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Field biology and identification of fruit flies in the Western Cape ProvinceHobololo, Vuyisile Lanele 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Two fruit fly species, Ceratitis capitata (Wiedemann) and C. rosa (Karsch)
(Diptera: Tephritidae) are known to attack deciduous fruit in the Western Cape
Province of South Africa. The relative abundance of these two pests was studied in
different kinds of fruit throughout the year.
To facilitate field monitoring, using the immature stages, morphological
differences between larval instars of C. capitata and C. rosa were investigated.
Morphological characters of the larvae, such as the spiracles (anterior and posterior),
mouth hooks and oral ridges were used. Many of these characters are only suitable to
distinguish between the second and third instar larvae as these structures are not yet
developed in the first instar larvae. Anterior spiracles were examined in terms of the
number of tubules (papillae) and size or shape of the felt chambers. The number of
papillae in both species was similar in the second and third instar larvae, but differed
between the larvae of the two species (8-10 for C. capitata and 10-13 for C. rosa). In
both species the felt chambers of the second instar larvae were narrow and elongate
whilst those of the third instar larvae were broad and short. The major difference
between the mouthhooks of the two tephritids was the presence of a sub-apical tooth in
the third instar larva of C. rosa, being absent in the third instar of C. capitata.
For the morphometric study, both laboratory-reared and field-collected specimens
were examined. Measurements of the body dimensions (length and width) and various
parts of the cephalopharyngeal skeleton (CPS) (mandible base, mandible length and
distance between the tip and notch) were recorded in all three instars of both C.
capitata and C. rosa. The data were analysed using finite mixture analysis (FMA-N1)
and Levene's test was used to test for homogeneity of variances. The results of these analyses were used to estimate the frequency distributions of the larval measurements.
In some cases overlaps in distributions were evident and were resolved using the same
program, finite mixture analysis (FMA-N1), based on the probability of the overlapping
measurements belonging to the designated instar (i.e. the one with highest probability).
Determination of growth ratios suggested an approximate conformation to Dyar's rule
thereby disputing the possibility of any hidden instar. However, in most cases
measurements of the field samples did not conform to Dyar's rule.
For the larval instars of C. capitata and C. rosa with overlapping morphological
features, the morphometric approach as a distinguishing tool was demonstrated. In the
field survey, the relative abundance of C. rosa at all experimental sites was very low in
both orchards and adjacent vines. This suggested that this pest was either not a threat
in these sites (crops) or the monitoring procedures applied, should be revised. Trap
catches indicated high levels of infestation by C. capitata on some sites and low
infestation levels at others. On the site with the highest population levels, activity peaks
in the orchards did not co-incide with those in the adjacent vineyards. This suggested
that these vineyards could be alternative hosts for fruit fly after the fruit in the orchards
have been harvested.
Forced oviposition (in vitro) studies indicated that Colombard (grown in
Simonsvlei) was the most suitable host for survival of C. capitata. Other wine grape
cultivars such as Chardonnay were also suitable for the total larval development of C.
capitata. / AFRIKAANSE OPSOMMING: Twee spesies van die vrugtevlieg, Ceratitis capitata (Wiedemann) en C. rosa
(Karsch) (Diptera: Tephritidae), val sagtevrugte in die Wes Kaap Provinsie van Suid-
Afrika aan. Die groot hoeveelheid van hierdie twee plae op verskillende soorte vrugte is
regdeur die jaar bestudeer.
Voordat enige insekplaag gemonitor kan word, is dit belangrik dat die identiteit
van die besondere plaag, insluitend sy onvolwasse stadiums, bekend moet wees. In
hierdie studie word die morfologiese verskille tussen die larwe stadiums van C. capitata
en C. rosa ondersoek.
Kenmerke soos die spirakels (voor en agter), mondhake en mondriwwe is
gebruik. Baie van hierdie morfologiese kenmerke kan net gebruik word om te onderskei
tussen larwes in die tweede en derde stadiums omdat hierdie strukture nog nie in die
eerste stadium ontwikkel is nie. Die voorste spirakels is ondersoek in terme van die
aantal tubules (papillae) en die grootte en vorm van die vilt kamers. In beide spesies is
die aantal papillae dieselfde vir die tweede en derde larwe stadiums, maar daar was en
verskil tussen die larwes van die twee spesies (8-10 vir C. capitata en 10-13 vir C.
rosa). In altwee spesies was die viIt kamers van die twee stadium larwes sma I en
verleng, terwyl dit in die derde stadium larwes breed en kort was. Die hoof verskil
tussen die mondhake van die twee vrugtevliee was die aanwesigheid van die
subapikale tand in die derde stadium larwe van C. rosa, terwyl dit afwesig is in die
derde stadium van C. capitata.
