing temperatures in harlequin bugs (i.e. supercooling points) to see if a physiological metric could be used to predict overwinter survival. Harlequin bug adults froze and died at -10.4oC, and similarly, their larger juvenile stages freeze at -11.0oC. Freshly hatched harlequin bugs and unhatched eggs froze at considerably lower temperatures with eggs forming ice crystals at -23.2oC and recent hatches at -21.6oC. Now with an understanding of how harlequin bugs likely survive winter extreme, we can then work on developing a trap to tally their populations in the spring and predict summer and fall pest severity. In the lab and field, harlequin bug adults and large nymphs were more likely found on green and black colors, and statistically less frequently on yellow, white, purple or red colors with the exception of adult females, which were most attracted to red and green in the lab, but green and black in the field. To increase harlequin bug attraction to and termination at traps square corrugated plastic panels were wrapped with an insecticide netting and baited with harlequin bug aggregation pheromone, murgantiol. Bugs were effectively drawn to the panels, with green panels having significantly more dead harlequin bugs and fewer dead beneficial lady beetles (Coleoptera: Coccinellidae) at their base than yellow panels. Thus, green was chosen as the ideal trap color to use for another field experiment that evaluated three trap types -- a corrugated plastic square panel, pyramidal trap, and ramp trap -- each with three lure treatments, murgantiol alone or murgantiol plus a low or high rate of mustard oil. More bugs were killed with the pyramidal trap than with the panel trap or the ramp trap, and more bugs were killed at traps containing murgantiol combined with benzyl isothiocyanate than at those with murgantiol alone. This research demonstrated that with the proper visual elements and odors, harlequin bugs can be drawn to traps and effectively killed after contact with insecticide-incorporated netting. / MSLFS / Harlequin bugs are orange and black aggregation pheromone emitting stink bug pests, specifically of cole crops such as kale, broccoli and collards. This nearly loyal crop preference makes an interesting challenge for trapping them and helping farmers predict pest severity. Harlequin bugs can be found in much of North America, and are a serious problem in the southeastern United States. Presumably their persistence into northern regions is limited by extreme winters. In 2014 and 2015 the arctic polar vortex extended into mid-latitudes bringing a blanket of sustained sub-freezing temperatures to much of the United States. We used these events to determine effects of extreme winter weather on harlequin bug survival. In both years we observed nearly identical low temperatures of -15℃ and this linked to high (80-96%) harlequin bug mortality. In the lab we measured exact lethal freezing temperatures in harlequin bugs (i.e. supercooling points) to see if a physiological metric could be used to predict overwinter survival. Harlequin bug adults froze and died at -10.4℃, and similarly, their larger juvenile stages freeze at -11.0℃. Freshly hatched harlequin bugs and unhatched eggs froze at considerably lower temperatures with eggs forming ice crystals at -23.2℃ and recent hatches at -21.6℃. Now with an understanding of how harlequin bugs likely survive winter extreme, we can then work on developing a trap to tally their populations in the spring and predict summer and fall pest severity. In the lab and field, harlequin bug adults and large nymphs were more likely found on green and black colors, and statistically less frequently on yellow, white, purple or red colors with the exception of adult females, which were most attracted to red and green in the lab, but green and black in the field. To increase harlequin bug attraction to and termination at traps square corrugated plastic panels were wrapped with an insecticide netting and baited with harlequin bug aggregation pheromone, murgantiol. Bugs were effectively drawn to the panels, with green panels having significantly more dead harlequin bugs and fewer dead beneficial lady beetles (Coleoptera: Coccinellidae) at their base than yellow panels. Thus, green was chosen as the ideal trap color to use for another field experiment that evaluated three trap types – a corrugated plastic square panel, pyramidal trap, and ramp trap – each with three lure treatments, murgantiol alone or murgantiol plus a low or high rate of mustard oil. More bugs were killed with the pyramidal trap than with the panel trap or the ramp trap, and more bugs were killed at traps containing murgantiol combined with benzyl isothiocyanate than at those with murgantiol alone. This research demonstrated that with the proper visual elements and odors, harlequin bugs can be drawn to traps and effectively killed after contact with insecticide-incorporated netting.

