Bibliography: leaves 140-158 / ix, 158 leaves, [23] leaves of plates : ill., 1 map ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1985) Dept. of Plant Pathology, University of Adelaide

Call number: LD2668 .T4 1959 B68

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3 pp. / Originally published: 2003 / True mistletoes are parasitic flowering plants with characteristic clumps of growth that are easily visible on the host plant. They reduce the growth of infected hosts, but it usually takes many years for true mistletoe infections to kill a mature tree or shrub. This article gives information about the disease cycle, the symptoms and prevention and control methods for true mistletoes.

Orientador: Carlos Amadeu Leite de Oliveira / Banca: Francisco Jorge Cividanes / Banca: Wilson Badiali Crocomo / Resumo: No Brasil, Brevipalpus phoenicis (Geijskes, 1939) é vetor da leprose na cultura dos citros, doença responsável por significativa redução na produtividade. Objetivou-se avaliar, a capacidade de colonização de B. phoenicis sobre cercas-vivas, quebra-ventos e plantas daninhas, e a potencialidade destas como hospedeiras do vírus da leprose. Realizou-se a colonização das plantas com ácaros procedentes de uma criação-estoque sobre frutos de citros Pêra-rio, para as seguintes plantas hospedeiras intermediárias: Hibiscus sp., Malvaviscus mollis, Grevillea robusta, Mimosa caesalpiniaefolia, Bixa orellana, Euphorbia splendens, Bidens pilosa, Commelina benghalensis, Sida cordifolia, Ageratum conyzoides e Citrus sinensis. Constatou-se que a exceção de E. splendens, todas comportaram-se como hospedeiras do ácaro. Ácaros contaminados, procedentes da criação-estoque, após serem transferidos e confinados em arenas delimitadas nas plantas hospedeiras intermediárias, por um período de 7 dias, não perderam a capacidade de transmitir o vírus para mudas cítricas de Valência e Natal. Ácaros não contaminados que tiveram acesso alimentar por 3 dias nessas mesmas arenas, somente se contaminaram e transmitiram o vírus para mudas de citros, aqueles que se alimentaram sobre: C. benghalensis, S. cordifolia, A. conyzoides, B. pilosa, B. orellana e C. sinensis. Resultados semelhantes foram conseguidos com ácaros criados, por um período de 90 dias, sobre as mesmas plantas hospedeiras intermediárias, inicialmente infestadas com ácaros contaminados também procedentes da criação-estoque. / Abstract: In Brazil, Brevipalpus phoenicis (Geijskes, 1939) is a vector of the leprosis in the culture of citrus, a disease that causes significant reduction in the productivity. In this work it was evaluated the B. phoenicis capacity of settling on common fence-lives, windbreaks and weeds, and their potentiality as hosts to the leprosis virus. The colonization of the plants was carried out with mites coming from a stock creation on fruits of "Pêra-rio" citrus, for the following intermediate host plants: Hibiscus sp., Malvaviscus mollis, Grevillea robust, Mimosa caesalpiniaefolia, Bixa orellana, Euphorbia splendens, Bidens pilosa, Commelina benghalensis, Sida cordifolia, Ageratum conyzoides and Citrus sinensis. It was verified that, except for the E. splendens, all species showed to be favorable to the B. phoenicis population growth. Infected mites, coming from the stock creation, that were transferred and confined in delimited arenas in the intermediate host plants for a period of 7 days, did not lose their capacity to transmit the virus for citric seedlings of "Valência" and "Natal". Non infected mites, that had access to feed for 3 days in the same arenas, became only infected and transmitted the virus for citrus seedlings that fed on: C. benghalensis, S. cordifolia, A. conyzoides, B. pilosa, B. orellana and C. sinensis. Similar results were obtained using mites created, for a period of 90 days, on the same intermediate host plants that were initially infested with infected mites coming from the same stock creation. / Mestre

