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Infection by dry, airborne Botrytis cinerea conidia and fungicide efficacy on different parts of grape bunches and vineletsVan Rooi, Cicelia 03 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The evaluation of fungicide efficacy in commercial vineyards can be influenced by the
sporadic occurrence of Botrytis cinerea at various positions on vines, differences in bunch
structure during bunch development and the phenomenon that symptom expression in shoots
and bunches is governed by the resistance reaction of the various shoot and bunch parts. It
has been postulated that, following air and water dispersal, infection by solitary conidia
should playa prominent role in the epidemiology of B. cinerea on grapevine. The aim of this
study was to determine (i) infection and (ii) fungicide efficacy at specific sites on shoots of
vinelets and bunches (table grape cultivar Dauphine and the wine grape cultivar Merlot)
inoculated with dry, airborne conidia of B. cinerea.
Vinelets, prepared from cuttings, and bunches obtained from the vineyards at full bloom,
pea size, bunch closure, véraison and harvest stages, were sprayed in a spray chamber at the
recommended dosages with iprodione, pyrimethanil, cyprodinil/fludioxonil and fenhexamid
or were left unsprayed. After 24 h the vinelets or bunches were dusted with dry conidia of
Botrytis cinerea in a settling tower and incubated for 24 h at a high relative humidity (±93%).
Following incubation, both the vinelets or bunches were divided into three groups. Vinelets
and bunches of the one group were surface-sterilised, the others were left unsterile. Vinelets
and bunches of one unsterile group were placed in dry chambers, kept for 14 days at 22°C
with a 12 h photoperiod daily and monitored for symptom expression and the development of
B. cinerea. Vinelets and bunches of the sterile group, and from one unsterile group were
used for isolation. From each of these vinelets leaf blades, leaf petioles, shoots and
inflorescences were removed. Sites used for isolation in bunch parts were rachises, laterals
and pedicels, and sites on berries were the pedicel-end, cheek and style-end. The different
parts and segments were placed in Petri dishes on Kerssies' B. cinerea selective medium, or
on water agar medium supplemented with paraquat and incubated for 14 days at 22°C with a
12 h photoperiod daily. Infection and fungicide efficacy was determined by observing intact vinelets and bunches for symptom expression, and by estimating the amount of B. cinerea at
the various sites on the vinelets and bunches with isolation studies. No symptoms of B.
cinerea decay developed on sprayed and unsprayed vinelets that were kept in dry chambers
during the 2 wk observation period. The isolation and incubation studies showed that the
different fungicides were highly and nearly equally efficient in reducing superficial B.
cinerea inoculum and latent infection. .In the case of leaf blades, which showed a high
amount of B. cinerea on unsprayed vinelets under the two sterility regimes, decay was
significantly reduced by each fungicide on both cultivars. This was not the case for the other
parts, which yielded B. cinerea at low incidences under the two sterility regimes.
The study with bunches showed that dry, airborne conidia, and the fungicide sprays,
penetrated loose and tight clustered bunches from bloom to harvest and evenly landed on the
various bunch parts. At full bloom, the amount of B. cinerea in unsprayed bunches was high
on the laterals and pedicels, but low on the embryos. Unsprayed intact bunches at full bloom
were highly susceptible to B. cinerea and developed symptoms of grey mould. The
fungicides inhibited symptom expression at full bloom, but could not prevent infection.
Unsprayed bunches inoculated at the other stages remained asymptomatic. The amount of B.
cinerea was generally high in the rachises and laterals at pea size and bunch closure stages,
and in the pedicel end of berries at harvest. Infection was constantly low in the berry cheek.
The fungicides had a differential effect on infection at the various sites. In the case of
rachises, the amount of B. cinerea was at each growth stage drastically reduced by each
fungicide. In laterals, it was effectively reduced at pea size and bunch closure. However, at
these two sites, significant differences were found between the fungicides in efficacy at
stages when the amount of B. cinerea was high. This study showed that if these fungicides
are applied properly to vine in commercial vineyards between budding and prebloom, during
flowering, and at bunch closure, they should effectively prevent infection and symptom
expression and thus the development of B. cinerea epiphytotics. / AFRIKAANSE OPSOMMING: INFEKSIE DEUR DROË, LUGGEDRAAGDE BOTRYTIS CINEREA
KONIDIA EN DIE EFFEK VAN FUNGISlEDE OP VERSKILLENDE
SETELS BINNE WINGERDTROSSE EN OP LOTE:
Evaluering van fungisieddoeltreffendheid in kommersiële wingerde word beïnvloed deur
die sporadiese voorkoms van Botrytis cinerea op verskeie posisies van wingerddele, verskille
in trosstruktuur tydens trosontwikkeling, en die feit dat simptoomuitdrukking in lote en trosse
deur die weerstandsaksie van die verskillende morfologiese dele van lote en trosse beheer
word. In die natuur speel infeksie deur enkel konidia 'n prominente rol in die epidemiologie
van B. cinerea van wingerd. Die doel van hierdie studie was om (i) infeksie en (ii) die effek
van fungisiede op verskillende posisies op lote en trosse (tafeldruif kultivar Dauphine,
wyndruif kultivar Merlot), wat met droë, luggedraagde konidia van B. cinerea geïnokuleer is,
te bepaal.
