O sul de Minas Gerais é a principal região produtora de morangos (Fragaria x ananassa Duch.) no Brasil. O ácaro-rajado, Tetranychus urticae Koch (Acari: Tetranychidae), é considerado uma das principais pragas do morangueiro no Brasil e em vários países. Uma prática importante na cultura do morango refere-se à cobertura de solo, usualmente realizada com filme de polietileno, porém além de ser caro gera resíduos muito persistentes no ambiente. Objetivou-se com este trabalho comparar a resistência de oito genótipos de morango (\'Albion\', \'IAC Guarani\', \'IAC Princesa Isabel\', \'Oso Grande\', IAC T-0104, IAC 12, IAC 4 e IAC 1.13) ao ácaro-rajado; determinar o efeito da cobertura de solo (com a polpa de café desidratada, conhecida como palha de café) nas pragas/ patógenos e ácaros predadores desta cultura; comparar a ocorrência de pragas, patógenos e inimigos naturais entre um cultivo orgânico e outro convencional de morango. Os resultados obtidos indicaram que \'IAC Princesa Isabel\', IAC T-0104 e IAC 12 são resistentes, IAC 1.13 e IAC 4 apresentam resistência moderada e \'IAC Guarani\', \'Oso Grande\' e \'Albion\' são suscetíveis ao ácaro-rajado. \'Oso Grande\' e \'Albion\' são bastante utilizadas pelos produtores do sul de Minas Gerais. O uso de palha de café aumentou o número de predadores edáficos, tanto no solo dos canteiros (campo) e em vasos (laboratório) como em folíolos de morangueiro. O Gamasina Proctolaelaps pygmaeus (Müller) (Melicharidae) foi visto sobre morangueiros, principalmente no período noturno. Maior número de ácaro-rajado e maior severidade de doenças foram observados em plantas cultivadas em solo coberto com polietileno. Além disso, foi maior o nível de infecção de ácaro-rajado pelo fungo Neozygites floridana (Weiser e Muma) em plantas cultivadas em solo coberto com palha de café. Não foi observada diferença significativa entre a produtividade da cultura em solo coberto com polietileno e em solo coberto com palha seca de café. Os resultados da comparação da ocorrência de ártropodes e patógenos entre sistema orgânico e convencional mostraram menor ocorrência de ácaro-rajado e predadores em cultivo de morangueiro convencional, porém ocorrência considerável de tripes, mosca-branca e mofo cinzento. A incidência de dendrofoma e mancha de pestalotia foi a mesma nos dois sistemas de cultivos. Os resultados sugerem a conveniência de se continuar o processo de desenvolvimento dos genótipos que se mostraram menos afetados pelo ácaro-rajado, para que estes possam no futuro ser utilizados pelos produtores, e a condução de estudos complementares, que avaliem o desempenho de cultivos em sistema orgânico que incorporem o uso da palha de café para a cobertura do solo. / The southern of Minas Gerais is the main region producing strawberries (Fragaria x ananassa Duch.) in Brazil. The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is considered one of the main strawberry pests in Brazil and in several countries. An important practice in strawberry cultivation refers to soil cover, which is usually made with polyethylene film, but it is expensive and generates very persistent residues in the environment. The objective of this study was to compare the resistance of eight strawberry genotypes (\'Albion\', \'IAC Guarani\', \'IAC Princesa Isabel\', \'Oso Grande\', IAC T-0104, IAC 12, IAC 4 and IAC 1.13); to determine the effect of soil cover (with dehydrated coffee pulp, known as coffee straw) on the pests mites/ pathogens and predatory mites of this crop; to compare the occurrence of pests, pathogens and natural enemies between an organic and a conventional strawberry crop. The results indicated that \'IAC Princesa Isabel\', IAC T-0104 and IAC 12 are resistant, IAC 4 and IAC 1.13 are moderately resistant, and \'IAC Guarani\', \'Oso Grande\' and \'Albion\' are susceptible to the two-spotted spider mite. \'Oso Grande\' and \'Albion\' are widely used by producers in the southern of Minas Gerais. The use of coffee straw increased the number of edaphic predators, both in the soil beds (field) and in pots (laboratory) as well as in strawberry leaflets. The Gamasina Proctolaelaps pygmaeus (Müller) (Melicharidae) was seen on strawberry leaftlets, mainly in the nocturnal period. Higher numbers of the two-spotted spider mites and disease severity were observed in plants grown on soil covered with polyethylene. In addition, the level of the two-spotted spider mite infected by the fungi Neozygites floridana (Weiser and Muma) was higher in plants cultivated in soil covered with coffee straw. No significant difference was observed between yield in soil covered with polyethylene and in soil covered with dry coffee straw. The results of the comparison of the occurrence of arthropods and pathogens between the organic and conventional systems showed fewer occurrences of the two-spotted spider mites and predators in conventional strawberry cultivation, but considerable occurrence of thrips, whitefly and gray mold. The incidence of dendrophoma and leaf spots caused by pestalotia was the same in both cropping systems. The results suggest the convenience to continue the development process of the genotypes that were less affected by the two-spotted spider mite, which could be used in the future by producers, and the conduction of complementary studies to evaluate the performance of crops in organic system that incorporate the use of coffee straw as soil coverage.

