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Biological control studies of Phytophthora Parasitica root rot of boxwood using multiple antagonistsGates, Melinda Mulesky January 1987 (has links)
Phytophthora parasitica is an important root rot pathogen of American and English boxwood, Buxus sempervirens and B. sempervirens var. suffruticosa, respectively, shrubs used extensively in the landscape in Virginia and North Carolina. Studies were undertaken to screen microorganisms for antagonism to Phytophthora in vitro; test two polymers, carboxymethyl cellulose (CMC) and methylcellulose (MC) for their suitability as carriers, storage media, and carbon substrates; and finally to determine the efficacy of selected antagonist pairs in controlling Phytophthora root rot on containerized American boxwood.
On the basis of in vitro inhibition tests, 14 organisms were selected. These included six bacteria, five fungi and three actinomycetes.
Populations of conidia-forming fungal isolates increased or remained fairly stable when stored in 0.25% suspensions of CMC and MC, indicating that spores may be a more suitable propagule than mycelial fragments when storing fungal isolates for more than 1 week. No significant or consistent changes in population viability occurred among the actinomycete and bacterial isolates.
Carboxymethyl cellulose was a more readily utilizable carbon source than MC as indicated by the smaller specific growth rates of microorganisms in MC. Methylcellulose was not utilized by actinomycete and non-spore-forming fungal isolates.
Six of seven antagonist pairs were efficacious in controlling root rot in the greenhouse when suspended in CMC. In general, application of antagonist pairs to boxwoods stimulated growth relative to control plants.
The polymers may provide the biocontrol organisms with a protective environment and/or food base for establishment of stable population levels in the infection court, providing protection of the root system when challenged with the pathogen. / M.S.
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The incidence and severity of Heterobasidion annosus (Fr.) Bref. in loblolly pine plantations and the effect on radial increment growthBradford, Bruce January 1977 (has links)
Fourteen plots of 25 loblolly pines each were excavated in order to determine incidence and severity of <u>Heterobasidion annosus</u> in asymptomatic loblolly pine in Virginia. Each plot was established between 30 m and 100 m from an identified source of inoculum. A bulldozer was utilized to excavate root systems of the trees. The root systems of all trees visually estimated to have greater than 1% infection (this included 51% of the trees sampled) were measured with a tape and the root length measurements were categorized as resin soaked, stringy or healthy. Of the trees sampled, 85% were infected with <u>H. annosus</u>. Basidiocarps were found on 9% of the sampled trees. The average frequency of roots per tree infected with <u>H. annosus</u> for all measured trees (>1%) was 30% of the primary roots and 31% of the secondary roots. The average root length infected for all the measured trees (>1%) was 14% for primary roots and 15% for secondary roots. The sample trees were tested for a growth difference with the t-test for unpaired plots. The sampled trees were placed into one of two classes: those trees with >1% infection of the root systems (diseased) and those with ≤1% infection of the root system (healthy). The average annual increment for each of the last five years was tested, and all five tests were significantly different in growth at the 0.01 level. The difference in growth between healthy and diseased trees over the five year period was 19% or approximately 4% per year. Of all the disease parameters measured in the study: crown rating, percentage of infected primary roots and percentage of infected secondary roots were the most effective parameters in describing the effect of disease on annual increment growth over the last five years prior to sampling. / Master of Science
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An investigation into the death of native Virgilia trees in the Cape Floristic Region of South AfricaMachingambi, Netsai 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The Cape Floristic Region (CFR) of South Africa is well-recognised for exceptionally high plant
species diversity and endemism. However, little attention has been bestowed on the pests
and pathogens in this region, even though these may greatly influence plant distribution and
evolution. In this study we identify various arthropods and fungi as pests and diseasecausing
organisms of the ecologically and economically important CFR-endemic tree taxa of
Virgilia. We isolated, identified and determined the pathogenicity of key fungal taxa from
diseased Virgilia trees throughout the CFR. In addition we evaluated the role of possible pest
arthropod taxa, including bark beetles, phoretic mites, larvae of a cerambycid beetle and
larvae of the endemic Leto venus (ghost moth), in the death of Virgilia trees. Key fungal
taxa were identified by comparisons of the internal transcribed spacer rDNA regions of the
isolated taxa with those available on GenBank. Pathogenicity of the most commonly
encountered fungal taxa was determined both in the field and under greenhouse conditions.
