This research investigated seasonal climate changes within greenhouses and the impacts they have on efficacy of the predatory mites Amblyseius swirskii and Neoseiulus cucumeris. Controlled environment chamber, greenhouse small-cage, and commercial greenhouse trials were conducted to determine which biological control agent is more efficacious for control of the pest western flower thrips (WFT), (Frankliniella occidentalis) on ornamental crops. When observed under laboratory conditions, predation and oviposition were increased at higher temperatures. Photoperiod and light intensity also have an impact on predatory mites. Predation rates for both mite species were greater when subjected to short day light conditions (8 h light, 11 W/m2). Climates typical of summer (higher temperature and light intensity, long day length), were most favourable in terms of predation and oviposition for A. swirskii. Neoseiulus cucumeris laid more eggs under short day as opposed to long day settings. In summer and winter greenhouse small cage trials, the performance of N. cucumeris and A. swirskii significantly reduced WFT numbers on potted chrysanthemum plants. However, in summer, A. swirskii provided significantly better thrips control than N. cucumeris. The number of adult mites recovered from plants was similar for both mite treatments in winter, while A. swirskii were present in higher numbers throughout the summer trials. Results from leaf damage assessments indicate that A. swirskii is more effective for control of heavy WFT feeding damage in both summer and winter. Results from commercial greenhouse trials yielded similar trends as those found in the summer and winter small cage trials. / University of Guelph, Agriculture and Agri-Food Canada, Vineland Research and Innovation Center, Flowers Canada

This thesis reports the effects of disturbance and harbourage on the fitness of Tribolium confusum and T. castaneum, as well as the the efficacy of pheromone monitoring traps for monitoring for populations of Tribolium in laboratory and mill settings. Behavioural studies were also carried out on mill and laboratory-reared beetles and the distributions of both species in a mill were examined. Twenty-four hour sieving disturbance decreased the rates of dispersal for both species, and decreased T. castaneum fecundity. Rolling disturbance decreased T. confusum dispersal rate while shaking disturbance decreased T. castaneum dispersal rate. When undisturbed beetles were given differing amounts of flour in the presence or absence of harbourage, beetles laid more eggs in larger amounts of flour, but harbourage only affected T. castaneum at one level of flour (2 g). Throughout disturbance and harbourage experiments, T. castaneum laid more eggs than T. confusum. Pheromone monitoring traps placed in three Canadian flour mills were not useful in predicting the degree of infestation inside Simons rollstands. Pheromone monitoring traps also showed low efficacy (i.e. caught few beetles) in both mill and laboratory settings, and T. confusum was caught less often than T. castaneum in both mills and in a warehouse. Mill-strain beetles of both species were caught less often than laboratory-strain beetles in a warehouse. In one Canadian flour mill, both T. castaneum and T. confusum were found inside rollstands but the two species were spatially segregated from one another, rarely being found together in the same rollstand. In contrast to this, both species were consistently found together in samples taken from the same mill less than a year beforehand. In behavioural laboratory studies, beetles collected directly from a mill moved slower than beetles collected from a laboratory culture and this response was shown to be phenotypic. Mill-strain and laboratory-strain beetles also differed in burrowing tendencies, with T. confusum from the laboratory strain burrowing less than T. confusum from a mill and T. castaneum from different mills sometimes burrowing more and sometimes less than T. castaneum from the laboratory strain.

