Studies focused on developing a semiochemical-based monitoring system for Plutella xylostella (L.) using sex pheromone and Z3-hexenyl acetate. A commercially available pheromone trapping system was used to capture male moths at sites in Alberta in 2007 and 2008. Larval sampling occurred every two weeks after the first males were captured. Male moth capture was predictive of larval density on individual sample dates during the growing season. The predictive capability of pheromone-baited trap capture was not in direct proportion to population density and was inconsistent. Modifications to the trapping system were tested to improve attractiveness. Adding Z3-hexenyl acetate at various doses to pheromone did not improve the attractiveness to males over pheromone alone and did not attract significant numbers of females when tested at various times during the flight season. Trap height and colour did not influence male capture. Pheromone dose and lure type did influence male moth capture in traps. / Plant Science

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2018-04-03T11:23:58Z No. of bitstreams: 1 texto completo.pdf: 6246480 bytes, checksum: 22d05834752231aeab0a313c35f9fad0 (MD5) / Made available in DSpace on 2018-04-03T11:23:58Z (GMT). No. of bitstreams: 1 texto completo.pdf: 6246480 bytes, checksum: 22d05834752231aeab0a313c35f9fad0 (MD5) Previous issue date: 2016-12-22 / Várias espécies de plantas produzem misturas de compostos odoríferos e voláteis conhecidos como óleos essenciais (OEs). Existem mais de 3000 OEs relatados na literatura com aproximadamente 300 em uso comercial, incluindo OEs de espécies de Eucalyptus, um grande gênero da família Myrtaceae. Muitos OEs de espécies de Eucalyptus têm encontrado aplicações em produtos farmacêuticos, agroquímicos, flavorizantes de alimentos e perfumes, sendo que estas aplicações estão relacionadas com as suas diversas propriedades biológicas e organolépticas. Diante destes fatos, no primeiro capítulo, foi realizada uma revisão das informações mais recentes sobre composição química e atividades biológicas de OEs de diferentes espécies de Eucalyptus, sendo destacadas as atividades antimicrobianas, acaricidas, inseticidas e herbicidas. No segundo capítulo, determinou-se a composição química dos OEs das folhas de vinte e duas espécies de plantas da família Myrtaceae, cultivados em Viçosa, Minas Gerais, sendo quatorze espécies de Eucalyptus (E. andrewsii, E. siderophloia, E. nitens, E. pyrocarpa, E. phaeotricha, E. umbra, E. crebra, E. resinifera, E. cinerea, E. phoenicea, E. punctata, E. sphaerocarpa, E. pellita e o híbrido E. alba x E. tereticornis), seis espécies de Corymbia (C. citriodora, C. maculata, C. intermedia, C. henryi, C. torelliana e C. ptychocarpa), além das espécies Lophostemon confertus e Syncarpia glomulifera. As folhas foram coletadas em duas épocas, ao final da estação seca e em estação chuvosa. A identificação e a quantificação dos constituintes dos OEs foram realizadas por CG-DIC e CG/EM. Algumas espécies estudadas mostraram constituir fontes promissoras de terpenos bioativos e produtos importantes na indústria química como C. maculata, C. torelliana, E. umbra, E. phoenicea e S. glomulifera que apresentaram elevados teores de α- e β-pineno, assim como C. citriodora que apresentou alto teor de citronelal nos OEs nas amostras coletadas ao final da estação seca. Os OEs das espécies E. cinerea, E. punctata, E. resinifera, E. phaeotricha, e o híbrido E. alba x E. tereticornis apresentaram altos níveis de 1,8-cineol e a espécie de E. pyrocarpa apresentou teor considerável dos isômeros de eudesmol em seus OEs. Este trabalho indica que a composição química dos OEs pode variar muito em função da época da coleta do material vegetal, além de apresentar relatos inéditos da composição viiquímica dos OEs das espécies E. andrewsii, C. henryi, E. phoenicea, C. ptychocarpa, E. pyrocarpa e o híbrido E. alba x E. tereticornis. No terceiro capítulo a investigação da atividade inseticida dos OEs contra Plutella xylostella (L.) (Lepidoptera: Plutellidae), principal praga