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Host-parasitoid interactions of Eldana Saccharina (Lepidoptera: Pyralidae) in Cyperus Papyrus.Conlong, Desmond Edward. January 1994 (has links)
Since becoming a pest in graminaceous crops in Africa, the African sugarcane
stalkborer Eldana saccharina Walker has been the subject of much study. Its
very cryptic habits have precluded more commonly available control measures
being used against it. Biological control is regarded as a viable control option,
but the apparent paucity of parasitoids in graminaceous crops leads to E.
saccharina being regarded as lacking parasitoids, and thus not a good candidate
for biological control in the classical sense. In contrast, this project argues that
interactions in indigenous hosts of E. saccharina had been ignored, and that
classical biocontrol principles and basic ecological theory could be applied by the
discovery, collection and introduction of parasitoids from its indigenous habitat
to its newly adapted habitat, sugarcane.
The habitat offered by Cyperus papyrus L. was shown to be heterogenous both
temporarily and spatially. Umbels, from young through mature to senescent,
were available in the same proportion for colonisation throughout the year.
Umbels with sexual reproductive stages (seeds) were present from early spring
into late summer, and provided an additional component to the already
heterogenous environment. Young umbels, in addition, developed from rhizomes
in an environment regarded as sub-optimal for photosynthesis, until they reached
the canopy.
All stages of umbels were attacked by E. saccharina, but larvae were only found
in rays of umbels and in the apex of the culm, which was the meristematic area
for rays, both high nutrient areas. Young umbels were never found with borer
pupae, only smaller larvae, indicating that E. saccharina development matched
growth of young umbels until they reached canopy height. Also, the majority of
borings found were occupied, indicating that infestation of young umbels was
recent. All stages of E. saccharina development were found in mature umbels,
which were also most abundant at anyone time. Numerous empty borings were
found in addition to those occupied, indicative of past occupation by E. saccharina. Very few young larvae were found in old umbels, the majority of life
stages found being pupae or empty pupal cases, and also many empty borings,
showing that old umbels were not suitable for E. saccharina development.
A guild of parasitoids which comprised Orgilus bifasciatus Turner, the most
common parasitoid of small and smaller medium E. saccharina larvae, Goniozus
indicus Ashmead the most common parasitoid of larger medium and large larvae,
and an entomogenous fungus Seauveria bassiana (Sals.) Vuill. attacking all life
stages of E. saccharina was found. Three uncommon parasitoids of smaller
saccharina were also found, viz. Sassus sublevis (Granger), Iphiaulax sp. and
Venturia sp. The former three natural enemies were instrumental in depressing
a major outbreak within two months of it being observed and then maintaining
the host population at a lower level in C. papyrus. G. indicus and B. bassiana
were most effective during the summer and autumn months, and O. bifasciatus
most effective during the winter months.
This study supports the hypotheses that the apparent paucity of parasitoids and
lack of biological control success thus far against E. saccharina in sugarcane has
been because very little was known about its ecology and biology in its
numerous indigenous host plants, and that studies of the latter factors coupled
with ecological theory could enhance biological control programmes against this
borer. As more indigenous host plants are investigated in the same way as has
been done with C. papyrus, more will become known of natural enemies of E.
saccharina. Parasitoid guilds could be selected, even from rare parasitoids in the
more stable indigenous habitats, which would provide control in the unstable
habitat of sugarcane. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1994.