This thesis reports the effects of disturbance and harbourage on the fitness of Tribolium confusum and T. castaneum, as well as the the efficacy of pheromone monitoring traps for monitoring for populations of Tribolium in laboratory and mill settings. Behavioural studies were also carried out on mill and laboratory-reared beetles and the distributions of both species in a mill were examined. Twenty-four hour sieving disturbance decreased the rates of dispersal for both species, and decreased T. castaneum fecundity. Rolling disturbance decreased T. confusum dispersal rate while shaking disturbance decreased T. castaneum dispersal rate. When undisturbed beetles were given differing amounts of flour in the presence or absence of harbourage, beetles laid more eggs in larger amounts of flour, but harbourage only affected T. castaneum at one level of flour (2 g). Throughout disturbance and harbourage experiments, T. castaneum laid more eggs than T. confusum. Pheromone monitoring traps placed in three Canadian flour mills were not useful in predicting the degree of infestation inside Simons rollstands. Pheromone monitoring traps also showed low efficacy (i.e. caught few beetles) in both mill and laboratory settings, and T. confusum was caught less often than T. castaneum in both mills and in a warehouse. Mill-strain beetles of both species were caught less often than laboratory-strain beetles in a warehouse. In one Canadian flour mill, both T. castaneum and T. confusum were found inside rollstands but the two species were spatially segregated from one another, rarely being found together in the same rollstand. In contrast to this, both species were consistently found together in samples taken from the same mill less than a year beforehand. In behavioural laboratory studies, beetles collected directly from a mill moved slower than beetles collected from a laboratory culture and this response was shown to be phenotypic. Mill-strain and laboratory-strain beetles also differed in burrowing tendencies, with T. confusum from the laboratory strain burrowing less than T. confusum from a mill and T. castaneum from different mills sometimes burrowing more and sometimes less than T. castaneum from the laboratory strain.

Trichogramma limit pest damage to Ord River Irrigation Area (ORIA) cotton crops by killing the developing embryo of their insect host at the egg stage, effectively reducing the number of emergent pests ingesting transgenic tissue. Their impact on the potentially resistant species, Helicoverpa armigera (Hübner), is considered integral to the Insect Resistance Management (IRM) strategy for transgenic cotton production in the ORIA. This thesis examines aspects of Trichogramma ecology pertinent to this strategy. The dominant species of egg parasitoid in ORIA cotton crops is the introduced Trichogramma pretiosum Riley. Other species make up less than one percent of collected specimens. Surveys revealed T. pretiosum has been introduced or adventitiously dispersed to all developed agricultural regions of northern Australia. Several new species were discovered during surveys in more pristine habitats. Based on field collected eggs, T. pretiosum appears to prefer H. armigera over H. punctigera Wallengren as a host in ORIA cotton. Measured as percent parasitism, Trichogramma activity appears highly variable and does not necessarily coincide with periods of peak insect pest density. Host abundance alone does not define conditions suitable for Trichogramma activity. Environmental constraints on wasp survival, such as the impact of temperature, humidity and insecticide applications, limit their effectiveness in biological control. Despite consistently high rates of percentage egg parasitism (60-99%), acceptable pest control is not readily achieved in ORIA cotton without the aid of insecticides as Helicoverpa numbers exceed damage thresholds. Insecticides inhibit Trichogramma considerably, hence the conundrum regarding initiation of insecticidal control. Trichogramma activity is relatively high early season (May to July), significantly limiting the buildup of pests. Trichogramma effectively stifle Helicoverpa population increase following initial pest egg lay at least during high density years. The impact of farming practices, especially insecticide applications, should be avoided early season to ensure pest mortality attributed to Trichogramma egg parasitisation is maximised. Pre-season habitat manipulation to establish large populations of Trichogramma in alternative hosts is advised. Despite being rare in surrounding habitats and suffering near 50% immature mortality in the field, Trichogramma effectively disperse into young crops attractive to ovipositing hosts and display a high intrinsic rate of increase. Spatial patterns of parasitism tend toward heterogeneity and do not necessarily coincide with host spatio-temporal dynamics. Both host abundance patterns and mean rates of parasitism are not good indicators of parasitoid patchiness. Parasitism rates are highest within the middle strata of the plant canopy prior to complete canopy closure despite a similar number of host eggs being available elsewhere in the plant. Pest density declines as the season progresses. However, insecticide applications become necessary if Bt expression in cotton plants wanes and larval damage increases. Measuring parasitism during periods of declining and low host density is prone to inaccuracy due to small sample size, but can be overcome with the use of egg cards. A better indication of parasitoid activity is achieved using egg cards during periods when insecticide applications are possibly required. As Trichogramma are most active in ORIA cotton from morning to early afternoon, insecticide applications if needed should occur outside of these periods. Trichogramma survival is constrained by environmental influences. Adult female T. pretiosum were exposed to ambient conditions in dialysis tubing sleeve cages to test survival and fecundity in cotton fields. Peak survival and fecundity occurs mid season with both life history variants displaying an inverse relationship to temperature. Adult female T. pretiosum survive longest in the field when provided with sustenance however mortality attributed to handling was considerable. Sleeve cages are not effective for survival measurement of small parasitoids if the cages are frequently moved. Trichogramma effectively reduce pest abundance but are clearly hindered by insecticides and hot dry conditions in ORIA cotton crops. The decision to initiate insecticide applications is best delayed unless absolutely necessary to avoid disruption of Trichogramma impact on pests. Parasitoid activity must be carefully monitored if chemical control becomes imminent. The impact of Trichogramma on pest species can then be optimally exploited.