de brássicas no mundo, mostrou que o OE mais ativo foi obtido a partir de folhas de C. citriodora coletadas durante a estação seca, que apresentou como componentes principais citronelal (86,8%) e (-)-isopulegol (4,7%). Com 30 μg mg -1 de inseto, este OE causou 80% de mortalidade de P. xylostella e apresentou atividade superior (DL 50 = 21,53 μg mg -1 de inseto, DL 90 = 42,29 μg mg -1 de inseto) ao óleo de neem (DL 50 = 30,79 μg mg -1 de inseto, DL 90 = 161,11 μg mg -1 de inseto) utilizado como controle positivo nos bioensaios, além de exercer rápido controle sobre P. xylostella. Estes OEs apresentam baixa toxicidade para Solenopsis saevissima (predador natural), mas alta toxicidade para Tetragonisca angustula (polinizador). Os bioensaios contra P. xylostella demonstraram efeito sinérgico entre os principais componentes do OE de C. citriodora da estação seca. Conforme a investigação, acima descrita, sugere-se que os OEs de C. citriodora possam ser uma alternativa ao controle por inseticidas de P. xylostella. Em outra investigação, no capítulo 4, a atividade inseticida dos OEs foram observadas em bioensaios de contato e fumigação contra Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), um dos principais insetos que causam grande perda em grãos armazenados em todo mundo. O OE mais ativo foi obtido a partir de folhas de E. resinifera coletadas após a estação seca, que apresentaram como componentes principais 1,8-cineol (59,3%), p-cimeno (12,9%) e α-pineno (9,7%). Nos bioensaios de contato numa dose de 30 μg mg -1 de inseto, este OE causou 83,3% de mortalidade a R. dominica, sendo que sua eficácia (DL 50 = 17,08 μg mg -1 de inseto; DL 95 = 56,17 μg mg - de inseto) foi inferior à do Actellic (DL 50 = 0,49 μg mg -1 de inseto; DL 95 = 1,14 μg mg -1 de inseto), utilizado como controle positivo. Já nos bioensaios de fumigação a mortalidade causada pelo OE de E. resinifera a 150 μL L -1 foi de 90,0%, apresentando eficácia (CL 50 = 70,55 μL L -1 ; CL 95 = 266,40 μL L -1 ) superior à do Actellic (CL 50 = 154,74 μL L -1 ; CL 95 = 334,95 μL L -1 ). O TL 50 sobre adultos de R. dominica para o OE de E. resinifera foi de 1,7 horas no bioensaio de contato (DL 95 de 56,17 μg mg -1 de inseto) e de 12,6 horas no bioensaio de fumigação (CL 95 de 266,40 μL L -1 ). Os bioensaios mostraram que o 1,8-cineol é o responsável pelo efeito fumigante do OE de E. resinifera, já em relação ao bioensaio de contato, não foi possível determinar o responsável pelo efeito tóxico, sendo, provavelmente, a toxicidade de contato do OE de E. resinifera a R. dominica causada pelo sinergismo entre substâncias presentes no OE. De acordo com os resultados obtidos neste trabalho, sugere-se que os OEs de E. resinifera apresentam potencial para ser utilizado como uma alternativa aos inseticidas comerciais no controle de R. dominica. / Several species of plants produce mixtures of odoriferous and volatile compounds known as essential oils (EOs). There are more than 3000 EOs reported in the literature, with approximately 300 in commercial use, including EOs of Eucalyptus species, a large genus of the Myrtaceae family. Many EOs of Eucalyptus species have found applications in pharmaceuticals, agrochemicals, food flavorings and perfumes, these applications being related to their diverse biological and organoleptic properties. In the first chapter, a review of the latest information concerning the chemical composition and biological activities of EOs from different species of Eucalyptus, with emphasis on antimicrobial, acaricidal, insecticidal and herbicidal activities. In the second chapter, the EOs contained in the foliage of twenty-two species of plants of the Myrtaceae family were chemically analyzed. Fourteen species of Eucalyptus (E. andrewsii, E. siderophloia, E. nitens, E. pyrocarpa, E. phaeotricha, E. umbra, E. crebra, E. resinifera, E. cinerea, E. phoenicea, E. punctata, E. sphaerocarpa, E. pellita and E. alba x E. tereticornis hybrid), six species of Corymbia (C. citriodora, C. maculata, C. intermedia, C. henryi, C. torelliana and C. ptychocarpa), as well