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Interações moleculares das proteínas CRY1 e VIP3 no controle de lepidópteros em cana-de-açúcar /Lemes, Ana Rita Nunes. January 2016 (has links)
Orientador: Janete Apparecida Desidério / Resumo: O potencial biotecnológico das proteínas Cry e Vip provenientes da bactéria Bacillus thuringiensis é amplamente conhecido. Porém, a evolução da resistência de pragas é a principal ameaça a longo prazo do controle de insetos-praga por plantas transgênicas com toxinas desta bactéria. Estudos relatam a necessidade de se retardar a evolução da resistência e dentre as possibilidades, a utilização de mais de um gene na construção de plantas transgênicas mostra-se eficiente. Dessa forma, é importante buscar novos genes, com diferentes modos de ação, e selecionar os que apresentam atividade entomotóxica diferenciada para Diatraea flavipennella e Elasmopalpus lignosellus, que são pragas secundárias e potenciais da cana-de-açúcar. Para tanto, proteínas Cry1 e Vip3 foram expressas em Escherichia coli e a toxicidade verificada por meio de bioensaios com lagartas neonatas de ambas as espécies de insetos-praga. As proteínas foram purificadas, solubilizadas, ativadas com tripsina e biotiniladas. As BBMVs (Brush Border Membrane Vesicles) foram preparadas a partir dos intestinos de lagartas das duas espécies para realização de ensaios de competição homóloga e heteróloga. Considerando a CL50, as proteínas Cry1Ac e Vip3Aa foram as mais efetivas no controle dos insetos-praga em estudo. O ensaio de ligação mostrou que ocorreu interação entre todas as proteínas e os receptores das duas espécies de lagartas. Os ensaios de competição heteróloga demonstraram não haver competição entre as proteínas Cr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The biotechnological potential of Cry and Vip proteins from the bacterium Bacillus thuringiensis is widely known. However, the evolution of pest resistance is a major threat to long-term control of insect pests by transgenic plants with toxins of this bacterium. Studies have reported the need to slow down the evolution of resistance and, among the possibilities, the use of more than one gene in the construction of transgenic plants is shown to be efficient. Thus, it is important to look for new genes with different modes of action, and select those with different entomotoxic activity to Diatraea flavipennella and Elasmopalpus lignosellus, which are secondary and potential sugarcane pests. Therefore, Cry1 and Vip3 proteins were expressed in Escherichia coli and the toxicity was verified by bioassays using neonate larvae of both species of the insect pests. The proteins were purified, solubilized, and activated with trypsin and biotinylated. The BBMVs (Brush Border Membrane Vesicles) were prepared using the intestines of the two species to perform the homologous and heterologous competition assays. Considering the LC50, the Cry1Ac and Vip3Aa proteins were the most effective in controlling the insect pests in this study. The binding assays showed that there was interaction between the proteins and the receptors of the two species of larvae. The heterologous competition assays showed no competition between Cry1 and Vip3 proteins for the same binding sites for both species studied... (Complete abstract click electronic access below) / Doutor
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Caracterização molecular de populações do inseto praga psilídeo de concha (Glycaspis brimblecombei) por meio de marcadores do tipo ITS 1 (Internal Tanscribed Spacer 1) /Costa, Suzana Regina Silveira. January 2011 (has links)
Orientador: Celso Luis Marino / Banca: Denise Selivon / Banca: Carlos Frederico Wilcken / Resumo: O gênero Eucalyptus é originário da Austrália e está estabelecido no Brasil há mais de um século. Atualmente, o Brasil tem a segunda maior área plantada, formando monoculturas, que favorecem o estabelecimento de insetos praga. No ano de 2003 foi verificada pela primeira vez no país a ocorrência de Glycaspis brimblecombei, espécie descrita por Moore (Hemiptera, Psyllidae). Tal espécie também é conhecida por psilídeo de concha, em plantios de Eucalyptus sp. no estado de São Paulo. Devido sua alta capacidade adaptativa, atualmente se encontra amplamente distribuído por todo território nacional. Os danos causados por sua infestação são inúmeros, resultando em perdas consideráveis para o setor florestal e consequentemente para a economia brasileira. As populações do psilídeo de concha apresentam baixa variação morfológica, dificultando sua identificação; assim, análises moleculares, tais quais o uso de marcadores, podem auxiliar a responder essas questões. Um marcador amplamente utilizado, por sua alta variabilidade, é o espaçador interno transcrito do DNA ribossomal (ITS). Deste modo, o marcador ITS foi utilizado neste trabalho para averiguar a dinâmica populacional do psilídeo de concha de quatro regiões do estado de São Paulo. A sequência do ITS1 apresentou um intervalo de 291 pb em 88,73% das amostras. Os sítios polimórficos foram identificados no intervalo de 80 a 200 pb, sendo que na população de Pedra Bela foi observada a maior distribuição destes. Além disso, observou-se a ocorrência de seis haplótipos distribuídos nas quatro populações. O haplótipo 1 esteve presente em todas as populações, enquanto que o haplótipo 6 foi somente identificado na população de Criação de Laboratório. A diversidade nucleotídica (Pi) das populações foi de 0,00445, sendo que a de Criação de Laboratório... