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Saprophagous caterpillars (Lepidoptera: Noctuidae: Herminiinae) effect of Bacillus thuringiensis var. kurstaki application in forest and laboratory settings /Kish, Karen Jeanine, January 2004 (has links)
Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains viii, 40 p. : ill. (some col.), map. Vita. Includes abstract. Includes bibliographical references (p. 36-39).
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Revisão e análise filogenética do gênero Dargida Walker, 1856 (Lepidoptera: Noctuidae: Hadeninae) / Revision and phylogenetic analysis of the genus Dargida Walker, 1856Quintero, Anderson Muñoz 22 November 2016 (has links)
Foi realizada a revisão e analise filogenética do gênero Dargida Walker, 1856, um gênero americano composto por 56 espécies válidas, normalmente encontradas em locais com predominância de gramíneas. Algumas das espécies deste gênero são consideradas pragas de importância econômica. Estão distribuídas desde o Canadá ao Chile, ocorrendo do nível do mar até quase 4000 metros de altitude, porém nenhuma das espécies apresenta distribuição contínua pelo Continente. O desenvolvimento do trabalho foi realizado com base na revisão de coleções entomológicas nacionais e estrangeiras. Analisou-se mais de 5000 espécimes, foi atualizada a distribuição geográfica conhecida para o gênero assim como obtidos novos registros para grande parte das espécies. Foi construída uma matriz de caracteres morfológicos, analisados nos programas TNT e Mr. Bayes. As topologias finais mostram que Dargida é um gênero polifilético formado por um grupo sensu stricto que contem as espécies que serão consideradas como Dargida (aquelas com maior semelhança à espécie-tipo), e um grupo denominado sensu lato menos sensu stricto, formado pelas espécies cujas características morfológicas são diferentes às da espécie-tipo. Devido aos resultados da analise filogenética, mas, também a os dados obtidos na analise morfológica, na revisão do gênero Dargida Walker, 1856 foram incluídas somente as espécies do grupo sensu stricto, sendo que as restantes espécies deveram ser realocadas em outras unidades genéricas ou deveram ser criados novos gêneros nos quais estás deveram ser arroladas. / Was carry out a revision and phylogenetic analysis of the genus Dargida Walker, 1856, an American genus composed by 56 valid species, usually founded in places with grass plants dominace. Some species of genus are considered pests of economic importance. The group is distributed from Canada to Chile, occurring from sea level to almost 4000 meters of altitude, however, no species has a continuous distribution throughout Continent. To develop this work were revised national and foreign entomological collections. More than 5000 specimens were analyzed. Was update the geographical distribution of genus as well as new records were obtained for most species. Was constructed a matrix of morphological characters and analyzed in TNT and Mr. Bayes programs. The final topologies show that Dargida is a polyphyletic genus formed by a sensu stricto group that contains species that will be considered as Dargida (those with more similarity to the type-species), and a group denominated sensu lato minus sensu stricto, formed by species whose morphological characters are different from those of type-species. Due to the results of the phylogenetic analysis, but also to data obtained from morphological analysis, only species of sensu stricto group were included in the revision of genus, the remaining species should be relocated in other generic groups or should be created new genera in which list thouse species.
