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Seasonal climatic variations influence the efficacy of predatory mites used for control of western flower thrips on greenhouse ornamental cropsHewitt, Laura 17 January 2013 (has links)
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
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Monitoring populations of the flour beetles Tribolium confusum Jacquelin du Val and Tribolium castaneum (Herbst) in flour mills and in laboratory settingsHawkin, Karen 14 July 2008 (has links)
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.
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Monitoring populations of the flour beetles Tribolium confusum Jacquelin du Val and Tribolium castaneum (Herbst) in flour mills and in laboratory settingsHawkin, Karen 14 July 2008 (has links)
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.
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ECOLOGY OF TRICHOGRAMMA SPP. IN THE ORD RIVER IRRIGATION AREA AND THEIR ROLE IN COTTON IPMDavies, Andrew Paul Unknown Date (has links)
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.
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Correlação entre lagartas e mariposas capturadas com feromônio sexual e tratamento de sementes de soja com diferentes inseticidas para o manejo de Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) na cultura da soja / Correlation between larvae and moths captured with sexual pheromone traps and soybean seed treatment with different insecticides for the management of Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) on soybean cropGrigolli, Mirian Maristela Kubota [UNESP] 04 July 2017 (has links)
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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.
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Seletividade de inseticidas recomendados para a produção integrada de citros sobre o parasitoide Tamarixia radiata (Waterston, 1922) (Hymenoptera: Eulophidae) / Selectivity of insecticides recommended for integrated citrus production on the parasitoids Tamarixia radiata (Waterston, 1922) (Hymenoptera: Eulophidae)Vitor Hugo Beloti 21 January 2014 (has links)
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.
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Toxicidade e efeito subletal dos principais inseticidas utilizados na cultura da soja para Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) / Toxicity and sublethal effect of the main insecticides used in soybean crop to Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)Ana Clara Ribeiro de Paiva 16 February 2016 (has links)
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.
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Strategie volby kroku a jeho délky u vybraných metod vnitřního bodu / Interior Point MethodsMatoušová, Hana January 2010 (has links)
In the present work we study Interior Point Algorithm used for solving linear problems
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Using Pheromone Lures, Insecticide Netting, and a Novel Food-Grade Repellent to Develop BMSB IPM StrategiesBush, Hayley Grace 21 August 2018 (has links)
The invasive brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), has resulted in increased use of insecticides on horticultural crops in the Mid-Atlantic US, which has diminished integrated pest management (IPM) programs that worked well otherwise. The research herein explored the use of three new tools in the development of BMSB management strategies. In one study, a BMSB pheromone lure was placed on insecticide-incorporated mesh netting to be used in an attract-and-kill strategy to protect bell peppers. The pheromone and netting deployed within a pepper field resulted in more BMSB feeding on plants within 6.1 m to the attract-and-kill screen than in further peppers or peppers in the weekly insecticide treatment. In another study, the insecticidal netting used as a row cover reduced stink bug damage to peppers, but also caused significant yield losses, possibly due to lack of light and/or pollination. The BMSB pheromone lure was also utilized in a sticky trap-based action threshold for insecticide application decisions. The trap and lure predicted densities of bugs on pepper plants and the use of an action threshold of 5 bugs per trap per week to trigger an insecticide spray reduced insecticide applications by 50% at one location, however population densities were lower at the other two locations and significance was not found among treatments. Lastly, BMSB is a nuisance pest to homeowners so we tested the exclusion efficacy of repellents on overwintering shelters and found an 8-fold reduction in BMSB that entered shelters treated with geranyl cyclopentanone (apritone). The use of BMSB pheromones paired with insecticide netting for attract-and-kill of BMSB, the development of action thresholds using captures in pheromone-baited sticky cards, and the use of apritone as a repellent are all promising IPM strategies worth refining in future studies. / MSLFS / The brown marmorated stink bug (BMSB) has become a serious household nuisance and agricultural pest in the US. BMSB feeds on and damages a large variety of crops including, fruits, vegetables, and field crops. Most growers of high value crops have increased their insecticide usage to battle this bug; thus, more sustainable integrated pest management (IPM) approaches need to be established. One main vegetable crop that BMSB damages is bell peppers. One study tested the efficacy of an attract-and-kill approach involving a BMSB pheromone lure paired with insecticide-impregnated mesh netting. When deployed in pepper fields, it was found that BMSB stayed on plants rather than receiving a lethal dose from the netting. Another study tested the netting as a row cover or as a fence between peppers and found that it did little at preventing damage. Furthermore, pepper yields were significantly lower under the row cover treatment. In another study, a clear sticky panel placed on a stake and paired with a BMSB pheromone lure was used to assist in making management decisions based on relative densities of bugs in plots. This can help determine if insecticide applications are needed. Not only is BMSB a pest of agriculture, but it is also a nuisance pest to homeowners when adults seek winter shelter during their fall dispersal period, sometimes entering homes by the thousands. The tactile repellent, geranyl cyclopentanone (apritone), was found to elicit an 8-fold reduction in the number of overwintering BMSB in overwintering shelters.
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Use of the egg parasitoid, Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) as a biological control agent of the European corn borer, Ostrinia nubilalis (Lepidoptera: Crambidae): An approach to integrated pest management in bell pepperBarlow, Vonny M. 05 May 2006 (has links)
Four to six separate inundative releases of ~30,000 to 50,000 T. ostriniae per 0.02 ha significantly reduced damage by O. nubilalis in bell pepper. Egg parasitization averaged 48.7% in T. ostriniae release plots, which was significantly higher than non-release plots (1.9%). Also, cumulative green pepper fruit damage averaged 8.7% in release plots, which was significantly less than non-release plots (27.3%). Pesticides tested against T. ostriniae were spinosad and methoxyfenozide. Spinosad adversely affected adult T. ostriniae producing 100% mortality at the field rate of 498 mg [AI]/L for both the preimaginal and adult toxicity tests. Use of T. ostriniae can provide effective control of O. nubilalis in pepper compared to conventional and organic spray regimes (Spinosad and methoxyfenozide respectively). Augmentative releases of T. ostriniae integrated with methoxyfenozide with its limited toxicity to both preimaginal and adult stages indicate that it is a superior candidate for control O. nubilalis.
To determine the behavioral differences of T. ostriniae and its response to O. nubilalis in green bell peppers, experiments were carried out to classify likely areas of O. nubilalis oviposition within the green pepper plant canopy. A total of 426 O. nubilalis egg masses were found on pepper plants during our study. Over 92% of egg masses were found on the lower surface of the leaf compared with the upper surface indicating a significant ovipositional preference for the undersides of leaves in 2002 ( x2 = 9.68; df = 1; P < 0.05) followed by similar results in 2004 (x2 = 4.34; df = 1; P < 0.05). No significant differences were found in the observed spatial distribution of egg masses among the three vertical strata in either 2002 or 2004 (x2 = 1.75; df = 2; P < 0.05 and x2 = 5.69; df = 2; P < 0.05 respectively). Field release rates of 17.0 foraging T. ostriniae females can achieve 80.0% parasitism of O. nubilalis egg masses distributed throughout the pepper plant canopy found primarily on the undersides of leaves. These data demonstrate that T. ostriniae has potential as a biocontrol agent for O. nubilalis in solanaceous crops. / Ph. D.
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