The roles of ocelli and octopamine in regulating the onset, intensity, and duration of cabbage looper moth flight activity were examined. This was achieved by studying the flight activity of control, sham, and anocellate moths with and without octopamine treatment. Sham and anocellate moths were produced by cauterization in last-instar larvae, of ocellar primordial cells for anocellate moths, and of non-involved cells for sham moths. Flight activity of moths was monitored by a computerized actograph under normal light (LD) conditions, under advanced-sunset, and under constant dark (DD) conditions to determine the effect of ocelli on flight activity. The role of octopamine was investigated by treating the three groups of moths topically with octopamine dissolved in dimethyl sulfoxide (DMSO) and with DMSO alone, and comparing flight activity before and after treatment. Results support a combined role for ocelli and the compound eyes in determining flight initiation times, and a role for ocelli in determining flight intensity. These roles were more pronounced in males than in females. It was found that the cauterization operation itself decreases flight activity in sham moths. No evidence was found that supports the existence of an octopamine effect on flight activity in any of the groups of moths when octopamine is topically applied. / Master of Science

PhD (Agric) (Plant Production) / Department of Plant Production / Brassicas are important vegetable crops grown for home consumption and market gardening in eastern and southern Africa. However, productivity is affected by aphids, through both direct feeding and disease transmission. Botanical insecticides have potential to control the aphids, but so far few plants have been evaluated for use on brassicas. This study was conducted to evaluate the effectiveness of Solanum panduriforme to control aphids on brassicas. Botanical extracts from three parts of S. panduriforme were assessed for their insecticidal effects on the cabbage aphid, Brevicoryne brassicae. The extracts from leaf powder (LP), ripe berry powder (BP), fresh ripe berries (RB) and fresh unripe berries (UB) were extracted with four solvents; water, ethanol, hexane and diethyl ether, using homogenisation, maceration and solvent-assisted / sequential extraction methods. The effectiveness of the extracts was determined by laboratory bioassays as well as by plant assays in the screen house and under field conditions. The experiments were replicated three or four times depending on the assays and the design used was completely randomized design (CRD). The immature (LP and UB) plant parts were generally more effective than the mature (BP and RB) plant parts, with mortalities ranging from 100 % down to 40 % respectively depending on assays. Ethanol extracts were more effective than aqueous extracts (LP 96% and 63%; BP 96% and 64%; RB 100% and 64%; UB 100% and 90%). The dried crude extracts from hexane were more effective than di-ethyl ether extracts. The group chemical analysis indicated presence of alkaloids in the berries (BP, RB and UB), which were absent in the leaves (LP). Phenolic compounds and flavonoids were present in all the extracts (LP, BP, RB, and UB). Saponins were present in the fresh parts (RB and UB). The results show how the locally available S. panduriforme plants can be used as an aphicide to control aphids on brassicas. Farmers can directly prepare an easy and cheap botanical / NRF

BACKGROUND: Black rot is a destructive bacterial disease causing large yield and quality losses in Brassica oleracea. To detect quantitative trait loci (QTL) for black rot resistance, we performed whole-genome resequencing of two cabbage parental lines and genome-wide SNP identification using the recently published B. oleracea genome sequences as reference. RESULTS: Approximately 11.5 Gb of sequencing data was produced from each parental line. Reference genome-guided mapping and SNP calling revealed 674,521 SNPs between the two cabbage lines, with an average of one SNP per 662.5 bp. Among 167 dCAPS markers derived from candidate SNPs, 117 (70.1%) were validated as bona fide SNPs showing polymorphism between the parental lines. We then improved the resolution of a previous genetic map by adding 103 markers including 87 SNP-based dCAPS markers. The new map composed of 368 markers and covers 1467.3 cM with an average interval of 3.88 cM between adjacent markers. We evaluated black rot resistance in the mapping population in three independent inoculation tests using F₂:₃ progenies and identified one major QTL and three minor QTLs. CONCLUSION: We report successful utilization of whole-genome resequencing for large-scale SNP identification and development of molecular markers for genetic map construction. In addition, we identified novel QTLs for black rot resistance. The high-density genetic map will promote QTL analysis for other important agricultural traits and marker-assisted breeding of B. oleracea.