Lote, verkry vanaf steggies, en trosse versamel vanuit die wingerde tydens blom-,
ertjiekorrel-, trostoemaak-, deurslaan- en oesstadium, is teen aanbevole dosisse met iprodione,
pyrimethanil, cyprodinillfludioxonil of fenhexamid in 'n spuitkas bespuit, of is onbehandeld
gelaat. Na 24 h is die lote en trosse met droë konidia van B. cinerea in 'n inokulasietoring
geïnokuleer en daarna vir 24 h onder hoë humiditeit [±93% RH] geïnkubeer. Na inkubasie is
die lote en trosse in drie groepe verdeel. Die een groep lote en trosse is oppervlakkig
gesteriliseer om die patogeen op die oppervlakte te elimineer, en die ander twee groepe is
onbehandeld gelaat. Die lote en trosse van een nie-steriele groep is vir 14 dae in droë
voghokke by 22°C met 'n 12 uur daaglikse fotoperiode geplaas, en daagliks vir siekteuitdrukking
en die ontwikkeling van B. cinerea gemonitor. Lote en trosse van die ander twee
groepe is vir isolasiestudies gebruik. Vanaf elke loot is blaarskywe, blaarstele, internodes en
ongeopende blomtrossies verwyder. Vanaftrosse is ragisse, laterale en korreisteie verwyder,
en vanaf korrels is skilsegmente aangrensend aan die korrelsteel, die stempel-end, en die
wang verwyder. Die dele en segmente is op B. cinerea selektiewe medium, en op paraquat
medium in Petri bakkies geplaas en vir 14 dae by 22°C met 'n 12 uur daaglikse fotoperiode
geïnkubeer. Infeksie en die fungisiedeffek is bepaal deur die intakte lote en trosse vir siekte- uitdrukking te monitor, en deur die hoeveelheid B. cinerea op verskeie posisies op lote en
trosse te bepaal. Geen simptome het op enige posisie op bespuite en onbespuite lote, wat in
droë hokke gehou is, ontwikkel nie. Die isolasie- en inkubasiestudies het getoon dat die
verskillende fungisiede hoogs effektief op lote was, en inokulumvlakke van die patogeen
doeltreffend verlaag het. In die geval van blaarskywe, wat hoë vlakke van B. cinerea op
onbespuite steggies onder die twee steriliteitskondisies getoon het, is verrotting op beide
kultivars betekenisvol deur die fungisiedes verlaag. Dit het egter nie vir die ander dele,
waarop daar 'n lae voorkoms van B. cinerea onder die twee steriliteitskondisies was, gegeld
me.
Die studie met trosse het getoon dat droë, luggedraagde konidia en fungisiednewels beide
oop en kompakte trosse vanaf blomstadium tot oes penetreer en eweredig op die verskillende
dele land. Met blomstadium was die hoeveelheid B. cinerea in onbespuite trosse hoog op
laterale en korrelstele, maar laag op die embrios. Onbespuite, intakte trosse was hoogs
vatbaar vir B. cinerea by blomstadium en het simptome van vaalvrot ontwikkel. Die
fungisiede het siekte-uitdrukking by blomstadium voorkom, maar kon nie infeksie voorkom
me. Onbespuite trosse wat op ander stadia geïnokuleer is, het geen siekte-uitdrukking getoon
me. Die hoeveelheid B. cinerea was hoër in die ragi, asook in laterale by ertjiekorrel- en
trostoemaak stadium, en hoër in korreisteie by oesstadium. Infeksie was konstant laag in die
korrelskil. Die fungisiede het 'n differensiële effek op infeksie by die verskillende posisies
gehad. In die geval van ragi was die hoeveelheid B. cinerea drasties deur elke fungisied by
alle groeistadia verlaag. In laterale was dit effektief by ertjiekorrel- en trostoemaakstadium
verminder. By hierdie twee posisies waar die hoeveelheid B. cinerea hoog was, is daar egter
betekenisvolle verskille in die doeltreffendheid van fungisiedes gevind. Hierdie studie toon
dat as fungisiede behoorlik in kommersiële wingerde tussen botvorming en blomstadium, en
tydens blom- en trostoemaakstadium toegedien word, infeksie en siekte-uitdrukking, en dus
ook die epifitotiese ontwikkeling van B. cinerea, voorkom behoort te word.