Vir die morfometriese studie is voorbeelde van laboratorium geteelde vrugtevliee,
asook vilee wat in die veld gevind is, ondersoek. Die liggaamsafmetings (Iengte en
breedte) is gemeet asook die skelet (mandibel basis, mandibel lengte en die afstand tussen die punt en die kerf) in al drie stadiums van C. capitata en C. rosa. Die data is
ontleed deur middel van eindige mengsel analise (FMA-N1) en Levene se toets is
gebruik om vir homogeniteit en variansies te toets. Die resultate van die ontleding is
gebruik om die frekwensie verspreiding van die larwale metings te skat. In sommige
gevalle was daar oorvleueling en dit is opgelos met die gebruik van dieselfde program
FMA-N1 baseer op die moontlikheid dat die metings wat oorvleuel, aan die aangeduide
stadium (d.w.s die een met die hoogste waarskynlikheid) behoort. Die vasstelling van
groei ratios dui aan dat dit naasteby ooreenstem met Dyar se reel en dus die
moontlikheid van 'n versteekte stadium betwis. Maar in die meeste gevalle stem die
veldmonsters nie ooreen met Dyar se reel nie.
Die feit dat die morfometriese benadering die verrnoe het om larwale monsters
met oorvleuelende morfologiese kenmerke, beteken dat dit kwalifiseer as In instrument
om tussen die larwe stadiums van C. capitata en C. rosa te onderskei. Baie min C. rosa
is in vrugteboorde en in nabygelee wingerde gevind. Dit dui of dat die plaag nie 'n
bedreiging vir die vrugte inhou nie, of dat die monitor prosedures hersien moet word.
Lokvalle dui aan dat daar 'n hoe vlak van infestasie van C. capitata in sommige
gebeide is en In lae vlak in ander. Op die plek met die hoogste bevolking van
vrugtevliee het die aktiwiteit in die boorde nie ooreengestem met die aktiwiteit in die
nabygelee wingerde nie. Dit dui aan dat hierdie wingerde 'n alternatiewe blyplek bied
aan die vrugtevliee nadat die vrugte in die boorde geoes is.
Gedwonge oviposisie studies dui aan dat C. capitata die beste kan oorleef in
Colombard (gekweek te Simonsvlei). Ander wyndruif kultivars is ook geskik vir die
ontwikkeling tot by die laaste larwe stadium van C. capitata.
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Development of a process for production of cantaloupe juice concentrate and determination of its composition and qualityGaleb, Abduljalil Derhm Saeed 05 October 1990 (has links)
Fresh ripe, cantaloupes were processed into juice and
juice concentrate. Processing trials were conducted on
fresh and frozen fruits with and without rind. The effects
of maceration enzymes and fining agents on yield and quality
were investigated. Compositional measurement included
°Brix, pH, titratable acidity, formol values, ascorbic acid
content, total carotenoids, sugar and nonvolatile acid
profiles, browning indices and Hunter color parameters.
Considerable ascorbic acid degradation occurred during
processing. The high juice yield (80%) and low acidity
suggest its potential use as an alternate sweetener source.
Sensory evaluation by a trained panel showed that concentrating the juice samples from flesh and rind can
remove the rind aroma and flavor characteristics. Juices
obtained from flesh and from flesh and rind were not
significantly different (p [less than or equal to] 0.05) except for overall
intensity and fresh fruit flavor characters. Single
strength juice was significantly different (p [less than or equal to] 0.05) from
concentrate on most aroma and flavor characters. / Graduation date: 1991
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The effect of physical and chemical agents on the storage characteristics of raw vegetables and fruitsApp, Jean, Lorant, George John 25 July 1949 (has links)
This investigation was concerned with the reduction of
waste in raw vegetables and fruits between the times of harvest
and consumption. Reduction of spoilage in produce was attempted
by means of chemical and. physical agents as well as a combination
of both.
