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'n Bydrae tot die biologie en beheer van die valskodlingmot Cryptophlebia leucotreta (Meyr.) (Lepidoptera : Eucosmidae) op nawelsSchwartz, A. (Allen) 12 1900 (has links)
Thesis (PhD )--Stellenbosch University, 1981. / EKSERP: Vanwee die voortdurende probleme wat die valskodlingmot,
Cryptoph lebia leucotreta (Meyr.), by die verbouing van nawels
in die Oos-Transvaalse Laeveld daarstel, is 'n indringende studie van hierdie insekprobleem onderneem. Die biologie van die insek
is onder sowel laboratorium as natuurlike toestande nagevors.
Daar is bevind dat temperatuur 'n belangrike rol in die ontwikkeling van die insek speel. By 20 tot 30°C het temperatuurstygings die ontwikkeling van die insek laat versnel. By 35°C het
die lewensduur van die volwasse motte afgeneem en is geen eiers gelê nie . Die valskodlingmot is deur middle van 'n kunsmatige metode geteel om genoegsame proefmateriaal te verkry. Verskeie verbeteringe
is in die bestaande tegniek aangebring.
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Die insekplaagkompleks op sitrus te VaalhartsMathewson, Johanna 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / Full text to be digitised and attached to bibliographic record. / ENGLISH ABSTRACT: The cultivation of citrus in the Vaalharts region is a fairly recent
development. With the introduction of this crop, an insect pest
complex has also developed in this region. The presence of these
pests was studied in eleven orchards, planted with three citrus cultivars
and of varying ages, distributed in the 300 square kilometer cultivation
area. Each orchard was inspected for the presence of pests by making
use of two weekly sampling techniques.
Ten of the most important insect pests of citrus in the Vaalharts
region are briefly described by refering to their general appearance, life
cycles, feeding and pest status and economic threshold. For every
pest various control options, including operational systems, crop
cultivation, biological and chemical control, are discussed and, where
applicable, illustrated by means of graphic presentations. The seasonal
presence of the cirtrus pests in the Vaalharts region is tabulated and
discussed individually. With these details as background, an insect
pest management programme for citrus in the Vaalharts region is
compiled. / AFRIKAANSE OPSOMMING: Die verbouing van sitrus in die Vaalhartsgebied is 'n redelik
onlangse ontwikkeling. Gepaard met die nuwe gewas het daar ook
'n insekplaagkompleks in die gebied ontstaan. Die voorkoms van die
plae is in elt .boorde, beplant met drie sitruskultivars en van
verskillende ouderdomme, verspreid in die 300 vierkante kilometer
verbouingsareaal, bestudeer. Elk van die boorde is weekliks ondersoek
vir die aanwesigheid van plae deur van twee moniteringstegnieke
gebruik te maak.
Die tien belangrikste insekplae van sitrus in die Vaalhartsgebied
word kortliks beskryf deur na hulle algemene voorkoms, lewenssiklus,
voeding en plaagstatus en ekonomiese drempelwaardes asook die
moniteringsmetodes wat gebruik is, te verwys. Vir elke plaag word
beheeropsies, wat operasionele stelsels, gewasverbouing, bloloqlese en
chemiese beheer insluit, bespreek wat, waar toepaslik, aan die hand
van grafiese voorstellings gemustreer word. Die seisoenale
aanwesigheid van die sitrusplae word in 'n tabel aangedui en
individueel bespreek. Met die gegewens as agtergrond is 'n
insekplaagbestuurprogram vir sitrus in die Vaalhartsgebied opgestel.
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Assessment of plants used for the treatment of cattle wounds and myiasis in Amatola Basin, Eastern Cape Province, South AfricaSoyelu, Oluseyi Temitope January 2010 (has links)
No description available.
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Source and identity of insect contaminants in export consignments of table grapesPryke, James Stephen 03 1900 (has links)
Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005. / The South African table grape industry exports approximately 60% of the table
grapes produced. A major threat to the export of these grapes is the phytosanitary risk
that insect pests pose. This study was conducted in the Hex River Valley, South
Africa’s main table grape producing area. The aim of this study was to reduce the
number of phytosanitary rejections from insects on table grapes from the Hex River
Valley. Thus the main objectives of the study were to identify the most important
phytosanitary pests in the Hex River Valley; the determination of their presence in the
vineyards with possible means to control them; and to assess the possibility of using
postharvest quarantine treatments in the Western Cape. Further aims were to
determine the effect of different colour harvesting crates on the phytosanitary pests and
whether the phytosanitary pests infested the grapes via packhouses.