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The role of the mediterranean fruit fly, Ceratitis capitata, in Botrytis bunch rot of grapeEngelbrecht, Rene 03 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Botrytis bunch rot of grape is caused by Botrytis cinerea Pers. :Fr. Conidia of the
pathogen, which is dispersed by wind, water droplets and by insects, can penetrate the intact
grape berry cuticle, but disease expression occurs only under predisposing conditions. Since
relatively high infection rates often occur in vineyards, predisposing factors must play a
fundamental role in primary infection and subsequent disease occurrence. Insects can play a
very important role in this regard by depositing inocula at wound sites during feeding and by
providing fresh wounds during their oviposition and feeding activities. The aim of this study
was (i) to determine the potential of the Mediterranean fruit fly to transfer B. cinerea and
other bunch and fruit rot fungi in natura, (ii) to investigate the transport, deposition and
subsequent disease expression on grape berries in vitro, and (iii) to investigate fruit fly
activities and the nature of deposited conidia and mycelia of B. cinerea by aid of digital
photography and epifluorescence microscopy, respectively.
Two Sensus fruit fly traps containing the para-pheromone, Capilure, were installed in
orchards and five neighboring vineyards on four farms in the Stellenbosch region. Ceratitis
fruit flies were collected weekly, identified and counted to determine the fluctuations in fruit
fly population. Following field collection, the fruit flies were plated on Kerssies' B. cinerea
selective medium and the number of flies yielding the pathogen was recorded. Two fruit fly
species, C. capitata and C. rosa, were captured during the study period. Ceratitis rosa
numbers comprised only 1% of the total number of fruit flies captured. Ceratitis capitata
numbers, and the percentage B. cinerea contaminated flies generally increased after harvest in
the different orchards and vineyards. Following harvest, the percentage flies yielding B.
cinerea was higher in vineyards compared to orchards. Furthermore, in each vineyard an
increase in percentage B. cinerea contaminated fruit flies was preceded by a corresponding
increase in its neighboring orchard. The levels of both Penicillium and Alternaria
contaminated fruit flies stayed high throughout the investigation period, especially after
harvest of the orchard cultivars. Low incidence of Aspergillus, Mucor and Rhizopus spp.
were recorded on C. capitata. These findings suggest that the Mediterranean fruit fly may play an important role in the dispersal of inocula of fungi associated with postharvest decay
from early-maturing stone fruit orchards to mid- and late-maturing wine grape vineyards, and
in disease induction under conditions unfavourable for natural infection.
Three experiments were conducted to determine the potential of fruit flies in provoking B.
cinerea decay. In the first experiment, transport of conidia and disease expression were
investigated on rachis segments bearing unwounded berries only. In the second experiment,
the effect of wounding on disease expression was investigated. In the third experiment, the
effect of inoculum type (mycelia and conidia) on transportation and disease expression was
investigated on rachis segments bearing unwounded berries, and on segments with wounded
berries. The table grape cultivar, Dauphine, and the wine grape cultivar, Shiraz, were used at
véraison, two weeks before harvest and harvest, and the transport studies were conducted in
ethanol-disinfected perspex cages. Disease expression was studied in dry (~56% RH),
ethanol-disinfected perspex chambers incubated at 22°C. The isolations from berries revealed
that the flies deposited, without preference, high amounts of B. cinerea at various positions on
the grape berry's surface. The freezing studies showed that the deposited conidia germinated
and penetrated the berry skin at various positions. However, B. cinerea developed more often
at the pedicel end than on the cheek or style end, which indicated a peculiar interaction
between B. cinerea, the fruit fly and host tissue at this part of the berry. This phenomenon
was substantiated by the finding that B. cinerea also developed more often at the pedicel end
of berries that were not frozen. Further evidence for this interaction was found on intact
berries exposed to flies that carried mycelia after feeding on berries without sporulating
colonies of the pathogen, but showing symptoms of slippery skin. Significantly more decay
developed on wounded berries compared to the unwounded berries and more so at the wound
site. In addition, female fruit flies were responsible for significantly more decay development
than male fruit flies. The study thus proved that the Mediterranean fruit fly can promote B.
cinerea disease development under conditions unfavorable to natural infection.
