Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.93-105).

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is an important pest of cruciferous crops worldwide. The prolonged use of synthetic chemical insecticides as a primary means of control has resulted in the development of resistance in pest populations. In addition, the pest has also evolved resistance to the bacterial insecticidal protein of Bacillus thuringiensis which is also widely used as a method of control. Baculoviruses are considered as effective alternatives to conventional methods of control when incorporated into integrated pest management (IPM) programmes. These viruses target the larval stages of insects, are generally host-specific and are safe for use in the environment. This study aimed to isolate a baculovirus from a laboratory-reared P. xylostella colony, characterise it genetically and then evaluate its virulence against neonate and fourth instar larvae. A laboratory colony of P. xylostella was established using pupae and asymptomatic larvae collected from a cabbage plantation outside Grahamstown in the Eastern Cape province of South Africa. The colony flourished in the laboratory due to prime conditions and availability of food. The duration of development from egg to adult was determined by observation and imaging of the various life stages. The mean developmental time from egg to adult was observed to be 14.59 ± 0.21 days. The population of the insects increased rapidly in number leading to overcrowding of the insect colony, and hence appearance of larvae with viral symptoms. Occlusion bodies (OBs) were extracted from symptomatic larval cadavers and purified by glycerol gradient centrifugation. Analysis of the purified OBs by transmission electron microscopy revealed the presence of a granulovirus which was named PlxyGV-SA. The virus isolate was genetically characterised by restriction endonuclease analysis of the genomic DNA, and PCR amplification and sequencing of selected viral genes. The complete genome sequence of a Japanese P. xylostella granulovirus isolate, PlxyGV-Japan, has been deposited on the GenBank database providing a reference strain for comparison with DNA profiles and selected gene sequences of PlxyGV-SA. BLAST analysis of the granulin gene confirmed the isolation of a novel South African PlxyGV isolate. Comparison of the restriction profiles of PlxyGV-SA with profiles of PlxyGV-Japan and other documented PlxyGV profiles obtained by agarose gel electrophoresis revealed that PlxyGV-SA is a genetically distinct isolate. The data obtained from the sequencing and alignment of ecdysteroid UDP-glucosyltransferase (egt), late expression factor 8 (lef-8) and late expression factor 9 (lef-9) genes with those of PlxyGV-Japan also showed that PlxyGV-SA is a genetically different isolate. In order to determine the biological activity of PlxyGV-SA against neonate and fourth instar P. xylostella larvae, surface dose bioassays were conducted. The median lethal concentration of the virus required to kill 50% (LC₅₀) and 90% (LC₉₀) of the larvae was estimated by feeding insects with a range of doses. In addition, the time to kill 50% of the larvae (LT₅₀) was determined by feeding insects with the LC₉₀ concentration. Larval mortality was monitored daily until pupation. The data obtained from the dose response assays were subjected to probit analysis using Proban statistical software. The time response was determined using GraphPad Prism software (version 6.0). The LC₅₀ and LC₉₀ values for the neonate larvae were 3.56 × 10⁵ and 1.14 × 10⁷ OBs/ml respectively. The LT₅₀ was determined to be 104 hours. The neonate larvae were found to be more susceptible to infection than the fourth instar larvae with the same virus concentration. The concentrations used for the neonate larvae assay did not have a significant effect on the fourth instar as no mortality was recorded. This is the first study to describe a novel South African PlxyGV isolate and the results suggest that PlxyGV-SA has significant potential for development as an effective biopesticide for the control of P. xylostella in the field.