Master of Science / Department of Entomology / John C. Reese / The soybean aphid, Aphis glycines Matsumura, is a pest of soybean, Glycine max (L.) Merr. Studies to find control methods were initiated in 2000 when it was first detected in the United States. Aphis glycines can reduce yields by as much as 50%, and vectors several viral diseases. Plant resistance to A. glycines is one important component of integrated control. In the first study, reproduction of A. glycines was compared on 240 soybean entries. Eleven had fewer nymphs produced compared with two susceptible checks (KS4202 and Pioneer® 95B15). Antibiosis and antixenosis were assessed in no-choice and choice tests, respectively. Nine entries showed moderate antibiosis and the other two (K1639 and Pioneer® 95B97) showed strong antibiosis and antixenosis as categories of resistance to A. glycines. In the second study, chlorophyll loss was estimated in no-choice tests on infested and uninfested leaves of KS4202. The minimum combined number to detect significant chlorophyll loss was 30 aphids confined for 10 days. Using this number, seven resistant entries found in the first study were evaluated. There was no significant chlorophyll reduction between infested and uninfested leaves of five of the resistant entries (K1621, K1639, 95B97, Dowling and Jackson). Jackson and Dowling had a significantly lower percentage loss than the susceptible checks. In the third study, assessment of feeding behavior of A. glycines was compared and recorded for 9 h on four resistant entries and KS4202. The average time needed to reach the first sieve element phase by A. glycines was 3.5 h in KS4202 while in the resistant entries it was 7.5 h, and the total duration in this phase was longer than an hour in KS4202, and only two to seven minutes in the resistant entries. These data suggest that phloem tissues in the resistant plants change feeding behavior. However, aphids first reached the xylem phase and then the sieve element phase, and the time that aphids spent ingesting xylem sap was not different among all entries; therefore, it is possible that xylem sap in the resistant entries may contain toxic substances that alter aphid behavior and restrain further activities on the sieve element phase.

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Submitted by (edna.saturno@ufrpe.br) on 2016-11-24T14:16:11Z No. of bitstreams: 1 Felipe Colares Batista.pdf: 401499 bytes, checksum: 66c8054daa99b1513bf4eeb2b13516c0 (MD5) / Made available in DSpace on 2016-11-24T14:16:11Z (GMT). No. of bitstreams: 1 Felipe Colares Batista.pdf: 401499 bytes, checksum: 66c8054daa99b1513bf4eeb2b13516c0 (MD5) Previous issue date: 2011-02-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of brassicas throughout the world. Prospective results toward DBM manage in cabbage have been achieved using host plant resistance and biological control. However, host plant characteristics conferring resistance against herbivores might also affect their natural enemies. Thus, this work evaluated the influence of red and green (Chato-de-quintal) cabbages on the biology and oviposition preference of P. xylostella and the interaction with the larval-pupal parasitoid Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae). Based on life history parameters for DBM, green cabbage was less favorable compared to red cabbage by delaying larval and pupal stages, and reducing female fecundity. However, under free choice tests for oviposition, DBM females preferred to lay eggs on green than red cabbage. Tests in olfactometer, isolating the color effect of the host plant, however, resulted in similar moth attraction between green and red cabbage. Foraging of O. sokolowskii females was similar on both cabbage cultivars infested with DBM larvae under large cage free choice tests. Furthermore, similar number of parasitized larvae, total number of emerged parasitoids, and adult female parasitoid longevity were found for DBM larvae reared on both cabbage cultivars under laboratory conditions. However, the period from parasitism to adult parasitoid emergence was one day shorter and a higher number of parasitoids produced per parasitized larva was achieved when parasitizing larvae reared on green cabbage. In conclusion, the results indicate a positive association of host plant resistance with the parasitism of O. sokolowskii to manage DBM and suggest that the cabbage color plays an important role on host preference for oviposition by the pest. / A traça-das-crucíferas, Plutella xylostella (L.) (Lepidoptera: Plutellidae), é considerada a principal praga das brássicas em todo o mundo. Resultados promissores para o manejo desta praga têm sido alcançados com o uso de cultivares resistentes e controle biológico. Entretanto, sabe-se que características conferindo resistência às plantas não afetam somente os herbívoros, mas também os inimigos naturais associados a eles. Assim, esse trabalho avaliou a influência das cultivares de repolho Roxo e Verde (Chato-de-quintal) na biologia e na preferência para oviposição de P. xylostella, e o efeito no desempenho do parasitóide Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae). Com base nos parâmetros da tabela de vida, a cultivar Chato-de-quintal mostrou-se menos favorável para o desenvolvimento de P. xylostella, por ocasionar maior duração das fases de larva e pupa e redução na fecundidade das fêmeas em relação a cultivar Roxo. Entretanto, a cultivar Chato-de-quintal foi a mais preferida por P. xylostella para oviposição em comparação a cultivar Roxo. Testes de livre escolha das mariposas em olfatômetro, isolando a coloração do hospedeiro, resultaram em semelhança de escolha entre repolho Roxo e Verde. O forrageamento de fêmeas de O. sokolowskii em plantas de ambas as cultivares infestadas com larvas da traça-das-crucíferas em testes de livre escolha foi similar. Também, não houve diferença no número de larvas parasitadas, número total de descendentes produzidos e longevidade média das fêmeas adultas do parasitóide em condições de laboratório. Entretanto, foi observado maior número de descendentes por larva parasitada e, aproximadamente, um dia a menos na duração do período ovo-adulto em larvas da traça-das-crucíferas criadas em repolho Chato-de-quintal. Assim, estes resultados mostram uma associação positiva entre a resistência de cultivares de repolho e o controle biológico com O. sokolowskii visando o manejo da traça-das-crucíferas e sugerem que a cor da cultivar possui papel importante na escolha do hospedeiro para oviposição pela praga.