Wireworms are the subterranean larval stage of click beetles (Coleoptera: Elateridae), generalist herbivores that feed on a wide range of crops and cause serious damage. Wireworm management is challenging due to their long life cycle, subterranean habitat, wide range of host plants, and lack of effective chemical approach in most crops. Thus, developing an effective alternative control approach is an urgent need. The overall aim of this research study was to evaluate alternative [to insecticides] tactics that could be used as components of effective IPM strategies against wireworms. In Chapter 1 we provide an overview of wireworm's biology and management practices. In Chapter 2 we focused on biological control to evaluate the efficacy of entomopathogenic nematodes and fungi as single and mixed application against Limonius californicus and L. infuscatus in organic vegetable farms. The results showed the higher efficacy of commercial EPN, Steinernema feltiae, against Limonius species than entomopathogenic fungi. In Chapter 3, we focused on cultural control as a component of integrated pest management for wireworm control. We evaluated the efficacy of brown and yellow mustard and their byproducts, including defatted seed meal and seed meal concentrated extract against Limonius spp. Our finding indicated the effectiveness of brown mustard concentrated extract on reducing the wireworm population. However, it has a negative impact on the field-residing entomopathogenic nematodes. In Chapter 4, in the component of cultural control, we evaluated the wireworm, L. californicus, preference to three different crops, pea, bean, and wheat, for identifying an effective trap crop. We also quantified CO2 and organic volatile compounds released from each plant's root and evaluated the wireworm response toward the synthetic volatiles. Detailed results are provided in chapter 4. Finally, we looked at the novel new technology of RNA interference to find the effective target genes in wireworms for application as bioinsecticides and/or transgenic plants to control wireworms. In the concluding chapter, Chapter 6, we summarized our findings on the efficacy of different management tactics, biological, cultural, and molecular, to control Limonius species in cereals and organic production systems. / Doctor of Philosophy / Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), are belowground pests that feed on a wide range of crops such as potatoes, cereals, vegetables, and sugar beet and can cause serious economic damage. Wireworm management is challenging because they live for long periods in the soil and feed on almost all crops. Moreover, most insecticides available for wireworm control, such as neonicotinoids, are not effective in reducing wireworm populations and just serve as feeding deterrents. Thus, developing an effective alternative control approach is an urgent need. The overall aim of this research study was to evaluate alternative [to insecticides] tactics that could be used as components of effective IPM strategies against wireworms. In Chapter 1 we provide an overview of wireworm's biology and management practices. In Chapter 2 we focused on biological control to evaluate the efficacy of entomopathogenic nematodes and fungi when applied individually and in combination with each other against sugar beet wireworm in organic vegetable farms. The results showed the commercial nematode, Steinernema feltiae was more effective in reducing sugar beet wireworm than fungi. In Chapter 3, we focused on cultural control as a component of integrated pest management for wireworm control. We evaluated the efficacy of brown and yellow mustard and their byproducts including defatted seed meal and seed meal concentrated extract against sugar beet wireworms in spring wheat. Our finding indicated the effectiveness of brown mustard concentrated extract in reducing the wireworm population. In Chapter 4, in the component of cultural control, we evaluated the sugar beet wireworm preference for three different crops, pea, bean, and wheat, for identifying an effective trap crop. We also quantified CO2 and organic volaille compounds released from each plant's root and evaluated the wireworm response toward the synthetic volatiles. Detailed results are provided in chapter 4. Finally, we looked at the novel new technology of RNA interference to find the effective target genes in wireworms for application as bioinsecticides and/or transgenic plants to control wireworms. In the concluding chapter, Chapter 6, we summarized our findings on the efficacy of different management tactics, biological, cultural, and molecular, to control wireworm species in cereals and organic production systems.