Five different disease symptoms were observed on Virgilia trees throughout the CFR. At
Table Mountain, Virgilia oroboides subsp. oroboides showed symptoms of: (1) several small
cankers on stems, seemingly caused by a Fusarium acuminatum-like fungus, (2) a root rot
disease caused by Armillaria mellea and (3) small bracket fungi on stems associated with
Schizophyllum commune. Virgilia oroboides from the Harold Porter National Botanical
Garden was diagnosed with a root disease consistently associated with an un-described
Phomopsis species. Virgilia oroboides subsp. ferruginea and V. divaricata from Knysna and
the Tsitsikamma area often showed symptoms of rapid wilting and death. The Virgilia stems
were damaged by the tunnelling larvae of the ghost moth and those of an unidentified
cerambycid beetle. Galleries and the surrounding wood tissues often housed the
ophiostomatoid fungi Ceratocystis tsitsikammensis and Ophiostoma plurianulatum. These
seem to originate from nitidulid beetles found feeding on gum exudate. Pathogenicity trials
confirmed the virulence of the undescribed Phomopsis species, the F. acuminatum-like
fungus, S. commune and C. tsitsikammensis to Virgilia. All four morpho-species of bark
beetles found in this study, together with phoretic mites on two of the beetle morphospecies,
were only collected from dead and dying Virgilia hosts and were classified as
secondary pests. Both beetle taxa and mites commonly carried spores of various Geosmithia
spp. These are not pathogenic to Virgilia trees, but may be an important food source for the bark beetles, as it dominated the fungal community in galleries. The phoretic mites were
unable to feed on their Geosmithia associates, but have been observed to feed on dead bark
beetle larvae within galleries. This suggests that the relationship of bark beetles, mites and
their associated Geosmithia species in this system is complex and in need of further study.
Our results show that natural populations of Virgilia play host to numerous destructive
pathogens, some of which are non-native (e.g. A. mellea) and a cause for special concern.
Additionally, the isolation of the undescribed Phomopsis species and A. mellea from
botanical gardens, with A. mellea now spreading to natural areas, calls for stricter control
over the movement of organic material from these areas. / AFRIKAANSE OPSOMMING: Die Kaapse Floristiese Streek (KFS) van Suid-Afrika is bekend vir buitengewoon hoë
plantspesie-diversiteit en endemisme. Min aandag is egter tot dusver geskenk aan die peste
en patogene in hierdie streek, al mag hulle plantverspreiding en evolusie dramaties
beinvloed. In hierdie studie identifiseer ons verskeie geleedpotige diere en fungi as peste en
organismes wat siektes veroorsaak in die ekologies en ekonomies belangrike, KFS-endemiese
boom genus Virgilia. Ons het die sleutel fungi vanaf Virgilia oor die hele KFS geisoleer,
geidentifiseer en hulle patogeniteit bepaal. Addisioneel het ons ook die rol van moontlike
pes geleedpotiges, insluitende baskewers, cerambycid kewerlarwes en die endemiese Leto
venus (spookmot) in die dood van Virgilia bome geevalueer. Sleutel fungi taksa is
geidentifiseer deur die interne getranskribeerde spasieerder rDNS streke van die geisoleerde
taksa met die wat op GenBank beskikbaar was te vergelyk. Patogenisiteit van die mees
algemeen geisoleerde fungi taxa is beide in die veld en onder glashuis-toestande bepaal. Vyf
verskillende siekte simptome is by Virgilia bome regdeur die KFS waargeneem. By Tafelberg
het Virgilia oroboides subsp. oroboides simptome getoon van: (1) verskeie klein kankers op
stamme, blykbaar veroorsaak deur ‘n Fusarium acuminatum-agtige fungus, (2) ‘n wortelvrot
siekte veroorsaak deur Armillaria mellea en (3) klein rakswamme op stamme geassosieer
met Schizophyllum commune. Virgilia oroboides in die Harold Porter Nationale Botaniese
Tuin is gediagnoseer met ‘n wortelvrot siekte wat altyd met ‘n onbeskryfde Phomopsis
spesie geassosieer is. Virgilia oroboides subsp. ferruginea and V. divaricata van Knysna en
die Tsitsikamma area het dikwels simptome getoon van vinnige verwelking en dood. Die
Virgilia stamme is deur die tonnelende larwes van die spookmot en dié van ‘n
ongeidentifiseerde cerambycid kewer beskadig. Galerye en die omringende houtweefsel het
dikwels die ophiostomatoid fungi Ceratocystis tsitsikammensis en Ophiostoma plurianulatum
gehuisves. Dit lyk asof hierdie fungi van nitidulid kewers afkomstig is wat op die
gomuitskeidings gevoed het. Patogeniteitsproewe het die kwaadaardigheid van die
onbeskryfde Phomopsis spesie, die F. acuminatum-agtige fungus, S. commune en C.