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / A necessidade de controlar os fitonematÃides existentes em determinada regiÃo à condiÃÃo bÃsica para se proceder ao seu manejo racional. Igualmente, tem-se a necessidade de proceder a estudos de produtos naturais, pois serà de grande valia como medida de controle alternativo, principalmente na agricultura orgÃnica. Em vista disso, este trabalho se propÃs a estudar a hospedabilidade de plantas ornamentais e medicinais a Meloidogyne incognita raÃa 2 e o controle alternativo com Ãleos essenciais. Para tanto, realizaram-se trÃs ensaios: no primeiro, avaliou-se a hospedabilidade de 20 espÃcies de plantas ornamentais e 10 medicinais a M. incognita raÃa 2; no segundo, avaliaram-se os Ãleos essenciais de seis espÃcies medicinais Cymbopogon winterianus Jowitt., C. citratus (D.C.) Strapf., Eucalyptus terenticornis L., Lippia alba L., L. sidoides Cham. e Ocimum gratissimum L., em sete concentraÃÃes (0; 0,3125; 0,0625; 1,25; 2,5; 5,0 e 10,0 ml.L-1) no controle de M. incognita raÃa 2, in vitro e no terceiro, avaliou-se o potencial nematicida dos Ãleos essenciais de L. sidoides e C. winterianus no controle de M. incognita raÃa 2, em solo com as espÃcies celÃsia (Celosia plicata L.) e tomate (Lycopersicon esculentum Mill). Dos resultados, observaram-se que todas as espÃcies ornamentais, exceto Tagetes patula L., e cinco das medicinais Rosmarinus officinalis L., Mentha arvensis L. var. piperascens Malinv. ex L. H. Bailey, Ocimum bassilicum L., Ocimum gratissimum L., Plectranthus amboinicus (Lour.) Spreng., sÃo hospedeiras de M. incognita raÃa 2. Todos os Ãleos essenciais revelaram-se efetivos na inibiÃÃo da eclosÃo e na mortalidade dos J2 nas concentraÃÃes de 5,0 e 10,0 ml.L-1, contudo, em diluiÃÃes mais elevadas (<1,25 ml.L-1), apenas os Ãleos de L. sidoides e C. winterianus foram eficazes. A reproduÃÃo do nematÃide mostrou-se menos eficiente em tomate que em celÃsia. Os Ãleos essenciais empregados reduziram a taxa reprodutiva do nematÃide das galhas em 83 e 29%, em tomate e celÃsia, respectivamente. Os Ãleos essenciais de L. sidoides e C. winterianus foram mais eficientes em ensaios in vitro, sendo promissores para o controle do fitonematÃide em solo. / The necessity to control the plant parasitic nematodes existing in a given region is basic condition to proceed to their rational management. Also, it has been the necessity studies of natural products as it will be of great value as a measure of alternative control, especially in organic agricultural. In view of this, this work is proposed to study the hospitability of ornamental and medicinal plants to Meloidogyne incognita race 2 and the alternative control with essential oils. For in such a way, become three tests: the first, evaluate the hospitability of 20 species ofornamental and 10 medicinal plants to M. Incognita race 2; in the second, it is evaluated essential oils of six medicinal species Cymbopogon winterianus Jowitt., C. citratus (DC) Strapf., Eucalyptus terenticornis L., Lippia alba L., L. sidoides Cham. and Ocimum gratissimum L., in seven concentrations (0, 0.3125, 0.0625, 1.25, 2.5, 5.0 and 10.0 ml.L-1) in control of M. Incognita race 2, in vitro; and in the third, evaluated the nematicidal potential of essential oils of L. sidoides and C. Winterianus in control of M. Incognita race 2 in soil with the species celosia (Celosia plicata L.)and tomato (Lycopersicon esculentum Mill). Of the results, noted that all ornamental species, except Tagetes patula L., and five of the medical Rosmarinus officinalis L., Mentha arvensis L. Var. Piperascens Malinv. Ex L. H. Bailey, Ocimum bassilicum L., O. gratissimum L., Plectranthus amboinicus (Lour.) Spreng. are hosts of M. Incognita race 2. All essential oils proved to be effective in inhibiting outbreak and the death of J2 at concentrations of 5.0 and 10.0 ml.L-1, however, at higher dilutions (<1.25 ml.L-1)only the oils of L. sidoides and C. winterianus were effective. A reproduction of the nematode proved to be less efficient in tomato that in celÃsia. The essential oils employees reduced the reproductive rate of the knot nematode in 83 and 29% in tomato and celÃsia respectively. The essential oils of L. sidoides and C. winterianus were more efficient in in vitro assays and are promising for the control of plant parasitic nematode in soil.

