Dissertations / Theses on the topic 'Pome fruit'
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Kirstein, Deon Louw. "Mechanical thinning of pome fruit." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97920.
Full textENGLISH ABSTRACT: Thinning is an important practice in pome fruit production which aims to ensure an optimal yield of high quality, large sized fruit as well as an adequate return bloom. In South Africa, pome fruit thinning is generally done by means of chemicals, with follow-up hand thinning. When thinning is effective, set and thus the hand thinning requirement should be reduced. This is important as labor cost associated with hand thinning is high and continually rising. Chemical thinning is weather dependent and can be environmentally harmful, which has led to a shift towards environmentally acceptable methods of thinning such as mechanical thinning. From 2013 until 2015 the mechanical string thinners, viz. Darwin 300™, BAUM, and Bloom Bandit™, were evaluated. These machines are used to thin trees during full bloom and reduce the number of flowers before fruit set. The aim of the trials was to reduce fruit set and therefore hand thinning requirement, while increasing fruit size and quality, maintaining yield and return bloom. A range of tractor speeds and rotational rates were evaluated with the Darwin 300™ on ‘Forelle’ pears and ‘Cripps’ Pink’ apples, while the BAUM was evaluated only on ‘Cripps’ Pink’ apples. The hand-held Bloom Bandit™ was evaluated on ‘Forelle’, ‘Cripps’ Pink’, ‘Fuji’ and ‘Cripps’ Red’. The tractor-driven mechanical thinning devices gave erratic results. The most consistent results on ‘Forelle’ were obtained using the Darwin 300™ at 5.2 km·h-1 and 300 rpm, while the BAUM gave no consistent results. The unreliability of results were due to South African pome fruit orchards currently being unsuitable for tractor-driven mechanical thinning machines. The ‘Forelle’ orchard trained to a Palmette system was the most suited for thinning, which is reflected in the more positive results obtained, but further improvements are possible. The Bloom Bandit™ effectively thinned pear and apple trees and increased fruit size without a decrease in yield or return bloom. More time is spent on thinning with the device compared to tractor-driven machines and this should be taken into account when considering using the Bloom Bandit™. Thinning intensities of 25%, 50% and 75% of clusters or flowers was applied to mature ‘Forelle’ and ‘Cripps’ Red’ trees during full bloom. Variable effects were seen on fruit set, yield was reduced to acceptable levels, while fruit size was improved in ‘Forelle’ but not ‘Cripps’ Red’. Results showed that when thinning mechanically, the aim should be to remove between 25% and 50% of flowers clusters in ‘Forelle’ and 50% of flowers clusters in ‘Cripps’ Red’. These levels of thinning gave the best results in terms of the remaining hand thinning requirements and improved return bloom in ‘Forelle’. We, however, only evaluated full cluster thinning and not within cluster thinning, which might also occur during mechanical thinning.
AFRIKAANSE OPSOMMING: Vruguitdunning is 'n belangrike praktyk in kernvrugproduksie en het ten doel om voldoende opbrengs van hoë kwaliteit, groot vrugte en voldoende opvolgblom te lewer. In Suid-Afrika, word kernvrugte gewoonlik chemies uitgedun, opgevolg met handuitdunning. Effektiewe uitdunning verminder set en dus die benodigde handuitdunning. Dit is belangrik aangesien die arbeidskoste verbonde aan die handuitdunning hoog is en voortdurend styg. Chemiese uitdunning is afhanklik van weerstoestande en dit kan ook omgewing-onvriendelik wees. Hierdie nadele het gelei tot 'n verskuiwing na omgewingsaanvaarbare metodes van uitdunning soos meganiese uitdun. Vanaf 2013 tot 2015 is die meganiese Darwin 300™, BAUM en Bloom Bandit™ uitdunmasjiene geëvalueer. Hierdie masjiene word gedurende volblom gebruik om blomme uit te dun en verminder die aantal blomme voor vrugset. Die doel van die proewe was om vrugset en dus die handuitdunvereiste te verminder met ‘n gepaardgaande verbetering in vruggrootte en kwaliteit sonder om opbrengs en opvolgblom nadelig te beïnvloed. Trekker en rotasiespoed is gevarieer met die Darwin 300 ™ op 'Forelle' pere en ‘Cripps’ Pink' appels, terwyl die BAUM net op 'Cripps' Pink' appels geëvalueer is. Daarbenewens was die hand-draagbare Bloom Bandit™ geëvalueer op 'Forelle', 'Cripps' Pink’, ‘Fuji’ en ‘Cripps' Red’. Die trekkergedrewe uitdunmasjiene het wisselvallige resultate opgelewer. Die mees konstante resultate op 'Forelle' is verkry met die Darwin 300™ teen 5.2 km·h-1 en 300 rpm, terwyl die BAUM nie konsekwente resultate gegee het nie. Die wisselvallige resultate van die Darwin 300™ en die BAUM is te wyte aan die boorde wat nie vir trekkergedrewe uidunmasjiene geskik is nie. Die 'Forelle’ boord, wat as 'n Palmette stelsel opgelei is, was die meeste geskik vir uitdunning, soos duidelik uit die positiewe resultate wat verkry is, maar verdere verbeterings is steeds moontlik. Die Bloom Bandit™ het peer en appel bome effektief uitgedun deur die handuitdunvereiste te verminder en vruggrootte te verbeter sonder verlies in opbrengs of opvolgblom. Meer tyd word gespandeer tydens uitdunning met hierdie toestel in vergelyking met trekkergedrewe masjiene, en dit moet in ag geneem word met oorweging van die Bloom Bandit™. Uitdunningsintensiteite van 25%, 50% en 75% van die trosse of blomme is tydens volblom toegepas op volwasse 'Forelle’ en ‘Cripps’ Red' bome. Vrugset het aansienlike variasie getoon terwyl opbrengs tot aanvaarbare vlakke verminder en vruggrootte verbeter is in 'Forelle' maar nie in 'Cripps' Red’ nie. Resultate het getoon dat die doel moet wees om tussen 25% en 50% van alle blomme in trosse in 'Forelle’ en 50% van blomme in trosse in 'Cripps’ Red’ tydens meganiese uitdunnig te verwyder. Hierdie vlakke van uitdunning het die beste resultate gegee ten opsigte van die oorblywende handuitdunvereistes en het opvolgblom in 'Forelle’ verbeter. Ons het egter net volledige trosse uitdunning gedoen en nie blomuitdunning binne die tros wat ook tydens meganiese uitdun kan plaasvind nie.
Le, Grange Monique. "Effect of kaolin applications on pome fruit." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52255.
Full textENGLISH ABSTRACT: Sunburn is a major problem in the apple industry worldwide. A kaolin product, M-97- 009 (100% kaolin), originally developed for insect control, was evaluated for its efficacy in controlling sunburn on pome fruit. Trials were conducted over two seasons in two different areas of the Western Cape, South Africa. During the first season, 'Royal Gala', 'Fuji' and 'Granny Smith' apples were evaluated in the Koue Bokkeveld. The kaolin was mixed with water and applied to the trees by means of a hand-gun regularly throughout the season. In addition to the effect on sunburn, effects on yield, colour development, snout beetle damage and other defects were determined. Sunburn was reduced on all the cultivars tested, although not significantly on 'Granny Smith'. Inconsistent effects on yield parameters were observed. The applications significantly reduced red colour on 'Fuji', but this problem was rectified by an improved application technique the following season. During the second season, additional apple cultivars and 'Rosemarie' pears were included in the trials. The apple trials were conducted in the Elgin area, and the 'Rosemarie' trial in the Koue Bokkeveld. Surround™ (95% kaolin) was applied to the trees by means of a commercial "blower". The effects on sunburn, yield, colour development and fruit maturity were determined. In contrast to the previous season, sunburn was not reduced on any of the cultivars examined. Yield parameters were not affected except in the case of 'Royal Gala' where the number of fruit was increased, and 'Cripps' Pink' where the number of fruit was reduced. Fruit colour was not affected in the apple cultivars, but chroma of 'Rosemarie' pears was reduced, indicating a less intense colour. The kaolin applications had a variable effect on fruit maturity. The effect of the foliar applications on photosynthetic photon flux density (PPFD), photosynthetic rate, stomatal conductance and transpiration rate was determined. In addition to these spot measurements, photosynthetic light response curves were determined. Measurements were taken on both the inner and outer canopies The applications significantly reduced photosynthetic rates in the inner canopy and reduced the apparent quantum efficiency of leaves on the outer canopy. No significant effect on PPFD was found. It appears that the white coating reflects light and allows less light to penetrate the leaf, thus reducing photosynthesis. Surround™ treatments could not counteract the damaging effects of the high temperatures experienced in the Western Cape during this season and was not effective as a control measure for sunburn. This does not appear to be a commercially viable solution for the sunburn problem and it would be worthwhile to investigate the use of alternative options, such as evaporative cooling.