tsitsikammensis teenoor Virgilia bevestig. Al vier morfo-spesies baskewer wat in hierdie
studie gevind is, sowel as die foretiese myte op twee van die kewer morfo-spesies, is slegs
van dooie of sterwende Virgilia gashere versamel, en is as sekondêre peste geklassifiseer. Beide kewerspesies en myt taksa het algemeen spore van verskeie Geosmithia spesies
(Geosmithia pallida, G. flava, G. microcorthyli, G. sp. 1 en G. sp. 2) gedra. Die Geosmithia
spesies is nie patogenies teenoor Virgilia bome nie, maar mag ‘n belangrike voedselbron vir
die baskewers wees, aangesien dit die fungus-gemeenskap in die galarye gedomineer het.
Die foretiese myte was nie instaat om op Geosmithia-assosiate te voed nie, maar is
waargeneem om op dooie baskewer larwes te voed binne die galerye. Dit stel voor dat die
verhouding van die baskewers, myte en hulle geassosieerde Geosmithia spesies in die
sisteem kompleks is, en verdere studie benodig. Ons resultate dui aan dat natuurlike
populasies van Virgilia gashere is vir verskeie destruktiewe patogene, sommige waarvan nieinheems
(bv. A. mellea) wat ‘n bron van groot kommer is. Verder noodsaak die isolasie van
die Phomopsis spesie en A. mellea, wat beide wortelvrot siektes in botaniese tuine
veroorsaak, strenger kontrole oor die verskuiwing van organiese materiaal uit hierdie areas,
veral gegewe dat A. mellea reeds na natuurlike areas versprei het. / The Centre of Excellence In Tree Health Biotechnology for a bursary and funding the research conducted in this study
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RNA viruses of Sphaeropsis sapinea and Diaporthe ambigua and their possible use as biological control agentsMoleleki, Ntsane 28 November 2005 (has links)
Sphaeropsis sapinea and Diaporthe ambigua are important pathogens of forest and orchard tree species, respectively. Some isolates of S. sapinea are co-infected with two dsRNA viruses, SsRVl and SsRV2. Isolates of D. perjuncta (formerly thought to be D. ambigua) are infected with a positive-stranded RNA virus known as DaRV. While S. sapinea is. infected with a heterogeneous mixture of dsRNA elements of different sizes, D. perjuncta is infected with a single virus. This presents excellent opportunity for biocontrol of Diaporthe. The aim of this study was to assess these three viruses for possible application as biological control agents of S. sapinea and D. ambigua. This was' done by transfecting these with in vitro-produced RNA from the cloned viral genomes and assessing the pathogenicity of the transfected isolates on apples and apple trees. Attempts to transfect S. sapinea spheroplasts with SsRVl and SsRV2 failed. Co¬transfection of S. sapinea spheroplasts with both viruses also failed. Three isolates of D. ambigua and a single isolate of a Phomopsis sp. were successfully transfected with DaRV. Attempts to transfect the same fungi with a mutant of DaRV, bearing six codons for histidine immediately downsteam of an AUG thought to be a start codon for the translation of ORFl, failed. DaRV was originally thought to be isolated from D. ambigua. The fungal isolates transfected with DaRV were thought to be D. ambigua. The transfectants did not resemble the naturally-infected isolate. The ITS regions from the ribosomal DNA operon of these isolates were amplified using ITS 1 and ITS4 primer pair. The blast search revealed that the ITS sequence of the naturally-infected isolates are identical to D. perjuncta. One virus-free isolate was identified as a Phomopsis sp. while three other virus-free isolates were identified as D. ambigua. A PCR-based RFLP was developed to differentiate the naturally-infected D. perjuncta isolates from the virus¬free Phomopsis sp. and D. ambigua isolates. In the growth and pathogenicity studies, a DaRV-transfected, wild-type and negative control isolate of one Phomopsis and three D. ambigua isolates, were used. The DaR V -transfected Phomopsis sp. had a higher growth rate than the wild-type isolate. This DaRV-transfected Phomopsis sp. was more virulent on apples than the wild-type isolate. The wild-type isolate was slightly more virulent than the DaR