Submitted by MIRIAN MARISTELA KUBOTA GRIGOLLI null (mi_kubota@hotmail.com) on 2017-07-10T04:04:09Z No. of bitstreams: 1 Tese_Mirian_Maristela_Kubota_Grigolli.pdf: 1763672 bytes, checksum: 517215ae1984f265cf8a36e79528bf57 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-07-13T19:42:37Z (GMT) No. of bitstreams: 1 grigolli_mmk_dr_jabo.pdf: 1763672 bytes, checksum: 517215ae1984f265cf8a36e79528bf57 (MD5) / Made available in DSpace on 2017-07-13T19:42:37Z (GMT). No. of bitstreams: 1 grigolli_mmk_dr_jabo.pdf: 1763672 bytes, checksum: 517215ae1984f265cf8a36e79528bf57 (MD5) Previous issue date: 2017-07-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A lagarta falsa-medideira, Chrysodeixis includens, é uma das principais pragas da cultura da soja no Brasil e o seu manejo integrado deve ser realizado para controlar a infestação. O uso de feromônios pode auxiliar na previsão de surtos e da densidade populacional de pragas. O tratamento de sementes é uma estratégia bastante eficaz para garantir o estabelecimento das plantas e proteção contra o ataque de pragas iniciais. Os objetivos foram avaliar o uso de feromônio sexual para monitorar a população de C. includens e relacionar o número de adultos coletados nas armadilhas com a densidade populacional de lagartas no pano de batida, e propor um nível de ação de falsa-medideira na cultura; bem como verificar o efeito do tratamento de sementes no estabelecimento inicial de plantas de soja e no manejo da lagarta falsa-medideira. Os experimentos de correlação foram conduzidos nos anos agrícolas 2013/14 e 2014/15 e os experimentos de tratamento de sementes em 2015/16 e 2016/17, na Estação Experimental da Fundação MS, em Maracaju e em Naviraí, MS. Nos experimentos de correlação entre mariposas capturadas em armadilhas com feromônio sexual e lagartas coletadas no monitoramento, foram realizadas avaliações semanais com 10 batidas de pano por talhão, bem como a contagem dos adultos nos pisos adesivos das armadilhas tipo Delta. Posteriormente realizou-se a análise de correlação na análise de variância entre o número de lagartas pequenas, médias, grandes e total e o número de mariposas de C. includens. Para o estudo de diferentes inseticidas aplicados em tratamento de sementes de soja, foram utilizados os seguintes inseticidas em gi.a. para cada 100 kg de sementes: fipronil (50,0 gi.a.), tiodicarbe + imidacloprido (157,5 + 52,5 gi.a.), clotianidina (60,0 gi.a.), tiametoxam (87,5 gi.a.), clorantraniliprole (62,5 gi.a.), ciantraniliprole (60,0 gi.a.) e ciantraniliprole + tiametoxam (60,0 + 87,5 gi.a.), além de uma Testemunha sem tratamento de semente. Foram realizadas avaliações de estande de plantas de soja, infestação de C. includens, número de vagens por planta, massa de cem grãos e rendimento de grãos dos diferentes tratamentos. Os resultados obtidos indicaram que há correlação significativa, linear e positiva entre o número de mariposas de C. includens coletadas nas armadilhas de feromônio sexual e de lagartas encontradas nos panos de batidas, estabelecendo-se o nível de ação de 15 mariposas coletadas por armadilha por semana para aplicações de inseticidas químicos