as the species Lophostemon confertus and Syncarpia glomulifera. These were grown in Viçosa, Minas Gerais, Brazil and collected during two seasons: at the end of the dry and rainy seasons. Identification and quantification of EOs constituents was performed by GC-FID and GC/MS. Some species have been shown to be promising sources of bioactive terpenes and important products in the chemical industry, such as C. maculata, C. torelliana, E. umbra, E. phoenicea and S. glomulifera, which presented high levels of α- and β- pinene, as well as C. citriodora that presented citronellal content in OEs samples collected at the end of the dry season. The E. cinerea, E. punctata, E. resinifera, E. phaeotricha and the hybrid E. alba x E. tereticornis showed high levels of 1,8-cineol and E. pyrocarpa species presented a considerable content of the isomers of eudesmol in their OEs. Furthermore they indicate that the EO’s chemical composition varies greatly depending on the harvesting season of the vegetable samples. Additionally, it reports unprecedented data on EOs chemical composition for species such as E. andrewsii, C. henryi, E. phoenicea, C. ptychocarpa, E. pyrocarpa and the hybrid E. alba x E. tereticornis. In the third chapter the investigation of the insecticidal activity of EOs against Plutella xylostella (L.) (Lepidoptera: Plutellidae), the main brassica pest worldwide, showed that the most active EOs was obtained from leaves of C. citriodora collected during the dry season and present as the main components citronellal (86.8%) and (-)-isopulegol (4.7%). At 30 μg mg -1 of insect, this EO caused 80% mortality of P. xylostella and presented superior activity (LD 50 = 21.53 μg mg -1 of insect; LD 90 = 42.29 μg mg -1 of insect) than neem oil (LD 50 = 30.79 μg mg -1 of insect; LD 90 = 161.11 μg mg - of insect) used as positive control in the bioassays. In addition, dry season leaf C. citriodora EO exert fast control on P. xylostella. The effects of this EO were also evaluated against Solenopsis saevissima, a natural predator of P. xylostella, and Tetragonisca angustula, a pollinator. While C. citriodora EO present low toxicity on S. saevissima, high toxicity was noticed against T. angustula. Bioassays demonstrated synergistc effects between the main components of dry season leaf C. citriodora EO. Based on the findings described in this investigation, it is suggested that C. citriodora EOs can be an alternative to insecticide control. In another investigation, in chapter 4, the insecticidal activity of EOs was observed in contact and fumigation bioassays against Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), one of the insects that most damage stored grains worldwide. The most active EO was obtained from the foliage of E. resinifera, of which the main components are 1.8-cineol (59.3%), p- cymene (12.9%) and α-pinene (9.7%). In contact bioassays at 30 μg mg -1 per insect, this EO lead to 83.3% mortality of R. dominica (with an efficiency of LD 50 = 17.08 μg mg -1 per insect; LD 95 = 56,17 μg mg -1 per insect). This was lower than that of the commercial insecticide Actellic (LD 50 = 0,49 μg mg -1 per insect); (LD 95 = 1,14 μg mg -1 per insect) was used as a positive benchmark. Mortality rates of 90.0% were achieved during fumigation bioassays (150 μL L -1 ) by E. resinifera’s EO equal to a performance of (LC 50 = 70.55 μL L -1 ; LC 95 = 266.40 μL L -1 ) which exceeds Actellic’s (LC 50 = 154.74 μL L -1 ; LC 95 = 334.95 μL L -1 ). The LT 50 of E. resinifera EO on R. dominica adults was of 1.7 hours for contact bioassays (LD 95 of 56,17 μg mg -1 per insect) versus 12.6 hours during fumigation bioassays (LC 95 of 266,40 μL L -1 ). Bioassays prove that 1.8-cineol is responsible for the EO’s fumigant properties of E. resinifera. Contact bioassays, however, were unable to identify the toxicity source (presumably the synergy between substances present in the EOs of both E. resinifera and R. dominica). Results obtained, suggest that E. resinifera’s EOs show potential as an alternative to commercial insecticides against R. dominica.

