Made available in DSpace on 2014-06-11T19:28:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-10Bitstream added on 2014-06-13T18:57:45Z : No. of bitstreams: 1 camillo_mf_me_jabo.pdf: 459342 bytes, checksum: 91a470a114ea0b0b91c4435f01edec49 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Usina São Martinho / A broca da cana-de-açúcar Diatraea saccharalis (Fabricius, 1794), destaca-se como a principal praga da cultura da cana-de-açúcar e dependendo do nível de infestação, pode causar sérios prejuízos financeiros a produtores. O sucesso no seu controle depende de estudos comportamentais das variedades e avaliação de seu parasitismo, principalmente por Cotesia flavipes (Cameron, 1891). Assim o objetivo da presente pesquisa foi verificar a infestação e os danos causados por D. saccharalis e seu parasitismo por C. flavipes em duas idades de corte das plantas em variedades de cana-de-açúcar. O experimento foi conduzido na Usina Laguna, localizada no município de Batayporã no Estado do Mato Grosso do Sul. O delineamento experimental utilizado foi em parcelas subdivididas, com 5 variedades, RB86-7515, SP81-3250, RB85-5453, SP80-1842 e RB82-5211 duas idades de corte, cana planta e cana soca de segundo corte e 4 repetições, dispostas em blocos casualizados, aplicando as variedades nas parcelas e as idades de corte nas subparcelas. Foram avaliadas a porcentagem e intensidade de infestação, porcentagem de danos no colmo, população da broca por hectare e a porcentagem de parasitismo. Pelos resultados obtidos conclui-se que as variedades menos atacadas por D. saccharalis foram SP81-3250 e RB92-5211; a variedade mais atacada por D. saccharalis foi SP80-1842; as liberações de C. flavipes incrementaram o parasitismo na área; o aumento da porcentagem de parasitismo proporcionou redução na população da broca; e o parasitismo independe da idade de corte da cana-de-açúcar / In the culture of sugar cane, and all, there are pests that directly affect production. The sugarcane borer Diatraea saccharalis (Fabricius, 1794), stands out as the main and depending on the level of infestation, can cause serious financial losses to producers. The success in controlling this pest depends on behaviour studies of varieties and evaluation of their parasitism, mainly by Cotesia flavipes (Cameron, 1891). Thus the aim of this research was to verify the infestation and the damage caused by D. saccharalis and its parasitism by C. flavipes in two plant ages in varieties of sugar cane. The experiment was conducted at the Laguna Plant, located in Batayporã borough in Mato-Grosso-do-Sul state. The varieties used in the experiment were RB86-7515, SP81-3250, RB85-5453, SP80-1842 and RB82-5211 conducted in plots of 10 080 m2, repeated four times, adopting the split plot design, applying the varieties in the plots and subplots cutting ages. It was evaluated the rate and intensity of infestation, percentage of damage in the stem borer population per hectare and percentage parasitism. By the results it is concluded that varieties less attacked by D. saccharalis were SP81-3250 and RB92-5211, the variety most attacked by D. saccharalis was SP80-1842, an increase of the parasitism decreased the population of the drill, the release of C. flavipes increased the parasitism the area, and the parasitism is independent of the sugar cane cut age