na cultura da soja. Já para os ensaios de tratamento de sementes, os verificou-se que tiametoxam, ciantraniliprole e ciantraniliprole + tiametoxam proporcionaram maior velocidade no estabelecimento inicial das plantas de soja e estes foram eficientes no manejo de C. includens na cultura da soja, resultando em mais vagens por planta, maior massa de cem grãos e rendimento de grãos. / The soybean looper, Chrysodeixis includens, is one of the main pests of soybean crop in Brazil, and its integrated management must carried out to control the infestation. The use of pheromones can help in forecasting outbreaks and population density of many pests. Seed treatment is a very effective strategy to ensure establishment of plants and protection against early pests. The objectives of the present study were to evaluate the use of sex pheromone to monitor the population of C. includens and to relate the number of adults collected in the traps with the population density of larvae in the beat cloth, to propose a threshold level of soybean looper on the crop. Also, verify the effect of the seed treatment in the initial establishment of soybean plants and the management of the soybean looper. The correlation experiments were realized during the seasons 2013/14 and 2014/15 and the seed treatment experiments in 2015/16 and 2016/17 seasons at the MS Foundation Experimental Station in Maracaju and Naviraí, MS. In the correlation experiments between moths trapped in sexual pheromone traps and caterpillars collected in the monitoring, weekly evaluations were performed with 10 beats of cloth per field, as well as the counting of adults on the adhesive floors of the Delta traps. Subsequently, correlation analysis weres performed in the analysis of variance between the number of small, medium, large and total larvae and the number of moths of C. includens. To study the different insecticides applied in seed treatment of soybean, the following insecticides were used in ga.i. per 100 kg of seeds: fipronil (50.0 ga.i.), thiodicarb + imidacloprid (157.5 + 52.5 ga.i.), clothianidin (60.0 ga.i.), thiamethoxam (87, 5 ga.i.), chlorantraniliprole (62.5 ga.i.), cyantranyliprole (60.0 ga.i.) and cyanthraniliprole + thiamethoxam (60.0 + 87.5 ga.i.), in addition to a control without seed treatment. Evaluations were performed considering plants per meter, infestation of C. includens, number of pods per plant, mass of 100 grains and grain yield of different treatments. The results indicate that there is a significant linear and positive correlation between the number of moths of C. includens collected in the sexual pheromone traps and caterpillars found in the beating cloth, establishing the threshold level of 15 moths collected per trap per week for applications of chemical insecticides in soybean crop. The seed treatment trials, thiamethoxam, cyantraniliprole and cyantraniliprole + thiamethoxam were found to provide higher speed in the initial establishment of soybean plants, and these were efficient in the management of C. includens in the soybean crop, resulting in more pods per plant, greater mass of 100 grains and yield of grains.