Made available in DSpace on 2014-06-11T19:25:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-22Bitstream added on 2014-06-13T20:32:41Z : No. of bitstreams: 1 viana_cltp_me_jabo.pdf: 681354 bytes, checksum: 292f317000f87f4932ed390de403036a (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A pesquisa foi desenvolvida no Laboratório de Biologia e Criação de Insetos (LBCI) e no Laboratório de Genética de Bactérias e Biotecnologia Aplicada (LGBBA) da FCAV-UNESP,Campus de Jaboticabal, SP. O objetivo geral foi selecionar novos isolados de Bacillus thuringiensis através da caracterização molecular, identificando as diferentes subclasses do gene cry1, determinar a patogenicidade contra lagartas de Plutella xylostella e avaliar a influência no ciclo biológico da praga. Foram utilizados 95 isolados de B. thuringiensis obtidos da coleção do LGBBA. O material genético foi extraído pela matriz de troca iônica Kit Instagene Matrix e submetido a PCR com iniciadores gerais para o gene cry1 e específicos para as subclasses. Realizaram-se bioensaios com 58 isolados, um controle positivo com a linhagem padrão HD-1 B. thuringiensis var. kurstaki, um controle negativo com B. thuringiensis var. tenebrionis e água com espalhante adesivo, como testemunha. O conteúdo das subclasses estudadas para o gene cry1 foi determinado para 58 isolados, o que representa 60% do total. Dentre os 95 isolados estudados, 27,4% demonstraram que o conjunto gênico cry1Aa, cry1Ca, cry1Da, cry1Fa e cry1Bd é a freqüência mais comum. Dos 58 isolados testados, 11 causaram mortalidade total das lagartas e os demais influenciaram negativamente o ciclo biológico da praga. Dentre as características avaliadas, a mortalidade larval e a pupal, bem como a duração larval foram as mais relevantes para se determinar quais isolados influenciaram a biologia da praga. Portanto, os isolados que causaram 100% de mortalidade larval têm grande potencial para formulação de produtos comerciais a serem utilizados em programas de manejo integrado de P. xylostella. / The research was developed in the Laboratório de Biologia e Criação de Insetos (LBCI) and in the Laboratório de Genética de Bactérias e Biotecnologia Aplicada (LGBBA) at the FCAV-UNESP-Campus de Jaboticabal, SP. The general objective was to select new strains of Bacillus thuringiensis through the molecular characterization, identifying the different subclasses of the gene cry1, to determine the patogenicity against caterpillars of Plutella xylostella and to evaluate the influence in the pest biological parameters. It was used 95 isolated of B. thuringiensis obtained of the collection of LGBBA. The genetic material was extracted by the head office of change ionic Kit Instagene Matrix and submitted to PCR with general initiators for the gene cry1 and specific for the subclasses. Bioassays were made using 58 strains of B. thuringiensis, a positive control with var. tenebrionis and water was used with adhesive spreader Tween20®, as a standard the strains HD1 from B. thuringiensis var. kurstaki, a negative control with B. thuringiensis check. The content of the subclasses studied for the gene cry1 was determined for 58 isolated, what represents 60% of the total. Among the 95 isolated studied, 27,4% demonstrated that the genic group cry1Aa, cry1Ca, cry1Da, cry1Fa and cry1Bd is the most common frequency. Total mortality of caterpillars was observed in 11 of studied strains and the remainders affected negatively pest biological lifecycle. Larvae and pupae mortality, and larvae period were more relevants parameters to determine which isolates affect P. xylostella biology. In this way, the isolates caused 100 % larval mortality have higher potential for development a commercial bioinseticide to use in Plutella xylostella integrated pest management programs.