Conura torvina (Cresson) (Hymenoptera: Chalcididae) is a solitary pupal endoparasite of numerous insect species. In Brassica crops it acts as a parasite of Plutella xylostella (L.) (Lepidoptera: Plutellidae) and was found as a hyperparasite of Cotesia rubecula (Marshall) (Hymenoptera: Braconidae) and several other parasitoid species. Cotesia rubecula was introduced into Virginia in 1987 as a biological control agent for Pieris rapae (L.) (Lepidoptera: Pieridae), and because C. torvina was thought to have eliminated this population of C. rubecula, studies of C. torvina's reproductive biology and behavior were initiated. A study using plants laden with "trap hosts" to detect C. torvina activity in the spring indicated no activity until late June, but proved trap host sampling to be an efficient and effective method of monitoring C. torvina activity. Studies of C. torvina's ability to reproduce in C. rubecula pupae of different ages indicated that C. torvina can successfully parasitize pupae at all stages of development, but was most successful in young to middle aged pupae. Studies of C. torvina's host species preference indicated the larger host species such as P. xylostella were preferred. Equal numbers of P. xylostella and C. rubecula were parasitized, but a greater proportion of fertile eggs were laid in P. xylostella. Smaller host species were often ignored. Host dissection studies indicated that caged C. torvina were inefficient at host finding and oviposition. Superparasitism was common, but declined as the females gained oviposition experience. Experienced C. torvina produced an average of 8.25 progenies per day for a period of 12 days when provided with 13 P. xylostella hosts each day. Conura torvina produced up to 14 progenies a day when provided 3 26 hosts. Dissection of C. torvina ovaries indicated three ovarioles per ovary with a mean of 9.2 and maximum of 15 mature eggs per female. Host dissection indicated that a mean of 18 and maximum of 30 eggs could be laid per day. New eggs were produced as oviposition occurred. Significantly larger eggs were laid in P. xylostella than in C. rubecula, and significantly more eggs were laid in C. rubecula than in P. xylostella. From these data and data from earlier studies I concluded that C. torvina has a poor reproductive ability and its impact as a hyperparasite is limited to the summer months. This makes C. torvina an unlikely cause of C. rubecula's disappearance. / Ph. D.

Prior exposure to plants cues can enhance assortative mating in insects. We hypothesized that, as previously reported for females, males of Cotesia congregata would display inherent responses to plant cues that could be modified by postemergence experience and further, that males originating from two different host-plant complexes (HPCs) would display different behavioral responses to these HPCs. In no-choice contact assays with a non-host plant, searching responses of males and females increased sharply at Day 2 and remained stable through Day 4. In no-choice assays with potential host plants, males searched longer on catalpa than tobacco; responses were not modified by postemergence experience. In choice assays with both HPCs, naïve males did not display orientation preferences; however, males experienced with their natal plant preferred their natal HPC. Results indicate that postemergence experience on the natal host plant induces an orientation preference for the natal HPC and thus, can facilitate assortative mating.

The catalpa sphinx, Ceratomia catalpae, is a specialist on Catalpa trees, which produce iridoid glycosides (IGs). Whereas some trees are defoliated every year, others escape herbivory. Caterpillar populations are either heavily parasitized by the braconid wasp, Cotesia congregata, or remain unparasitized. We hypothesized that these patterns could be explained by variable IG concentrations among trees and insect responses to these chemicals. IG concentrations varied among trees. Percent defoliation was positively related to IG concentration. In comparisons of insect responses to relatively high or low IG concentrations, moths preferred to oviposit on trees with high IG concentrations. Caterpillars did not display a feeding preference nor did wasps differ in searching responses to leaf discs with high or low IG concentrations. Results indicate that observed patterns of herbivory can be explained by moth oviposition preferences for trees with high IG concentrations.

Among the predicted impacts associated with global climate change, warming is of special interest because the rates of physiological processes are temperature-dependent. Insects and other ectotherms are likely to be affected due to their limited ability to control body temperature. In this study, I measured the tolerance to extreme high temperatures, i.e., critical thermal maximum (CTmax), of component species in a tri-trophic system, including an herbivore (Manduca sexta), a primary larval parasitoid (Cotesia congregata) and a hyperparasitoid (genus Silochalcis). For wild insects, the parasitoid had the lowest CTmax, the hyperparasitoid had the highest, and the herbivore was intermediate. For laboratory insects, the parasitoid had a lower CTmax than the herbivore. Results suggest that laboratory colonies can be used to predict relative thermal performance of interacting species in the field. Variations in tolerance to high temperature among component species could disrupt the outcome of interactions in multi-trophic systems.