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Revisão e análise filogenética do gênero Dargida Walker, 1856 (Lepidoptera: Noctuidae: Hadeninae) / Revision and phylogenetic analysis of the genus Dargida Walker, 1856Anderson Muñoz Quintero 22 November 2016 (has links)
Foi realizada a revisão e analise filogenética do gênero Dargida Walker, 1856, um gênero americano composto por 56 espécies válidas, normalmente encontradas em locais com predominância de gramíneas. Algumas das espécies deste gênero são consideradas pragas de importância econômica. Estão distribuídas desde o Canadá ao Chile, ocorrendo do nível do mar até quase 4000 metros de altitude, porém nenhuma das espécies apresenta distribuição contínua pelo Continente. O desenvolvimento do trabalho foi realizado com base na revisão de coleções entomológicas nacionais e estrangeiras. Analisou-se mais de 5000 espécimes, foi atualizada a distribuição geográfica conhecida para o gênero assim como obtidos novos registros para grande parte das espécies. Foi construída uma matriz de caracteres morfológicos, analisados nos programas TNT e Mr. Bayes. As topologias finais mostram que Dargida é um gênero polifilético formado por um grupo sensu stricto que contem as espécies que serão consideradas como Dargida (aquelas com maior semelhança à espécie-tipo), e um grupo denominado sensu lato menos sensu stricto, formado pelas espécies cujas características morfológicas são diferentes às da espécie-tipo. Devido aos resultados da analise filogenética, mas, também a os dados obtidos na analise morfológica, na revisão do gênero Dargida Walker, 1856 foram incluídas somente as espécies do grupo sensu stricto, sendo que as restantes espécies deveram ser realocadas em outras unidades genéricas ou deveram ser criados novos gêneros nos quais estás deveram ser arroladas. / Was carry out a revision and phylogenetic analysis of the genus Dargida Walker, 1856, an American genus composed by 56 valid species, usually founded in places with grass plants dominace. Some species of genus are considered pests of economic importance. The group is distributed from Canada to Chile, occurring from sea level to almost 4000 meters of altitude, however, no species has a continuous distribution throughout Continent. To develop this work were revised national and foreign entomological collections. More than 5000 specimens were analyzed. Was update the geographical distribution of genus as well as new records were obtained for most species. Was constructed a matrix of morphological characters and analyzed in TNT and Mr. Bayes programs. The final topologies show that Dargida is a polyphyletic genus formed by a sensu stricto group that contains species that will be considered as Dargida (those with more similarity to the type-species), and a group denominated sensu lato minus sensu stricto, formed by species whose morphological characters are different from those of type-species. Due to the results of the phylogenetic analysis, but also to data obtained from morphological analysis, only species of sensu stricto group were included in the revision of genus, the remaining species should be relocated in other generic groups or should be created new genera in which list thouse species.
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The status of the American bollworm, Heliothis armigera (Hubner) (Lepidoptera : Noctuidae), on sunflower in the central TransvaalVon Maltitz, Emil Friedrich January 1992 (has links)
Sunflower production in South Africa has increased four fold since the 1970's. This study was done to elucidate the pest status of Heliothis armigera (Hiibner) on sunflower. Field studies were undertaken at Warmbaths, Brits and Delmas during the summer seasons of 1988/89 to 1990/91. The infestations at the latter two areas were negligible throughout the study period and their statistics have not been included in this thesis. Plant development and oviposition by natural H. armigera populations were found to be correlated as, regardless of planting date, oviposition started at six to seven weeks after planting; when the flowering stage began. A peak in egg numbers was reached by the tenth week with an average for the three seasons at two eggs per plant. The eggs were laid singly on the bracts and bases of the flower buds. A peak in larval numbers was reached at the thirteenth week after planting with the average for the three seasons of 0,4 larvae per plant. The preferred feeding sites were on, between and under the bracts from where the larvae burrow into the pithy tissue of the receptacle. Only six percent of the larvae were found feeding directly on the achenes. Eggs and larvae collected were reared to determine the degree of parasitism. Overall, 19% of the eggs were parasitised; 18% by Telenomus ullyetti Nixon (Scelionidae) and one percent by Trichogrammatoidea lutea (Trichogrammatidae). Larval parasitism at Warmbaths was 23% in 1988/89, 27% in 1989/90 and 34% in 1990/91. Of the parasitised larvae, 44% succumbed to Palexorista prob. laxa (Tachinidae). The remainder were unidentified Braconidae and Ichneumonidae. Predators, such as chrysopids, were observed during the study but their effect on egg and larvae numbers was not studied in detail. A polyhedral virus occurred late in the seasons and caused mortality of the larvae. The low numbers of H. armigera on sunflower, the slight damage to the crop and the reasonably high rate of parasitism, all seem to indicate that H. armigera is not an economica1ly important pest of sunflower and that additional control methods are not justified.