A mariposa Plutella xylostella (L., 1758) (Lepidoptera, Plutellidae), conhecida popularmente como traça das crucíferas, é uma importante praga da cultura das brássicas no Brasil e em diversos países. Seu controle normalmente é realizado com aplicações freqüentes de inseticidas convencionais, porém esse controle tem se mostrado ineficiente, além dos problemas ambientais, econômicos e de resistência de insetos que pode causar. A quimioesterilização apresenta-se como uma alternativa para o manejo desta praga, utilizando inseticidas modernos, mais seletivos aos inimigos naturais e de menor impacto ambiental. O objetivo deste trabalho foi estudar o emprego de alguns inseticidas com propriedades esterilizantes sobre a fase adulta de Plutella xylostella determinando as dosagens adequadas que atuaram sobre sua reprodução. Os produtos foram fornecidos às mariposas em forma de iscas que consistiram em: solução do produto + melaço 10%. Os inseticidas utilizados e suas respectivas dosagens foram abamectina (0,0025 g i.a./L calda), diflubenzurom (0,005 g i.a./L calda), lufenurom (0,005 g i.a./L calda) e piriproxifem (0,01 g i.a./L calda), além da testemunha. Apenas o tratamento com abamectina afetou a fecundidade de Plutella xylostella, apresentando 10,23 ± 4,41 ovos em média, enquanto na testemunha obteve-se 64,54 ± 15,11 ovos, porém a fertilidade foi afetada por todos os produtos. A viabilidade média dos ovos dos tratamentos com abamectina, diflubenzurom, lufenurom e piriproxifem foi, respectivamente 3,35%; 46,69%; 9,31% e 12,47%; todos diferiram estatisticamente da testemunha que apresentou viabilidade de 83,89%. A longevidade dos insetos tratados com os produtos não diferiu dos não tratados, com exceção dos indivíduos tratados com abamectina que apresentaram uma redução no tempo de vida. Quando os produtos testados foram oferecidos isoladamente para machos e fêmeas, a ação esterilizante apenas pode ser observada em fêmeas desta espécie, os machos não apresentaram nenhuma diferença com relação à testemunha quando alimentados com as iscas esterilizantes. / Plutella xylostella (L., 1758) (Lepidoptera, Plutellidae), commonly known as diamondback moth, is an important pest of Brassicaceae in Brazil and several other countries. Its control is usually done with frequent applications of conventional insecticides. However, this approach is sometimes ineffective, besides some drawbacks such as environmental contamination, the high cost of application and the development of insecticides resistance. Chemosterilization using modern insecticides presents an alternative for this pest management. The aim of this study was to evaluate a range of insecticides with sterilizing properties on the adult reproduction of Plutella xylostella. Pesticides were provided to moths in baits, diluted in 10% molasses water solution. The insecticides used and respective doses were: abamectin (0.0025 g a.i./L), diflubenzuron (0.005 g a.i./L), lufenuron (0.005 g a.i./L) and pyriproxyfen (0.01 g a.i./L). A 10% molasses solution was used as a control treatment. Only abamectin affected the fecundity of Plutella xylostella, with a reduction from 64.54 ± 15.11 eggs/moth obtained in the control treatment to 10.23 ± 4.41 eggs/moth, when adults were fed this pesticide. However, fertility was affected by all pesticides. Egg viability when adults were feed abamectin (3.35%), diflubenzuron (46.69%), lufenuron (9.31%) and pyriproxyfen (12.47%) were reduced when compared to the control (83.89%). Only adults that were abamectin fed had their longevity reduced as compared to all other treatments. When the tested pesticides were offered isolated to males or females, their sterilizing activity was observed only when females had access to treated baits.

A traça das crucíferas, Plutella xylostella (L.) (Lepidoptera: Plutellidae), é uma das pragas mais importantes de Brassicaceae no Brasil e no mundo, causando sérios danos em repolho, couve-flor e couve comum, entre outras. O objetivo desta pesquisa foi estudar os parâmetros populacionais e a resposta comportamental de P. xylostella criada por dezoito gerações, utilizando três variedades: Brassica oleracea var. acephala couve manteiga hibrida HS-20, B. oleracea var. italica couve brócolis Piracicaba e B. oleracea var. capitata repolho Bob Cat. Para condução dos experimentos foram separados três lotes de pupas de P. xylostella da criação mantida no laboratório, no qual foram utilizadas apenas folhas de couve para sua manutenção. Cada lote foi mantido em substrato diferente, ou seja, a criação inicial foi dividia em três populações tendo como variável o substrato alimentar e de oviposição utilizado na criação (couve, brócolis ou repolho). Com os dados biológicos de P. xylostella foram estimados os parâmetros populacionais de tabela de vida de fertilidade a cada três gerações, comparando-se as cultivares testadas em relação ao desenvolvimento, sobrevivência e reprodução da praga. Além disso, lotes de insetos oriundos de cada substrato de criação foram separados a cada três gerações para realização de testes de dupla e múltipla chance de escolha (preferência para alimentação e oviposição). Os parâmetros populacionais de P. xylostella indicam que as brassicáceas testadas permitem o crescimento populacional do inseto nos respectivos hospedeiros. O comportamento de seleção hospedeira na fase pré-imaginal e imaginal de P. xylostella não é afetado pela experiência alimentar e de oviposição nos substratos testados até a geração F18. / The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is one of the most important pests of Brassicaceae in Brazil and worldwide, causing serious damage to cabbage, cauliflower and kale common, among others. The aim of this research was to study the population parameters and the behavioral response of P. xylostella reared for eighteen generations, using three varieties: Brassica oleracea var. acephala - cabbage hybridizes HS-20, B. oleracea var. italica - Piracicaba broccoli and B. oleracea var. capitata - cabbage Bob Cat. To conduct the experiments were separate three batches of DBM from pupae held in the laboratory setting, in which only kale leaves were used for maintenance. Each batch was kept at different substrate, namely the initial rearing was divided into three populations having as variable the feeding and oviposition substrate used in rearing (kale, broccoli, and cabbage). With biological data of P. xylostella were estimated the population parameters of fertility life table every three generations, comparing the tested cultivars in relation to the development, survival and reproduction of the pest. Moreover, lots of insects derived from each rearing substrate were separated every three generations for performing dual choice and multiple-choice tests (preference for feeding and oviposition). The population parameters of P. xylostella indicate that brassicas tested allow the insect population growth in their hosts. The host selection behavior in pre-imaginal and imaginal stage of P. xylostella is not affected by food and oviposition experience on substrates up to F18 generation.