Apesar de o Brasil ser um dos principais produtores de laranja no mundo e o maior exportador de suco concentrado, atualmente a cultura vem sofrendo perdas em razão do ataque de diversas pragas e doenças, sendo a principal o Huanglongbing (HLB), ou Greening, que foi relatada pela primeira vez em 2004 no estado de São Paulo. Essa doença está associada às bactérias do gênero \"Candidatus Liberibacter sp.\", sendo que no Brasil ocorrem as bactérias \"Ca. Liberibacter asiaticus\" e \"Ca. Liberibacter americanus\", tendo como seus vetores o psilídeo Diaphorina citri, praga importante devido a sua distribuição geográfica e características biológicas. Existe registro de cerca de 50 espécies da família Rutaceae, que incluem as espécies do gênero Citrus (laranjas, limões, limas, etc.), que podem hospedar esse inseto, além da murta (Murraya paniculata). Na natureza, D. citri é controlado por uma série de fatores, podendo ser outros insetos, fungos ou até condições climáticas desfavoráveis para seu desenvolvimento. Porém, os resultados de pesquisas indicam que ectoparasitoide Tamarixia radiata é eficiente no controle de D. citri. Entretanto, levantamentos realizados nos últimos anos verificaram que o parasitismo natural vem sendo reduzido consideravelmente, devido, principalmente, à aplicação intensiva de agroquímicos. Dessa forma, a utilização de produtos seletivos, ou seja, que atue contra o psilídeo D. citri e tenha o menor impacto possível sobre o parasitoide T. radiata é imprescindível para o sucesso do manejo integrado de pragas em que se utiliza o controle químico juntamente com a liberação do parasitoide. Assim, objetivou-se com esse trabalho: 1) Estudar o efeito direto e a persistência de inseticidas sobre o parasitoide T. radiata; 2) Estudar o efeito de inseticidas sobre a fase pupal do parasitoide; 3) Determinar a interferência dos inseticidas na capacidade de parasitismo; 4) Avaliar a toxicidade diferencial dos inseticidas para o parasitoide T. radiata e para o psilídeo D. citri. Dos 25 inseticidas testados no efeito direto, 20% foram considerados inócuos (classe 1); 12% levemente nocivo (classe 2); 12% moderadamente nocivo (classe 3); e 56% como nocivo (classe 4). Apesar de vários serem nocivos para adultos do parasitoide, apenas Lorsban® 480 BR e Perfekthion® afetaram a emergência do parasitoide quando pulverizados sobre a sua fase de pupa, sendo que os demais permitiram a emergência e não afetaram a duração, razão sexual e longevidade. No teste de persistência, 25% dos inseticidas testados foram considerados de vida curta (classe 1); 37,5% como levemente persistentes (classe 2); 29,2% moderadamente persistentes (classe 3); e apenas 8,3% persistentes (classe 4). Portanto, para a escolha de um inseticida para controle de pragas dos citros, deve-se levar em consideração seu efeito no adulto, fase imatura e sua persistência biológica na planta. / Although Brazil is one of the major orange producers and largest exporter of juice concentrate in the world, currently the citrus culture suffers losses due to the attack of several pests and diseases. Huanglongbing (HLB), or Greening, is the main disease and it was first reported in 2004 in the State of São Paulo, Brazil. This disease is associated with bacteria of the genus \"Candidatus Liberibacter sp.\", and in Brazil the bacteria \"Ca. Liberibacter asiaticus\" and \"Ca. Liberibacter americanus\" occur, and the psyllid Diaphorina citri is its main vector, an important pest insect because of its geographical distribution and biological characteristics. There is record of about 50 species of the family Rutaceae, including the species of the genus Citrus (oranges, lemons, limes, etc.) that can host this insect, in addition to orange jasmine (Murraya paniculata). In nature, a number of factors control D. citri, namely other insects, fungi or even adverse weather conditions for their development. However, studies show that the ectoparasitoid Tamarixia radiata is efficient in the control of D. citri. However, recent studies indicate that natural parasitism has been reduced considerably, mainly due to the intensive application of pesticides. Thus, the use of selective products, i.e., which act against the psyllid D. citri with the lowest possible impact on the parasitoids T. radiata is indispensable for the success of the integrated pest management that uses chemical control along with the release of parasitoids. Thus, the objectives of this work were: 1) to study the direct effect and the persistence of insecticides on the parasitoid T. radiata; 2) to investigate the effect of insecticides on the pupal stage of the parasitoids; 3) to determine the effect of insecticides on parasitism capacity; 4) to assess the differential toxicity of insecticides to the parasitoid T. radiata and psyllid D. citri. Of the 25 insecticides tested in terms of direct effect, 20% was considered harmless (class 1); 12% slightly harmful (class 2); 12% moderately harmful (class 3); and 56% as harmful (class 4). Although several are harmful to adult of the parasitoid, only Lorsban® 480 BR and Perfekthion® affected the emergence of the parasitoid when sprayed in the pupal stage, and the others allowed the emergence and did not affect the duration, sex ratio and life span. In the test of persistence, 25% of the insecticides were considered short life (class 1); 37.5% slightly persistent (class 2); 29.2% moderately persistent (class 3); and only 8.3% persistent (class 4). Therefore, choosing an insecticide for control of pests of citrus requires consideration of its effect on adults, immature phase and their biological persistence in the plant.