The most important phytosanitary pests of table grapes of the Hex River Valley
are in order of importance: Phlyctinus callosus (Schonherr) (Coleoptera: Curculionidae),
Epichoristodes acerbella Walker (Lepidoptera: Tortricidae), Planococcus ficus
(Signoret) (Hemiptera: Pseudococcidae), Ceratitis capitata (Wiedemann) (Diptera:
Tephritidae), Gonocephalum simplex Fabricius (Coleoptera: Tenebrionidae) and
Dysdercus fasciatus Signoret (Hemiptera: Pyrrhocoridae). 12.71% of rejections were
from species that were not identified, while a further 33% of the rejections were possibly
identified incorrectly.
Phytosanitary control of P. callosus appeared to be far more effective using
Plantex® than pesticides. Weather conditions appeared to affect the abundance of P.
callosus, especially warm weather, while bunches harboured less P. callosus later in
the day. Control of E. acerbella with DiPel® (Bacillus thuringiensis var. kurstaki)
appeared to at least reduce the population within the vineyards, and so its use is
recommended. P. ficus is a non-actionable species for the USA market and is not
listed as a phytosanitary pest for the Israeli market and so should not be causing any
phytosanitary rejections. C. capitata appeared to be successfully controlled by the fruit
fly sterile release program and the cold sterilisation it currently undergoes. G. simplex
caused few rejections. It is still unclear where this pest infests the grapes, as it was found in both the field and in the packhouses. D. fasciatus occurrence on grapes was
probably accidental. It was shown that picking during the early and late parts of the
day, when this species was less active, reduced its occurrence in bunches. Gryllus
bimaculatus (De Geer) (Orthoptera: Gryllidae), although not reported as a reason for
rejections in table grapes for the past two years, was an actionable species that was
present in large numbers in the Hex River Valley. There was a strong correlation
between increasing quantities of pesticides and higher abundances of G. bimaculatus.
It appeared to be an indicator of the overuse of pesticides. Results of this study
showed that infestation by the phytosanitary pests came from neighbouring vineyards.
The creation of barriers to prevent the movement of these pests between vineyards is
suggested.
Methyl bromide is the most commonly used postharvest quarantine treatment.
Owing to the ozone-depleting properties of methyl bromide, it is scheduled to be
outlawed in many countries from 2005. Alternative postharvest treatments are
irradiation, extreme temperatures, forced air, vapour-heat treatments and the use of
controlled atmospheres. Irradiation treatments appeared to control the pests at doses
that do not damage the grapes. Controlled atmosphere treatments also have a high
probability of success, although more research is required on this treatment. Low
temperature treatments are relatively cheap as most exported fruit already undergoes
cold storage, and appears to control species in the families Pseudococcidae and
Tephritidae, although further research is required for the other pest.
Colour or location of the harvesting crates in the vineyards appeared not to
influence the number of phytosanitary pests collected, as they were not attracted to
these crates.
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Composition and phenology of insect pests of Capsicum (Solanaceae) cultivated in the Makana District, Eastern Cape Province, South AfricaHepburn, Colleen January 2008 (has links)
Capsicum baccatum var. pendulum was first grown in the Makana District in 2005. Extremely little was known about best practices for cultivation or the insects and diseases associated with the crop in this area. The study was conducted during the second year of production, November 2005 and November 2006, in an attempt to identify the composition and phenology of insects occurring on C. baccatum. In the more rural parts of the Eastern Cape, and more particularly in Grahamstown, there are very few industries. With the advent of this new agricultural venture, a processing factory has been opened in Grahamstown creating more than 600 seasonal jobs in the factory and 1000 seasonal jobs on farms for local people. This business enterprise has not only brought about the creation of jobs, but also training and skills development and empowerment, generating much-needed income in this area. An extensive literature review yielded limited information on insect pests associated with Capsicum. Data from a pilot sampling trial undertaken were statistically analyzed to establish the number of plants to be scouted per site and the most effective scouting techniques to use. Based on the data available and insects collected during the pilot sampling trial, a surveillance programme was designed. Five different types of monitoring traps were placed in each of the eight study sites. Collection of trap catches and scouting of fifteen individual plants per site was undertaken on a weekly basis over the 52-week study period. The most commonly occurring potential insect pests were African Bollworm Helicoverpa armigera (Hübner), False Codling Moth Thaumatotibia leucotreta (= Cryptophlebia leucotreta) (Meyrick), Mediterranean Fruit Fly Ceratitis capitata (Wiedemann) and several species of thrips. Population densities of these pests and their phenology on Capsicum were determined. Statistical analyses established the efficacy of the monitoring traps for each pest, tested for differences among and between study sites, calculated an estimate of the number of pods damaged and a measure of plant damage.The results show that the majority of damage caused to the Capsicum baccatum cropping system was due to Mediterranean Fruit Fly populations. It was established that, although African Bollworm and False Codling Moth were present during the study period, their numbers were negligible and only nominal damage was caused by these pests. Damage caused by thrips species was apparent but not quantifiable. Intervention strategies using an Integrated Pest Management approach, are discussed.
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