The first phase of the work consisted of an evaluation
of a number of chemical compounds with respect to their effectiveness
in reducing post-harvest spoilage. The second part
dealt with an evaluation of several transparent films applied
to raw produce as wrappers and their effect on the keeping
quality of the plant material until consumed. Finally combinations
of surface disinfection and overwrapping were evaluated
for effectiveness against raw produce spoilage.
1. Disinfection
Approximately 26 compounds were tested as aqueous
dips using 3 concentrations of each on 7 major vegetables and
2 fruits. The following types of compounds were studied.
1. Quaternary ammonium compounds (chlorides,
bromides and pyridinium derivatives)
2. Chlorine liberators (organic and inorganic)
3. Phenols (simple and poly-phenols)
4. Quinones and hydroquinones
5. Salts of fatty acids
6. SO₂ liberators
7. Benzoates
The chemical treatments were evaluated for each produce
by comparison with untreated controls using duplicate tests
with triplicate samples for each chemical and concentration.
Promising treatments were found for all but one produce (strawberries).
The treatments showing promise for each of Pascal celery
and Emperor grapes were further tested on a larger scale
uaing commercial size units of produce as test samples and long
term cold storage. Three chemical treatments for each product
were judged satisfactory enough to warrant further testing by
means of field trials. The chemicals found most promising for
celery were Onyxide, Cetab and Decco while Roccal, Dowicide C
and Phygon were selected for grapes.
A field test of the three above mentioned treatments
for Pascal celery was completed. One thousand bunches per
chemical were tested under commercial conditions of dipping
and storing. An equal number of untreated bunches was also
tested. Half-lots of each treatment were evaluated on each
bunch for 11 subjective characteristics and standard mold
and bacterial counts of each crate of celery were made after
8 and 14 weeks of storage.
On the basis of a statistical analysis of the results,
0.1% Decco of pH=5 can be recommended for the reduction of
general rot development in cold storage Pascal celery. Onyxide
and Cetab significantly reduce the development of mold but
commercial application cannot be recommended because the
amount of visible stalk injury was significantly increased
over that shown by corresponding untreated or Decco treated
celery.
2. Prepackaging
The following films were compared for their merit
in prolonging the salable life of raw produce. Pliofilm 75FF,
Pliofilm 75N2, Pliofilm 75P6A, Cellophane 300LSAT, Cellophane
300MSAT-86, Lumarith P-912, Dupont Acetate 100CA48, Polythene
and Kodapak II-130.
Wrapping techniques were also evaluated using the followng
variations; Complete seals, tent-flap closures, single
hole punctures, multiple punctures and windo bags.
The following products were studied: celery, tomatoes,
carrots, lettuce, cauliflower, chopped salad mix, spinach,
strawberries, raspberries, blackberries, and boysenberries.
Harvested produce was packaged both before and after
the removal of field heat. Behavior of the pre-packaged products
in both 33°F storage and subsequent 8O°F storage was
studied. Cold storage was extended as long as 120 days while
subsequent holding at room temperature varied widely from
produce to produce. Observations were made at regular intervals
for each product. Several hundred uniform samples were
evaluated for most products using duplicates of each treatment
for every observation period. Evaluation of most samples included
weightloss, C0₂ (and sometimes O₂) of the container atmosphere, mold and decay development, flavor, color, odor, wilting and shriveling.
The following conclusions were drawn:
All films and wrapping methods affect produce quality.
For each produce, treatments could be singled out which were
superior to unwrapped controls. However any particular film
and type of seal found to be superior for one produce was
often not acceptable for another fruit or vegetable. Among
the factors found to be critical for the proper choice of
treatment were type of produce, produce temperature when
packed, length of storage, and temperature of storage.
A. Cold Storage
For most products, the partially sealed, low
permeability MSAT containers and the completely
sealed Polythene wraps scored highst for overall
product quality. These treatments prevented the
accumulation of undesirable CO₂ while at the same
time protecting the produce against weightloss and
consequent wilting. For some produce, especially
berries, wilting was not apparent even in high permeability
films such as acetates.
B. Warm Storage
For produce with high respiration rates
(spinach, and berries) only acetate films were acceptable
as wraps.
The partially sealed low permeability films
maintained good quality in warm storage but the
high humidity within the package was conducive to
micro-organism activity. Thus, in many cases
samples disinfected prior to packaging in those
films improved the warm storage quality.
Disinfection also improved the quality of
tomatoes and chopped salad mix in acetate wraps.