The activities of the Mediterranean fruit fly, Ceratitis capitata, on grape berries were
monitored by aid of digital photography. In addition, the deposition of conidia and mycelia of
Botrytis cinerea at three sites (pedicel end, cheek and style end) on the grape berry,
germination of the fungal structures after dry (±56% RH) and moist (±93% RH) incubation
and wounds inflicted during ovipositioning were examined with an epifluorescence
microscope. The observations revealed that the fruit fly's activities were generally restricted to the grape berry. They visited the grape berry cheek more often, but visitations to the
pedicel end of berries increased substantially from véraison to harvest, indicating the
possibility of nutrient leakages at this site. Microscopy revealed that the flies deposited
conidia singular, in feeding packages and in faecal excrements on the berry surface. The
conidia in feeding packages were ensheathed by salivical fluids and occurred in clusters of 10
to 50 conidia. An average of 60% of the conidia in feeding packages germinated under dry
conditions (±56% RH). Conidia that passed through the intestinal tract of the fruit fly and that
were deposited in faecal excrements were deformed and low in viability. These conidia did
not occur in cluster format, but were proportionally spread with the faeces on the surface of
the grape berry. Conidia that were deposited singular and in faecal excrements did not
germinate unless incubated under moist conditions (± 93% RH). Wounds inflicted by female
fruit flies during ovipositioning were most frequently observed on the cheek. This
predisposition to B. cinerea infection of grape berries by the activities of fruit flies, suggested
an important role for the flies in the initiation of Botrytis bunch rot epidemics in vineyards. / AFRIKAANSE OPSOMMING: DIE ROL VAN DIE MEDITERREENSE VRUGTEVLIEG, CERATITIS CAPITATA,
IN BOTRYTIS CINEREA TROSVERROTTING VAN DRUIWE
Botrytis-trosverrotting van druiwe word deur Botrytis cinerea Pers. :Fr. veroorsaak.
Konidia van die patogeen wat deur wind, waterdruppels en insekte versprei word, kan die
intakte druiweskil binnedring, maar siekte-uitdrukking vind slegs onder spesiale
omstandighede plaas. Aangesien relatief hoë infeksie vlakke algemeen in wingerde voorkom,
moet predisponerende faktore 'n fundamentele rol in die primêre infeksie, en die daaruit
voortspruitende siektetoestand speel. Insekte kan 'n baie belangrike bydrae lewer deur
inokuia tydens voeding by wonde te deponeer. Nuwe wonde kan ook tydens oviposisionering
en voeding ontstaan. Die doel van hierdie studie was om (i) die potensiaal van die
Mediterreense vrugtevlieg om B. cinerea en ander tros- en vrugverrottingswamme in natura
oor te dra, te bepaal; om (ii) die verspreiding, deponering en daaropvolgende siekteuitdrukking
op druiwekorrels in vitro te ondersoek; en om (iii) die aktiwiteite en aard van die
gedeponeerde konidia en miselia met behulp van digitale fotografie sowel as epifluoressensiemikroskopie
waar te neem.
Twee Sensus-vrugtelokvalle met die paraferomoon, Capilure, IS In vrugteboorde en
aangrensende wingerde in die Stellenbosch-omgewing aangebring. Ceratitis-vrugtevlieë is
weekliks versamel, geïdentifiseer en getel om fluktuasies in die vrugtevliegpopulasie te
bepaal. Na die veldversameling is die vrugtevlieë op Kerssies se B. cinerea-selektiewe
medium uitgeplaat. Gedurende die studie is twee spesies vrugtevlieë, C. capitata en C. rosa,
gevang. Na oesstyd het die aantal Ceratitis-vrugtevlieë en die persentasie vrugtevlieë, besmet
met B. cinerea, in die verskillende boorde en wingerde toegeneem. Na oestyd was die
persentasie vrugtevlieë wat B. cinerea gedra het, hoër in die wingerde as in die boorde. Elke
toename in die persentasie B. cinerea-besmette vrugtevlieë in 'n wingerd is voorafgegaan
deur 'n ooreenkomstige toename in die aangrensende vrugteboord. Die aantal vrugtevlieë
besmet met Penicillium en Alternaria spp. het tydens die navorsingstydperk deurgaans hoog
gebly, veral nadat die vrugteboord-kultivars geoes is. Die voorkoms van Aspergillus-,
Mucor- en Rhizopus spp. op Ceratitis-vrugtevlieë was deurgaans laag. Hierdie bevinding wys
daarop dat vrugtevlieë 'n belangrike rol speel in die verspreiding van swarninokula, wat met na-oes verrotting geassosieer word, van vroegrypwordende steenvrugteboorde na mid- en
laatrypwordende wyndruifwingerde.
Drie eksperimente is in vitro onderneem om vrugtevlieë se potensiaal om B. cinereaverrotting
te veroorsaak te bepaal. In die eerste eksperiment is ragi met slegs ongewonde
korrels gebruik om die oordrag van konidia en siekte-ontwikkeling te ondersoek. In die
tweede eksperiment is die effek van verwonding op siekte-ontwikkeling ondersoek. In die
derde eksperiment is die effek van inokulumtipe (miselia en konidia) op verspreiding en
siekte-ontwikkeling ondersoek deur ragis-segmente met gewonde korrels sowel as ragissegmente
met ongeskonde korrels te gebruik. Die tafeldruif-kultivar Dauphine en die
wyndruif-kultivar Shiraz, by kleurbreuk, twee weke voor oes en by oestyd, is in die
eksperimente gebruik. Die oordragstudies is in etanol-ontsmette perspex-hokke uitgevoer.