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Behaviour and ecology of the primary parasitoids Cotesia urabae and Dolichogenidia eucalypti (Hymenoptera: Braconidae) and their host Uraba lugens (Lepidoptera: Noctuidae) / by Geoffrey Rowland Allen.Allen, Geoffrey Rowland January 1989 (has links)
Includes bibliography. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, 1989
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The Migration Systems of Helicoverpa punctigera (Wallengren) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in AustraliaRochester, Wayne Allan Unknown Date (has links)
The contemporary view of insect migration is one of a behaviourally distinct form of movement that is an adaptation to temporary habitats. Migratory insects are characterised by a syndrome of behavioural and physiological traits that promote migration. The migration syndromes of particular species are variations on the general syndrome, and depend on both selective pressures from the environment and the evolutionary response that is supported by the genetics of the syndrome traits. The pattern and role of migration in a particular population are determined by the interaction between the environment and the species migration syndrome. Complete understanding of migration in a population therefore requires a combined consideration of the populations environment, migration syndrome and genetics. A recently developed conceptual model of a generalised insect migration system facilitates such a holistic treatment of insect migration. The model is built around four components: the migration arena (the environment); the population trajectory (the changing population demography); the migration syndrome (the traits that implement migration and determine the fitness of migrants); and the genetic complex underlying the migration syndrome. Specific variants of the model can be derived for particular species and locations. The migratory moth species Helicoverpa punctigera (Wallengren) and Helicov-erpa armigera (H¨ ubner) are widely distributed in Australia, and occur in both crop-ping and non-cropping areas. The habitats occupied by the species are often tem-porary and geographically separated. Moths colonise new habitats by long-distance migration. Both species are abundant in the periphery of the continent during summer. In winter, H. punctigera is almost exclusively confined to the far inland, whereas H. armigera mostly remains near the coast. This thesis describes the development and application of conceptual models of the migration systems of H. punctigera and H. armigera in Australia. The model for H. punctigera was used to formulate and test hypotheses on the species population trajectory. That for H. armigera was used to determine the effects of differences between the migration syndromes of the two species on the trajectory. The models incorporated data from empirical models and simulation models developed for selected parts of the migration systems. Bioclimatic models estimated the portion of the continent that is climatically favourable for colonisation by each species in each season. A second type of bioclimatic model estimated the effect of year-to-year variation in habitat quality on the distribution of H. punctigera breeding in the inland. Finally, a simulation model of moth migration estimated the frequency with which wind patterns support various migration pathways. For H. punctigera the portion of the continent predicted to be climatically favourable for breeding tended to cycle between the inland and the periphery, al-though, contrary to observations, central Queensland was predicted to be favourable year-round. In the far inland the winter breeding period was predicted to be sub-stantially shorter in Western Australia than in south-western Queensland. For H. armigera the potential distribution tended to expand and contract around a core area in central Queensland. The probability of H. punctigera breeding at a given site in the far inland during winter was positively correlated with the increase in vegetation greenness at the site between April and July. It was also related to soil and climate variables. Although breeding was predicted to occur more often in some areas than in others, the esti-mated distribution of breeding varied greatly from year to year, and breeding was predicted at any given site in only a minority of years. Validation analyses indicated that the migration model was sufficiently accu-rate for use in characterising the migration system. However, the limited vertical structure present in the available weather data (e.g. representing low-level jets) will prevent the model from confidently forecasting particular migration events. Complete annual cycles of the population trajectory of H. punctigera could be constructed within the limits of the migration arena and the known migration syn-drome. In eastern Australia the cycle included return migration from the eastern cropping areas to the far inland during autumn, as has previously been proposed in the literature. In Western Australia two trajectories were possibleone including spring diapause and a late summer generation in the south-west, and one including a summer generation in the far south-west. Additional trajectories were possible when pupae in spring diapause were assumed to emerge later than has been observed, or when summer quiescence was assumed to be more frequent than would be expected from our currently limited knowledge of its induction. These assumptions enabled H. punctigera to persist throughout the year in the far inland of eastern Australia, but not in that of the west. The conceptual models enabled certain hypotheses on the population trajectories to be tested with existing field and biological data. For other hypotheses they identified data that would enable testing. For a decision on which, if any, of the above H. punctigera trajectories operate in nature, we need more information on the frequency and duration of spring diapause and summer quiescence, plus additional data on breeding activity in parts of Western Australia.
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Behaviour and ecology of the primary parasitoids Cotesia urabae and Dolichogenidia eucalypti (Hymenoptera: Braconidae) and their host Uraba lugens (Lepidoptera: Noctuidae) /Allen, Geoffrey Rowland. January 1989 (has links) (PDF)
Thesis (Ph.D) -- University of Adelaide, Dept. of Entomology, 1989. / Includes bibliography.