Of the high permeability films, no significant difference
was found among the Dupont acetate, Lumarith and
Kodapak II.
The type of seal also did not affect the characteristics
of these wraps. The low permeability films differed
principally in the amount of CO₂, retained by the container
during storage. The Pliofilms retained the highest C0₂,
levels followed by LSAT and then MSAT Cellophane.
The sealed polyethylene, the single puncture and
tent flap MSAT wraps exhibited similarity, especially with
respect to C0₂ accumulation.
The multiple puncture low permeability wraps showed
characteristics between acetates and the last mentioned group.
Correlation between CO₂ accumulation and off-flavor
formation could be determined for most products. Higher CO₂
levels were tolerated at short storage intervals without off-
flavor formation by most products but the rate of change in
CO₂ tolerance varied from produce to produce. Correlation
between % weightioss and degree of wilting could also be expressed
as a function of the pre-packaging treatments used.
Storage infection was eliminated by all films independent
of the type of seal used.
It should be emphasized that only a study of the resuits
and relationships discussed under each product can
serve as a basis for future work and commercial application
of the methods presented in this work. / Graduation date: 1950
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The ecology of vision in a passeriform bird : the blue tit (Parus caeruleus)Hunt, Sarah January 2000 (has links)
No description available.
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Controlled and modified atmosphere storage of tomatoesBatu, Ali January 1995 (has links)
No description available.
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Genetic Studies of CLAVATA Pathway Receptor Mutants Reveal Distinctions between Pathway Components in Meristems and FruitDurbak, Amanda Rita January 2010 (has links)
The CLAVATA1 (CLV1), CLV2 and CORYNE (CRN) receptors egulate cell proliferation in shoot meristems through inhibition of WUSCHEL (WUS). Mutations in these receptors produce more floral organs. The prevailing model proposes that the extra organs are generated from enlarged floral meristems. Using forward and reverse genetics, I identified new alleles in clv1, clv2 and crn and found that most alleles only affect fruit organ number and not sepal, petal or stamen number. Analysis of inflorescence and floral meristems of clv1, clv2 and crn mutants revealed that most mutants do not have altered meristem size. I show that mutations in the ERECTA gene enhance the extra valve phenotype in crn mutants by increasing proliferation in floral meristems. Further data indicate that all mutants tested generate extra organs during fruit development and that CLV1, CLV2 and CRN expression in developing fruit overlaps with regions of increased cell division and extra organs formation. In addition, I provide evidence that CLV1 regulates the transcription factor SHOOTMERISTEMSLESS (STM) in these same regions, as mutations in STM suppress the fruit development phenotype in clv1 mutants.Analysis of the relationship between CLV pathway receptors in meristems and fruit revealed that during fruit development, all three are required to regulate fruit organ number. In meristems, I find that CLV1 appears to play a predominant role, based on evidence that the CLV1 homolog BARELY ANY MERISTEM1 (BAM1) compensates for the absence of CLV1 in the meristem but not in fruit. The fact that BAM1 does not interact genetically with CLV2 or CRN in meristems, further supports the hypothesis that BAM1/CLV1 receptor complexes play key roles in meristems. My analyses suggest that CLV3 acts specifically in the meristem pathway, and not in fruit. Also, I provide genetic data for a CLV3-related CLE gene as a ligand for the fruit-specific pathway. The work presented here provides evidence that a CLV/CRN-STM pathway acts in fruit to restrict cell division and consequently organ number via a mechanism analogous to the CLV/CRN-WUS pathway in shoot meristems, supporting the hypothesis that plants use conserved CLE/Receptor-like kinase/Homeodomain signaling module to maintain meristematic regions throughout the plant.
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Factors affecting carotenoid absorption and a comparative assessment of carotenoid intake in five European countriesO'Neill, Maura January 1997 (has links)
No description available.
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Observations on anthracnose of chilli pepper (Capsicum annuum L.) caused by Colletotrichum species in Sri LankaRajapakse, Rajapakse Gamaralalage Anura Sirimevan January 1998 (has links)
No description available.
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Economic analysis of management for the Mediterranean fruit fly (Ceratitis capitata Wied.)Enkerlin Hoeflich, Walther Raul January 1997 (has links)
No description available.
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Transcripts from the head of Drosophila melanogasterMilligan, Colin D. January 1995 (has links)
No description available.
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