Siekte-ontwikkeling is bestudeer in droeë (±56% RH), etanol-ontsmette perspex-kamers en
geinkubeer by 22°C. By ondersoek is gevind dat vlieë, sonder voorkeur, groot hoeveelhede
B. cinerea op verskeie dele op die druiwekorrel-oppervlak deponeer. Bevriesingstudies het
aangetoon dat die gedeponeerde konidia op verskeie dele van die korrelontkiem en die skil
binnedring. Botrytis cinerea het egter meer dikwels by die korrelsteelkant as by die
stempelkant, of op die wang, ontwikkel. Hierdie bevinding het 'n eiesoortige interaksie
tussen B. cinerea, die vrugtevlieg en gasheerweefsel by die korrelsteelkant van die korrel
aangetoon. Die verskynsel is gestaaf deur die bevinding dat B. cinerea ook meer dikwels by
die korrelsteelkant van die korrels wat nie gevries is nie, ontwikkel het. Verdere bewys van
hierdie interaksie is gevind by ongeskonde korrels wat aan die vlieë wat miselia gedra het
blootgestel is. Die siekte het beduidend meer dikwels op gewonde as ongewonde korrels en
verder aansienlik meer dikwels op die wondoppervlakte ontwikkel. Dit was ook duidelik dat
vroulike vrugtevlieë baie meer vir verrotting verantwoordelik was as manlike vrugtevlieë.
Die studie bewys dus dat Mediterreense vrugtevlieë die ontwikkeling van B. cinerea kan
bevorder in omstandighede wat ongunstig is vir natuurlike infeksie.
Die aktiwiteite van die Mediterreense vrugtevlieg C. capitata op die druiwekorrels is met
behulp van digitale fotografie waargeneem. Verder is die deponering van konidia en miselia
van B. cinerea op die verskillende dele (korrelsteelkant, wang en stempelkant) van die korrel,
ontkieming van die swamstrukture na droeë (±56% RH) en nat (±93% RH) inkubasie en
wonde wat tydens oviposisionering veroorsaak is, met epifluoressensie-mikroskopie
ondersoek. Die waarnemings het onthul dat die vrugtevlieg se aktiwiteite gewoonlik tot die druiwekorrel beperk is. Hulle het korrelwange meer dikwels besoek. Besoek aan die
korrelsteelkant het aansienlik toegeneem van kleurbreuk tot oestyd, wat op die moontlikheid
van voedingstof-lekkasie by die deel aandui. Mikroskoopstudies het aangedui dat vlieë
konidia enkel, in voedingspakkies en in fekale uitskeidings op die korreloppervlakte
deponeer. Die konidia in die voedingspakkies is deur speekselvloeistof omhul en het in
groepe van 10 tot 50 konidia voorgekom. Gemiddeld 60% van die konidia in
voedingspakkies het in droeë omstandighede (±56% RH) ontkiem. Konidia wat deur die
spysverteringskanaal van die vrugtevlieg gegaan het en in die fekale ekskresie gedeponeer is,
was misvorm en het lae lewensvatbaarheid gehad. Laasgenoemde konidia was nie in groepe
gedeponeer nie, maar is proporsioneel met die feces op die oppervlak van die druiwekorrel
versprei. Konidia wat enkel en in feces gedeponeer is, het nie ontkiem nie, tensy toestande
vogtig (±56% RH) was. Wonde wat deur die vroulike vrugtevlieë tydens oviposisionering
veroorsaak is, is meer dikwels op die wang van die korrelopgemerk. Hierdie predisposisie
van druiwekorrels tot B. cinerea-infeksie, meegebring deur die aktiwiteit van die vrugtevlieg,
dui daarop dat die rol wat die vrugtevlieg in die inisiëring van Botrytis trosverrottingepidemies
in wingerde speel, van beduidende belang is.
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Biochemiese veranderinge in druiwemos veroorsaak deur Botrytis cinerea en Rhizopus nigricansHofmann, Gerhard 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 1964. / ENGLISH ABSTRACT: no abstract available / AFRIKAANSE OPSOMMING: geen opsomming
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Studies on the wastage of export grapes : with special reference to that caused by Botrytis cinerea, Pers.Du Plessis, S. J. January 1935 (has links)
Thesis (PhD(Agric)--Stellenbosch University, 1935. / No Abstract Available
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Study of nanofibrous membranes for application in post harvest technologyHarmzen, Elrika 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Grapes are lost annually due to spoilage by Botrytis cinerea. Botrytis cinerea is currently controlled using fungicides and SO2 fumigation in storage rooms but with limited success.