V -transfected Phomopsis sp. on apple trees. There were no significant differences in growth rates between the DaRV-transfected and wild-type isolates of D. ambigua CMW5587 and D. ambigua CMW5287. There were no significant differences in virulence on apples between the DaRV-transfected and wild-type isolates of these fungi. The DaRV-transfected D. ambigua CMW5287 was more virulent than the wild-type isolate on apple trees. The DaRV-transfected D. ambigua CMW5587 had the same virulence as the wild-type isolate on both apples and apple trees. The DaRV-transfected D. ambigua CMW5288 had a slower growth rate than the wild-type isolate. There were no significant differences in virulence on apples between these isolates. The wild-type isolate of this isolate was significantly more virulent on apple trees than the DaRV-infected isolate. Although transfection was successfully done, the effects of DaRV on the Phomopsis sp. and D. ambigua isolates are not conclusive. In order to obtain conclusive results, virus-free isolates of D. perjuncta must be transfected. During the course of this study, there were no available virus-free isolates of this fungus. / Dissertation (PhD)--University of Pretoria, 2006. / Genetics / Unrestricted
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Aspectos bioecológicos do pulgão-gigante-do-pinus, Cinara atlantica (Wilson, 1919) (Hemiptera: Aphididae), em Pinus spp. (Pinaceae)Ottati, Angelo Luiz Tadeu [UNESP] 17 February 2004 (has links) (PDF)
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ottati_alt_dr_botfca.pdf: 651467 bytes, checksum: a1b92614d7fbcfa2a73dbf3cf0eb427b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Empresa Privada / Os afídeos são um dos grupos de pragas amplamente distribuídos, causando perdas consideráveis em sistemas agrícolas e florestais. O pulgão-gigante-do-pinus, Cinara atlantica, é atualmente a espécie de pulgão mais disseminada nos plantios de Pinus no Brasil. Devido à sua importância econômica, esse trabalho objetivou avaliar o efeito de diferentes temperaturas e da espécie hospedeira no desenvolvimento de ninfas e na longevidade e capacidade reprodutiva de adultos de C. atlantica, sob condições de laboratório, e determinar a flutuação populacional, a estrutura etária e a caracterização da estrutura espacial do afídeo em áreas florestadas com Pinus taeda e P. caribaea var. caribaea. A determinação do efeito de diferentes temperaturas (18o C, 22o C, 26o C e 30o C) e de hospedeiros (P. taeda e P. caribaea var. hondurensis) no desenvolvimento de C. atlantica foi conduzida sob fotofase de 12 h e umidade relativa do ar de 70 10%. Utilizaram-se 20 insetos (repetições) para cada combinação dos fatores temperatura e hospedeiro e obtiveram-se resultados para variáveis nos estágios ninfal e adulto e ciclo de vida. A determinação da flutuação populacional e da caracterização espacial (50 árvores/avaliação) e da estrutura etária (cinco colônias/avaliação) de C. atlantica foi realizada em áreas de 1 ha com P. taeda e P. caribaea var. caribaea nos municípios de Buri e Nova Campina/SP em 21 avaliações entre julho de 2001 e agosto de 2002. Concluiu-se que o desenvolvimento de ninfas e a longevidade e potencial reprodutivo dos adultos de C. atlantica não foram influenciados pelos hospedeiros P. taeda e P. caribaea var. hondurensis. Entretanto, as temperaturas constantes de 18o C e 22o C conferem as melhores condições, enquanto a de 30o C as piores condições de desenvolvimento aos insetos mantidos em P. taeda e P. caribaea var. hondurensis. C. atlantica... . / Aphids are one of the most widespread groups of pests, causing severe damages on agricultural and forestry systems. Nowadays, the giant conifer aphid, C. atlantica, is widely distributed on pine forests in Brazil. Due to its economic importance, this study aimed to evaluate the effects of different constant temperatures and host plants on the development of nymphs and adults and reproductive capacity in adult of C. atlantica in laboratory, monitoring the populational fluctuation, the age structure and to characterize spatial pattern of C. atlantica in