Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 16, 2010). Includes bibliographical references. Also issued in print.

The gregarious pupal endoparasitoid, Tetrastichus howardi Olliff (Hymenoptera: Eulophidae), was introduced into South Africa as a biocontrol agent against the maize and the sorghum stem borers, Busseola fusca Fuller and Chilo partellus Swinhoe. Preovipositional behaviour, ovipositional behaviour, development, fertility, sex-ratio, and longevity were studied in the laboratory. A complex courtship behaviour was observed, however 35.3% of females were mated before emergence from the host pupa. Preoviposition period ranged from 100 mins up to 5 days. Host searching time in Petri dishes was shorter for lepidopteran pupae than for their parasitoid pupae, and shortest when T. howardi had previously experienced the host. Duration of oviposition was significantly longer in the lepidopteran pupae than in the smaller tachinid puparia. T. howardi showed no difference in preference for hosts of different ages. The lepidopteran hosts were preferred to their parasitoids. If T. howardi had previously experienced a certain host its pereference for that host tended to increase, but not significantly. When reared on a certain host, the preference for that host did increase. The parasitoid was able to discriminate between parasitzed and unparasitzed pupae although this ability developed only 2 days after the pupa was parasitized. Cotesia sesamiae Cameron, the main indigenous parasitoid of B. fusca and C. partellus, was not attacked by T howardi. The total duration of development from egg deposition to the adult stage ranged from 18 to 26 days at 24°C and 60% RH. Emergence of adults began after first light, mean emergence time in winter being 09h00. Emergence rate of T. howardi from parasitized hosts, and mortality rate of parasitized hosts, was higher for C. partellus and H. armigera than for Eldana saccharina Walker and Palexorista laxa Curran. This decreased for C. partellus and H. armigera when superparasitized. A strong correlation existed between total parasitoids emerging from a host and percentage of females. When a lepidopteran pupa was parasitized by a single T. howardi female, 55 progeny emerged of which 94% were females. Larger females showed greater fertility and also produced a higher percentage of females. Younger hosts were more suitable for development of T. howardi. Females lived for 5.4 to 52.5 days, and males lived for 3.1 to 28.6 days, depending on presence or absence of food, water and hosts. Reasons for releasing T. howardi in the field are discussed. Only 2 recoveries of parasitized C. partellus pupae were made from the field.

Made available in DSpace on 2015-03-26T13:39:52Z (GMT). No. of bitstreams: 1 texto completo.pdf: 372648 bytes, checksum: cd5ac829f35876d55f37150e845599f9 (MD5) Previous issue date: 2012-07-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The family Cucurbitaceae presents dicotyledonous plants with food, economic and social importance. Diaphania hyalinata (Linnaeus, 1758) (Lepidoptera: Crambidae) can reduce yield by damaging leaves and fruits of these plants. This pest is controlled primarily with chemical insecticides, but less aggressive methods are been studied. The aim was to evaluate the development of Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae), the effects of density on parasitism age of the pupae of D. hyalinata on reproduction of the parasitoid, besides evaluating the toxicity of both essential oils and the commercial product Azamax® on eggs, larvae and pupae of this pest. The experiments were developed at the Laboratory of Biological Control of Insects (LCBI) of the Institute of Biotechnology Applied to Agriculture (BIOAGRO) of the University Federal of Viçosa (UFV) in Viçosa, Minas Gerais. In the first study, reproductive aspects of T. diatraeae were evaluated. Ten 48 hours old D. hyalinata pupae were individualized and exposed to parasitism by ten females of this parasitoid during 24 hours. The parasitism and emergence of the progeny was 100% and 90% respectively. Duration of the life cycle of T. diatraeae was 19.11 ± 0.11 days with 167.78 ± 23.79 offspring per pupae and sex ratio of 0.94 ± 0.01. The second study (parasitoid density and age of pupae) had 12 replications per treatment. Pupae of D. hyalinata were exposed to different densities of T. diatraeae (1:1, 4:1, 8:1, 12:1, 16:1, 20:1 and 24:1) females for 24 hours. Parasitoid density did not affect percentage of parasitism and emergence of T. diatraeae. Increasing density of T. diatraeae reduced progeny, sex ratio, longevity and width of head capsule of females and males of this parasitoid. The duration of the life cycle of T. diatraeae was proportional to density increased of its females. The effect of pupae age was assessed with isolating them with different ages (24, 48, 72, 96, 120 and 144h) and being exposed for 24 hours to eight parasitoids each. Age of D. hyalinata pupae did not affect percentage of emergence, parasitism, sex ratio and longevity of T. diatraeae females and males. Increasing pupae age reduced offspring, life cycle and head capsule of T. diatraeae. In the third study, each development stage of D. hyalinata received different concentrations of essential oils of cinnamon, clove, orange and the Azamax® product (0.25% to 25%) dissolved in acetone and the control with only, acetone. Paper disks