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Eucalyptus genus is derived from Australia and is settled in Brazil for more than a century now. Currently, Brazil has the second largest planted area, forming monocultures that smooth infestation with pest-insects. In 2003, the occurrence of Glycaspis brimblecombei, species described by Moore (Hemiptera, Psyllidae), was detected in Brazil for the first time. The said species is also known as red gum lerp, in Eucalyptus sp plantations in the State of São Paulo. Because of their high capacity of adaptation, nowadays they are found widely distributed all over the domestic territory. Damages caused by their infestation are numerous, resulting in considerable losses for the forestry sector and, consequently, for the Brazilian economy. Red gum lerp populations present a low rate of morphological variation, which makes their identifiction more difficult. Accordingly, molecular tests, such as the use of markers, may help answering such questions. A widely used marker, due to its high variability, is the internal transcribed spacer of ribosomal DNA (ITS). Thus, the ITS marker was used in this paper to investigate the population dynamics of red gum lerps from four regions in the State of São Paulo. ITS1 sequence showed a range of 291 bp in 88.73% of the samples. Polymorphic sites were identified in the range of 80-200 bp, with the population from Pedra Bela showing the highest distribution. Moreover, the occurrence of six haplotypes distributed in the four populations was found. Haplotype 1 was present in all populations, while haplotype 6 was identified in lab-developed population only. The nucleotide diversity (Pi) of populations was 0.00445, while the lab-developed population showed the highest Pi value as between the four populations. In Botucatu, no diversity was found. Specific oligonucleotides flanking the polymorphic regions of the... (Complete abstract click electronic access below) / Mestre
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Control of mint root borer, Fumibotys fumalis, with the entomopathogenic nematode, Steinernema carpocapsaeTakeyasu, Joyce 10 November 1994 (has links)
Graduation date: 1995
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Suppression of bruchids infesting stored grain legumes with the predatory bug Xylocoris flavipes (Reuter) (hemiptera: anthocoridae)Sing, Sharlene E. January 1997 (has links)
Biological control of pest Bruchidae may provide an important management strategy against infestation of stored grain legumes, a key source of dietary protein in developing countries. Previous related research has focused on the potential of parasitoids to control bruchids; the role of generalist predators in this application has not yet been extensively explored. / The anthocorid true bug Xylocoris flavipes (Reuter) exhibited a Type II density dependent functional response to five species of adult bruchids. The rate of kill of these large prey was quite low but fairly consistent and female predators were generally more effective. Of the species examined, only the eggs and neonate larvae of A. obtectus were accessible and predation on these stages was high. / Population interaction studies evaluating the effects of predator density and of time elapsed between infestation of commodity and predator addition indicated that adding the predator simultaneously with the pests significantly reduced the number of F$ sb1$, bruchid progeny for all species. Predator density contributed less to bruchid suppression than time of predator addition and bruchid progeny suppression was much greater than anticipated given the rate of kill observed in the functional response experiments. Reproduction by A. obtectus was almost entirely inhibited by the predator. / The high levels of suppression achieved with the predator indicated a significant biological control potential; however, the more fecund bruchid species with inaccessible immature stages continued to produce a large number of progeny. The predator was then combined with larval parasitoids capable of utilizing the internally-developing stages of the bruchids; bruchid suppression was considerably enhanced over the predator alone, and for the most fecund pests, suppression was greater than for the parasitoids alone.