Pinus taeda and P. caribaea var. caribaea plantations. The effect of constant temperatures (18o C, 22o C, 26o C e 30o C) and host plants (P. taeda and P. caribaea var. hondurensis) on the development of C. atlantica was carried out at 12 h of photophase (12 h) and 70 + 10% relative humidity. Twenty nymphs (replications) were tested for each treatment (temperature x host plant) to estimated biological variables of nymph and adult stages and life span. The study of the populational fluctuation, the spatial characterization (50 trees sampled per sampling date) and the age structure (5 aphid colonies per sampling date) of C. atlantica was carried out on P. taeda and P. caribaea var. caribaea plantations in 1 ha area in Buri and Nova Campina municipalities (SP, Brazil), between July 2001 and August 2002 (21 sampling dates). This research indicated that nymph and adult development and reproductive capacity of C. atlantica were not affected by host plants. However, temperatures of 18o C and 22o C provided better conditions for aphid development than 30o C when reared on P. taeda and P. caribaea var. hondurensis. In the field, C. atlantica had highest peaks of abundance in the winter and spring and lowest during the summer. The age structure study can give support to predict population peaks and the occurrence of stable populations indicates a low... (Complete abstract, click electronic address below).
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Aspectos bioecológicos do pulgão-gigante-do-pinus, Cinara atlantica (Wilson, 1919) (Hemiptera: Aphididae), em Pinus spp. (Pinaceae)/Ottati, Angelo Luiz Tadeu. January 2004 (has links)
Orientador: Carlos Frederico Wilcken / Banca: Carlos Alberto Hector Flechtmann / Banca: Célia Regina Lopes Zimback / Banca: Sonia Maria Noemberg Lazzari / Banca: Carlos Alberto Fleichmann / Banca: Edson Tadeu Iede / Resumo: Os afídeos são um dos grupos de pragas amplamente distribuídos, causando perdas consideráveis em sistemas agrícolas e florestais. O pulgão-gigante-do-pinus, Cinara atlantica, é atualmente a espécie de pulgão mais disseminada nos plantios de Pinus no Brasil. Devido à sua importância econômica, esse trabalho objetivou avaliar o efeito de diferentes temperaturas e da espécie hospedeira no desenvolvimento de ninfas e na longevidade e capacidade reprodutiva de adultos de C. atlantica, sob condições de laboratório, e determinar a flutuação populacional, a estrutura etária e a caracterização da estrutura espacial do afídeo em áreas florestadas com Pinus taeda e P. caribaea var. caribaea. A determinação do efeito de diferentes temperaturas (18o C, 22o C, 26o C e 30o C) e de hospedeiros (P. taeda e P. caribaea var. hondurensis) no desenvolvimento de C. atlantica foi conduzida sob fotofase de 12 h e umidade relativa do ar de 70 10%. Utilizaram-se 20 insetos (repetições) para cada combinação dos fatores temperatura e hospedeiro e obtiveram-se resultados para variáveis nos estágios ninfal e adulto e ciclo de vida. A determinação da flutuação populacional e da caracterização espacial (50 árvores/avaliação) e da estrutura etária (cinco colônias/avaliação) de C. atlantica foi realizada em áreas de 1 ha com P. taeda e P. caribaea var. caribaea nos municípios de Buri e Nova Campina/SP em 21 avaliações entre julho de 2001 e agosto de 2002. Concluiu-se que o desenvolvimento de ninfas e a longevidade e potencial reprodutivo dos adultos de C. atlantica não foram influenciados pelos hospedeiros P. taeda e P. caribaea var. hondurensis. Entretanto, as temperaturas constantes de 18o C e 22o C conferem as melhores condições, enquanto a de 30o C as piores condições de desenvolvimento aos insetos mantidos em P. taeda e P. caribaea var. hondurensis. C. atlantica... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: Aphids are one of the most widespread groups of pests, causing severe damages on agricultural and forestry systems. Nowadays, the giant conifer aphid, C. atlantica, is widely distributed on pine forests in Brazil. Due to its economic importance, this study aimed to evaluate the effects of different constant temperatures and host plants on the development of nymphs and adults and reproductive capacity in adult of C. atlantica in laboratory, monitoring the populational fluctuation, the age structure and to characterize spatial pattern of C. atlantica in Pinus taeda and P. caribaea var. caribaea plantations. The effect of constant temperatures (18o C, 22o C, 26o C e 30o C) and host plants (P. taeda and P. caribaea var. hondurensis) on the development of C. atlantica was carried out at 12 h of photophase (12 h) and 70 + 10% relative humidity. Twenty nymphs (replications) were tested for each treatment (temperature x host plant) to estimated biological variables of nymph and adult stages and life span. The study of the populational fluctuation, the spatial characterization (50 trees sampled per sampling date) and the age structure (5 aphid colonies per sampling date) of C. atlantica was carried out on P. taeda and P. caribaea var. caribaea plantations in 1 ha area in Buri and Nova Campina municipalities (SP, Brazil), between July 2001 and August 2002 (21 sampling dates). This research indicated that nymph and adult development and reproductive capacity of C. atlantica were not affected by host plants. However, temperatures of 18o C and 22o C provided better conditions for aphid development than 30o C when reared on P. taeda and P. caribaea var. hondurensis. In the field, C. atlantica had highest peaks of abundance in the winter and spring and lowest during the summer. The age structure study can give support to predict population peaks and the occurrence of stable populations indicates a low... (Complete abstract, click electronic address below). / Doutor
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Remote sensing of forest health : the detection and mapping of Pinus patula trees infested by Sirex noctilio.Ismail, Riyad. January 2008 (has links)
Sirex noctilio is causing considerable mortality in commercial pine forests in KwaZulu-
Natal, South Africa. The ability to remotely detect S. noctilio infestations remains
crucial for monitoring the spread of the wasp and for the effective deployment of
suppression activities. This thesis advocates the development of techniques based on
remote sensing technology to accurately detect and map S. noctilio infestations. To date,
no research has examined the potential of remote sensing technologies for the detection
and mapping of Pinus patula trees infested by S. noctilio.
In the first part of this thesis, the focus was on whether high spatial resolution
imagery could characterize S. noctilio induced stress in P. patula forests. Results
showed that, the normalized difference vegetation index derived from high spatial
resolution imagery has the potential to accurately detect and map the later stages of
S. noctilio infestations. Additionally, operational guidelines for the optimal spatial
resolutions that are suitable for detecting and mapping varying levels of sustained
S. noctilio mortality were defined. Results showed that a pixel size of 2.3 m is
recommended to detect high (11-15%) infestation levels, and a pixel size of 1.75 m is
recommended for detecting low to medium infestation levels (1-10%).
In the second part of this thesis, the focus was on the ability of high spectral
resolution (hyperspectral) data to discriminate between healthy trees and the early
stages of S. noctilio infestation. Results showed that specific wavelengths located in the
visible and near infrared region have the greatest potential for discriminating between
healthy trees and the early stages of S. noctilio infestation. The researcher also evaluated
the robustness and accuracy of various machine learning algorithms in identifying
spectral parameters that allowed for the successful detection of S. noctilio infestations.
Results showed that the random forest algorithm simplified the process by identifying
the minimum number of spectral parameters that provided the best overall accuracies.
In the final part of this thesis spatial modelling techniques were used to
proactively identify pine forests that are highly susceptible to S. noctilio infestations.