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Resposta bioquímica da lagarta da soja ao inibidor de protease benzamidina e seus efeitos no desenvolvimento pós-embrionário / Biochemical answer of the soy caterpillar to the inhibitor of protease benzamidine and its effects in the post-embryonic developmentPilon, Anderson Martins 11 February 2004 (has links)
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Previous issue date: 2004-02-11 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Dos seres vivos existentes, 72% são insetos, sendo que 50% destes são fitófagos. Na coevolução entre plantas e insetos, as plantas desenvolveram mecanismos de defesa contra o ataque de insetos. Dentre estes mecanismos destaca-se a produção de inibidores de protease. É postulado que, quando uma planta é atacada ou ferida, ela propicia um aumento nos níveis de inibidores de proteases na região ferida (resposta local) e ou por toda a planta (resposta sistêmica). Nesta interação inseto-planta, os insetos podem desenvolver mecanismos de defesa contra os inibidores de proteases produzidos pela planta. Esta possibilidade demanda um conhecimento mais elaborado do comportamento das enzimas proteolíticas do intestino médio dos insetos, a partir da ingestão crônica de inibidores de protease no momento do ataque à planta. Plantas de soja atacadas por larvas de Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) induzem, através da via das lipoxigenases, o aumento na síntese de inibidores de proteases, como uma forma de defesa ao ataque do inseto (FORTUNATO, 2001). Este inseto apresenta proteases tripsinas-like como enzimas digestivas (XAVIER, 2002). Tomando conhecimento destas informações e por ser a soja uma importante cultura para a economia brasileira, buscamos realizar a caracterização bioquímica e fisiológica do efeito do inibidor de tripsina benzamidina na digestibilidade protéica, crescimento e desenvolvimento de Anticarsia gemmatalis. Neste sentido, o presente trabalho baseou-se na determinação da digestibilidade e os efeitos no crescimento e desenvolvimento de larvas de A. gemmatalis, assim como a avaliação da atividade das proteases digestivas presentes no intestino médio da lagarta, quando alimentadas com o inibidor de tripsina benzamidina nas concentrações 0; 0,25; 0,50 e 0,75 (% p/p de dieta artificial). Verificamos, através do teste de Tukey (p < 0,05), que a adição de benzamidina alterou significativamente a digestibilidade do alimento proteico. Tal alteração está correlacionada com impactos negativos ocasionados na fase larval desse inseto, tais como aumento do ciclo larval, diminuição de ganho de peso e aumento da mortalidade. Verificamos que tanto a atividade proteolítica quanto a atividade amidásica apresentaram maiores índices em lagartas de 5o instar. Observamos também que a presença do inibidor alterou os perfis de atividades, sugerindo que os insetos, após a ingestão alta de inibidores de proteases, podem apresentar respostas de defesa através da hiperprodução de proteases sensíveis à benzamidina e/ou síntese de proteases insensíveis ao inibidor. Portanto, estes dados sugerem que a utilização de inibidores de protease possa ser uma estratégia promissora no controle de Anticarsia gemmatalis na cultura da soja. / From the existent beings living creatures, 72% are insects, and 50% of these are phytophagous. In the co-evolution between plants and insects, the plants developed defense mechanisms against the attack of insects. Among these mechanisms stand out the production of protease inhibitors. It is postulated that, when a plant is attacked or wounded, it propitiates an increase in the levels of proteases inhibitors in the wounded area (local answer) and or for the whole plant (systemic answer ). In this interaction insect-plant, the insects can develop defense mechanisms against the proteases inhibitors produced by the plant. This possibility demands an elaborated knowledge of the behavior of the proteolytic enzymes of the medium intestine of the insects, starting from the chronic ingestion of protease inhibitors in the moment of the attack to the plant. Soy plants attacked by larvas of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) they induce, through the lipoxigenases way, the increase in the synthesis of proteases inhibitors, as a defense form to the attack of the insect (FORTUNATO, 2001). This insect presents proteases trypsin-like as digestive enzymes (XAVIER, 2002). Becoming aware of these informations and for being the soy an important culture for the Brazilian economy, we tried to accomplish the biochemical and physiologic characterization of the effect of the inhibitor of trypsin benzamidine in the proteic digestibility, growth and development of Anticarsia gemmatalis. In this way, the present work based on the determination of the digestibility and the effects in the growth and development of larvas of Anticarsia gemmatalis, as well as the evaluation of the activity of the present digestive proteases in the medium intestine of the caterpillar, when fed with the inhibitor of trypsin benzamidine in the concentrations 0; 0,25; 0,50 and 0,75 (% p/p of artificial diet). It was verified, through the test of Tukey (p <0,05), that the benzamidine addition altered