Delia radicum L. (Diptera: Anthomyiidae), the cabbage root fly, is a specialist root-feeding insect pest of Brassica crops. The impending withdrawal of chlorpyrifos, one of the main pesticides used against D. radicum, opens new opportunities to research alternative pest management strategies. Manipulating host plant location cues to influence D. radicum adult and larval behaviour, along with induced plant defence responses, offer potential integrative crop protection solutions (Chapter 1). This thesis aimed to identify the semiochemistry underpinning D. radicum larval host plant location, and to investigate whether plant defence induction treatments (methyl jasmonate [MeJA], D-Fructose) and a herbivore induced volatile (dimethyl disulfide [DMDS]) affect D. radicum larval performance and adult oviposition preference. In choice-test bioassays, larvae were inconsistent in their responses to root exudates collected from Brassica host plants (Chapter 2). A combined bioassay and EthoVision® video-tracking approach was developed to record and analyse larval movements in response to volatiles emitted from host and non-host plant roots (Chapter 3). Larvae were significantly attracted to host plant root volatiles. Olfactory stimuli from roots of the non-host plant onion (Allium cepa L. ‘Ailsa Craig’), which share overlapping, yet distinctive volatile profiles to that of Brassica plants, also elicited positive taxis. By analysing the volatile metabolome of broccoli (B. oleracea L. convar. botrytis L. Alef. var. cymosa Duchesne ‘Parthenon’) and onion roots using solid phase micro extraction-gas chromatography-mass spectrometry (SPME-GCMS), a suite of candidate volatile orientation cues were identified. A SPME-based method was developed to non-invasively collect root volatiles in situ from glasshouse- and field-grown broccoli plants pre- and post-D. radicum infestation (Chapters 4, 5 and 6). GC-MS analyses revealed that sulfur compounds, showing characteristic temporal emission patterns, were the principal volatiles released by roots in response to damage. This new method, which has potential for wide application in chemical ecology research, allows the study of volatiles in the soil in situ that are critical for interactions between trophic levels. In EthoVision® bioassays, a major volatile constituent of broccoli roots, DMDS, was attractive to larvae, but toxic at the highest dose tested (Chapter 3). Glasshouse and on-farm experiments using broccoli were conducted to evaluate the efficacy of MeJA, D-Fructose and DMDS against D. radicum compared to commercially available crop protection products (chlorpyrifos [Dursban® WG], spinosad [Tracer®], Steinernema feltiae Filipjev [Nematoda: Steinernematidae] [Entonem] and garlic granules [ECOguard®]). MeJA and garlic reduced larval performance under glasshouse conditions whereas D-Fructose and DMDS did not at the concentrations tested (Chapter 7). In field studies, MeJA combined with reduced rate chlorpyrifos, spinosad, and S. feltiae all showed partial efficacy for controlling D. radicum larvae. Inherent field site, weather and D. radicum population density variability highlighted that glasshouse results cannot always be reproduced in more complex field environments (Chapter 8). Further research is needed into formulation, mode of application and timing to improve efficacy of promising treatments that may help in future integrated pest management (IPM) for this key pest in the absence of existing pesticides.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Pollination and fruit set of four species of native New Zealand flowering plant species were examined through two field seasons. Bird exclusion, pollinator exclusion, natural and supplemental pollination treatments were initiated on individuals of Cordyline australis (Cabbage tree), Phormium tenax (Flax), Kunzea ericoides (Kanuka), and Pseudopanax arboreus (Five-finger). The species differed in the self-compatibility as well as in their floral syndrome. No species showed any evidence of pollen limitation, and two species. K. ericoides and P. arboreus set fruit from more than 70% of their flowers. The response of fruit set to treatment in C. australis varied from season to season, with birds appearing important to pollination in the first but not the second field season, while birds were important in pollination across both seasons for P. tenax. K. ericoides was resilient to treatment, setting high fruit set in every treatment, compared to P. arboreus which set high fruit set when pollinators had access, but low when all pollinators were excluded. No trends relating to fruit set or PLI and self-compatibility or floral syndrome were found. That there was no evidence of pollen limitation for any species, despite variation in fruit set from some treatments, indicates that these species are performing well and not at risk of decreased population size due to pollen limitation.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1975.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.93-105).