AFRIKAANSE OPSOMMING: Sonbrand is een van die grootste probleme wat wêreldwyd in die appelbedryf ondervind word. 'n Nuwe produk, M-97-009 (100% kaolien), is oorspronklik ontwikkel vir insekbeheer in geïntegreerde plaagbeheer, maar daar is beweer dat dit moontlik sonbrand op kemvrugte kan verminder. Proewe is oor twee seisoene uitgevoer in die Koue Bokkeveld en ook in die Grabouw-omgewing in die Wes-Kaap. Tydens die eerste seisoen is die effek van M-97-009 op 'Royal Gala', 'Fuji' en 'Granny Smith' appels beoordeel. Die kaolien is met water gemeng en deur die loop van die seisoen met 'n handspuit op die bome gespuit. Die effek van die produk op sonbrand, oesgrootte, vruggrootte, kleurontwikkeling, kalanderskade en ander defekte is bepaal. Sonbrand is op alle kultivars verminder, alhoewel nie betekenisvolop 'Granny Smith' nie. Die effek van kaolien op oesparameters was rue konsekwent nie. kleurontwikkeling op 'Fuji' benadeel, heel moontlik Die toedienings het as gevolg van die toedieningstegniek. Met verbeterde toedieningsmetodes die volgende seisoen, is kleurontwikkeling van 'Fuji' nie benadeel nie. Tydens die tweede seisoen is die effek van kaolien op nog appelkultivars en 'Rosemarie' pere ge-evalueer. Die appelproewe is in Elgin uitgevoer, terwyl die 'Rosemarie'-proefin die Koue Bokkeveld uitgelê is. Surround™ (95% kaolien) is met kommersiële spuitpompe toegedien. Weereens is die effek van die produk op sonbrand, oesgrootte, vruggrootte, kleurontwikkeling en vrugrypheid bepaal. Sonbrand is nie verminder nie. Vruglading tydens oes is nie betekenisvol beïnvloed nie, behalwe in die geval van 'Royal Gala' waar die vruglading verhoog is, en 'Cripps' Pink' waar daar minder vrugte op die gespuite bome was. Die Surround™ toedienings het geen uitwerking op kleur van appels gehad nie, maar het die chromawaarde van 'Rosemarie' pere verlaag, d.w.s die vrugkleur was minder intens. Die kaolienspuite het 'n uiteenlopende effek op vrugrypheid gehad. Fotosintetiese foton vloeddigtheid (FFV), fotosintesetempo, huidmondjieweerstand en transpirasietempo is gemeet en ligreponskurwes van beide die buitenste en binneste blaardak is bepaal. Die Surround™ toedienings het fotosintese van blare ill die binneste gedeelte van die blaardak verminder en die kwantumdoeltreffendheid van blare op die buitenste deel van die blaardak verminder. Geen betekenisvolle effek is op FFV gekry nie. Dit wil voorkom asof die wit laag kaolien op die bome lig weerkaats en veroorsaak dat minder lig na die blaar deurdring. Dit verminder dan die fotsintesetempo. Met die baie warm weer wat in die Wes-Kaap gedurende die tweede seisoen ervaar is, kon die SUITound™behandelings nie sonbrand verhoed nie. Dit wil voorkom asof Surround™ nie 'n baie doeltreffende oplossing in kommersiële boorde sal wees nie. Alternatiewe oplossings, soos byvoorbeeld evaporatiewe verkoeling, saloorweeg moet word.
Mhelembe, Khethani Give. "Molecular characterisation of ARC pome fruit collections in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96716.
Full textENGLISH ABSTRACT: Apple (Malus pumila Mill.) and pear (Pyrus communis L.), commonly known as pome fruits, are important deciduous fruit crops in South Africa. The challenges of climate change, disease incidence, distant markets and fluctuating consumer preferences necessitate new cultivars. The Agricultural Research Council (ARC) Infruitec-Nietvoorbij conducts a breeding programme aimed at developing new cultivars that are well adapted, resistant to pests and diseases and good storage potential. A recent review of the pome fruit gene banks, the breeders’ raw material, revealed misidentification and poor characterisation limitating the efficiency of its utilisation. To address these problems, the current study used microsatellite markers to investigate the trueness to type of accessions in the ARC gene banks. In addition, accessions of apple identified as true to type, were genotyped for the ACS1 gene involved with ethylene production and fruit ripening. Two sets of 12 microsatellite markers recommended by a European working group on Pyrus/Malus, one for apple and one for pear, were utilised to fingerprint 540 apple and 197 pear accessions. Eleven and eight of 12 markers, were used respectively to successfully discriminate across the apple and pear accessions, with the exception of clones and sports of particular cultivars. Where possible, fingerprints were compared with those of their reported parents. The use of recommended markers facilitated the comparison of ARC pear accessions with those of the collection in Brogdale (UK). Trueness to type of accessions were established and misidentified accessions were also detected. A similar comparison will be conducted for apple when the Brogdale apple accessions fingerprints become available. Several accessions were found to be false, 78 apple and 22 pear, and removal from the collection was recommended. For ACS1 genotyping of 292 apple accessions, customised fluorescently labelled ACS1-Pr were used rather than the published ACS1-5 primers. Of the 292 apple accessions, 29 were homozygous for the b allele associated with low ethylene and good storage potential. Novel size variation in one allele of the ACS1 gene, was detected in some Malus species and ornamental hybrids. Successful amplification in a multiplex reaction was achieved and proves to be a cost effective method for simultaneous molecular fingerprinting and ACS1 genotyping. True to type material will facilitate confident use of genetic resources in the breeding programmes, and the ACS1 genotypes will identify candidate parents for developing good storage performing cultivars for distant markets.
AFRIKAANSE OPSOMMING: Summary not available
Yaseen, Mehwish. "Manipulation of Fruit Ripening, Quality and Storage Life in Pome Fruits Using Novel Ethylene Antagonists." Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/75530.
Full textCloete, Mia. "Pome fruit trees as alternative hosts of grapevine trunk disease pathogens." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4169.
Full textENGLISH ABSTRACT: A survey was undertaken on apple and pear trees in the Western Cape Province to determine the aetiology of trunk diseases with reference to trunk diseases occurring on grapevine. Grapevine trunk diseases cause the gradual decline and dieback of vines resulting in a decrease in the vine’s capability to carry and ripen fruit. In recent years, viticulture has been expanding into several of the well established pome fruit growing areas. The presence of trunk pathogens in pome fruit orchards may affect the health of the pome fruit trees as well as cause a threat to young vineyards planted in close proximity to these potential sources of viable inoculum. Several genera containing species known to be involved in trunk disease on pome fruit and grapevine were found, including Diplodia, Neofusicoccum, Eutypa, Phaeoacremonium and Phomopsis. Diplodia seriata and D. pyricolum, were isolated along with N. australe and N. vitifusiforme. Four Phaeoacremonium species, P. aleophilum, P. iranianum, P. mortoniae and P. viticola, two Phomopsis species linked to clades identified in former studies as Phomopsis sp. 1 and Phomopsis sp. 7, and Eutypa lata were found. In addition, Paraconiothyrium brasiliense and Pa. variabile, and an unidentified Pyrenochaetalike species were found. Of these the Phaeoacremonium species have not been found on pear wood and it is a first report of P. aleophilum occurring on apple. This is also a first report of the Phomopsis species and Eutypa lata found occurring on pome trees in South Africa Two new coelomycetous fungi were also found including a Diplodia species, Diplodia pyricolum sp. nov., and a new genus, Pyrenochaetoides gen. nov. with the type species, Pyrenochaetoides mali sp. nov., were described from necrotic pear and apple wood. The combined ITS and EF1-α phylogeny supported the new Diplodia species, which is closely related to D. mutila and D. africana. The new species is characterised by conidia that become pigmented and 1-septate within the pycnidium, and that are intermediate in size between the latter two Diplodia species. Phylogenetic inference of the SSU of the unknown coelomycete provided bootstrap support (100%) for a monophyletic clade unrelated to known genera, and basal to Phoma and its relatives. Morphologically the new genus is characterised by pycnidial with elongated necks that lack setae, cylindrical conidiophores that are seldomly branched at the base, and Phoma-like conidia. The phylogenetic results combined with its dissimilarity from genera allied to Phoma, lead to the conclusion that this species represents a new genus. A pathogenicity trial was undertaken to examine the role of these species on apple, pear and grapevine shoots. N. australe caused the longest lesions on grapevine shoots, while Pyrenochaetoides mali, Pa. variabile, D. seriata and P. mortoniae caused lesions that were significantly longer than the control inoculations. On pears, D. pyricolum and N. australe caused the longest lesions, followed by D. seriata and E. lata. On apples, the longest lesions were caused by N. australe and P. iranianum. D. seriata, D. pyricolum, E. lata, N. vitifusiforme, Pa. brasiliense, P. aleophilum and P. mortoniae also caused lesions on apple that were significantly longer than the control. The study demonstrated that close cultivation of grapevine to apple and pear orchards may have inherent risks in terms of the free availability of viable inoculum of trunk disease pathogens.
No Afrikaans abstract available.
Curtiss, Robert T. "Attractiveness of semiochemicals to green lacewings for biological control in pome fruit." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Spring2008/R_Curtiss_050808.pdf.
Full textMantyka, Daylin Lindsay. "Detection, quantification and biological control of post-harvest pathogens of pome fruit." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/26270.
Full textKruger, Albertus Lambertus. "Agricultural extension programmes : problem conceptualisation and guideliness for the SA pome fruit industry." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52643.
Full textENGLISH ABSTRACT: No effective programmed extension exists in the South African pome fruit industry. There is a lack of farmer response and involvement, a lack of coordinated dissemination of information and no systematic and scientific approach in the development of extension programmes for the industry. Particularly important is the lack of a systematic conceptualisation of problems and specifically the lack of identification of the most direct determinants of behaviour (the psychological field forces) and a lack of the systematic addressing of these human constraints. DOvel's revised extension programme model was used as basis for this study. It included the identification, prioritisation, conceptualisation and determination of perceived problems that need to be addressed in the extension programmes. The most important identified problems that needs attention in an extension programme are producers' knowledge relating to all aspects of strategic planning (ie knowledge of basic principles, what is attainable, the advantages and disadvantages and the practical implementation), knowledge relating to the practical implementation of irrigation, bitter pit control and practices to increase fruit size, and knowledge that relates to basic principles of marketing.
AFRIKAANSE OPSOMMING: Geen doelgerigte geprogrammeerde voorligting bestaan vir die Suid-Afrikaanse kernvrugindustrie nie. Daar is 'n tekort aan produsentebetrokkenheid, 'n tekort aan gekoordineerde verspreiding van inligting en daar is geen sistematiese en wetenskaplike benadering in die ontwikkeling van voorligtingsprogramme vir die industrie nie. Besonder belangrik is die afwesigheid van 'n sistematiese konseptualisering van probleme en meer spesifiek die tekort aan die identifisering van die meer direkte determinante van gedrag (die psigiese veldkragte) en die aanspreek van hierdie menslike beperkings. DOvel se hersiene model vir geprogrameerede voorligting het as basis gedien vir die studie. Die studie het ingesluit die identifisering, prioritisering, konseptualisering en bepaling van produsente se persepsie van aangespreek behoort te word. probleme wat binne voorligtingsprogramme Die belangrikste probleme wat in die studie geïdentifiseer is wat aandag moet geniet in voorligtingsprogramme is die produsente se kennis van alle aspekte van strategiese beplanning (kennis van basiese beginsels, kennis wat betrekking het op wat bereikbaar is met strategiese beplanning, die voor- en nadele daarvan asook die praktiese implementering van strategiese beplanning), kennis wat betrekking het op die praktiese implementering van besproeiing, bitterpit beheer en die verbetering van vruggroote asook die kennis wat betrekking het op die basiese beginsels van bemarking.