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Field and laboratory trials in Mali to determine the effects of neem extracts on three millet pests, Heliocheilus albipunctella De Joannis (Lepidoptera: Noctuidae), Coniesta ignefusalis Hampson (Lepidoptera: Pyralidae) and Kraussaria angulifera Krauss (Orthoptera: Acrididae)Passerini, Julien January 1991 (has links)
Formulations of aqueous neem extracts were sprayed in field experiments. Results showed that a 0.5% and 1% concentrations were effective in reducing grasshopper feeding and diminishing damage caused by the millet stemborer, C. ignefusalis. In 1988, neem diminished egg-laying and mine damage by the headminer, H. albipunctella, but no data were available for 1989 because of the low infestation levels of this pest. / Neem exhibited some systemic activity. Soil applied neem kernel powder partially protected millet against K. angulifera and C. ignefusalis. Neem treated plots yielded more grain and suffered less damage by insect pests than four different cultural practices. Only the addition of fertilizer was superior to neem in reducing yield losses but it was inferior in limiting pest losses. / Experiments to test the residual activity of neem showed that this botanical insecticide can effectively protect millet against K. angulifera for at least seven days, and possibly longer if ultra-violet rays and rainfall are not prevalent. Analysis of plant selection behavior of K. angulifera showed that neem is an antifeedant rather than a repellent. On first to third instar nymphs, growth regulating activity expressed as a difficulty in molting or an absence of sclerotization may occur. Topical applications of neem to the stemborer, C. ignefusalis, also caused growth abnormalities, mostly molting disturbances. Treated larvae that reached the adult stage were malformed. / This research indicates that neem based insecticides offer considerable promise for Sahelian farmers for protecting millet crops. It is effective against K. angulifera, but less effective against the stemborer, C. ignefusalis. Although the data obtained for H. albipunctella in 1988 was promising, it was insufficient to reach any conclusions regarding neem's efficacy with respect to this pest.
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Induced systemic resistance against Pythium aphanidermatum by plant growth-promoting rhizobacteria on cucumber (Cucumis sativus L.)Chen, Chunquan, 1958- January 1998 (has links)
Cucumber root rot caused by Pythium aphanidermatum can be suppressed by introduced plant growth-promoting rhizobacteria (PGPR). Preliminary experiments clarified that this root disease could be suppressed by strains of Pseudomonas aureofaciens, P. corrugata, and P. fluorescens. To determine whether the mechanism was a systemic resistance induced by PGPR, a split root technique was employed on greenhouse cucumbers grown in soilless substrates. On the split roots, bacteria which were introduced into one side of the root were completely separated from pathogen challenged-inoculated roots-on the other side of the roots. Results from the series of experiments conducted with this design demonstrated that (i) the resistance against root rot induced by PGPR was systemic, (ii) germination of P. aphanidermatum zoospores was reduced in extracts from bacterized roots compared to non-treated control, and (iii) spread of Pythium mycelia was delayed and zoospore germination was inhibited on the distant induced root, compared to the non-bacterized control. Furthermore, enzyme analysis indicated that phenylalanine ammonia lyase, peroxidase and polyphenoloxidase increased on cucumber roots two days after they were bacterized with Pseudomonas strains 13 or 63--28. When the bacterized roots were challenged with P. aphanidermatum, these plant defense enzymes increased as the symptoms appeared, but this accumulation of enzymes was not any higher on roots induced with each of the Pseudomonas strains compared to the Pythium inoculated control. This enzyme stimulation was also systemically induced by PGPR or P. aphanidermatum on cucumber roots. The patterns of iso-peroxidase induced with the PGPR and P. aphanidermatum treatments were different. High levels of salicylic acid (SA) accumulated in bacteria-induced roots, as well as in pathogen-infected roots, which suggests that SA may be associated with cucumber resistance response. But exogenous application of SA did not induce any systemi
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Near infrared analysis of sugarcane (Saccharum spp hybrid) bud scales to predict resistance to Eldana stalk borer (Eldana saccharina Walker).Coetzee, N. A. 05 November 2013 (has links)