Includes bibliographical references (leaves 204-230). Investigates the behaviour and ecology of the two major larval parasitoids of the diamondback moth, Plutella xylostella; Cotesia plutellae and Diadegma semiclausum.

Includes bibliographical references (leaves 204-230). / xvi, 230 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the behaviour and ecology of the two major larval parasitoids of the diamondback moth, Plutella xylostella; Cotesia plutellae and Diadegma semiclausum. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001

A three-year field experiment was conducted to evaluate the tolerance and compensatory response of rice (Oryza sativa L.) to injury caused by the sugarcane borer, Diatraea saccharalis (F.). Two mechanisms of within-plant tolerance/compensation were observed. Stem injured plants produced ca. 0.69 more tillers than uninjured plants, while tillers with leaf and leaf sheath injury produced larger panicles, up to 39.5% and 21.0% heavier than uninjured tillers, when injury occurred at 3rd tiller stage and at panicle differentiation, respectively. A 2-year field cage experiment was conducted to determine the biological control potential of Cotesia flavipes (Cameron) against the sugarcane borer on rice. The effective search rate was 49 cm2 ground area (2.2 tillers) parasitoid-1 day-1. A cohortbased age-structured model was developed to simulate the population dynamics and economic value of the sugarcane borer and C. flavipes in rice, as affected by overwintering larval density, timing and rate of parasitoid aerial release, and year-to-year climate (temperature and rainfall). The results suggest C. flavipes was most effective when released during the 1st sugarcane borer generation. The maximum simulated economic benefit ($112.05 ha-1) was ca. 7.8% of that provided by insecticide-based control. The inability of C. flavipes to provide economic control in temperate-subtropical areas is due to its high rearing cost, a low effective search rate, a low maximum rate of parasitism per female, and both spatial and temporal asynchrony of parasitoid emergence with the larval hosts. The biocontrol capability of Trichogramma galloi Zucchi was also simulated. The maximum economic benefit provided by T. galloi was $1128.75 ha-1, ca. 79.0% of that provided by insecticide-based control. Theoretical analyses were conducted to estimate the effectiveness of augmentative releases, using data from previous studies of parasitism of lepidopteran pests by hymenopteran parasitoids with host and parasitoid density as factors. The maximum daily parasitism per female was highest for parasitoids that attack exposed larvae, followed by parasitoids that attack eggs, semi-exposed larvae, and concealed larvae. Simulation analyses were conducted to estimate the population dynamics and economic value of D. saccharalis, herein used as a model host, and each of 5 parasitoid categories (solitary parasitoids that attack eggs, exposed larvae, and semi-exposed larvae, gregarious parasitoids that attack eggs and concealed larvae) in rice, as affected by overwintering larval density, timing of parasitoid release, and year-to-year climate. Among the 13,500 simulations that were conducted, 480 (3.6%) provided a greater economic value than insecticide-based control. All 480 simulations were obtained using solitary parasitoids that attack exposed or semi-exposed larvae. Solitary egg parasitoids provided an average of 42.2% of the economic value provided by insecticide-based control when released 30 days after planting. Gregarious parasitoids that attack eggs or concealed larvae provided almost no positive economic benefit. For parasitoid species that do not overwinter successfully in areas where they are released or that exhibit temporal or spatial asynchrony with their host early in the spring, our results suggest augmentative biological control is only effective for solitary parasitoids that attack either exposed or semi-exposed larvae, with current rearing, shipping and release costs.