Van, Schoor Louise. "Effect of biological amendments on soil microbial properties and performance of pome fruit trees." Thesis, Stellenbosch : Stellenbosch University, 2009. http://hdl.handle.net/10019.1/4602.
Full textENGLISH ABSTRACT: The global movement in agriculture is towards more environmentally friendly, sustainable production practices, since the role of soil microbial functions in ensuring crop production and soil fertility has become more evident in agricultural systems. Furthermore, with the impeding phase-out of methyl bromide, apple replant disease (ARD) is becoming an increasingly important problem and biological management practises are needed. Since microbial activity is generally carbon-limited in agricultural soil, it is widely accepted that management practices providing a range of organic compounds on a regular basis will tend to maintain an active and diverse microbial population. It was hypothesised that the application of various biological amendments can affect soil microbial numbers and function, thereby having a positive effect on fruit tree growth and yield. The effect of continued applications of organic material, various microbial inoculants and biostimulants on tree performance were evaluated in conventional management systems. Field trials were established in a conventional pear orchard, potential apple replant disease sites, as well as an optimally managed, high density apple orchard under controlled fertigation. The use of compost, compost extracts, a Bacillus inoculant and humates were investigated intensively. Furthermore, to improve our understanding of soil biological systems a combination of simple, practical methods were used to evaluate the effect of biological amendments on soil microbial properties and effects were related to tree performance. Regular application of compost extract in combination with compost showed the most significant effect in improving tree performance in commercial pome fruit orchards under various conditions. In the pear orchard, cumulative yield over the first two seasons was improved by more than 50% compared to controls, while in the fertigated orchard yield was improved by 22%. Biological amendments also showed improved growth in orchards suffering from stunted growth symptoms typical of ARD. However, in severe ARD cases methyl bromide fumigation showed the most consistent effects. Other biological amendments which showed positive effects on yield were application of Bacillus inoculants (Biostart®) in combination with a labile C source and a low dosage humate product, as well as a combination of compost and humates. It was clear that a combination of labile organic matter and a diverse group of microorganisms showed most promise. Although for some specific treatments increased microbial numbers and activity may have resulted in improved tree performance, in general, changes in culture-based plate counts, soil enzyme activity and carbon utilisation profiles could not be used as an indicator of yield. It was suggested that improved synchronisation of nutrient release and plant uptake, as well as microbial phytohormone production, may play an important role in improving tree performance with application of biological amendments. More research is needed on the exact mechanisms through which compost extracts improve yield and studies on root growth proliferation, as well as effects in the rhizosphere are recommended.
AFRIKAANSE OPSOMMING: Binne lanbouverband is daar tans wêreldwyd die neiging om die uitwerking van produksie-praktykte op die omgewing in ag te neem en sodoende meer verantwoordelik op te tree. Omdat die belangrike rol wat grondmikro-organisme funksionering in volhoubare verbouingspraktyke speel nou deeglik besef word, word meer volhoubare bestuurspraktyke bepleit. Hiermee saam, noodsaak aspekte soos die uitfasering van metielbromied vir die beheer van appelhervestigingsiekte, dat biologiese bestuurspraktyke meer aandag geniet. Daar word geredelik aanvaar dat gereelde toediening en aanvulling van organiese materiaal ‘n aktiewe, diverse mikrobe populasie in die grond tot gevolg sal hê. Die hipotese is gestel dat die toediening van ‘n verskeidenheid biologiese produkte grondmikrobe getalle en werking gunstig kan beïnvloed. Dit kan moontlik weer aanleiding gee tot positiewe reaskies wat die groei en drag van vrugtebome betref. In hierdie studie is die uitwerking van voortgesette toedienings van organiese materiaal, mikrobiese inokulante, asook biostimulante, op die prestasievermoë van vrugtebome ondersoek. Veldproewe is uitgelê in ‘n konvensionele peerboord, verskeie boorde met moontlike appelhervestigingsiekte probleme, asook ‘n hoëdigtheidsaanplanting appelboord onder optimale bestuur. ‘n Deeglike ondersoek is gedoen met betrekking tot die gebruik van kompos, komposekstrak, Bacillus-inokulante en humate. Eenvoudige, praktiese metodes is aangewend om vas te stel hoe biologiese toevoegings grondmikrobe eienskappe beïnvloed en of dit verband hou met veranderinge in boomprestasie. Die studie het aangetoon dat die gereelde toediening van komposekstrak saammet kompos, betekenisvolle verbetering in boomprestasie van kernvrugboorde teweeg bring onder verskeie omstandighede. Die kumulatiewe opbrengs van ‘n peerboord is oor twee seisoene met meer as 50% verhoog teenoor die kontrole. In ‘n optimaal bestuurde appelboord onder sproeibemesting, is opbrengs met 22% verhoog in vergelyking met die kontrole. Biologiese toevoegings het ook groei verbeter in boorde waar appelhervestigingsiekte bome se groei vertraag het. In die geval van ernstige appelhervestigingsimptome het metielbromied egter steeds die mees konstante positiewe uitwerking gehad. Ander biologiese toevoegings wat ‘n gunstige uitwerking op opbrengs getoon het, was ‘n kombinasie van Bacillus inokulante, ‘n lae dosis humaat en ‘n aktiewe koolstofbron, asook kompos in kombinasie met humate. Dit is duidelik dat ‘n kombinasie van ‘n maklik afbreekbare koolstofbron (soos kompos) tesame met ‘n diverse groep mikroorganismes mees belowend is vir gebruik in biologiese verbouingssisteme. Resultate toon dat veranderings in aantal organismes gemeet deur plaattellings, die aktiwiteit van grondensieme, en verbruikspotensiaal van verskillende koolstofbronne, nie as ‘n aanduiding van boomprestasie gebruik kan word nie. Daar is voorgestel dat verbeterde sinkronisasie van voedingselementvrystelling en plantopname, sowel as produksie van plantgroeihormone deur mikrobe, moontlik ‘n rol speel by boomreaksies op biologiese toevoegings. Meer navorsing wat verband hou met die meganisme waardeur komposekstrak opbrengs verbeter, is nodig. Verder word studies op fynwortelontwikkeling sowel as aspekte van die wortelrisosfeer aanbeveel.
Thorpe, Peter Tulloh. "Future-proofing food : striving towards minimal insecticidal application in Western Cape pome fruit orchards." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96734.
Full textENGLISH ABSTRACT: Increasing pressure on food production and the concern over maintenance of biodiversity and ecosystem services is creating an urgent need to future-proof food production, while maintaining the natural environment for future generations. Within the Cape Floristic Region (CFR) biodiversity hotspot in the Western Cape of South Africa, deciduous fruit is widely grown, contributing significantly to the local economy. To ensure access is maintained to important export markets, this study reviews the current available pest control options with focus on techniques able to preserve the biodiversity of the CFR, while simultaneously providing effective control over arthropod pests in pome fruit. A scenario planning technique is then used to depict potential future scenarios and the options we have in dealing with them. Emphasis here is placed on economically important arthropod species, particularly Mediterranean fruit fly Ceratitis capitata (Wiedemann) and codling moth Cydia pomonella (L.). Biological control (biocontrol) is discussed in detail, covering predators, parasitoids and pathogens. Biocontrol is an important, sustainable pest control measure. However, certain risks associated with releasing living organisms into the environment must not be ignored. Monitoring of release programmes is essential. The sterile insect technique (SIT) offers a species-specific approach to controlling pests. However, the technique is research and management intensive. Globally SIT has shown great success, but lack of financial support has limited SIT uptake locally. SIT has shown increased effectiveness as an integrated technique, particularly with parasitoid release and pheromone-based mating disruption. The management of orchards as agroecosystems shows that preservation of natural vegetation and beneficial plant species increases crop resilience, encourages conservation biological control and maintains crop health. The importance of area-wide control is discussed under each section, as a favourable strategy which deals with entire pest populations rather than isolated farm-by-farm approaches. Other techniques covered include pheromone-based mating disruption, attract-and-kill and physical barriers such as sticky tree-bands, which all show integration potential with biologically-based techniques while minimising insecticide application. The usefulness of insecticides as a curative approach is recognised, and ways of preserving insecticide life-spans by limiting insecticide resistance are discussed. Social, economic, political, environmental and technological driving forces are used to develop four realistic future scenarios for pome fruit production in the CFR. The scenarios are based on the extremes of two key uncertainties: development of resistance to chemical insecticides, and changes in legislation regulating insecticide usage. The options we face in dealing with each potential scenario, with the suite of arthropod pest control techniques currently developed, is discussed. It is hypothesised that a best-case scenario, in which environmentally-friendly techniques which support healthy, productive agroecosystems, can be reached. We should carefully assess our options, and begin to shift pest control from a predominantly chemical basis to one in which habitat management and biocontrol form the basis of control, with techniques such as SIT, mating disruption and physical barriers assisting in creating holistic arthropod pest control systems. In light of the uncertainty that the future holds, a scenario planning exercise such as this, can assist in decision making today that will best prepare us to deal with future threats such as climate change and new pest invasions.