Helicoverpa armigera é uma espécie que até 2013 era considerada praga quarentenária A1 no Brasil. Tratamentos com inseticidas são indispensáveis para o manejo de H. armigera em quase todas as culturas do mundo. Uma alternativa à utilização de inseticidas sintéticos para o controle de pragas é o uso de parasitoides do gênero Trichogramma. Em consideração a grande quantidade de aplicações de agroquímicos no sistema de produção de grãos, torna-se essencial avaliar a seletividade dos inseticidas utilizados, garantindo informações que auxilie na manutenção do T. pretiosum na área, podendo potencializar o controle biológico de H. armigera, sendo isto, importante para o estabelecimento do manejo integrado de pragas nas grandes culturas. Portanto, objetivou-se com esse trabalho: estudar a toxicidade aguda e a persistência de inseticidas sobre o parasitoide; estudar o efeito de inseticidas sobre a fase pupal do parasitoide; determinar a interferência dos inseticidas na capacidade de parasitismo. Dos inseticidas testados em condições laboratoriais, Nomolt®, Avatar®, Belt®, Premio® e Intrepid® foram considerados inócuos para adultos. Lorsban® e Engeo Pleno® são nocivos à fase de pupa, enquanto Acefato®, Pirate® e Belt® apesar de inócuos afetam as gerações seguintes. Pirate®, Lorsban® e Engeo Pleno interferem na capacidade de parasitismo, e Acefato® tem efeito deletério na geração que tem contato com o resíduo. Os inseticidas Nomolt®, Avatar®, Belt®, Acefato®, Premio® e Intrepid® foram classificados como inseticidas de vida curta (classe 1). Lorsban® tem efeito moderadamente persistente (classe 3) e Engeo Pleno® e Pirate® classificados como persistentes (classe 4). Portanto, visando um bom programa de MIP, deve-se optar pelo uso de inseticidas seletivos, ou inseticidas nocivos para adultos do parasitoide podem ser utilizados no campo desde que estes não estejam ocorrendo naturalmente ou que não coincida com épocas de liberação do mesmo. / Helicoverpa armigera is a specie that until 2013 was considered A1 quarantine pest in Brazil. Treatments with insecticides are indispensable for the management of H. armigera in almost every crops in the world. An alternative to the use of synthetic insecticides for pest control is the use of parasitoids of the genus Trichogramma. Considered the large number of agrochemical applications in grain yield, it is essential assess the selectivity of insecticides used, providing informations to assist in the maintenance of T. pretiosum in the area and can enhance the biological control of H. armigera, this being important for the establishment of integrated pest management in field crops. Therefore, the aim of this work was study the acute toxicity and the duration of the harm effects of insecticides on the parasitoid, study the effect of insecticides on the pupal stage of the parasitoid and determine the interference of insecticides on the parasitism capacity. Insecticides tested in laboratory conditions, Nomolt®, Avatar®, Belt®, Premio® and Intrepid® were considered innocuous to the adults. Lorsban® and Engeo Pleno® were harmful to the pupal stage, while Acefato®, Pirate® and Belt® although were considered innocuous they affect the next generations. Pirate®, Lorsban® and Engeo Pleno® interfered on the parasitism capacity, and Acefato® have a deleterious effect on the generation that has contact with the insecticide residue. The insecticides Nomolt®, Avatar®, Belt®, Acefato®, Premio® and Intrepid® were classified as short live (class 1). Lorsban® was moderately persistent (class 3) and Engeo Pleno® and Pirate® were classified as persistent (Class 4). Therefore, for an effective IPM program, it is important to use the selective insecticides. Insecticides that were harmful to the parasitoid adults could be used in the field, provided that the parasitoids do not occur naturally and the chemical applications do not coincide with the parasitoids release.