Submitted by (edna.saturno@ufrpe.br) on 2016-11-22T16:29:59Z No. of bitstreams: 1 Alexandre Conte de Oliveira.pdf: 285466 bytes, checksum: dde44764fcdc48d6862c5cda4477617c (MD5) / Made available in DSpace on 2016-11-22T16:29:59Z (GMT). No. of bitstreams: 1 Alexandre Conte de Oliveira.pdf: 285466 bytes, checksum: dde44764fcdc48d6862c5cda4477617c (MD5) Previous issue date: 2009-02-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Plutella xylostella is a recurring pest on cruciferous crops around the world. The susceptibility of diamondback moth populations to the insecticides abamectin, deltamethrin, and spinosad, from three Brazilian regions was compared through collard leaf dipping bioassays in laboratory for the different treatments. Mortality data were assessed 48 hours after exposition to every insecticide and submitted to Probit analysis. All the populations showed significant resistance to at least one of the insecticides. The Bonito-PE population showed the highest resistance ratio (20.2 times) to abamectin when compared with the susceptible population and to other insecticides. The deltamethrin LC50s were very high for all the populations tested, ranging from 85.2 to 360.1 mg/L. All the populations from Pernambuco State were considered resistant to deltamethrin, with resistance ratios varying from 2.2 to 4.2 times. Five populations showed significant resistance to spinosad with ratios varying from 2.3 to 5.1. These results are discussed based on the spectrum of insecticides used in the regions. In conclusion, the need of resistance toinsecticides management programs for P. xylostella in conjunction with an integrated pest management is urgent in these regions. / A Plutella xylostella destaca-se como o inseto de maior importância devido aos sérios danos causados à cultura das brássicas. A suscetibilidade de populações de traça-das-crucíferas aos inseticidas abamectina, deltametrina e espinosade, provenientes de três regiões brasileiras, foram comparadas através de bioensaios com imersão de folhas de couve. A mortalidade foi avaliada após 48 horas de exposição aos inseticidas e os dados foram submetidos à análise de Probit. Os resultados demonstraram que sete populações de traça-das-crucíferas apresentaram significativa resistência a um ou mais inseticidas. A população de Bonito-PE apresentou a maior razão de toxicidade (20,2 vezes) ao abamectina quando comparados com a população suscetível. As CL50s para deltametrina foram altas para as populações de traça-das-crucíferas, variando de 85,2 a 360,1 mg/L do inseticida. Todas as populações do Estado de Pernambuco foram consideradas resistentes ao deltametrina, apresentando razões de toxicidade variando entre 2,2 e 4,2 vezes. Cinco populações apresentaram moderada resistência ao espinosade com níveis de resistência variando de 2,3 a 5,1. Assim, a necessidade de desenvolvimento de programas de manejo de resistência de P. xylostella a inseticidas associados ao manejo integrado de pragas torna-se evidente nestas regiões produtoras de brássicas.