AFRIKAANSE OPSOMMING: Toenemende druk op voedselproduksie en kommer oor die handhawing van biodiversiteit en ekosisteemdienste lei tot „n dringende behoefte om voedselproduksie toekoms-bestand te maak, asook om tegelykertyd die natuurlike omgewing vir toekomstige generasies te bewaar. Binne die Kaap Floristiese Streek (KFS) „biodiversiteitskern‟ in die Wes-Kaap van Suid-Afrika word sagte vrugte algemeen verbou en lewer „n aansienlike bydrae tot die plaaslike ekonomie. Om toegang tot belangrike uitvoermarkte te verseker ondersoek hierdie studie die plaagbeheer opsies tans beskikbaar, met die fokus op tegnieke wat die biodiversiteit van die KFS kan bewaar en tegelykertyd effektiewe beheer oor geleedpotige plae van kernvrugte kan verskaf. „n Scenario-beplannings-tegniek word dan gebruik om moontlike toekomstige scenario‟s en die opsies tot ons beskikking om hulle te hanteer, uit te beeld. Klem word hier geplaas op geleedpotige spesies van ekonomiese belang, veral die Mediterreense vrugtevlieg, Ceratitis capitata (Wiedemann) en die kodlingmot Cydia pomonella (L.). Biologiese-beheer (biobeheer) word in diepte bespreek, en dek predatore, parasiete en patogene. Biobeheer is „n belangrike, volhoubare plaagbeheer-middel; alhoewel sekere risiko‟s verbonde met die vrystelling van lewende organismes in die omgewing nie verontagsaam moet word nie. Dit is noodsaaklik dat vrystellingsprogramme gemoniteer word. Die steriele-insek-tegniek (SIT) bied „n spesies-spesifieke benadering tot die beheer van plae, alhoewel dit navorsings- en bestuursintensief is. SIT het wêreldwyd al groot suksesbehaal, maar „n tekort aan finansiële ondersteuning het die plaaslike toepassing van SIT beperk. SIT het verhoogde effektiwiteit as „n geïntegreerde tegniek vertoon, veral met die verlies van parasiete en feromoon gebaseerde parings-ontwrigting. Die bestuur van boorde as agro-ekosisteme wys dat die bewaring van natuurlike plantegroei en voordelige plant spesies oes-herstelvermoë verhoog, bewaring-biologiese-beheer aanmoedig en oes-welstand handhaaf. Die belang van streekswye beheer word bespreek onder elke afdeling as „n gunstige strategie wat te doen het met algehele plaagbevolkings, eerder as afsonderlike plaas-tot-plaas benaderings. Ander tegnieke wat gedek word sluit in feromoon gebaseerde parings-ontwrigting, lok-en-doodmaak en fisiese versperrings soos taai boom-bande, wat alles integrasie-potensiaal wys met biologies gebaseerde tegnieke en tegelykertyd insekdoder aanwending verminder. Die nuttigheid van insekdoders as „n herstel benadering word erken en maniere om die leffektiwiteit van insekdoders te behou deur insekdoder-weerstand te beperk, word bespreek. Sosiaal-, ekonomies-, polities-, omgewings- en tegnologies-gedrewe kragte word gebruik om vier realistiese toekomstige scenario‟s vir kernvrug-produksie in die KFS te ontwikkel. Die scenario‟s is baseer op die ekstreme van twee belangrike onsekerhede: ontwikkeling van weerstand teen chemiese insekdoders, en veranderinge in wetgewing wat die gebruik van insekdoders reguleer. Die opsies wat ons in die gesig staar om elke potensiële scenario te hanteer met die verskeidenheid van geleedpotige plaagbeheer-tegnieke tans ontwikkel is, word bespreek. Dit word veronderstel dat „n beste scenario, waar omgewings-vriendelike tegnieke wat gesonde, produktiewe agro-ekosisteme onderhou, bereik kan word. Ons moet ons opsies versigtig assesseer, en begin om plaagbeheer vanaf „n oorwegend chemiese basis te skuif na een waar habitat-bestuur en biobeheer die basis van beheer vorm, en waar tegnieke soos SIT, parings-ontwrigting en fisiese versperrings help om holistiese geleedpotige-plaagbeheer sisteme te vorm. In die lig van die onsekerheid wat die toekoms inhou, kan „n scenario-beplannings oefening soos hierdie besluitneming vandag aanhelp wat ons die beste sal voorberei vir die hantering van toekomstige bedreigings soos klimaats-verandering en nuwe en vreemde plaag-indringing.
Berry, Tarl Michael. "Resistance to airflow and the effects on cooling efficiency of multi-scale ventilated pome fruit packaging." Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85685.
Full textENGLISH ABSTRACT: Inadequate cooling of produce after it has been packed into ventilated packaging can result in inconsistent fruit quality. Misalignment of ventilation holes during stacking as well as the use of internal packaging, such as trays, polyliner bags and thrift bags reduces airflow distribution through the packaging. Consequently, the complex needs of maintaining the cold chain of perishable produce and the considerable variations in packaging designs have made it challenging to find an optimal ventilated package and stacking arrangement. The aims of this study were, therefore, to assess the status of ventilated packaging in the South African pome fruit industry, and to characterize the effects of package design and multi-scale packaging components on the resistance to airflow and cooling performance of apples under forced-air cooling conditions. A survey of the pome fruit industry identified over twenty packaging designs which were grouped into eleven unique designs and further categorised into either ‘display’ or ‘telescopic’ designs. Although South African fruit industry standards recommend ventilation areas of at least 5%, the ventilation areas of package designs identified from the survey varied considerably between <1 and 11%. Furthermore, the study showed that use of stacking renders many of the ventilation holes ineffective, due to blockages from adjacent cartons. The contribution of each component of the multi-scale packages used for handling apples was determined by analysis of pressure drop during forced-air cooling. The results showed when utilising a combination of cartons, fruit trays and plastic liner bags, the total pressure drop contribution of the cartons (8%) and fruit trays (3%) was minimal, while the use of plastic liner bags contributed 89%. However, in a carton and thrift bag packaging combination, the thrift bags contributed 66% to the pressure drop while the carton contributed 34%. The cooling results indicated a negative correlation between the total stack ventilation area and the cooling heterogeneity. In addition, the airflow velocity was correlated positively with fruit cooling rate and negatively with total moisture loss. Fruit packed inside polyliner bags had cooling rates four times slower than fruit on trays and three times slower in thrift bags. The use of liner bags blocked the ventilation holes, thereby reducing the airflow velocity. As a result of the longer cooling times in the polyliner bags, fruit remained at higher temperatures for longer periods, resulting in up to three times more moisture loss during forced-air cooling. In addition, a temperature gradient formed due to a progressive increase in air temperature through the stack, thereby resulting in a similar gradient of moisture loss. This research showed that airflow velocity and distribution were the most important factors contributing to the effectiveness of fruit cooling in multi-scale packaging. From a cold chain perspective, future packaging designs should therefore focus on optimising ventilation characteristics and alignment during stacking to ensure adequate airflow. Given the contribution of internal packaging to high resistance to airflow, such packaging components should be used with caution and only when necessary to meet physiological and market requirements.
AFRIKAANSE OPSOMMING: Onvoldoende verkoeling van vars produkte nadat hulle verpak is kan lei tot wisselende vruggehalte. Wanbelyning van ventilasiegate tydens stapeling sowel as die gebruik van interne verpakking soos rakkies (eng. “trays”), poli-etileensakke en drasakkies (eng. “thrift bag”) verminder die lugverspreiding deur die verpakking. Komplekse behoeftes om bederfbare produkte in die koue ketting te behou en die aansienlike verskille in verpakkingsontwerpe het dit 'n uitdaging gemaak om 'n optimale geventileerde verpakking en stapelskikking of -rangskikking te vind. Die doelwitte van hierdie studie was dus om die status van geventileerde verpakking in die Suid-Afrikaanse kernvrugbedryf te asseseer, en die gevolge van die verpakkingsontwerp en multi-skaal verpakkingskomponente op die weerstand teen lugvloei en verkoeling van appels onder geforseerde lugverkoeling te bepaal. ‘n Opname van die kernvrugbedryf het meer as twintig verpakkingsontwerpe geïdentifiseer, wat in elf unieke ontwerpe gegroepeer is en verder getipeer word in ‘vertoon’ en ‘teleskopiese’ kartonontwerpe. Alhoewel die Suid-Afrikaanse vrugindustrie-standaarde ventilasie areas van ten minste 5% aanbeveel, het die ventilasie areas van die verpakkingsontwerpe geïdentifiseer uit die opname aansienlik gewissel tussen <1 en 11%. Verder het die studie getoon dat gebruik van stapeling baie van die ventilasiegate ondoeltreffend laat weens blokkasies veroorsaak deur aangrensende kartonne. Die bydrae van elke komponent van die multi-skaal verpakkingskombinasies gebruik vir die hantering van appels was bepaal deur analise van die afname in lugdruk tydens geforseerde lugverkoelingskondisies. Die resultate het getoon dat wanneer ‘n kombinasie van kartonne, polietileensakke en vrugte plus rakkies gebruik word, die bydrae van die kartonne (8%) en vrugte plus rakkies (3%) tot die totale afname in lugdruk minimaal was, terwyl die gebruik van polietileensakke ‘n 89% bydrae gemaak het. In ‘n karton en drasakkie kombinasie het die drasakkies 66% bygedra tot die afname in lugdruk, terwyl die karton 34% bygedra het. Die verkoelingsresultate het 'n negatiewe korrelasie getoon tussen die totale stapelventilasie-area en die verkoelingsheterogeniteit. Daarbenewens was die lugvloeisnelheid positief gekorreleer met vrugverkoelingstempo en negatief gekorreleer met totale vogverlies. Die verkoelingstydperk van vrugte in die poli-etileensakke was vier keer langer as die rakkie met vrugte kombinasie en drie keer langer in die drasakkies. Die poli-etileensakke het die ventilasiegate versper en dus die lugvloeisnelheid verlaag. Weens die langer verkoelingstye in die poli-etileensakke was vrugte veel langer aan hoër temperature blootgestel, wat uiteindelik gelei het tot drie keer meer massaverlies gedurende geforseerde lugverkoeling. Daarby het ‘n temperatuurgradiënt gevorm as gevolg van ‘n progressiewe verhoging in lugtemperatuur deur die stapel wat gelei het tot ‘n gelykstaande gradiënt van vogverlies. Hierdie navorsing het getoon dat die lugvloeisnelheid en -verspreiding die belangrikste faktore was wat die doeltreffendheid van vrugverkoeling in multi-skaal verpakking geaffekteer het. Uit 'n koelketting perspektief moet die toekomstige verpakkingsontwerpe dus fokus op die optimalisering van ventilasie eienskappe en belyning (eng. “alignment”) tydens stapeling om voldoende lugvloei te verseker. Gegewe die bydrae van die interne verpakking tot hoë weerstand teen lugvloei, moet sulke verpakkingskomponente met omsigtigheid gebruik word en slegs wanneer dit nodig is om aan markvereistes te voldoen.
de, Kock Lorren. "Carbon intensive but decarbonising quickly? Retrospective and prospective life cycle assessments of South African pome fruit." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29886.