Although these techniques have been used for decades they have been associated with numerous of disadvantages. Fungicides are restricted from being used during storage due to legislation and toxicity of the fungicides present on the surface of the berries. SO2 fumigation does not kill the dormant infections present inside the grape tissue and if the SO2 concentration is too high the berries are damaged.
During this study two different polymer nanofibrous platforms was synthesized in an attempt to prevent the rotting effect of B. cinerea.
The first polymer was modified to yield a polymer with a positively charged quaternized nitrogen moiety, which was subsequently reacted with sodium metabisulfite through an ion exchange process. The modified polymer was electrospun into nanofibrous mats for the benefit of the nanofibers’ high available surface area. A further functionalization was done to increase the quantity of sodium metabisulfite on the surface of the polymer nanofibers. Sodium metabisulfite salt released SO2 gas upon reaction with water vapour present in the atmosphere which resulted in the inhibition of conidial germination of B. cinerea.
The second polymer was synthesized and then electrospun into polymer nanofibrous mats followed by chemical modification of the electrospun polymer nanofibers. This post-electrospun modification resulted in the covalent attachment of a fungicide-derivative to the surface of the polymer nanofibers. The fungicide-derivative showed excellent inhibition of B. cinerea mycelium growth. Anti-fungal studies were conducted using the two modified polymer nanofibrous mats against B. cinerea to evaluate these nanofibrous surfaces as B. cinerea inhibiting membranes. Results indicated that B. cinerea conidial germination and mycelium growth were successfully inhibited. / AFRIKAANSE OPSOMMING: Druiwe bederf jaarliks weens die verrottende effek van die fungi Botrytis cinerea. Botrytis cinerea word tans beheer deur gebruik te maak van swamdoders en swaweldioksied (SO2) besproeiings in stoorkamers, maar met beperkte sukses.
Alhoewel hierdie tegnieke al vir dekades in gebruik is, word dit geassosieer met verskeie probleme. Die gebruik van swamdoders word in stoorkamers verbied, weens die moontlike skadelike inname daarvan deur die mens aangesien die swamdoders op die druiwe se oppervlakte teenwoordig is. SO2-gasbesproeiings maak nie dormante infeksies binne-in die druiwe self dood nie en indien SO2 -konsentrasies te hoog is kan dit die druiwe beskadig.
Tydens hierdie studie is twee verskillende polimeer-nanoveselplatforms gesintetiseer met die doel om die verrottende effek van B. cinerea te voorkom.
Die eerste polimeer is aangepas met ’n primêre amienverbinding met die doel dat dit deur ‘n opvolgende modifikasiereaksie verander om sodoende ’n polimeer met ‘n kwatenêre ammoniumgroep te verkry. Die doel van die kwatenêre eienskap is dat ioniese uitruiling plaasvind tussen die anioon van die polimeer en die natruimmetabisulfiet-anioon van die sout. Die voorbereide kopolimeer is geëlektrospin in nanoveselmatte deur middel van die enkelnaald-en-enkelbal-elektrospintegniek om SMI-qC12 nanovesels te lewer wat gefunksionaliseer is. Die nanoveselmatte is na die elektrospinproses verder aangepas om die hoeveelheid natruimmetabisulfiet op die oppervlak van die nanovesels te verhoog.
Die natruimmetabisulfiet stel SO2-gas vry sodra dit in aanraking kom met waterdamp in die lug wat ’n beperkende effek op spoorontkieming van B. cinerea tot gevolg het.
Die tweede polimeer is voor en na die elektrospinproses gefunksionaliseer met gesintetiseerde organiese verbindings (swamdoder). Die aanpassing van die polimeer met die organiese verbindings het plaasgevind op ‘n kovalente wyse om te verhoed dat die organiese verbinding vrygelaat word tydens gebruik. Die organiese verbindings het effektiewe beperking van miselium-groei getoon. Anti-swamstudies is uitgevoer tussen die twee gefunksionaliseerde polimeer platforms en B. cinerea om die oppervlaktes van die gefunksionaliseerde polimeer/nanovesels te evalueer as B. cinerea beperkende platforms. Resultate het aangetoon dat spoorontkieming en miselium groei van B. cinerea suksesvol beperk is.
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Secondary metabolites in fungal biotic interactionsKuang, Yi 09 May 2014 (has links)
No description available.