The eldana stalk borer (Eldana saccharina Walker) is the most serious pest of the Southern African sugarcane industry, and it is imperative that effective control measures are available to minimize economic damage. Because conventional control methods have had limited success, cultivar resistance is seen as the most viable method of controlling infestation. However, due to the space- and time-consuming nature of the present screening methods, only small numbers of cultivars can be tested relatively late in the Plant Breeding selection programme. Increased resistance in breeding and selection populations is therefore slow. Buds are a preferred entry point of eldana larvae as they are softer than the rind that is present on the rest of the stalk surface. Preliminary results by other workers suggested that near infrared spectroscopy (NIRS) could provide a rapid screening method for the chemical profile in bud scales, the outer coating of buds and therefore the first contact point of an invading larva. If feasible, analysis of samples using this method could be done in the South African Sugar Experiment Station's (SASEX) stage two selection trials, providing an early indication of eldana resistance on large numbers of cultivars, without the necessity of separate trials. However, knowledge of how environments, position of bud scales on the stalk and age affect NIRS is required in order to determine the feasibility of the method. Planting of a trial with an identical set of genotypes across a range of environments, sampled at a number of ages, would provide the necessary information on
environmental effects, whilst simultaneously providing the necessary range of samples to develop a calibration between bud scale chemical profiles and eldana resistance ratings. Inheritance patterns of the characteristics being measured is also required if they are to be used in a breeding programme. The original work by Rutherford (1993) was carried out on only five calibration sets (a set of standard clones with relatively well-known eldana resistance ratings), and different sets were not comparable due to what was assumed to be environmental differences between
calibration sets. One aspect of the current experiment was to examine more closely the effect of genotype x environment interaction (G x E) on the performance of the NIRS technique under a range of conditions. Two sites were chosen to represent the conditions encountered in trials carried out by SASEX. The crops were sampled at three ages, representing the range of ages at which sugarcane is harvested in South Africa. Two
locations on the stalk were also examined, top and bottom, for removal of bud scales, based on the assumption that aging of bud scales may affect chemical composition. A new NIRSystems 6500 instrument was acquired during the course of this study. Data from the new instrument indicated that there were no longer differences between the different calibration sets, and therefore no longer differences between environments. Spectra for different samples were very close, the differences being of the same scale as those recorded with repeated measures of the same samples, or between the readings for the standard solvent solution. This led to the conclusion that the differences observed on the original NIRSystems 5000 instrument were due to instrument error, not environmental differences. More importantly, the different calibration sets were not comparable despite
being similar to each other. Prediction from one calibration set to another was low. These observations led to the conclusion that NIRS was not a suitable method for determining chemical compounds associated with tolerance of sugarcane genotypes to eldana borer. The original NIRS instrument was subject to error, and the small number of calibration sets included in the study led to the erroneous conclusion that NIRS was
suitable for the prediction of varietal tolerance to eldana. With the acquisition of the new instrument, the errors generated by the old instrument became apparent. With the increase in number of calibration sets included in the study, it also became apparent that a global
calibration covering all environments was not possible. An analysis of the heritability of the chemical compounds associated with eldana resistance
was also included in this study. A biparental progeny design of 24 crosses with 33 unselected offspring per cross was used. This trial would have been analysed once the calibration had been developed using the environmental trial, and it would have provided knowledge of the breeding behaviour of the chemical compounds associated with tolerance to eldana. Because the NIRS technique proved to be unsuitable for detection of chemical compounds associated with eldana resistance, the heritability of these chemical compounds could not be studied. As the NIRS study did not produce data, the G x E interaction analysis and determination of heritability was applied to the bud scale mass data set. This study showed a relatively low positive correlation between bud scale mass and resistance to eldana. The broad sense heritability estimate for bud scale mass from the G x E interaction analysis was 0.45, and the narrow sense heritability estimate from parent-offspring regression analysis was approximately 0.27, suggesting a low degree of genetic determination in bud scale mass.