Full textBlomefield, Thomas Loftus. "Bionomics, behaviour and control of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), in pome fruit orchards in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53312.
Full textENGLISH ABSTRACT: The codling moth, Cydia pomonella (L.) has been a major pest of pome fruits since before the turn of the last century. However, despite its high economic profile little is known about the bionomics and . behaviour of this pest in apple orchards in South Africa, information required for the development of a sustainable integrated management programme. In field trials there was contingency between the time of year and the upper and lower half of the tree. First generation moths laid significantly more eggs in the bottom half of the tree while second and third generation moths laid significantly more eggs in the top half of the tree. The preferred oviposition sites on Granny Smith (GS) and Golden Delicious (GD) cultivars, in order of preference, were leaves, fruit and wood. More eggs were laid on the fruit ofGS spurs (35.6 %) than on those ofGD spurs (10.7 %). On fruit spurs there was a significant increase in the number of eggs on GD leaves and GS fruit over the season, whereas the number of eggs on GS leaves and GD fruit remained constant. On branches there was an increase in the number of eggs on GD and GS leaves, but not on the fruit or wood. The preferred oviposition site on the fruit was the fovea of the stalk insertion and the rounded cheek area surrounding the fovea. The distribution within different fruit bearing classes (1 - 4 fruit per spur) was random only for one fruit per spur, while on the other spur classes clustering occurred. In laboratory studies of the embryonic and immature stages there was a linear relationship between rate of development and constant temperatures of 15, 17,20,25 and 30·C ± l·C. The lower threshold temperatures for embryonic, larval and pupal development were 11.1, 7.9, 9.9°C respectively. The degree-days required to complete embryonic, larval and pupal development were 80.5, 345, and 279 respectively. The response of the different stages to constant temperatures was similar to that under fluctuating temperatures. At temperatures below 16°C or abouve 27°C moths did not mate and few eggs were laid. Moth longevity decreased with increasing temperature. There was seasonal variation in longevity and oviposition at constant and fluctuating temperatures. Summer adults produced significantly more eggs than spring adults at constant temperatures. At a constant temperature of2S·C and fluctuating temperatures there were five distinct larval instars. The similarity between the mean head capsule width and ranges for each instar reared on fruit of different stages of development at fluctuating temperatures indicates that fruit development and temperature have little influence on mean head capsule width. From sleeve-cage studies in the orchard there was no significant difference in the fecundity of spring and summer moths. In the beginning of October spring moths produced significantly fewer eggs than in November. Egg mortality increased from 8.2 %in spring to 21.2 %in summer. Failure of 1st instar larvae to penetrate the fruit ranged from 4.9 % to 19.5 %, while mortality oflarvae from egg hatch to emergence from the fruit ranged from 29.7 % to 42.9 %. Mortality of 5th instar larvae after emerging from the apples ranged from 0 % to 8.7 % and pupal mortality from 0 % to 3.5 %. On large 27-year old trees more overwintering larvaewere found on Golden Delicious (13.9) than on Granny Smith trees (5.7), with over 70 % oflarvae being found in pruning wounds on both cultivars. On small 7-year old Golden Delicious and Granny Smith trees the mean number oflarvae was 0.5 and 2.0 per tree. A combined mating disruption and insecticide control programme reduced codling moth resistant populations to levels requiring a minimum to no insecticide intervention for several seasons. The efficacy of a pheromone based strategy, number of pheromone treatments, number of dispenserslha and level of insecticide intervention required are strongly influenced by prevailing weather conditions. Fruit infestation in orchards under a mating disruption programme and under an insecticide programme were greater along the borders compared to the interior. The presence of horticultural mineral oil on the leaves and branches did not have a detrimental effect on oviposition nor was there any significant ovicidal effect. A significant ovicidal effect was obtained when applied after oviposition. In field trials, insecticides with lower levels of efficacy than the primary insecticide, azinphos-methyl, provided acceptable control when successfully incorporated into a spray programme which followed a policy of alternation of insecticides across generations. The least variation in the number of degree-days between biofix and first egg hatch of the spring flight was when the second trap catch (Biofix 2) was used as the biofix. A biofix based on the first evening when the temperature reached or exceeded 1TC at 18:00 after first trap catch also showed less variation than when the biofix was based on first trap catch. The mean number of degree-days accumulated between Biofix 2 and first egg hatch was found to be 139.1 ° D. The number of degreedays between the first and second flight biofixes varied between 531.2 and 488.87°D with a mean of 508.1°D.
AFRIKAANSE OPSOMMING: Kodlingmot (Cydia pomonella) is reeds sedert die vorige eeu 'n sleutelplaag van kemvrugte. Ten spyte van die hoë ekonomiese profiel, is daar min kennis betreffende die bionomie en gedrag van hierdie plaag in appelboorde in Suid-Afrika. Hierdie inligting is noodsaaklik vir die ontwikkeling van 'n volhoubare geïntegreerde bestuursprogram. Tydens veldproewe is 'n korrelasie tussen die tyd van die jaar en eierlegging in die boonste of onderste helfte van bome gevind. Eerste-generasie motte het betekenisvol meer eiers in die onderste helfte van die bome gelê, terwyl tweede- en derde-generasie motte meer eiers in die boonste helfte van die bome gelê het. In toenemende volgorde was die voorkeur eierleggingsposisies op Granny Smith (GS) en Golden Delicious (GD) appels die blare, vrugte en hout. Meer eiers is op vrugte van GS spore (35.6%) as op dié van GD spore (10.7%) gelê. Op vrugspore was daar 'n betekenisvolle toename in aantal eiers op GD blare en GS vrugte deur die seisoen, terwyl die getal eiers op GS blare en GD vrugte konstant gebly het. Op takke was daar 'n toename in aantal eiers op GD en GS blare, maar nie op vrugte of hout nie. Die voorkeur eierleggingsposisie op vrugte was die fovea van die steelaanhegting en die wang rondom die fovea. Die verspreiding tussen verskillende vrugdraende klasse (1 - 4 vrugte per spoor) was slegs in die een-Vrug-per-spoorklas ewekansig, terwyl daar in die ander spoorklasse groepering voorgekom het. In laboratoriumstudies van embrioniese en onvolwasse stadia is 'n lineêre verband tussen ontwikkelingskoers en konstante temperature van 15, 17,20,25 en 30°C±I°C gevind. Die onderste drempel-temperature vir embrioniese, larwale en papie-ontwikkeling was onderskeidelik II. 1°C, 7.f?C en 9.9°C. Graaddae benodig vir voltooiing van embrioniese, larwale en papie-ontwikkeling was onderskeidelik 80.5,345 en 279. Die respons van verskillende stadia by konstante temperature het ooreengestem met hul respons onder wisselende temperature. Motte het nie gepaar nie en min eiers is gelê by temperature onder 16°C of bo 27°C. Die lewensverwagting van motte het afgeneem met toename in temperatuur. Seisoenale variasie in . lewensverwagting en eierlegging het voorgekom by konstante sowel as wisselende temperature. By konstante temperature het somer-volwassenes betekenisvol meer eiers as lente-volwassenes geproduseer. By 'n konstante temperatuur van 25°C, sowel as by wisselende temperature, het vyf duidelik onderskeibare larwale instars voorgekom. Die ooreenkoms tussen die gemiddelde kopkapsulewydte en wydte-reeks vir elke instar wat op vrugte van verskillende stadiums van ontwikkeling by wisselende temperature geteel is, dui daarop dat vrugontwikkeling en temperatuur weinig invloed op gemiddelde kopkapsule-wydte het. Tydens mou-hok studies in die boord is geen betekenisvolle verskil in die fekunditeit van lente- en somer-motte waargeneem nie. Vroeg in Oktober het lente-motte betekenisvol meer eiers as in November geproduseer. Eiermortaliteit het van 8.2% in die lente tot 21.2% in die somer toegeneem. Faling van 1ste instar larwes om vrugte te penetreer het van 4.9% tot 19.5% gewissel, terwyl mortaliteit van larwes vanaf uitbroei tot uitkoms uit die vrug van 29.7% tot 42.9% gewissel het. Mortaliteit van Sde instar larwes na uitkoms uit die vrug het van 0% tot 8.7% gewissel, en papie-mortaliteit van 0% tot 3.5%. Op groot, 27-jaar oue bome is meer oorwinterende larwes op Golden Delicious (13.9) as op Granny Smith (5.7) gevind, en meer as 70% van die larwes op beide kultivars is op snoeiwonde gevind. Op klein, 7-jaar oue bome was die gemiddelde aantallarwes op Golden Delicious en Granny Smithbome 0.5 en 2.0 onderskeidelik. 'n Gekombineerde paringsontwrigting- en insekdoder beheerprogram het weerstandbiedende kodlingmot-populasies verminder tot 'n vlak waar minimum tot geen insekdoder-toedienings vir verskeie seisoene gemaak is. Die effektiwiteit van 'n feromoon-gebaseerde strategie, aantal feromoonbehandelings, aantal vrystellers/ha en vlak van insekdoder-toediening word sterk deur heersende weersomstandighede beïnvloed. Die rande het hoër vruginfestasie as die middel getoon in boorde onder paringsontwrigting sowel as boorde onder insekdoder-programme. Die teenwoordigheid van minerale olie op blare en takke het geen nadelige effek op eierlegging gehad nie en dit het geen betekenisvolle eierdodende effek gehad nie. Indien die olie ná eierlegging toegedien is, is daar wel 'n betekenisvolle eierdodende effek waargeneem. Tydens veldproewe het insekdoders met laer effektiwiteit as die primêre insekdoder, azinfos-metiel, aanvaarbare beheer verskaf indien dit suksesvol geïnkorporeer is in 'n spuitprogram deur 'n beleid van afwisseling van insekdoders oor generasies. Die kleinste variasie tussen die aantal graaddae tussen biofix en eerste uitbroei van eiers is gevind indien die tweede lokvalvangs as biofix gebruik is. 'n Biofix gebaseer op die eerste aand na die eerste lokval vangste wat die temperatuur 17°Cofhoër was teen 18:00, het ook 'n kleiner variasie getoon as die eerste lokvalvangs. Die aantal graaddae tussen die tweede en derde vlug biofix het tussen 531.2 en 488.87°D gewissel, met 'n gemiddelde van 508.1°D.