In the present work we study Interior Point Algorithm used for solving linear problems

No description available.

Some of the most problematic agricultural weeds found in the Midwest United States are found in the Amaranthaceae family, such as Amaranthus palmeri and A. tuberculatus. These summer annual weeds are troublesome due to their competitive ability, high seed production, and resistance to herbicides from several modes of action which complicates management in field crops and has led to significant yield loss. Achyranthes japonica and Iresine rhizomatosa are two perennial species in the same family as A. palmeri and A. tuberculatus that occur in similar habitats as one another, but differ in invasiveness. Achyranthes japonica is a non-native, invasive species that is becoming a threat to forested areas and has been observed along agricultural field margins. Iresine rhizomatosa also occurs in forest habitats but is an endangered species in Illinois. This research seeks to determine the comparative life history and relative competitiveness of closely related weedy species when challenged with a dominant species. Specifically, select, closely related weedy species in the Amaranthaceae plant family that occur in southern Illinois were compared, i.e., Achyranthes japonica, Amaranthus palmeri, Amaranthus tuberculatus, and Iresine rhizomatosa. The first study examined the life history characteristics of A. japonica in regards to survivorship, growth and fecundity at two sites in southern Illinois (Chapter 2). Achyranthes japonica is a relatively new invasive species that has been poorly studied. This experiment showed that regardless of site, environmental factors had a significant effect on seedling emergence and seed viability, which decreased from 2012 to 2013 during a drought year and rebounded from 2013 to 2014 following flooding. On average, individuals at the driest site had higher performance and fecundity, regardless of year. The second experiment tested the relative competitive effect and response of the Amaranthaceae species to Glycine max, first in a greenhouse study that tested shading and nitrogen resource drawdown for each species, and second in a controlled field experiment that tested intraspecific competition (Chapter 3). In addition, A. japonica seedlings were planted as either unmanipulated seedlings (uncut A. japonica) or as a seedling cut back to the soil surface at the four-node stage (cut A. japonica) at which point seedlings have reached a perennial growth stage. The greenhouse experiment showed that the four species each drew down light significantly, but not nitrogen. Shading decreased the aboveground biomass of the species in comparison to unshaded controls. Supplemental nitrogen, however, increased the aboveground biomass of A. palmeri and A. japonica. The supporting controlled field experiment showed that the competitive response of the weed species to the presence of G. max showed a reduction in height compared to the weed species grown in monocultures. Glycine max and the weed species, except I. rhizomatosa, showed a similar competitive effect and response when aboveground biomass was measured. Achyranthes japonica attained the highest belowground biomass when grown as a monoculture and in the presence of G. max. A competitive effect ranking was determined to be A. palmeri > A. tuberculatus > cut A. japonica = uncut A. japonica = I. rhizomatosa with the competitive response ranking being the inverse. The third study implemented an integral projection model (IPM) to determine the population growth rate of each species and how they compared to one another (Chapter 4). This experiment showed that A. palmeri, A. tuberculatus and A. japonica each had a population growth rate greater than one indicating rapidly growing populations. By contrast, I. rhizomatosa had a population growth rate less than one indicating a declining population. The results suggest that A. japonica has not yet shown the ability to escape management strategies in agricultural fields implemented by farmers, but it is still an aggressive invasive species that farmers and land owners need to be able to identify. This species has many similar characteristics to the Amaranthus species, such as the ability to colonize in areas with limiting resources, continual flushes of germination throughout the growing season, the ability to outcompete other weed species, and high fecundity but, A. japonica also is a perennial species that can withstand removal of shoot material and has a high germination rate. Based on these results, only early detection and rapid response methods should be relied on to keep these species out of areas in and around agricultural fields. Iresine rhizomatosa’s performance in these studies was consistent with its rarity.