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Control biológico in vitro de Botrytis cinerea (Pers) mediante el uso de hongos antagonistas, en vid (Vitis vinifera)Memenza Zegarra, Miriam Estela January 2009 (has links)
En el cultivo de la vid, se reporta a Botrytis cinerea Pers como el hongo patógeno causante de lesiones cancrosas, necrosamiento de brotes y racimos de flores, y pudrición de frutos y semillas, que ocasionan grandes pérdidas económicas a los agricultores. El control de este patógeno se realiza hasta nuestros días con sustancias de origen químico: plaguicidas; los cuales son aplicados al follaje, a las semillas y al suelo, ocasionando problemas en el ambiente.
En el presente trabajo, se colectaron 56 muestras de hojas de vid, infectadas con Botrytis cinerea Pers, en un viñedo del caserío La Huaca, en el distrito de San Benito, provincia de Contumaza, departamento de Cajamarca, durante el verano del 2006; de las cuales se aislaron e identificaron 12 cepas de Trichoderma viride. En la evaluación de la actividad antagonista de las 12 cepas de T. viride sobre B. cinerea mediante el método Precolonizado de Placas a 24° C y 28° C, se seleccionó a las cinco cepas: CH-13, CH-25, CH-30, CH-38 y CH-52 que presentaron los mayores porcentajes de área ocupada sobre el patógeno. Estas cepas presentaron actividad antagonista del tipo micoparasitismo, observándose enrollamiento y penetración de las hifas de las cepas de T. viride sobre las hifas de B. cinerea.
De las cinco cepas seleccionadas de T. viride, la cepa CH-30 presentó el mayor porcentaje de área ocupada sobre B. cinerea a 24° C y 28° C con un 54.67% y 98% respectivamente.
Por los resultados obtenidos, las cinco cepas nativas de Trichoderma viride pueden ser consideradas como una alternativa ecológica para su evaluación como agentes potenciales de control biológico del patógeno B. cinerea. / --- In the culturing of grapevine, there is reported Botrytis cinerea Pers as the fungus pathogenic causative of canker injuries, necrotizing of outbreaks and clusters of flowers, and rotting of fruits and seeds, which cause big economic losses to the farmers. The control of this pathogenic is realized actually by substances of chemical origin: pesticides; which are applied to the foliage, to the seeds and to the soil, causing environment problems.
In this present work, there were collected 56 samples of leaves of grapevine, infected with Botrytis cinerea Pers, in a vineyard of The Huaca hamlet, in San Benito district, Contumaza province, Cajamarca department, during the summer of 2006; from these ones, there were isolated and identified 12 strains of Trichoderma viride. In the evaluation of the antagonist activity of these 12 strains of T. viride on B. cinerea by the method of Plates pre-colonized in 24° C and 28 °C, was selected five strains: CH-13, CH-25, CH-30, CH-38 and CH-52 that presented the major percentages of occupied area over the fungus pathogenic. These strains showed antagonist activity of mycoparasitism kind, being observed rolling and penetration of mycelium of T. viride strains on the mycelium of B. cinerea. From 5 T. viride strains selected, the CH-30 one showed the major percentage of occupied area on B. cinerea in 24° C and 28 °C with 54.67% and 98% respectively.
For the results obtained, five native strains of Trichoderma viride can be considered as an ecological alternative for its evaluation as potential agents of biological control of the pathogenic B. cinerea.
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The Ecology of Fear: Oviposition and Colonization in Aquatic SystemsPletcher, Leeanna 24 April 2008 (has links)
Amphibians and aquatic invertebrates have complex life histories that link aquatic and terrestrial food webs. It has been suggested that amphibian reproduction is an important source of carbon to some aquatic systems. This process of energy flow may be shaped by shifts in habitat selection in response to predators. We hypothesized that predators decrease colonization and oviposition of prey, reducing active inputs. Thus predation risk is expected to shift the relative amounts of active and passive subsidies. We manipulated the presence of fish predators in aquatic mesocosms. Results suggest hylid treefrog eggs and hydrophilid beetles were less abundant in predator treatments. This difference in oviposition and colonization translated into small reductions in calories and ash free dry mass of active inputs. However, passive allochthonous inputs were more than double active amounts and variable, therefore relative amounts of active and passive inputs did not differ across the levels of predation risk.