Bancroft, Roger David. "The effects of a surface coating on the development of post-harvest fungal rots of pome fruit with special reference to 'Conference' pears." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596331.
Full textMudavanhu, Pride. "An investigation into the integrated pest management of the obscure mealybug, Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae), in pome fruit orchards in the Western Cape Province, South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2620.
Full textENGLISH ABSTRACT: Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) (obscure mealybug), is a common and serious pest of apples and pears in South Africa. Consumer and regulatory pressure to produce commodities under sustainable and ecologically compatible conditions has rendered chemical control options increasingly limited. Information on the seasonal occurrence of pests is but one of the vital components of an effective and sustainable integrated pest management system needed for planning the initiation of monitoring and determining when damage can be expected. It is also important to identify which orchards are at risk of developing mealybug infestations while development of effective and early monitoring tools for mealybug populations will help growers in making decisions with regards to pest management and crop suitability for various markets. It is also essential to determine the presence and efficacy of naturally occurring biological control agents in orchards so as to ascertain the potential of biological control as a viable alternative in orchards. However, under the current integrated pest management protocol, it has been difficult to determine this, due to the sporadic and relatively low incidence of mealybug infestations in some orchards, or by simply relying on naturally occurring field populations of biocontrol agents. Knowledge of the environmental conditions under which P. viburni population levels may become destructive is also essential for timing the release of insectary reared natural enemies as well as understanding the population ecology of this pest and its natural enemies. Information was gathered regarding the seasonal phenology of P. viburni and its natural enemies in pome fruit orchards in the Western Cape Province during the 2007/08 and 2008/09 growing seasons. Seasonal population studies showed that P. viburni has multiple overlapping generations with all life stages present throughout the year. The highest orchard infestations occurred during the summer period until early winter (January to early June). This was followed by a decrease in population from late June to November, before another increase in December. Presence-absence sampling of mealybugs on the host plant revealed that woody parts of the tree, such as the trunk and old stems were the most preferred sites for mealybug habitation, due to the availability of protected refuge sites. Migration of mealybug populations to newer growth and the upper sections of the tree crown, such as the new stems, leaves and eventually the fruit, was observed from December throughout the summer period until the early winter in June. Fruit colonization in both apples and pears commenced in January, when the fruit had developed a size sufficient for P. viburni to penetrate and occupy spaces such as the fruit core, calyx and stem end. There was no evidence of P. viburni occurring beneath the soil surface or on the roots of host trees. Two natural enemies of mealybugs, namely Pseudaphycus maculipennis (Mercet) and Coccidoxenoides perminutus (Girault), were found to be active in apple and pear orchards in the Western Cape. However, the status of C. perminutus as a parasite of P. viburni still needs to be verified despite evidence of emergence from P. viburni mummies, which was not sufficient enough to suggest that it is a useful biological control agent. Seasonal abundance trends of the two natural enemies revealed that their lifecycle is synchronized with that of the host. However, there was no evidence of P. maculipennis activity in Ceres. No predators were found during the course of this study. The rate of P. viburni parasitism at harvest was 46.52%, with P. maculipennis and C. perminutus constituting 98.966% and 1.034% of the parasitoids recovered from mealybug mummies, respectively. Studies on the use of pheromone traps as early monitoring tools for P. viburni showed that there was a positive and significant relationship between the fruit infestation and number of P. viburni adult males caught in pheromone-baited traps (r2 = 0.454). The action threshold level was estimated to be 2.5 male P. viburni caught per trap per fortnight at an economic threshold of 2% fruit infestation.
AFRIKAANSE OPSOMMING: Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) (ligrooswitluis), is ‘n algemene en ernstige plaag van appels en pere in Suid-Afrika. Druk deur verbruikers en regulasies om kommoditeite onder volhoubare en ekologies verenigbare toestande te produseer het chemiese beheeropsies toenemend beperk. Inligting oor die seisoenale voorkoms van plae is een van die essensiële komponente van ‘n effektiewe en volhoubare geïntegreerde plaagbestuurprogram. Dit is in die aanvanklike beplanning van monitering en om te bepaal wanneer skade verwag kan word. Dit is ook belangrik om boorde vroegtydig te identifiseer wat die risiko het om witluisbesmettings te ontwikkel. Die ontwikkeling van effektiewe en vroeë moniteringstegnieke vir witluisbevolkings sal produsente help met besluitneming rakende plaagbestuur en die geskiktheid van gewasse vir verskeie markte. Dit is ook noodsaaklik om die teenwoordigheid en effektiwiteit van biologiese beheer agente wat natuurlik in boorde voorkom te bepaal ten einde die potensiaal van biologiese beheer as ‘n lewensvatbare alternatief vas te stel. Onder die huidige geïntegreerde plaagbestuurprotokol was dit egter moeilik om laasgenoemde te bepaal weens die sporadiese en relatiewe lae voorkoms van witluisbesmettings in sommige boorde of deur bloot staat te maak op die veldpopulasies van biologiese beheer agente wat natuurlik voorkom. Kennis van die omgewingstoestande waaronder P. viburni bevolkingsvlakke skadelik raak is ook noodsaaklik vir die beplanning van vrylating van biologiese beheer agente, asook om die bevolkingsekologie van hierdie plaag en sy natuurlike vyande te verstaan. Inligting oor die seisoenale fenologie van P. viburni en sy natuurlike vyande in sagtevrugte boorde in die Westelike Kaapprovinsie is gedurende die 2007/08 en 2008/09 groeiseisoene versamel. Seisoenale bevolkingstudies het getoon dat P. viburni verskeie oorvleuelende generasies het met alle stadia teenwoordig regdeur die jaar.
Long, Robert Llewellyn, and bizarrealong@hotmail com. "Improving fruit soluble solids content in melon (Cucumis melo L.) (reticulatus group) in the Australian production system." Central Queensland University. Biological and Environmental Science, 2005. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20051019.144749.
Full textStenekamp, Daleen. "Optimization of a mass-rearing system to produce codling moth, Cydia pomonella, for a Sterile Insect Release programme in South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6658.
Full textENGLISH ABSTRACT: Codling moth, Cydia pomonella, is a worldwide pest and of major economic importance to the South African pome fruit industry. Sterile insect release is applied as a component of area-wide integrated pest management and includes the mass-rearing, sterilization and the release of the sterile insects. For sterile insect release, the improvements of rearing methods in terms of the quality of the diet ingredients and the economical aspect of the rearing method are examined. The effect of genetically modified maize meal, containing the Bacillus thuringiensis gene, in an artificial medium for codling moth rearing, is determined. The use of even a small amount of Bacillus thuringiensis resulted in larval mortality and prolonged development. These results are detrimental to a mass-rearing facility and must be considered by any rearing facility that uses genetically modified maize meal if the insect is sensitive to the gene. An alternative to maize meal in the artificial medium was tested and whole wheat flour was considered to be a suitable replacement. Agar agar is an expensive gelling agent used in the artificial medium. An alternative for agar agar (Kelcogel, Elastigel and carrageenen) is tested and the biological effect on codling moth is determined. Factors such as mortality, pupal and moth weight, longevity, fecundity and development time were used as quality parameters. Results showed that Elastigel was a suitable replacement for agar agar, with bigger pupae and moths, higher fecundity and increased longevity. The economical advantage of the replacement is a 40.91% reduction of the diet cost. The other gelling agents tested also gave acceptable results and can be considered if shortages of agar agar or Elastigel occur. A new method of mass-rearing codling moth larvae in a closed rearing system using large trays placed in a ventilated box is designed. This method is more cost and space effective as a smaller area is needed to rear a large number of moths. The risk of diet contamination is less because of the closed environment and more economical and effective air handling. This is the first report of its kind to describe the mass-rearing of codling moth in a closed environment and the risks involved in using genetically modified maize meal in an artificial diet for the codling moth. These results should be incorporated into existing mass-rearing facilities or taking into consideration when designing new mass-rearing facilities.
AFRIKAANSE OPSOMMING: Die kodlingmot, Cydia pomonella, is van ekonomiese belang vir die Suid-Afrikaanse kernvrugte bedryf. Die steriele insek tegniek word gebruik as ‘n komponent in area-wye geïntegreerde plaagbeheer en sluit in die massa-aanteel, sterilisering en vrylaat van steriele insekte. Vir die steriele insek tegniek is die verbetering van die massa-aanteel van die kodlingmot in terme van kwaliteit van die dieet en die ekonomiese aspek van die aanteel metode ondersoek. Die effek van genetiese gemanipuleerde mieliemeel wat die Bacillus thuringiensis geen bevat, in ‘n kunsmatige voedselmedium vir die aanteel van kodlingmot, is bepaal. Daar is gevind dat die gebruik van selfs ‘n klein persentasie Bacillus thuringiensis in die mieliemeel, mortaliteit en ‘n verlengde lewenssiklus in kodlingmot veroorsaak. Die gevolge is nadelig vir ‘n massa-aanteel fasiliteit en behoort in ag geneem te word vir enige insek wat op ‘n kunsmatige medium, wat mieliemeel bevat, geteel word, mits die insek sensitief is vir Bacillus thuringiensis. ‘n Alternatiewe bestanddeel vir mieliemeel, volkoringmeel, word aanbeveel. Agar agar is ‘n duur verdikkingsagent wat in kunsmatige mediums gebruik word. ‘n Alternatief vir agar agar (Kelcogel, Elastigel en carrageenen) is getoets en die biologiese effek op die kodlingmot is bepaal. Faktore soos mortaliteit, papie en mot gewig, langlewendheid, vrugbaarheid en lengte van lewenssiklus was gebruik as kwaliteit parameters. Resultate het getoon dat Elastigel ‘n geskikte plaasvevanger is van agar agar, met groter papies en motte, groter vrugbaarheid en langlewendheid. Die ekonomiese gevolg van die plaasvervanger, is ‘n vermindering van 40.91% van die dieetkoste. Die ander verdikkingagente wat is getoets is, het aanvaarbare resultate gelewer wat noodsaaklik is indien daar ‘n tekort van Elastigel of agar agar ontwikkel. ‘n Nuwe metode van massa-aanteel van kodlingmot larwes is bepaal. Die metode behels ‘n geslote sisteem, waar groter aanteel bakke in ‘n geslote, geventileerde boks geplaas word. Die metode is koste en spasie effektief en ‘n kleiner area word benodig om ‘n groter aantal motte te lewer. Die risiko van kontaminasie van die dieet word verminder as gevolg van die geslote sisteem wat gebruik word en meer ekonomiese en effektiewe lugversorging word gebruik. Hierdie is die eerste verslag van sy soort wat die massa-aanteel van kodlingmot in ‘n geslote sisteem beskryf en wat die risiko aandui van geneties gemanipuleerde mieliemeel in ‘n kunsmatige medium vir die kodlingmot. Hierdie resultate behoort in ag geneem te word vir reeds bestaande massa-aanteel fasiliteite of met die ontwerp van nuwe massa-aanteel fasiliteite.