containing 20 eggs were sprayed with each material on four disks per treatment each representing a replication. Squash leaves were immersed pretreatment and provided to third instar D. hyalinata caterpillars of with four replications of 10 larvae each. Moth pupae were immersed for five seconds in each treatment, with four replications of 10 pupae each. The LC50 was 1.70, 0.97, 40.08 and 1.18 μL/ml for eggs, 14.07, 48.92, 90.31 and 6.18 μL/ml for pupae and LC90 was 6.17, 2.38, 648.50 and 15.67 μL/ml for eggs and 269.06, 642.23, 1079.63 and 16.08 μL/ml for pupae, respectively, with cinnamon, clove and orange oils and Azamax®. The toxicity of cinnamon and clove oils had values for LC50 of 10.82 and 18.75 μL/ml respectively and for the LC90 of clove oil (46.21 μL/ml) and cinnamon (37.21 μL/ml) were estimated for caterpillars of D. hyalinata due to the low mortality on the other treatments. Trichospilus diatraeae parasitized and produced offspring in pupae of D. hyalinata and have the potential to control pupae of this insect. Pupae age is not discriminate by this the parasitoid and up to eight parasitoids per pupae are favorable for its development. The commercial product Azamax® has potential to control this pest. The cinnamon oil was more toxic for larvae and pupae and clove oils more toxic to eggs of D. hyalinata. / Cucurbitaceae apresenta plantas dicotiledôneas com importância alimentícia, econômica e social. Diaphania hyalinata (Linnaeus, 1758) (Lepidoptera: Crambidae), pode causar perdas na produção por danos à folhas e frutos e se destaca entre as pragas dessa família. Seu controle é realizado principalmente com inseticidas químicos, porém métodos menos agressivos ao ambiente vem sendo estudados. O objetivo deste trabalho foi avaliar o desenvolvimento de Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae), o efeito da densidade de parasitismo e da idade da pupa na reprodução desse parasitoide no hospedeiro natural D. hyalinata, além de avaliar a toxicidade de óleos essenciais e do produto comercial Azamax® nas fases de ovo, lagarta e pupa dessa praga. Os experimentos foram realizados no Laboratório de Controle Biológico de Insetos (LCBI) do Instituto de Biotecnologia Aplicada a Agropecuária (BIOAGRO) da Universidade Federal de Viçosa (UFV) em Viçosa, Minas Gerais. No primeiro estudo, aspectos reprodutivos de T. diatraeae foram avaliados. Dez pupas de D. hyalinata com 48 horas de idade foram individualizadas e expostas ao parasitismo por dez fêmeas do parasitoide, cada uma, por 24 horas. O parasitismo e a emergência de progênie foram de 100% e 90%, respectivamente. A duração do ciclo de vida de T. diatraeae foi de 19,11 ± 0,11 dias com 167,78 ± 23,79 descendentes por pupa e razão sexual de 0,94 ± 0,01. No segundo estudo, cada tratamento (densidade de parasitoide e idade de pupa) teve 12 repetições. Pupas de D. hyalinata foram expostas a diferentes densidades de fêmeas de T. diatraeae (1:1, 4:1, 8:1, 12:1, 16:1, 20:1 e 24:1) por 24h. A densidade do parasitoide não afetou a porcentagem de parasitismo e a emergência de T. diatraeae. O aumento da densidade de T. diatraeae reduziu a progênie, razão sexual, longevidade e a cápsula céfalica de fêmeas e machos desse parasitoide. A duração do ciclo de T. diatraeae foi proporcional ao aumento da densidade de suas fêmeas. O efeito da idade de pupas foi avaliado com estas isoladas com diferentes idades (24, 48, 72, 96, 120 e 144h) e expostas por 24h a oito parasitoides cada uma. A idade das pupas de D. hyalinata não afetou a porcentagem de emergência, o parasitismo, a razão sexual e a longevidade (fêmeas e macho) de T. diatraeae. O aumento da idade das pupas reduziu a descendência, ciclo de vida e a cápsula cefálica de T. diatraeae. No terceiro estudo, cada fase do desenvolvimento de D. hyalinata recebeu diferentes concentrações de óleos essenciais (canela, cravo, laranja) e do produto Azamax® (variando de 0,25% a 25%) diluídos em acetona e o controle teve, apenas, acetona. Discos de papel com 20 ovos foram pulverizados com cada material, utilizando-se quatro discos por tratamento, cada um representando uma repetição. Discos de folhas de abóbora foram imersos em cada tratamento e oferecidos às lagartas no terceiro estádio de D. hyalinata, com quatro repetições de 10 lagartas cada. Pupas dessa praga foram imersas por cinco segundos em cada um dos tratamentos, com quatro repetições de 10 pupas cada. As CL50 de 1,70; 0,97; 40,08 e 1,18 μL/ml para ovos, e 14,07; 48,92; 90,31 e 6,18 μL/ml para pupas e CL90 de 6,17; 2,38 e 648,50 e 15,67 μL/ml para ovos e 269,06; 642,23; 1079,63 e 16,08 μL/ml para pupas respectivamente, foram estimados para os óleos de canela, cravo, laranja e do produto Azamax®. Apenas a toxidade dos óleos de canela e cravo com valores para CL50 de 10,82 e 18,75 μL/ml respectivamente e CL90 para os óleos de cravo (46,21 μL/ml) e canela (37,21 μL/ml) foram estimados para lagartas de D. hyalinata devido à baixa mortalidade nos outros tratamentos até o tempo avaliado. Trichospilus diatraeae parasitou e produziu progênie em pupas de D. hyalinata e apresenta potencial para seu controle por não discriminar pupas por idade e até oito parasitoides por pupa são favoráveis para o desenvolvimento desse parasitoide. O produto comercial Azamax® mostrou potencial para o controle dessa praga. O óleo de canela foi mais tóxico nas fases de lagarta e pupa e o de cravo mais tóxico para ovos de D. hyalinata.