Flea beetles (FB), (Coleoptera: Chrysomelidae), are common pests of cabbage and eggplant, but little is known about the FB populations in Virginia, their impact on yield, or the most effective control methods. This research investigates the FB populations and impact of their feeding injury on cabbage and eggplant in Southwest Virginia, and determines the most efficacious control methods. In Whitethorne, VA, cabbage and eggplant crops were vacuum sampled weekly throughout two summers. Crucifer flea beetle, Phyllotreta cruciferae (Goeze), and striped flea beetle, Phyllotreta striolata Fabr. were found on cabbage; whereas, eggplant flea beetle, Epitrix fucula (Crotch), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) were found on eggplant. To evaluate the impact of FB feeding on these plants, insecticides were used to create a range of pest pressure. Flea beetle densities and defoliation was visually assessed weekly and individual plant as well as whole plot yields assessed at harvest. In both crops, as little as 20% defoliation significantly reduced yield, with higher defoliation resulting in lower yield. The efficacy of various insecticides was also evaluated; soil application of the systemic neonicotinoid dinotefuran had the fewest beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. Lastly, deltamethrin-incorporated mesh row covers were evaluated and shown to provide excellent control of FB compared to an untreated row cover or a control; and comparable to the standard insecticide, dinotefuran. This research helps vegetable growers to better understand the severity of these pests and how to effectively combat them. / MSLFS / Flea beetles are tiny leaf-chewing pests of vegetables, particularly cabbage and eggplant. High populations of FB chewing on leaves can kill plants in early stages of development, and insecticides are the most common defense. Little is known about which FBs are in Virginia, their effect on vegetables grown in the state, or what the best way of controlling these pests. This research investigates FBs to determine the how they affected yield of cabbage and eggplant in Southwest Virginia, as well as determine the best methods for controlling these pests. Cabbage and eggplant were sampled weekly throughout two seasons, and two species were found on cabbage, the crucifer flea beetle and the striped flea beetle, whereas the eggplant flea beetle and the tobacco flea beetle were found on eggplant. To evaluate FB damage on these plants, defoliation of leaves was evaluated then yield was assessed. In both crops as little as 20% defoliation reduced yield, with higher defoliation resulting in lower yield of surviving plants. Various insecticides were evaluated to determine which treatment and application method were the most effective for controlling FB. A soil-applied systemic insecticide, dinotefuran, had the lowest density of beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. Lastly, insecticide treated mesh row covers were evaluated and shown to be an effective method for controlling flea beetles on these crops. Treated row covers reduced FB numbers and feeding damage on these crops when compared to an untreated row cover. This research can benefit vegetable growers by helping them understand the severity of these pests and by providing effective management strategies to combat them.

As part of a USAID-funded integrated pest management (IPM) project, this thesis presents research conducted across four communities in midwestern Nepal We conducted semi-structured interviews, focus group discussions, and participant observation with local farmers and NGOs. Grounded in feminist political ecology (FPE) and drawing on the social relations approach (SRA), we sought to engage with the feminization of agriculture narrative and understand how it interacts with IPM practices and decision-making. This research responds to a growing interest within development in the feminization of agriculture as a potentially empowering or disempowering global process of change, conceptualized through the ways that male out-migration affects the labor and decision-making roles of women and other household members left behind on the farm. We find that contextual factors change the implications of the feminization of agriculture narrative. Co-residence with in-laws and varied migration patterns influence the dynamic nature of household structure and headship. Migration patterns have pushed women to take on new agricultural duties and manage increasing household labor responsibilities. Additionally, IPM vegetable cultivation is changing how farmers use and value their land through increasing crop diversification. Agricultural decision-making processes related to these different forces extend beyond the household, and participation in community spaces through the IPM project may contest traditional gender norms. We contend that the heterogeneity of household power dynamics muddies the potentially empowering or disempowering effects of the feminization of agriculture, and we emphasize the importance of community spaces as a locus of decision-making in the sustainability of new agricultural technologies. / M. S. / This research aims to understand how gender affects and is affected by new agricultural practices in rural Nepal. Several changes are occurring across Nepal; these changes include men migrating for work at increasing rates, as well as farmers growing different crops in new ways. This study is specifically concerned with integrated pest management (IPM) practices, whereby farmers manage pests on their farm while minimizing the use of chemical pesticides. These IPM practices are developed through partnerships between university scientists and in-country organizations under the USAID-funded Feed the Future IPM Innovation Lab. As men look for work outside of their home communities and agricultural production diversifies, gender norms and expectations of migrant-sending communities influence how both men and women farmers participate in learning and practicing IPM across different seasons. Through interviews, focus group discussions, and participant observation, we contend that women in migrant-sending communities are taking on new labor roles on the farm, depending on if they reside with their mother-in-law and father-in-law. Furthermore, decisions about agricultural production and IPM are made within farmer cooperative meetings and social spaces between men and women members, contesting traditional gender norms that previously limited interactions between men and women in public gatherings. These findings help support the sustainability of projects within the IPM Innovation Lab, as well as highlight the importance of community, social spaces as places of decision-making and changing gender norms beyond the household. We emphasize the need to carefully assess social and cultural implications of development interventions within the geographic context and incorporate this specificity into project and research design.