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Cabbage (<i>Brassica oleracea</i> L.) production in Virginia is concentrated in the mountainous southwest region of the state where soil erosion and soil-moisture deficits are major problems associated with row-crop agriculture. The objectives of this study were to assess the applicability of conservation tillage systems for cabbage production. Four tillage systems (conventional tillage, CT; no-tillage, NT; and two types of strip tillage—Ro-till, RT, and chisel plow, CP) and three planting dates (early, mid and late) were compared in 1985 and 1986. Plants were set with a locally adapted no-till transplanter into a cover crop of cereal rye (<i>Secale cereale</i> L.). Under unusually rainy conditions in 1985, cabbage yields with NT were lower than with CT; while with dry weather prevailing in 1986, NT and CT yields were equal for all planting dates. Yields in strip tillage systems were equal or higher than NT and CT with ample or deficit soil moisture. RT out-yielded both CT and NT in 1986. Yield was positively correlated with soil moisture content in 1986, but not in 1985. Once-over resetting was done in all plots resulting in no differences in plant numbers among tillage treatments. Head size was affected by tillage systems and was highly correlated with yield. These data indicate that (i) conservation tillage systems are viable alternatives to CT for production of cabbage, and (ii) available water resources and soil drainage should be important considerations in selection of the most productive tillage system. / M.S.

M.S.

Possible effects of steady low strength magnetic fields on insects were studied using the cabbage looper moth, Trichoplusia ni (Hubner). In the first tests, adult loopers were used to determine their locational preference in response to areas of stronger or weaker magnetic field ranging from slightly above the geomagnetic field strength to a strength of 120 gauss. In a second series of tests, looper eggs were continuously exposed to steady magnetic fields of various strengths ranging from 10 to 1850 gauss. In a third series of tests t individual adult loopers were exposed to a steady 500 gauss field for five minutes. Oxygen consumption was monitored to indicate the level of moth activity before, during, and after this exposure. Results of the tests conducted revealed no effect of low magnetic fields on moth locational preference, egg hatchability, or activity level. / Master of Science

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2018-02-07T14:23:10Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Sheila Avila.pdf: 1444685 bytes, checksum: 5af742f17f8020ce9558feb7331065cc (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-02-08T12:36:21Z (GMT) No. of bitstreams: 2 Dissertação_Sheila Avila.pdf: 1444685 bytes, checksum: 5af742f17f8020ce9558feb7331065cc (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-08T12:36:21Z (GMT). No. of bitstreams: 2 Dissertação_Sheila Avila.pdf: 1444685 bytes, checksum: 5af742f17f8020ce9558feb7331065cc (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Pesquisar adubações orgânicas que almejam o equilíbrio trofobiótico na cultura de interesse é de extrema importância na busca de sistemas de produção de alimentos mais sustentáveis. Com esta premissa objetivou-se no trabalho analisar a influência de diferentes adubações orgânicas sobre a preferência alimentar de Brevicoryne brassicae em Brassica oleracea var. acephala, estabelecendo inter-relações entre o metabolismo vegetal da couve, as fontes de adubação testadas e a resistência e/ou suscetibilidade aos afídeos. Para tanto, foi feito o cultivo da hospedeira em casa de vegetação, onde a mesma foi cultivada em vasos com adubação orgânica acrescentada ou não de fitoprotetores, obedecendo aos seguintes tratamentos: T1) substrato orgânico comercial a 70% + 30% de húmus (SO+H) como controle; T2) (SO+H) + biofertilizante Vairo via solo; T3) (SO+H) + biofertilizante Supermagro via solo T4) (SO+H) + urina de vaca via solo; T5) (SO+H) + Húmus líquido pulverizado; T6) (SO+H) + soro de leite pulverizado e, T7) (SO+H) + biodinâmico pulverizado. O delineamento experimental foi inteiramente casualizado com 10 repetições, sendo cada repetição (parcela) uma planta. Para os bioensaios de preferência alimentar de múltipla escolha em laboratório foi feita a criação do afídeo, sendo as avaliações realizadas as 24 e 48 horas através da contagem de indivíduos em todas as folhas (halos) representando todos os tratamentos. Também foi feito análise química dos substratos e das couves, além dos fitoconstituintes das mesmas após receber os diferentes tratamentos. Os dados foram submetidos ao teste de hipótese de KruskalWallis (p<0,05), com comparação de grupos pelo método de Simes-Hochberg, sendo após, submetidos à análise de componentes principais. A aplicação dos tratamentos influenciou na preferência alimentar de B. brassicae em B. oleracea var. acephala. Estes forneceram diferentes fontes de nutrientes ao substrato e à planta hospedeira, afetando assim, seu metabolismo vegetal e conseqüentemente a resistência e/ou suscetibilidade aos afídeos. As plantas tratadas com húmus líquido e Vairo apresentaram menor preferência pelos pulgões. Estes induziram a resistência, envolvendo o acúmulo de ácido ascórbico que se correlacionou ao manganês. Os tratamentos urina de vaca, Supermagro e em menor grau o soro de leite foram os que apresentaram folhas com maior preferência pelos afídeos, sendo estes ricos em nitratos e açúcares solúveis, estando estes compostos relacionados respectivamente aos nutrientes nitrogênio, ferro e cálcio. Já os tratamentos controle e biodinâmico apresentaram resultados intermediários de preferência e de correlação aos nutrientes e fitoquímicos. / To search for organic fertilizers that target the trophobiotic balance in the culture of interest and of extreme importance in the search for more sustainable food production systems. The objective of this work was to analyze the influence of different organic fertilizers on the Brevicoryne brassicae food preference in Brassica oleracea var. acephala, establishing interrelations between the vegetable metabolism of the cabbage, the sources of fertilization tested and the resistance and / or susceptibility to the aphids. For this, the host was cultivated in a greenhouse, where it was cultivated in pots with organic fertilization added or not of phytoprotectants, following the following treatments: T1) commercial organic substrate at 70% + 30% humus (SO + H) as control; T2) (SO + H) + biofertilizer Vairo via soil; T3) (SO + H) + biofertilizer Supermagro via soil T4) (SO + H) + cow urine via soil; T5) (SO + H) + pulverized liquid humus; T6) (SO + H) + powdered whey and, T7) (SO + H) + pulverized biodynamic. The experimental design was completely randomized with 10 replicates, each replicate (plot) being one plant. For the bioassays of multiple choice food preference in the laboratory was created the aphid, and the evaluations were performed at 24 and 48 hours by counting individuals on all leaves (halos) representing all treatments. Chemical analysis of the substrates and cabbage was carried out, besides the phyto-constituents of the same ones after receiving the different treatments. The data were submitted to the Kruskal-Wallis hypothesis test (p <0.05), with a comparison of groups by the Simes-Hochberg method, after which they were submitted to principal components analysis. The application of the treatments influenced the food preference of B. brassicae in B. oleracea var. acephala. These provided different nutrient sources to the substrate and host plant, thus affecting its plant metabolism and consequently the resistance and/or susceptibility to aphids. Plants treated with liquid humus and Vairo showed less preference for aphids. These induced resistance, involving the accumulation of ascorbic acid that correlated with manganese. The treatments of cow urine, Supermagro and, to a lesser extent, whey were the ones that presented leaves with a higher preference for aphids, being these rich in nitrates and soluble sugars, these compounds being related respectively to nutrients nitrogen, iron and calcium. The control and biodynamic treatments presented intermediate results of preference and of correlation to nutrients and phytochemicals.