the digestibility of the proteic food significantly. Such alteration is correlated with negative impacts caused in the larval phase of that insect, such as increase of the larval cycle, decrease of weight gain and increase of the mortality. It was verified that not only the proteolytic activity but also the starch activity presented larger indexes in caterpillars of 5th urge. It was also observed that the presence of the inhibitor altered the profiles of activities, suggesting that the insects, after the high ingestion of proteases inhibitors, they can present defense answers through the hyper-production of sensitive proteases to the benzamidine and/or synthesis of insensitive proteases to the inhibitor. Therefore, these data suggest that the use of protease inhibitors can be a promising strategy in the control of Anticarsia gemmatalis in the culture of the soy. / Dissertação importada do Alexandria
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The biology of Palexorista laxa (Curran) (Diptera : Tachinidae) : an internal larval parasitoid of Heliothis armigera (Hübner) Lepidoptera : Noctuidae)Van Heerden, Desireé January 1993 (has links)
The Tachinid fly, Palexorista laxa (Curran) is an important parasitoid of Heliothis armigera (Hubner) in Africa and India. The biological characteristics of the parasitoid were studied with an emphasis on its host instar preference, host range, seasonality and percentage parasitism. The developmental stages were also studied and described. A high host mortality (48%-100%) due to parasite attack occurred when small larvae were parasitised (2nd & 3rd instars). A preference for the 4th and 5th host instars was shown by the flies. P. laxa was found to be a non-specific parasitoid and parasitised a number of lepidopterous larvae in the laboratory including Busseola fusca (Fuller), Chilo partellus (Swinhoe) and Eldana saccharina Walker, but preferred Ii. armigera. The percentage parasitism on H. armigera in the field was variable peaking at 48% in 1988/89. Of the various parasitoids recorded from H. armigera on sunflower P. laxa was by far the most abundant. Mating occurred immediately after emergence with the males emerging a day earlier than the females. Males were capable of multiple matings whereas females mated only once in a lifetime. P. laxa females produced incubated macrotype eggs which hatched almost immediately after oviposition. The duration of development of the incubated egg and larval stage was 6,7 days, the pupa 10,4 days for females and 9,4 days for males, and the adult lived up to 50 days at 25°C. A reduction in pupal weight, an increase in the duration of the pupal stage and higher pupal mortality accompanied an increase in density of parasitoids per host. A linear relationship was shown between adult mass and number of ovarioles and eggs in P. laxa females. The oviposition period was 26,9 days with a high variation in daily progeny production. The total fertility per female was 126,3 puparia. "Inexperienced" females deposited incubated eggs on all parts of the host body while "experienced" females confined oviposition to the head and thorax. P. laxa females did not discriminate between previously parasitised and non-parasitised hosts. The effect of temperature on larval and pupal survival and development time was studied at 20°, 22°, 25°, 28°and 30°C. As expected, duration of development decreased with an increase in temperature, and there was a reduction in mortality.
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Interações de folhas de soja e algodão com a atividade do vírus de poliedrose nuclear de Chrysodeixis includensBaldo, Gizele Rejane 28 February 2018 (has links)
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Previous issue date: 2018-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os vírus de poliedrose nuclear são importantes agentes de controle microbiano de
larvas de lepidópteros. No entanto, sua atividade pode ser comprometida durante a
interação com suas plantas hospedeiras. Entender como ocorre a interação do vírus
da lagarta Chrysodeixis includens, ChinNPV, com dois de seus hospedeiros, soja e
algodão, pode auxiliar a expandir o uso de pesticidas biológicos amenizando suas
limitações. A interação planta/vírus foi estudada a fim de verificar a influência da
planta sobre o processo de infecção, alterando a forma e o momento em que as
larvas se alimentam desses substratos. Os tratamentos foram: disco de folha,
incorporação de folha (liofilizada e seca em estufa) em dieta, alimentação com
substrato foliar antes da inoculação viral, persistência e exposição do vírus sobre a
planta. As avaliações foram realizadas até o 10º ou 12º dias após a inoculação,
quando foram determinados o peso e o estágio de desenvolvimento de cada
sobrevivente. Os dados de mortalidade foram submetidos à análise de sobrevivência
com riscos competitivos e os demais dados à ANOVA. Alterações histopatológicas
no intestino médio das lagartas alimentadas com folhas de soja e algodão e
inoculadas com o ChinNPV foram analisadas por microscopia de luz. A fixação das
partículas virais foi avaliada através da extração da cera epicuticular com cinco
solventes, seguida de aplicação, lavagem e contagem do vírus remanescentes.