Submitted by (edna.saturno@ufrpe.br) on 2016-12-01T11:35:30Z No. of bitstreams: 1 Vanessa Correa Santos.pdf: 426382 bytes, checksum: 7f2a707e64c6b920d1e709bfb3336891 (MD5) / Made available in DSpace on 2016-12-01T11:35:30Z (GMT). No. of bitstreams: 1 Vanessa Correa Santos.pdf: 426382 bytes, checksum: 7f2a707e64c6b920d1e709bfb3336891 (MD5) Previous issue date: 2010-02-01 / Plutella xylostella (L.) (Lepidoptera: Plutellidae), popularly known as diamondback moth, is a major pest of brassicaceae crops (e.g., kale, cauliflower, broccoli, and cabbage) throughout the world. Several insecticides have been intensively used during several cultivation cycles and, even in some areas, up to 15 to 20 applications per season have been observed. Besides the problems they may cause to human and environmental health, the frequent use of these products has been associated to the evolution of resistance in P. xylostella populations to various insecticides such as the pyrethroids, carbamates, organophosphates, and even Bacillus thuringiensis. The current study objective was to identify the resistance in P. xylostella populations from Pernambuco State, when exposed to abamectin, methomyl, lufenuron, indoxacarb, and diafentiuron. Concentration-response regressions were established using 2nd-instar larvae of P. xylostella. All P. xylostella populations showed significant resistance ratio (RR) to at least one insecticide. The smallestCL50s values were estimated for abamectin, which varied from 0.01 to 0.74 mg/L and the highest CL50s were estimated for diafentiuron, which varied from 47.9 to 122.2 mg/L. The Bezerro County population presented the highest resistance ratios to indoxacarb (25.3-fold), abamectin (61.7-fold), and lufenuron (705.2-fold), compared to the reference population. TheBonito and Jupi Counties populations were 33.0- and 12.0-times more resistant to lufenuron and abamectina, respectively. These results demonstrate that intensive and indiscriminate use of insecticides in Pernambuco must be a concern, which suggests the immediate establishment of a resistance management program associated to integrated pest management in these areas. / Plutella xylostella (L.) (Lepidoptera: Plutellidae), conhecida popularmente como traça-das-crucíferas é considerada a principal praga do cultivo de brássicas (ex: couve, couve-flor, brócolis e repolho) em todo o mundo. Diversos inseticidas têm sido utilizados intensivamente durante o ciclo da cultura, e em algumas áreas já foram detectadas 15 a 20 aplicações por ciclo. Além dos problemas gerados à saúde do agricultor e ao meio ambiente, o uso excessivo desses produtos tem proporcionado o aparecimento de populações resistentes deste inseto-praga a diversos compostos químicos, como é o caso dos inseticidas piretróides, carbamatos, organofosforados e Bacillus thuringiensis. O presente estudo teve como objetivo identificar a resistência em populações de P. xylostella do Estado de Pernambuco, utilizando os inseticidas abamectina, metomil, lufenurom, diafentiuron e indoxacarbe. Curvas de concentração-resposta foram estabelecidas usando lagartas de 2º instar de P. xylostella. Todas as populações pernambucanas de P. xylostella apresentaram razão de resistência (RR) significativa a pelomenos um inseticida. As menores CL50s foram registradas para o inseticida abamectina, variando de 0,01 a 0,74 mg/L e as maiores CL50s foram para o inseticida diafentiuron, 47,9 a 122,2 mg/L. A população do município de Bezerros apresentou as maiores razões de resistência 25,3 a indoxacarbe, 61,7 a abamectina e 705,2 a lufenurom, quando comparadas àpopulação suscetível. A população do município de Bonito apresentou uma razão de resistência 33,0 a lufenurom e Jupi 12,0 para abamectina. Estes resultados demonstram que o uso intensivo e indiscriminado de inseticidas na região Agreste de Pernambuco é preocupante, sugerindo o estabelecimento de um programa de manejo da resistência associado ao manejo integrado de pragas nesta área.

No description available.

Diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae) is a serious pest of crucifer vegetables (Brassica sp.) worldwide because of a lack of effective natural enemies in certain regions and because of insecticide resistance. In 2003, laboratory and field studies were initiated in Virginia to better understand P. xylostella, its primary natural enemies, and their susceptibilities to insecticides in order to develop an economically and environmentally sound integrated pest management program for collards in the state. Ecological life table studies of P. xylostella immature stages on collards located on the Eastern Shore and on Kentland Farm, near Blacksburg at the New River Valley, VA revealed that most (98 to 99%) of P. xylostella died from natural causes. Mortality factors varied between the two regions. Neonates, small larvae, and large larvae disappearing were major mortality factors. Rainfall, predation, and dispersal probably contributed the most to this mortality. Egg mortality played a bigger role at the New River Valley compared with the Eastern Shore. Three parasitoid species were found that contributed to the mortality of P. xylostella: Diadegma insulare (Cresson) (Hymenoptera: Ichneumonidae); Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae); and Microplitis plutellae (Muesebeck) (Hymenoptera: Braconidae). Additional studies conducted in the laboratory using leaf-dip bioassays revealed that P. xylostella collected from the Eastern Shore of Virginia, showed significant tolerance levels to esfenvalerate, acetamiprid, methomyl, methoxyfenozide, indoxacarb, and acephate compared with a susceptible strain of P. xylostella. The highest tolerance ratio (1,876 fold) was to esfenvalerate, a commonly-used pyrethroid. All of the insecticides tested in this study were quite toxic to the adult stage of the parasitoids, D. insulare and O. sokolowskii. The insect growth regulator, methoxyfenozide was considerably less toxic than other insecticides such as esfenvalerate, methomyl, acephate, spinosad, indoxacarb, and emamectin benzoate at field-rate and 1% of field-rate concentrations. The aforementioned insecticides as well as some other insecticides were evaluated several times in the field for efficacy against P. xylostella as well as other pests of collards. The most efficacious insecticides over five field experiments included acephate, emamectin benzoate, esfenvalerate, methomyl, methoxyfenozide, novaluron, indoxacarb, and spinosad. These insecticides were followed in relative efficacy by Bt kurstaki, acetamiprid, and azadirachtin, which provided relatively inconsistent control of lepidopteran larvae over the experiments. Effective insecticide options in collards that are less toxic to natural enemies and that can fit well into integrated pest management programs include indoxacarb, spinosad, novaluron, emamectin benzoate, methoxyfenozide, and Bacillus thuringiensis subsp. kurstaki. / Ph. D.

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Doctor of Philosophy / Department of Entomology / Raymond A. Cloyd / James R. Nechols / Raymond A. Cloyd / James R. Nechols / Greenhouse studies were conducted to examine direct effects of light intensity and nitrogen source on primary and secondary metabolism of pac choi (Brassica rapa L. var. chinensis cv. ‘Mei Qing Choi’) and indirect effects on diamondback moth (Plutella xylostella L.)(DBM). In the first study, plants were exposed to high and low light intensities during different times of the year, resulting in a range of light intensities. From four experiments, plants exhibited higher phenolic content, greater shoot biomass, and higher C:N ratios under high light intensity, whereas plants under low light intensity contained higher protein. Ferulic acid increased under high light intensity, and this increase was negatively correlated with male DBM body weights. However, DBM developed faster on plants in the August experiment (high light), compared to the July experiment (lower light). This implies that light intensity may not be affecting DBM through plant-mediated changes unless reduced male weights confer a reduction in larval consumption. In the nitrogen source study, application of an organic source of nitrogen (fish hydrolysate fertilizer) was compared to a conventional fertilizer to determine whether nitrogen source directly impacts pac choi chemistry and biomass, thus indirectly impacting DBM fitness. In two experiments, there was no significant effect of fertility treatment on pac choi nutrients or biomass, with the exception of percent leaf phosphorus, which was significantly higher in the conventional fertility treatment. For DBM, percent survival and cohort development were significantly reduced on pac choi receiving the organic fertilizer. Calcium and magnesium were significantly higher in pac choi infested with DBM larvae than plants without DBM. In addition, calcium was negatively correlated with female DBM body weights in one experiment for the organic treatment. Overall, this study demonstrated that pac choi plants that received the organic fertilizer were similar to pac choi plants that received a conventional fertilizer with the exception of phosphorus. Furthermore, female DBM body weights were negatively impacted by calcium in the organic treatment. As multiple fitness traits for DBM were negatively affected in the organic treatment, pac choi crops grown with fish hydrolysate fertilizer may experience less feeding from DBM.