Magistrantūros studijų baigiamajame darbe pateikiami kopūstinės kandies skraidymo bei kenkimo dinamikos vasarinių rapsų ir gūžinių kopūstų pasėliuose tyrimų rezultatai. Darbo objektas – kopūstinė kandis (Plutella xylostella L.) Darbo metodai – kopūstinės kandies skraidymo dinamika tirta naudojant feromonines “delta” tipo gaudykles, 2012 m. gegužės – rugpjūčio mėnesiais, vasarinių rapsų ir ankstyvųjų bei vėlyvųjų baltagūžių kopūstų pasėliuose. Vasarinių rapsų pasėlyje buvo įrengta 12 gaudyklių (po 3 su kiekvienos rūšies feromonu), o kopūstų – po 5 gaudykles su veiksmingiausiu feromonu, į jas patekę vabzdžiai buvo registruojami kas 3–5 dienas. Tyrimams naudoti 4 skirtingos sudėties sintetiniai feromonai. Kandžių pažeidimai rapsuose buvo fiksuojami birželio 7 - liepos 11 dienomis. Apskaitos buvo atliekamos kas 3–4 dienas, 3 rendomizuotai pasirinktose vietose, patikrinant po 50 augalų. Darbo rezultatai – Tyrimų metu sugautos 617 kopūstinių kandžių. Vasariniuose rapsuose vidutiniškai 1 gaudyklei per sezoną teko 79, ankstyviesiems kopūstams – 60, o vėlyviesiems kopūstams – 19 kandžių. Rapsuose skraidymo intensyvumo pikas užfiksuotas liepos 17–20 d., ankstyvuosiuose kopūstuose liepos 11–14 d., o vėlyvuosiuose kopūstuose liepos 20–23 d. Feromonas, savo sudėtyje turintis Z11-16:Ald : Z11-16:Ac : Z11-16:OH : Z9-14:Ac (0,7:0,3:0,01:0,010) labiausiai viliojo kopūstines kandis. Su šiuo feromonu rapsuose pagauti 56 % visų kandžių. Nustatyti statistiškai patikimi efektyvumo skirtumai... [toliau žr. visą tekstą] / The master thesis presents the results of studies of dynamics of flight activity, intensity of damage of Plutella xylostella. Object of the research - Diamonback moth (Plutella xylostella L.) Method of the research – ‘Delta’ traps loaded with 4 different synthetic pheromones were used for trapping of adults of P. xylostella. The investigations were carried out in the fields of summer rape as well as early and later types of cabbages during May to August in 2012. Twelve traps (by three with each pheromone) were used in summer rape; meanwhile five traps were equipped in cabbage crops and each of them was loaded with the best pheromone. The traps were visited every 3–5 days and trapped insects were registered. The damage by the Diamonback moth was registered in summer rape from 7 of June to 11 of July. Accountings were done in 3 random places checking 50 plants each 3–4 days during the study. The results of the research – The number of captured individuals of P. xylostella during the study has amounted 617. The highest activity of moths has been registered in rape i.e. on the average 79 specimens have been caught per one trap during the season, while the lower activity has been observed in early cabbages reaching 60 specimens and finally the lowest one attributing to later maturing types of cabbages which numbered 19 specimens. The peak of activity was registered from 17 to 20 July in rape, from 11 to 14 July in early cabbages and from 20 to 23 July in later maturing... [to full text]

No description available.