Fixação, morfologia e persistência dos poliedros sobre folhas de soja e algodão, em
ambiente controlado e campo, foram avaliadas por MEV em diferentes períodos. A
mortalidade das lagartas foi comprometida pelo algodão em quase todos os
bioensaios realizados. A inoculação do NPV sobre discos de folha de soja resultou
em mortalidades semelhantes à dieta. No entanto, quando tecidos liofilizados foram
incorporados à dieta, os folíolos de soja reduziram a mortalidade de C. includens por
NPV, com mortalidade análoga à provocada pelo algodão e, quando secos em
estufa, a mortalidade larval foi intermediária, entre o apresentado pela dieta artificial
e as folhas de algodão. Quando o vírus foi exposto na superfície da soja e
posteriormente recuperado, o tempo de contato com a folha (72h) reduziu a
atividade do vírus, o mesmo não foi válido para o algodão. A análise histopatológica
mostrou desestruturação das células epiteliais no tratamento de alimentação prévia
com folha, entretanto este fenômeno não alterou a mortalidade das lagartas.
Enquanto em campo, a distribuição dos poliedros foi uniforme no filoplano das duas
culturas, no laboratório, os poliedros formaram agregados sobre a superfície da soja.
Já quando a cera epicuticular foi removida, a interação da folha com o vírus foi
afetada. A atividade do ChinNPV foi comprometida tanto por folhas de soja quanto
algodão, sendo que a persistência do vírus começa a reduzir após o terceiro dia de
contato com o filoplano. Foi possível observar que a inativação do vírus somente
ocorre quando folha de algodão e vírus são fornecidos em conjunto, enquanto na
soja, o tempo de contato do vírus com a folha parece influenciar reduzindo a
mortalidade das lagartas. Assim, seria interessante estudar formulações e doses
para compensar a perda de atividade viral provocada pelos tecidos foliares. / Nucleopolyhedrovirus are important microbial control agents of lepidopteran larvae.
However, their activity may be compromised during interaction with their host plants.
Understanding the interaction process of the caterpillar virus Chrysodeixis includens,
ChinNPV, with two of its hosts, soybean and cotton, may help to expand the use of
biological pesticides by alleviating their limitations. The plant/virus interaction was
studied in order to verify the influence of the plant on the infection process, changing
the form and the moment in which the larvae feed on these substrates. The
treatments were: leaf disc, incorporation of leaf (lyophilized and oven-dried) in diet,
feeding with leaf substrate before viral inoculation, persistence, and virus exposure
on the plant. Evaluations were carried out until the 10th or 12th days after inoculation,
when the weight and stage of development of each survivor were determined.
Mortality data were submitted to survival analysis with competitive risks and the other
data to ANOVA. Histopathological changes in the midgut of caterpillars fed with
soybean and cotton leaves and inoculated with ChinNPV were analyzed by light
microscopy. Fixation of the virus particles was evaluated by extracting the
epicuticular wax with five solvents followed by the application, washing and counting
of the remaining virus. Fixation, morphology and persistence of the polyhedra on
soybean and cotton leaves, under controlled environment and field, were evaluated
by SEM on different periods. The mortality of caterpillars was compromised by cotton
in almost all bioassays performed. NPV inoculation on soybean leaf discs resulted in
diet-like mortalities. However, when lyophilized tissues were incorporated into the
diet, soybean leaflets reduced the mortality of C. includens by NPV, with mortality
similar to that caused by cotton, and when drying in oven, the larval mortality was
intermediate between that presented by artificial diet and cotton leaves. When the
virus was exposed on the soybean surface and later recovered, the time of contact
with the leaf (72h) reduced the activity of the virus; the same was not true for cotton.
The histopathological analysis showed disruption of epithelial cells in treatments of
previous leaf feeding; however, this phenomenon did not change the mortality of
caterpillars. While in the field, the polyhedra distribution was uniform on the
phylloplane of the two cultures, in the laboratory, the polyhedra formed aggregates
on the surface of the soybean. Already when the epicuticular wax was removed, the
interaction of the leaf with the virus was affected. The activity of ChinNPV was
compromised by both soybean and cotton leaves, and the persistence of the virus
begins to decrease after the third day of contact with the phylloplane. It was possible
to observe that the inactivation of the virus only occurs when cotton leaf and virus are
supplied together, while in soybean, the time of contact of the virus with the leaf
seems to influence, reducing the mortality of the caterpillars. Thus, it would be
interesting to study formulations and doses to compensate for the loss of viral activity
caused by foliar tissues.
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