Submitted by (edna.saturno@ufrpe.br) on 2016-11-22T14:40:50Z No. of bitstreams: 1 Christian Sherley Araujo da Silva.pdf: 746244 bytes, checksum: 46bc29b14cc397ec58c00ff6566278b8 (MD5) / Made available in DSpace on 2016-11-22T14:40:50Z (GMT). No. of bitstreams: 1 Christian Sherley Araujo da Silva.pdf: 746244 bytes, checksum: 46bc29b14cc397ec58c00ff6566278b8 (MD5) Previous issue date: 2009-12-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Parasitoid dispersion and host location can be affected by abiotic and biotic factors related to the parasitoid and its host. Therefore, we investigated the effects of age, photoperiod, and parasitism of Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) under different densities of Plutella xylostella (L.) (Lepidoptera: Plutellidae), in the laboratory, green house and field. Moreover, we investigated the effect of superparasitism on O. sokolowskii fitness, its dispersion ability in the field, and the effect of a multiple host plant systems on its parasitism capacity. Results showed that there was no effect of the light regime (light or darkness) on the parasitization; although parasitoid was more active after 3h of light exposure. Female parasitization activity was maintained up to the age of 20 days, but the offspring emerged per host decreased as wasps aged. Parasitism rate increased with parasitoid age up to 96 h and when wasps received a constant number of hosts daily in comparison with a random number (13.3 versus 8.9 larvae). In addition, the number of larvae parasitized increased with host density, varying from 1.7 to 10.4, in the laboratory, and from 0.61 to 7.0, in the field. In the green house,parasitism was higher in microparcels with higher host infestation, and with more exposition time to parasitization (24h: 52.4% and; 72h: 80.7%). Regarding the superparasitism, it increased thenumber and longevity of offspring produced per larva, but decreased offspring body size. However, developmental time and sex ratio of parasitoid offspring were not affected. Parasitoids were able to disperse and parasitize larvae at similar rates throughout the field up to 24m from the releasing point. Intercropping of cabbage with broccoli, Napa cabbage, cilantro and green onion did not negatively affect parasitism rates of O. sokolowskii. Then, results suggest that O. sokolowskii could be favored by superparasitism and have the potential to control P. xylostella under different densities, regardless of the cropping system. / A dispersão de parasitóides e a localização do hospedeiro podem ser influenciadas por fatores abióticos e bióticos inerentes ao parasitóide e ao seu hospedeiro. Portanto, investigou-se o efeito da idade, do fotoperíodo, e parasitismo de Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) submetido a diferentes densidades de Plutella xylostella (L.) (Lepidoptera: Plutellidae), em laboratório, casa telada e campo. Além disso, o efeito do superparasitismo em lagartas no desempenho de O. sokolowskii, a sua capacidade de dispersão em campo, e o efeito do sistema de cultivo de brássicas na sua capacidade de parasitismo foram investigados. Resultados mostram que não houve efeito do regime de luz (luz ou escuro) na taxa de parasitismo; porém, parasitóides apresentaram maior atividade após 3h de exposição à luz. Fêmeas de O. sokolowskii parasitam até 20 dias de idade, mas com redução na progênie com a idade. Houve maior parasitismo até a idade de 96 h das fêmeas e ao receberem diariamente um número constante de lagartas comparado à disponibilidade randômica (13,3 versus 8,9 lagartas).Adicionalmente, o número de lagartas parasitadas aumentou com a densidade do hospedeiro variando de 1,7 a 10,4, em laboratório, e de 0,61 a 7,0, em campo. Em casa telada, um maior parasitismo foi observado em microparcelas com maiores infestações de lagartas, e com o tempode exposição das lagartas aos parasitóides (24h: 52,4% e; 72h: 80,7%). Com relação ao superparasitismo, este aumentou o número e a longevidade dos descendentes produzidos por lagarta, mas com redução do tamanho do corpo dos descendentes. No entanto, a duração do desenvolvimento e a razão sexual dos descendentes não foram afetadas. Com relação à dispersão, parasitóides se dispersaram e parasitaram lagartas em taxas semelhantes até 24m a partir do ponto de liberação, e o policultivo de repolho com brócolis, couve-chinesa, coentro e cebolinha não afetou o parasitismo de lagartas por O. sokolowskii. Assim, resultados demonstram que O. sokolowskii pode ser beneficiado pelo superparasitismo e tem potencial para controlar P. xylostella em diferentes densidades e independente do sistema de cultivo.