For the first time the random forest algorithm was used in conjunction with geographic
information systems for mapping pine forests that are susceptible to S. noctilio
infestations. Overall, there is a high probability of S. noctilio infestation for the majority
(63%) of pine forest plantations located in Mpumalanga, South Africa. Compared to
previous studies, the random forest model identified highly susceptible pine forests at a
more regional scale and provided an understanding of localized variations of
environmental conditions in relation to the distribution of the wasps. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
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Dinâmica populacional de Megastigmus transvaalensis (Hymenoptera Torymidae) em Schinus terebinthifolius na região de Sorocaba, Brasil / Population dynamics of Megastigmus transvaalensis (Hymenoptera: Torymidae) in Schinus terebinthifolius in the region of Sorocaba, BrazilGhiotto, Thaís Carneiro 09 May 2016 (has links)
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Previous issue date: 2016-05-09 / Não recebi financiamento / Megastigmus transvaalensis is an exotic wasp that attacks Brazilian pepper tree drupes Schinus terebinthifolius in native forests and areas of restoration and ecological restoration in Brazil. The parasitism begins with the oviposition M. transvaalensis in drupes S. terebinthifolius where the larvae hatch and remain internally feeding of nutrients and tissue, affecting germination. The aim of this work was to study the effect of temperature, rainfall and humidity in the population dynamics of M. transvaalensis and determine the parasitism rate and sex ratio of this wasp in drupes S. terebinthifolius. The study was performed with yellow sticky traps and collection of S. terebinthifolius drupes in seasonal semideciduous forest during August 2014 to September 2015, in the region of Sorocaba, São Paulo, Brazil. The capture of insects through the sticky traps proved satisfactory, and thus can be applied to the monitoring of small Hymenopteros. Populations of M. transvaalensis were negatively correlated with the maximum temperature and population peak in the fall of 2015, meaning that when the maximum temperature has reduced, there is a higher incidence of insect field. The parasitism rate of S. terebinthifolius drupes ranged from zero to 36.34% during this period, making this value an aggravating factor for the emergence of new individuals, since this phytophagous wasp has the potential to be spread throughout Brazil and It poses a threat to the natural regeneration of S. terebinthifolius. The sex ratio of M. transvaalensis was 0.42 and 0.08 in the laboratory field. The bio-ecology and the damage caused by M. transvaalensis in drupes S. terebinthifolius warrant further studies to integrated management / Megastigmus transvaalensis é uma vespa exótica que ataca drupas de aroeira-pimenteira Schinus terebinthifolius em florestas nativas e em áreas de recomposição e restauração ecológica no Brasil. O parasitismo inicia com a oviposição de M. transvaalensis nas drupas de S. terebinthifolius, onde as larvas internamente eclodem e permanecem alimentando-se dos nutrientes e tecidos, prejudicando a germinação. O objetivo desse trabalho foi estudar o efeito da temperatura, precipitação e umidade na flutuação populacional de M. transvaalensis e determinar o índice de parasitismo e razão sexual dessa vespa nas drupas de S. terebinthifolius. O estudo foi realizado com armadilhas adesivas amarelas e coleta de drupas de S. terebinthifolius em fragmento de floresta estacional semidecidual, durante agosto de 2014 a setembro de 2015, na região de Sorocaba, São Paulo, Brasil. A captura dos insetos através das armadilhas adesivas se mostrou satisfatória, podendo assim ser aplicada para o monitoramento de pequenos Hymenopteros. As populações de M. transvaalensis apresentaram correlação negativa com a temperatura máxima e pico populacional no outono de 2015, significando que, quando a temperatura máxima apresenta redução, há maior incidência do inseto em campo. O índice de parasitismo das drupas de S. terebinthifolius variou de zero a 36,34% no período avaliado, tornando este valor um agravante para o surgimento de novos indivíduos, uma vez que, essa vespa fitófaga tem potencial de ser disseminado por todo Brasil e representa ameaça para a regeneração natural de S. terebinthifolius. A razão sexual de M. transvaalensis foi de 0,42 no laboratório e 0,08 em campo. A bioecologia e os danos causados por M. transvaalensis em drupas de S. terebinthifolius justificam mais estudos visando o manejo integrado dessa vespa fitófaga.
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