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

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Brassica vegetables and oilseeds are economically important crops worldwide. These crops are associated with several destructive and widespread insect pests. In Australia these pests include six species, Plutella xylostella (Linnaeus), Pieris rapae (Linnaeus), Hellula hydralis Guenée, Helicoverpa punctigera (Wallengren), Brevicoryne brassicae (Linnaeus) and Myzus persicae (Sulzer), which are the focus of this research. Among them P. xylostella (diamondback moth or DBM) is the most serious and destructive insect pest. Little is known about the potential of predators, which may be able to contribute to control diamondback moth, although some field studies have shown the overall importance of predators in controlling this key pest. The aim of this study was to develop a method that allows study of predator-prey trophic interactions in the field. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1294814 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Brassica vegetables and oilseeds are economically important crops worldwide. These crops are associated with several destructive and widespread insect pests. In Australia these pests include six species, Plutella xylostella (Linnaeus), Pieris rapae (Linnaeus), Hellula hydralis Guenée, Helicoverpa punctigera (Wallengren), Brevicoryne brassicae (Linnaeus) and Myzus persicae (Sulzer), which are the focus of this research. Among them P. xylostella (diamondback moth or DBM) is the most serious and destructive insect pest. Little is known about the potential of predators, which may be able to contribute to control diamondback moth, although some field studies have shown the overall importance of predators in controlling this key pest. The aim of this study was to develop a method that allows study of predator-prey trophic interactions in the field. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1294814 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007

Resumo: A traça-das-crucíferas (Plutella xylostella) é uma praga que ataca culturas de brássicas, causando enormes prejuízos econômicos aos agricultores. O aparecimento de populações resistentes a inseticidas tem dificultado seu manejo, fazendo-se necessário a busca por alternativas de controle que viabilizem a economia do custo de produção, preservando o ambiente de inseticidas químicos em altas doses. As plantas possuem um mecanismo constitutivo de resistência que atua na sua defesa frente às diferentes adversidades bióticas e abióticas, o que representa altos gastos metabólicos. O mecanismo de resistência pode ser melhorado com a indução de resistência por um ou mais elicitores, como é o caso das bactérias promotoras de crescimento. O objetivo deste estudo foi detectar sequências gênicas expressas em resposta à indução de resistência de repolho à traça das crucíferas. A bactéria utilizada como indutora das respostas de defesa foi a Kluyvera ascorbata devido à ação já descrita anteriormente com repolho e traça-das-cruciferas, onde ficou evidente sua influência na defesa contra essa praga. Por meio do sequenciamento de cDNA foi possível identificar uma significativa alteração no metabolismo de plantas que abrigavam esta bactéria, suprimindo da ação de muitos genes, durante o processo de defesa da planta contra o estresse causado pela injúria de lagartas de P. xylostella / Abstract: The diamondback moth Plutella xylostella is a pest that attacks brassics causing great economic losses to the growers. The rise of resistant populations to the chemical insecticides imposes difficulties on this pest management, so the search of other ways to overcame this situation became quite relevant so as to help to reduce production costs and at the same time avoiding the use of high dosage of the commonly used pesticides. Plants exhibit a constitutive resistance mechanism that acts favoring their defense towards biotic and abiotic stress situations, which involves high metabolic energetic challenges. The defense mechanisms may be improved with the induction of resistance by a number of different elicitors, such as the use of plant growth promoting bacteria. The aim of the present work was to detect plant gene sequences in response to cabbage resistance induction against the diamondback moth. Kluyvera ascorbata was used to induce the plant's growth promotion elicitor due to previously described influence. Analyzing DNA sequencing procedures from cDNA library samples, it was possible to observe drastic differences on the plants metabolism when such bacteria was used, either by suppressing the action of several genes while the plant's defense mechanisms was in action against injuries caused by P. xylostella larvae / Orientador: Manoel Victor Franco Lemos / Coorientador: Robson Thomaz Thuler / Banca: Janete Apparecida Desidério Sena / Banca: João Roberto Spotti Lopes / Mestre