The cinnabar moth, Tyria jacobaeae (L.) (Lepidoptera:Arctiidae), was released in 1959 to control the grassland weed tansy ragwort, Senecio jacobaea L. (Asteraceae), despite evidence that caterpillars of this species can feed on native plants within the genera Senecio and Packera. Previous studies confirmed the moth's ability to develop on the native Senecio triangularis Hook., although no systematic study has been conducted to determine the extent of non-target impact on all potential host species. To address the lack of systematic studies we conducted a regional survey to determine the consequences of exposure of non-target plants to cinnabar moth caterpillars. We also conducted a local field experiment to determine the influence of habitat on the patterns of association of the moth and non-target plants. In the regional survey, we mapped the potential distribution of the cinnabar moth in Oregon to determine the extent of exposure of native Senecio and Packera species, and systematically sampled exposed species to assess the frequency and severity of feeding on these plants. We found that nine of the 20 native non-target species in Oregon were exposed to the cinnabar moth, three of the 10 native Senecio and six of the 10 native Packera. Ten of the native species escaped exposure because they occur east of the Cascade Mountain Range where the cinnabar moth does not occur. We found feeding damage on three of the nine exposed species: Packera cymbalarioides, P. pseudaurea, and S. triangularis were attacked at one of three (33%), two of six (33%), and seven of 15 (47%) sites that supported populations of each species, respectively. Within sites, attack frequency of stems was 33% (of six total stems sampled) for P. cymbalarioides, and ranged from 53% to 56% (of 20 to 108 total stems sampled) for P. pseudaurea and 7% to 64.5% (of 32 to 458 total stems sampled) for S. triangularis. Conditional median damage per site (median of attacked stems only) was 10% in P. cymbalarioides, 5% to 17.5% in P. pseudaurea, and 5% to 37.5% in S. triangularis. The attack rate on non-target plants (7.1 to 64.5 percent of stems attacked at a singe site) was equal to or greater than on the target weed (8.3 to 50.0 percent of stems attacked at a single site). At three sites, caterpillars attacked non-target plants but the target weed was absent, and at one site, the target was present but caterpillars fed on non-target plants only. We conclude that attack frequency and severity on the three species is not high, but equaled or exceeded the level of attack on the target weed. We also conducted a mark-release-recapture experiment to relate habitat preference to patterns of non-target host use in the field. We compared adult moth dispersal patterns and larval development between a meadow habitat and a forest habitat. We found that long-term dispersal distance (spanning days) was similar in both habitats but we recaptured a higher percentage of moths from the meadow (47%) compared to the forest (10%). Short-term displacements, based on direct observations of flights immediately after release, differed between habitats: moths in the meadow flew short distances (8.5m ± 1.5, n=13) at or below the herbaceous canopy (0.8 m ± 0.2, n=13) while moths in the forest flew longer horizontal (22.8 m ± 2.8, n=15) and vertical distances (5.9 m ± 0.9, n=15). We recovered seven fifth instar larvae (of 278 eggs) from the meadow habitat but no larvae beyond the second instar (of 119 eggs) were recovered from the forest habitat. We conclude that the cinnabar moth is limited to meadow habitats because adult moths display movement patterns that remove them from forest habitats (possibly due to disorientation) and larvae are unable to survive on plants growing in the forest. Taken together, the regional survey and the local field-experiment indicate that the cinnabar moth uses only a small proportion of available non-target host plant species. Other species are likely unused because of geographic isolation from the moth, habitat selection by the moth, or phenological differences between the moth and non-target plants. / Graduation date: 2003

The probing behavior and feeding activity of green peach aphid, Myzus persicae Sulzer, on Bacillus thuringiensis ssp. tenebrionis- transgenic potatoes, insecticide treated potatoes, and host plants with different preference were electronically monitored. I found that first, transgenic potatoes had no effect on green peach aphid probing suggesting that transmission of green peach aphid-borne viruses would not be affected. Second, the probing behavior of green peach aphid was not modified by the insecticides, aldicarb, Admire, and Di-syston. However, the postfeeding behavior of aphids was different over time and with insecticides, which might have an influence on virus transmission in the field. Third, the probing behavior of green peach aphid on host plants with different preference varied. Aphids probed more when they moved from a higher-preference host plant (radish) to a lower preference host plant (potato). In addition, the settling rate was low when aphids were moved from higher to lower preference host plants. This difference might affect virus transmission in the field. Vector efficiency, relationship of virus transmission between vector and host plants, and vector control strategies are discussed. In addition, the probing behavior of two mosquito species, Aedes aegypti and Anopheles stephensi, on mice was recorded electronically to examine waveform patterns and to quantify sporozoite output. My studies indicated that sporozoite output of malaria-infected mosquitoes was not detected by using the electronic monitoring system. The relationship between waveform patterns and penetration activities of mosquitoes needs clarification before further studies can be conducted. / Graduation date: 1994

Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2008.