Mashau, Fhumulani Mathilda. "Risk assessment of fire blight om pome fruits in South Africa." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-02012006-114148.
Full textMcGinley, Susan. "Salad at the South Pole: Growth Chamber Will House Vegetable and Fruit Crops." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/622233.
Full textSilva, Sandra da Conceição Liz da. "Caracterização de fungos do género Stemphylium associados a pomóideas em Portugal." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4485.
Full textBrown spot of pear, associated to Pleospora allii/Stemphylium vesicarium, is economically important in pear production in Europe and was detected, in 1996, in Portugal. The causal agent is known to share similar morphological characteristics with other fungi in the genus, namely S. botryosum known as a storage fungus, making the identification between them quite difficult. With the aim to contribute for a better knowledge of brown spot in pears, the pathogens involved in this disease and its presence in other fruit trees, we studied, from 30 Stemphylium monosporics isolates obtained from apples and pear fruits, and pears leaves, from Portugal, the optimal grow temperature, cultural, morphologic and biometric characteristics from anamorphs and/or teleomorphs, the time required for ascospore prodution and phylogenetic relationships, inferred from ITS and gpd sequence data. The optimum growth temperature stood between 22.5º C and 27.5º C, the ratio between length and width ranged from 1.38 to 2.38. The number of days until mature ascospores were produced ranged between 10 and 54 days. The gpd fragments of 28 isolates clustered with S. vesicarium from NCBI bank and the whole data allowed to identify 29 isolates as S. vesicarium
Winisdorffer, Guillaume. "Caractérisation de la microstructure spatiale de la pomme en lien avec ses propriétés mécaniques par des méthodes quantitatives d'IRM." Nantes, 2014. http://archive.bu.univ-nantes.fr/pollux/show.action?id=de877516-31c3-4c88-8773-b1d421c58ea2.
Full textMechanical properties of the pericarp of apple fruit are defined by multiple factors. Dry matter, as an insoluble fraction (cell wall) and a soluble fraction, water status and distribution within cell and tissues, the fraction of air between the cells and their size and organization influence the mechanical behavior of the tissue. Quantitative MRI is an interesting tool as it can non-destructively measure water status and distribution, which have seldom been studied. An original approach was applied by measuring the MRI multi-exponential relaxation signal of the fruit to extract the signal of different water pools. Studying the variations in amplitude and relaxation times of these fractions in fruit of different calibers allowed characterizing the heterogeneity of the fruit and the influence of cell size on MRI signal. A multi-instrumental approach applied to the parenchyma during cold storage then allowed comparing its viscoelastic properties (dynamic mechanical analysis) to its water distribution and its porosity (MRI) and the size, shape (macro-vision) and chemical composition (dosage of soluble sugars, cell wall hemicellulose and pectin) of its cells. Finally, the MRI signal of the tissues of whole fruit was studied at 1 and 6 month's storage. This study demonstrated the interest of MRI approach for characterizing the heterogeneity of the tissue according to water status and distribution and porosity. A better undestanding of some mechanisms implied in the NMR relaxation and of the relative influence of the structural and composition parameters on mechanical properties of the tissues was achieved
Yuwana, Yuwana. "Contribution à l'étude des propriétés de résistance mécanique des fruits (cas de la pomme Golden Delicious)." Aix-Marseille 2, 1997. http://www.theses.fr/1997AIX22068.
Full textMikol-Segonne, Sandrine. "Etude des réseaux de régulation de gènes qui gouvernent l'élaboration de la texture de la pomme." Thesis, Rennes, Agrocampus Ouest, 2015. http://www.theses.fr/2015NSARI073/document.
Full textApple fruit is one of the most consumed fruits in the world. Apple mealiness is an important textural deterioration which occurs during storage. This phenotype refers to a dry andgrainy sensory perception during mastication. Despite its significance, this phenotype is still rather poorly characterized, the few available results mostly depending on sensory analyses. Understanding the molecular mechanisms involved in the development of this unwanted character is essential for the improvement of fruit quality and fruit production.The work presented here is focused on the identification of key genes associated with apple mealiness through global transcriptome analyses. A first multiscale analysis combining transcriptomic, biochemical and phenotypic analyses was performed on pairs of individuals displayingcontrasted phenotypes for mealiness.This analysis led us to the identifi cation of one pectin methylesterase gene, MdPME2, which appears as an early molecular marker of mealiness in this genetic background. Next, a transcriptome analysis enlarged to 34 cultivars allowed the identification of the jasmonate hormonal pathway as a key driver of apple fruits ripening. By regulating ethylene and oxidative stress pathways, jasmonates appear as a fi ne-tuning regulator onthe postponement of apple mealiness. In addition, a new quantitative test of mealiness has also been developed to allow the validation of this model by means of pharmacological approaches. The main outcome of this work is to propose a new molecular model to explain apple mealiness development. This work shed
Vidot, Kevin. "Distribution et fonction des ions métalliques et des composés phénoliques dans les parois de fruits charnus : modèle pomme et raisin." Thesis, Nantes, 2019. http://www.theses.fr/2019NANT4020/document.
Full textColour, firmness, taste and long storage ability, are the main quality parameters that define consumer choice, processing and shelf-life of fleshy fruits. These quality criteria rely on physiological and physicochemical mechanisms that involve metallic ions, phenolic compounds and cell wall. To better understand these mechanisms, the thesis study was realised on two cider apples varieties and extended to wine grapes. The development of cryo-microscopy methods associated to X-ray and deep UV fluorescence highlighted the identification and distribution at the tissue scale of metallic ions and phenolic compounds. Transition metals and flavanols were mostly found in the cuticle while calcium, magnesium and phenolic pigments were co-localised in the sub-cuticle tissue layers. A homogeneous distribution of potassium was observed from the sub-cuticle to the outer cortex cell layers, a region that is rich in phenolic acids. Among these acids, hydroxycinnamic acids were found to be potentially esterified within cell wall. The impact of these compounds on the quality of fruit during consumption or processing was considered by studying the interactions between metal ions, cell wall pectin and phenolic compounds in the presence of hydrogen peroxide. All results: distribution of metal ions and phenolic compounds, as well as possible interactions and mechanisms of reaction, are summarized in a conceptual model that will serve as a basis for future work aiming at better controlling the organoleptic properties of fresh and processed fruit
Benhabiles, Ali. "Étude d'un nouveau procédé de concentration de solutions thermosensibles : l'évaporation osmotique : optimisation et application à la concentration de jus de pomme." Compiègne, 1998. http://www.theses.fr/1998COMP1135.
Full textMorin, Françoise. "Metabolisme de l'ethylene et senescence apres recolte de deux fruits climacteriques : la pomme pyrus malus l. cv golden delicious, la poire pyrus communis l. cv passe crassane." Orléans, 1988. http://www.theses.fr/1988ORLE2012.
Full textMorin, Françoise. "Métabolisme de l'éthylène et sénescence après récolte de deux fruits climactériques, la pomme Pyrus malus L. cv Golden Delicious, la poire Pyrus communis L. cv Passe Crassane." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37616762h.
Full textChedhomme, Francine. "Caracteristiques electriques des vesicules de tonoplaste en suspension dans le jus de kiwi (actinidia chinensis p. )." Paris 7, 1987. http://www.theses.fr/1987PA077025.
Full textAubert, Christophe. "Influence de traitements fongicides inhibiteurs de la biosynthèse de l'ergostérol sur le potentiel aromatique du raisin Muscat d'Alexandrie, de la pomme Golden delicious et des produits dérivés." Montpellier 2, 1997. http://www.theses.fr/1997MON20139.
Full textBavay, Cécile. "Adaptation des méthodologies d'évaluation sensorielle aux produits agroalimentaires à forte variabilité." Phd thesis, Université d'Angers, 2013. http://tel.archives-ouvertes.fr/tel-00846841.
Full textCHEVERRY, JEAN-LUC, and Daniel Côme. "Quelques aspects de la regulation de la biosynthese autocatalytique de l'ethylene de fruits (la pomme malus domestica borkh. Cv. Granny smith et la banane musa cavendishii lamb. ) par le dioxyde de carbone, les polyamines et le calcium." Paris 6, 1991. http://www.theses.fr/1991PA066696.
Full textEspinosa, Munoz Brisset Lucia Carolina. "Texture de la purée de pomme : influence de la structure sur les propriétés rhéologiques et la perception sensorielle - effet du traitement mécanique." Thesis, Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0008/document.