The effects of intraspecific and interspecific competition, host plant, and prior host plant experience on fecundity, rate of oviposition and mortality of adults and larval survival of Delia radicum Bouche (Cabbage Maggot (CM)), D. antiqua Meigen (Onion Maggot (OM)), and D. platura Meigen (Seed Corn Maggot (SCM)), were studied on cabbage, onion and bean plants. / An optimum density for maximum fecundity per female was observed when the four experimental densities were compared. This optimum density was higher on host than on non-host plants. CM females were host specific and did not oviposit on non-host plants. Rates of oviposition and mortality over a 30-day period were calculated for each density. The rate of oviposition was slower at higher densities on host plants for CM, OM and SCM. The rate of mortality increased at the highest density for CM (cabbage), OM (bean) and SCM (cabbage), but remained unaffected for OM on onion and cabbage and for SCM on onion and bean, when densities were compared. For OM, a delay in the rate of oviposition and mortality on cabbage (non-host plant) when compared with onion (host plant), suggests that cabbage was not as readily accepted as an oviposition site. Interspecific competition experiments at six density ratio's of SCM:OM indicated increased fecundity, or an increase in the rate of oviposition for OM, at the lower densities when single and mixed species were compared. For SCM no effects on fecundity were recorded, but the rate of oviposition was slower and rate of mortality faster at the lowest density in the presence of OM. Similar studies with SCM and CM showed no such effects of competition. / Host plant exposure of SCM females during the pre-oviposition period resulted in a delay in initial acceptance of subsequent host plants as oviposition sites. This happened only when females were exposed to a secondary host during the pre-oviposition period. Once oviposition began, host discrimination ceased and a switch in oviposition sites to the preferred host did not alter the rate of oviposition. In CM, the rate of larval development increased at density 6 (optimum density). Above this density a decrease in the rate of development and a significant reduction in pupal weight was observed. Time required for fly emergence was not affected by increasing larval densities.

In Quebec 11 840 kg of insecticides are used against the cabbage maggot, Delia radicum L. (Diptera: Anthomyiidae) each year. It is possible to decrease this quantity of insecticide by using natural enemies such as fungi, nematodes, predators and parasitoids. Aleochara bilineata Gyllenhal (Coleoptera: Staphylinidae) is a natural enemy of the cabbage maggot. Adults of this species are predators of eggs and larvae of cabbage maggot and the first instar larvae are ectoparasitoids of cabbage maggot pupae. A. bilineata oviposits its eggs in the soil, near plants infested with cabbage maggots. / Differences in size have been noted in the eggs of A. bilineata . In insects several factors can affect egg size. Certain females can oviposit small trophic eggs which serve as food for emerging larvae or egg size can be affected by factors such as size and age of female, as well as, food and host quality. These factors have been studied in A. bilineata in order to determine the conditions that favor the production of small eggs. (Abstract shortened by UMI.)

The purpose of the present study is to determine the ascorbic acid content of raw cabbage salads as influenced by the method of shredding and by the kind of salad dressing used.

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