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Population Densities of the Cuban Treefrog, <em>Osteopilus septentrionalis</em> and Three Native Species of <em>Hyla</em> (Hylidae), in Urban and Natural Habitats of Southwest FloridaPiacenza, Teresa 02 April 2008 (has links)
The Cuban treefrog, Osteopilus septentrionalis, is an invasive species in Florida that may be negatively impacting adult and larval native treefrog species through competition via direct predation. The purpose of this study was to determine the abundance and distribution of O. septentrionalis in urban, semi-urban and natural habitats. The distribution and abundance of native treefrogs within the study area, Hyla cinerea, Hyla femoralis and Hyla squirella, were also estimated and compared to that of O. septentrionalis. Treefrogs were captured using PVC pipes with two internal diameters, 1.9 cm and 4.45 cm, hung on three tree types, Pinus, Quercus and Sabal. Distance to water, time of year and monthly rainfall were also considered as a potential influence of treefrog captures. O. septentrionalis was found in sites with both urban and natural habitats in frequencies far greater than those of native treefrogs. Results indicate that O. septentrionalis are captured more frequently in sites with urban habitat; however recapture rates and estimates of population size indicate that the population sizes of O. septentrionalis may actually be larger at sites with natural habitat. O. septentrionalis are found significantly more frequently in Quercus. H. femoralis and H. squirella were found significantly more frequently in PVC pipes with an internal diameter of 4.45 cm. A weak, although significant, positive correlation was found between distance to water and treefrog abundances for O. septentrionalis and H. squirella. Native treefrogs were found less frequently in PVC pipes that also contained O. septentrionalis; this result is perhaps the most interesting because it may indicate that native treefrogs will avoid habitat or refuges where O. septentrionalis are present. If O. septentrionalis is a real threat to species of treefrogs in Florida, these results should be of concern. Findings suggest that PVC pipes may give biased estimates of treefrog densities. Available refuge, temperature and precipitation all appear to have an effect on how attractive PVC pipes are to treefrogs.
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Ecologie des moisissures présentes sur les baies de raisin / Fungal ecology on grapesDiguta, Camelia Filofteia 16 December 2010 (has links)
La microflore des raisins est importante d’un point de vue technologique car elle conditionne en partie la qualité du vin. Or, la diversité des flores fongiques présentes sur baies de raisin ainsi que leur potentiel de contamination du produit final ne sont pas encore pleinement connus. Dans ce cadre, la caractérisation des flores fongiques cultivables présentes sur baies de raisin a été réalisée par PCR ITS-RFLP. 41 espèces de moisissures différentes sur les 43 étudiées appartenant à 11 genres différents ont été caractérisées de façon fiable. Seules les espèces Penicillium thomii et Penicillium glabrum ont présenté le même profil. Ainsi 96.3% des souches étudiées ont été caractérisées avec au maximum 4 enzymes de restriction et 41.5% des souches ont pu l’être avec seulement 2 enzymes de restriction. Ces résultats ont permis d’enrichir les bases de données, moyennement pourvues en séquences ITS caractéristiques de genres ou d’espèces de moisissures présentes sur baies de raisin. De plus, une étude exhaustive des moisissures présentes sur baies de raisin en Bourgogne a permis, par PCR ITS-RFLP, d’identifier 199 souches au niveau de l’espèce et ce quelque soit le genre. Penicillium spinulosum est l’espèce majoritaire isolée pour le millésime 2008 en Bourgogne. Parallèlement, la quantification de Botrytis cinerea, choisi comme micro-organisme modèle, a été réalisée par qPCR. La technique qPCR décrite dans ce travail présente (i) une bonne sensibilté avec une limite de détection de 6.4 pg d’ADN correspondant à 540 spores, (ii) l’originalité de travailler en échantillons naturellement contaminés et la fiabilité d’utiliser un standard interne. L’évaluation de l’efficacité de différentes stratégies de traitements anti-Botrytis a confirmé l’importance de la prophylaxie (effeuillage) dans la lutte contre Botrytis cinerea. / Microbial population of grapes is important from a technological point of view because it determines the quality of wine. But few studies have focused on fungal populations of grapes. A better knowledge of the fungal diversity on grapes, particularly as concerns species responsible for wine defects, may help efforts to control their development.We report the development of a PCR ITS-RFLP method as a fast and easy technique for identifying species of fungal genera present on grapes. By this methode, 41 different fungal species among 43 studied species belonging to 11 genera were characterized at the species level. Only P. thomii remained indistinguishable from P. glabrum. Using this PCR-ITS-RFLP, 96.3% strains tested could be differentiated to the species level with only four enzymes and 41.5% only with two enzymes. Moreover this work has contributed to the enriching of the database of fungal ITS sequences.Thus 199 isolated strain were on grapes in Burgundy vineyard were chacacterized at species level indepdantly of the genus by this method. P. spinolusum was the most frequently isolated species of Penicillium in Burgundy for 2008 vintage. Paralelly, the quantification of Botrytis cinerea, used as model, was developped by qPCR. The assay contained an internal amplification control to compensate for variations in DNA extraction and the various compounds from grapes, had high efficiency and the limit of detection was estimated to be 6.3 pg DNA (corresponding to 540 spores). This method was applied to assess the effects of various treatment strategies against Botrytis in the vineyard and demonstrates the importance of the prophylactic method.
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