Includes bibliographical references (leaves 204-230). / xvi, 230 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the behaviour and ecology of the two major larval parasitoids of the diamondback moth, Plutella xylostella; Cotesia plutellae and Diadegma semiclausum. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001

Made available in DSpace on 2014-06-11T19:31:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-21Bitstream added on 2014-06-13T20:02:57Z : No. of bitstreams: 1 viel_sr_dr_jabo.pdf: 828115 bytes, checksum: b974e906f04ebb44b4d4434000bd82f4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Visando melhorias qualitativas na criação de Cotesia flavipes Cameron, 1891, realizaram-se testes com alimentação de adultos antes do parasitismo em Diatraea saccharalis Fabricius,1794, com 14 dietas: (2,5%; 5% e 10% sacarose; 2,5%; 5% e 10% sacarose + 2,5% lêvedo de cerveja; 2,5%; 5% e 10% mel; 2,5%; 5% e 10% mel + 2,5% lêvedo de cerveja; 2,5% lêvedo de cerveja; água) e testemunha. Avaliaramse: adultos emergidos, razão sexual, porcentagem de emergência, peso das massas de pupas e a longevidade nas gerações F1 e F2. O delineamento foi o inteiramente casualizado com 15 tratamentos e cinco repetições. As dietas a base de 5% de sacarose, 5 e 10% de mel aos adultos de C. flavipes podem proporcionar acréscimo considerável na longevidade dos parasitoides. O consumo de dietas artificiais por C. flavipes antes do parasitismo em D. saccharalis proporcionou melhorias qualitativas. O estudo visou ainda testar um protocolo de qualidade de C. flavipes, quanto à eficiência na busca pelo hospedeiro D. saccharalis. Foi usada uma arena de testes (copo plástico translúcido de 700 mL, com tampa). Lagartas de D. saccharalis foram colocadas em tolete de cana-de-açúcar de 13 cm, perfurado transversalmente e oferecidas ao parasitoide. Os tratamentos foram: (0, 6, 12, 18 e 24 horas de fotofase - L), (6, 12, 18 e 24 horas de disponibilidade do hospedeiro - H), (1, 2, 3, 4 e 5 lagartas por arena - T) e o orifício de entrada da lagarta na cana-de-açúcar (aberto - A ou fechado - F). Foram realizados os testes de Kolmogorov e a homogeneidade da variância foi analisada pelo teste de Bartlett, além das análises de agrupamento e de componentes principais. Foi criado um Índice de performance da qualidade (IPQ), que foi determinante na escolha do melhor tratamento. Foi proposto, o uso do tratamento: 6 horas de disponibilidade... / Aiming at qualitative improvements in the rearing of Cotesia flavipes, tests were carried out with adults feed before parasitism in Diatraea saccharalis, with 14 diets (2.5%, 5% and 10% sucrose, 2.5%, 5% and 10% sucrose + 2.5% brewer's yeast, 2.5%, 5% and 10% honey, 2.5%, 5% and 10% honey + 2.5% yeast, 2.5% yeast, water) and control. Were evaluated: emerging adults, sex ratio, percentage of emergency, mass weight of pupae, and longevity in F1 and F2 generations. The design was completely randomized with 15 treatments and five repetitions. The diets based on 5% sucrose, 5 and 10% honey to adults of C. flavipes, may provide considerable increase in longevity. Consumption of artificial diets by C. flavipes before parasitism in D. saccharalis provides quality improvements. The study also aimed to test a protocol for quality of C. flavipes, for efficiency in the search for host D. saccharalis. We used a testing arena (700 mL plastic cup with lid). Larvae of D. saccharalis were placed in 13 cm cutting canes, drilled across, and offered to the parasitoid. The treatments were: (0, 6, 12, 18 and 24 hours of photophase - L) (6, 12, 18 and 24 hours of availability of the host - H) (1, 2, 3, 4 and 5 larvae per arena - T) and the entrance hole of the larvae in sugar cane (open - A or closed - F). We performed the Kolmogorov´s test and the homogeneity of variance was analyzed by Bartlett's test. Were also carried out cluster analysis and principal components. It created an index of performance quality (IPQ). It is proposed the use of treatment 6 hours of availability, 0 hours of light, one larvae per arena, using the cutting cane with the hole closed, as quality protocol C. flavipes