Full textFruit purees are considered as concentrated dispersions of deformable and insoluble particles in a continuous phase or serum rich in water, sugar and soluble pectin. The dispersed phase consists of cells or cell clusters of parenchyma tissue and the insoluble cell wall material dispersed in the serum represents a very low weight (~ 1% w/w). The structure and the rheological properties of purees will depend on many internal factors such as the variety and ripeness of the fruit and external factors occurring during the processing (mechanical and thermal treatment). Texture is a key quality attribute of purees and thus constitutes an important potential source for new product development. The main objective of this study was to better understand the relationship between the rheological, structural and sensory properties of apple puree, in order to pilot and control the texture of the products. The study was performed with a single batch of apple puree prepared industrially from fresh mature Golden Delicious. In order to create purees with varied structure and texture, three structural parameters were identified and modified: the cell walls concentration (related to the amount of pulp), the particle size and the viscosity of the continuous phase. A separation-reconstitution strategy joined to a grinding step and the modification of the serum viscosity allowed us to obtain a wide range of products with different structures and textures. The construction of two experimental designs made it possible the controlled preparation of the products so as to study the relatioins between structure, rheology and texture of the apple puree. Physical and sensory characterization highlighted the importance of structural parameters on the rheological behaviour and perception of the texture of the puree. Thus, the concentration of particles is the main parameter influencing these properties, followed by the particle size and the serum viscosity. The increase in particle content translates directly at the “overcrowding” that also depends on the particle size. Mechanical treatment leads to the separation of clusters of parenchyma cells in to individual cells; this change in structure involves marked changes of properties. Rheological and structural characterization made it possible the generation of rheological models and the better understanding of the behaviour, the state and the role of particles (soft and deformable) on the structure of the medium and the volume occupied by them. This approach has been completed and validated by the observation of dispersions by various microscopic techniques. The different regimes of concentration were identified. Texture perception of apple puree can be described basically by their “consistency” and their “graininess”. The viscosity of the continuous phase has an impact on the perception of “graininess” and in the cohesion of the particle network. Our results show that the texture of plant food dispersions can be “mastered” by controlling a few selected key parameters: the concentration of cell walls (pulp) and particle size, completed by the viscosity of the continuous phase. High possibilities for innovation are opened by playing on these parameters that can be modified during the processing
Fernández, Darío E. "Cydia pomonella (L.) (LEPIDOPTERA: TORTRICIDAE). Aspectos de su taxonomía, comportamiento y monitoreo aplicados a programas de control en grandes áreas." Doctoral thesis, Universitat de Lleida, 2012. http://hdl.handle.net/10803/94521.
Full textLa carpocapsa [Cydia pomonella (L.) (Lepidoptera: Tortricidae)] es una de las plagas principales de los frutales de pepita (peras, manzanas y membrillos) y nogales. Su control es crítico para lograr una producción sustentable y con calidad de exportación. La implementación de programas de control a nivel regional o de grandes áreas ha probado ser una estrategia altamente efectiva que permite lograr muy buenos resultados de control con bajos niveles de daño y una sustancial reducción en el uso de insecticidas. En estos programas, la colecta, registro y flujo de información para la toma de decisiones es un factor crítico, siendo necesario contar con metodologías confiables desde el punto de vista biológico y sustentables desde lo económico. El monitoreo de las poblaciones es un factor clave para determinar el riesgo de ataque de la carpocapsa y tomar decisiones de control. En este contexto se evaluaron diferentes aspectos de la taxonomía y el monitoreo de C. pomonella, como un caracter para la rápida diferenciación de machos y hembras, el comportamiento y eficacia de un nuevo atractivo para su monitoreo, el uso de la geoestadística y los sistemas de información geográfica para la interpretación y manejo de grandes cantidades de datos de captura en trampas, el efecto del viento en la distribución espacial de los adultos y finalmente, se propuso un sistema de vigilancia a nivel regional. Se determinó que la mancha negra presente en la parte inferior del primer par de alas de los machos de C. pomonella es un caracter sexual secundario confiable para la diferenciación de machos y hembras de la especie capturados en trampas que contienen cebos con cairomona. Las trampas cebadas con feromona mas cairomona, son mas atractivas para los machos y hembras de la carpocapsa que los cebos de cairomona sola y un 50% mas atractivas para los machos que los cebos con 1 o 10 mg de feromona, en áreas tratadas con la técnica de confusión sexual. La geoestadística puede ser una herramienta valiosa para evaluar la distribución espacial de la carpocapsa en éstos programas de control e implementar modelos que consideren la delimitación de zonas de riesgo parael control de plagas. La actividad de vuelo de la carpocapsa durante el mes de noviembre (vuelo de la generación invernante) ocurre cuando la temperatura supera los 15°C y entre las 18:30 y las 02:00 h. No se detectó una influencia significativa del viento durante el período mencionado en la distribución espacial de la plaga, por lo que no se recomienda una distribución de las trampas con un distanciamiento diferencial según la dirección considerada. Se determinó que una grilla de 200 m entre trampas ofrece información confiable para los fines de vigilancia fitosanitaria, con una reducción cercana al 60% en el número de trampas respecto a la grilla actualmente en uso de 100 m. Esta grilla además permitirá la disminución del costo del sistema de vigilancia y monitoreo. En resumen, se evaluaron y desarrollaron metodologías y herramientas que facilitan y tornan más eficiente el monitoreo y el proceso de toma de decisiones en el control de C. pomonella en programas de grandes áreas tratadas con la técnica de la confusión sexual.
The codling moth [Cydia pomonella (L.) (Lepidoptera: Tortricidae)] is one of the main pest attacking pome fruits (apples, pears, and quince) and walnuts. Its control is critical in order to obtain a sustainable production and exportable fresh fruit. The implementation of control strategies like areawide programs has proven to be very effective, allowing for a substantial reduction on damaged fruits and on the use of insecticides. Collection, registration and delivery of the information needed for the decision-making process, is a critical factor in these programs, being necessary to use proved and reliable biological and economically sustainable methodologies. Population monitoring is a key factor in order to assess the risk of attack of the codling moth and to decide the application of a control measure. Under this scenario, different aspects of C. pomonella taxonomy and biology were evaluated as long with new analytical tools. Among them, a sexual character for the quick differentiation of sexes, the efficacy of a new lure, the use of geostatistical analysis and Geographical Information Systems aimed to the manage bulk data of trap capture, the effect of the wind on the spatial distribution of adults, and finally a proposal of a regional surveillance system for the pest. As a result it was found that the black spot in the inner side of the forewings of males of C. pomonella is a reliable character for the differentiation of the sexes when they are trapped with lures containing kairomone. Traps lured with codlemone plus kairomone were more attractive to males and females of the codling moth than lures with kairomone alone, and 50% more attractive for males than lures containing 1 or 10 mg of codlemone, when used in orchards permeated with pheromones as a control measure. Geostatistical analysis could be a very valuable tool in order to evaluate de spatial distribution of codling moth in area-wide programs and to implement control strategies with the delimitation of riskareas of action. Adult flight activity during November (peak of overwinter generation flight) takes place when temperatures are above 15°C and from 18:30 to 2:00 h. No significant effect of the wind direction on the spatialdistribution of the pest was observed during this time of the year. In consequence, trap distance in different directions do not need to be modified. A grid with traps set at 200 m from each other, provides reliable information in order to keep an efficient phytosanitary surveillance program. The reduction of almost 60% of the number of traps used today, allows for a marked reduction of monitoring costs. In summary, several methodologies and tools were evaluated with the aim to make more simple and efficient the monitoring and control decision of C. pomonella in area-wide programs treated with mating disruption.
Nguyen, Thu Ha. "Étude expérimentale et modélisation du procédé de séchage des végétaux." Thesis, Lorient, 2015. http://www.theses.fr/2015LORIS370/document.
Full textGreat research works support the sector of drying of fruits and vegetables in a number of ways. Each year, experimental results and mathematical modelling try through conventional and innovative technological processes to protect agricultural products from seasonality and variability in the market prices. Nonetheless, there still exist considerable issues to improve and control this strategic agricultural sector. Swell-drying is very relevant drying process coupling hot air dehydration with Instant Controlled Pressure Drop (DIC). In the present work, carrot and apple were used as a fruit and vegetable model. Scientific literature on drying is unanimous that the drying time decreases with increasing air temperature, decreasing air relative humidity, and reducing thickness. However, the effect of airflow velocity leads to contradictory conclusions. Some authors have claimed that it does not trigger any modification of drying; while some articles tried to establish empirical models of the effective diffusivity versus airflow velocity; what is fundamentally erroneous. This thesis aims at analyzing external and internal transfer phenomena during drying. So, it was possible to recognize the Critical Airflow Velocity CAV depending on the effective diffusivity and the product size, to have the internal water transfer as the limiting phenomenon. From experimental results, an empirical model was established between the effective moisture diffusivity and airflow temperature, water content, and absolute expansion ratio
Bourles, Erwan. "Aptitude variétale des pommes à la transformation : Recherche d'indicateurs biochimiques de l'évolution de la texture et de marqueurs d'intérêt nutritionnel." Phd thesis, Université d'Angers, 2010. http://tel.archives-ouvertes.fr/tel-00538900.
Full textLouw, Johannes Petrus. "The pathogenicity and host specificity of Penicillium spp. on pome and citrus fruit." Diss., 2014. http://hdl.handle.net/2263/43149.
Full textDissertation (MScAgric)--University of Pretoria, 2014.
lk2014
Microbiology and Plant Pathology
MScAgric
Unrestricted
Mbili, Nokwazi Carol. "Evaluation of integrated control of postharvest grey mould and blue mould of pome fruit using yeast, potassium silicate and hot water treatments." Thesis, 2012. http://hdl.handle.net/10413/7984.
Full textThesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
Chi, Ming-Chun, and 紀明君. "Research on the Concepts of Fruit and Vegetable Cut-section Browning Effect for Kindergarten Children through POE Teaching Strategy." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/01874562117688841064.
Full text朝陽科技大學
應用化學系生化科技碩博士班
103
In this article, we investigate the learning outcomes, including the science misconception and its correction, for preschool children on a science curriculum with the topic of “browning effect of the cut-section of vegetable and fruits” through prediction-observation-explanation (POE)teaching strategy. The subject includes 28 pre-school children in level 1 and level 2 of the kindergarten the author taught. The teaching program, composed of six activities integrating four major concepts, was carried out in 16 successive curriculums over a period of two months. The teaching effects were quantitatively analyzed by descriptive statistics, independent-samples and paired-samples T tests and analysis of covariance (ANCOVA)together with qualitative observation. The results showed that: 1.In the prediction stage, the misconception of pre-school children toward the browning effect of vegetable and fruits was restricted by the experience and expression ability 2.In the observation stage, the systemic and multiple observation activities lead to enrich the children’s experience toward the browning effect and shape the relative scientific conceptions. 3.In the explanation stage, utilization of teaching aids could promote the cognition toward natural phenomena. 4.POE teaching strategy is helpful in constructing the scaffold for scientific inquiry for pre-school children. 5.In some of the activities, the learning outcomes for level 1 children is higher than that of level 2 children. This result indicates the earlier the systematic teaching strategy could be involved in the observation of natural phenomena, the more prominent the effect to assist the children to build up their scientific conception. 6.There is no significant difference in learning outcomes between genders.