Thesis (M.Sc.(Agric.))(Horticulture)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Orientador: Edson Luiz Lopes Baldin / Banca: Arlindo Leal Boica Junior / Banca: André Luiz Lourenção / Resumo: A couve-de-folha, Brassica oleracea (L.) var. acephala, é atacada por diversas pragas, e o curuquerê, Ascia monuste orseis (Godart) (Lepidoptera: Pieridae), destaca-se como uma das mais importantes, causando intensas desfolhas às plantas. O principal método de controle deste inseto é feito através da aplicação de inseticidas sintéticos, com reconhecidos prejuízos ao meio ambiente. Considerando-se a importância desse inseto para a cultura da couve-de-folha e também os efeitos indesejáveis decorrentes de aplicações de inseticidas para seu controle, a presente pesquisa teve como objetivo avaliar a resistência de genótipos de couve-de-folha frente A. monuste orseis e estudar os tipos de resistência envolvidos através da realização de ensaios com adultos (atratividade e preferência para oviposição) e lagartas (preferência alimentar e antibiose), sob condições de laboratório e casade- vegetação. Para a instalação dos bioensaios, foi mantida uma criação de A. monuste orseis em casa-de-vegetação. Foram avaliados 29 genótipos de couve-de-folha: Manteiga de Ribeirão Pires I-2620 (MRP I-2620), Manteiga I-1811 (M I-1811), Roxa I-919 (R I-919), Manteiga de São Roque I-1812 (MSR I-1812), Gigante I-915 (G I-915), Manteiga I-916 (M I- 916), Crespa I-918 (C I-918), Manteiga de Ribeirão Pires I-2446 (MRP I-2446), Crespa de Capão Bonito (CCB), Manteiga de Tupi (MT), Couve de Leguminosas (CL), Manteiga de Jundiaí (MJ), Manteiga de Mococa (MM), Manteiga São José (MSJ), Verde-escura (VE), Pires 1 de Campinas (P1C), Pires 2 de Campinas (P2C), Japonesa (J), Hortolândia (H), Orelha de Elefante (OE), Vale das Garças (VG), Comum (C), Introduções do município de Arthur Nogueira: variedades Y (IMAN Y); W (IMAN W); Z (IMAN Z) e comerciais: Cabocla (CS);Couve de folhas Manteiga 900 Legítima Pé Alto (CFMLPA), Couve de folhas Manteiga Tronchuda Portuguesa (CFMTP) Couve Manteiga... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cabagge (Brassica oleracea L. var. acephala), is attacked by several pests, being the caterpillar Ascia monuste orseis (Godart) (Lepidoptera: Pieridae), pointed as one of the most important, causing severe defoliation on plants. The main method of controlling this insect was done by the application of synthetic insecticides with recognized damage to the environment. Considering the importance of the insect for the cabagge culture and the undesirable effects arising of the insecticides application for their control, the present research had as objective to evaluate the resistance of cabagge genotypes against A. monuste orseis, and verify the types of resistance involved through the accomplishment of assays with adults (attractiveness and oviposition preference) and caterpillars (feeding preference and antibiosis), in laboratory and greenhouse conditions. A rearing of A. monuste orseis was maintained in the greenhouse in order to instal the bioassays. 29 genotypes of cabagge were evaluated: Manteiga de Ribeirão Pires I-2620 (MRP I-2620), Manteiga I-1811 (M I-1811), Roxa I-919 (R I-919), Manteiga de São Roque I-1812 (MSR I-1812), Gigante I-915 (G I-915), Manteiga I-916 (M I-916), Crespa I-918 (C I-918), Manteiga de Ribeirão Pires I-2446 (MRP I-2446), Crespa de Capão Bonito (CCB), Manteiga de Tupi (MT), Couve de Leguminosas (CL), Manteiga de Jundiaí (MJ), Manteiga de Mococa (MM), Manteiga São José (MSJ), Verde-escura (VE), Pires 1 de Campinas (P1C), Pires 2 de Campinas (P2C), Japonesa (J), Hortolândia (H), Orelha de Elefante (OE), Vale das Garças (VG), Comum (C), Introduções do município de Arthur Nogueira: variedades... (Complete abstract click electronic access below) / Mestre