The G x E interaction analyses gave varying results depending on the method used. The ANOVA analysis suggested that ages, sites and years had an effect on bud scale mass, while deviation from maximum plot showed no significance for G x E interactions. The number and choice of genotypes selected as unstable also varied with the method used to
determine the stability of individual genotypes. Regression analysis and rank order analysis revealed a number of unstable genotypes, whilst stability variance and ecovalence, which produced similar results, detected only two unstable genotypes. In the rank order analysis correction of data to remove genotype effect, reduced the number of unstable genotypes, suggesting that the G x E interaction effect was partially confounded with the bud scale mass of the genotypes. This was a more reliable method than the uncorrected rank order analysis, and would be the preferred analysis type of all those tried. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
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Biological control of Phytophthora root rot of citrus seedlings and cuttings.Abraham, Abraha Okbasillasie. January 2005 (has links)
With an increasing realization that many agrochemicals are hazardous to animals and humans, came the desire to replace these chemical agents with biological approaches that are more friendly to the environment and human health. Microorganisms play an important role in plant disease control, as naturally occurring antagonists. Microorganisms may also have beneficial
effects on plant development when applied to plant roots. Research efforts worldwide have recorded successes in biological control and growth stimulation on many crops, particularly when using members of the genera Bacillus and Trichoderma. Their use on citrus rootstock could be advantageous to nurserymen and growers in reducing the incidence of seedling mortality and increasing production. To achieve these objectives, laboratory and tunnel experiments were conducted to develop effective biocontrol agents for citrus seedlings and cuttings. Nineteen 0 ut 0 f 23 Trichoderma isolates tested in vitro against Phytophthora p arasitica sp
showed antagonistic activity by hyperparasitism and four out of eight Bacillus isolates resulted in antagonism by forming inhibition zones. The positive in vitro activity of Trichoderma and Bacillus isolates on Phytophthora provided motivation step for further trials in the greenhouse to evaluate their biological control activity on citrus seedlings and cuttings. A greenhouse trial was carried out to evaluate the biological control potential of 23 Trichoderma isolates (drenched at 5 x 105 spores / rnI) and two Bacillus isolates (drenched at 1 X 106 or 1 X 108 colony forming units (CFU) / rnI) to suppress Phytophthora parasitica sp. of rough lemon (Citrus jambhirini Lush.) seedlings. Five isolates ofTrichoderma (AA12, AA5, Trichoderma harzianum (AA16), SY3F and Eco-T~ were highly effective in suppressing Phytophthora root rot, with AA12 providing the best control. The Bacillus isolates also suppressed the pathogen but were not as effective as the Trichoderma isolates. This trial was used to test for growth stimulation activity by some of the biocontrol agents. To verify these results, a further trial was carried out to evaluate growth stimulation capabilities in the absence of any pathogen. Trichoderma Isolates AA13 and AA17 caused no 111 change in seedling growth, while other Trichoderma and Bacillus isolates had an inhibitory effect on the seedling growth. This trial indicated that the biocontrol activity was affected by
inoculum densities, and as a result in vitro sporulation capacity was evaluated. TrichodermaIsolate AA16 was the largest spore producer, followed by Eco-T®. Spore production was lowest from Trichoderma isolates AA4 and AA12. Growth stimulation responses of Trichoderma Isolates AA4, AA16, Eco-TID and SYN6 were further studied at four different doses (1 X 103, 1 X 104, 5 X 105 or 1 X 106 spores / ml) on rough lemon and trifoliate orange seedlings. Trifoliate oranges responded positively to 1 X 104 and 5 X 105 spores / ml of Eco-TID, but rough lemon responded negatively to all dosages of the Trichoderma isolates applied. This indicates that the inoculum density responses may be host specific. Higher population density of 1 X 106 spores / ml of all tested Trichoderma isolates had a stunting effect on seedling growth of both species. Based on t he positive results 0 f individual applications of some Trichoderma and Bacillus isolates, of the biological control agents on rough lemon seedlings against Phytophthora
parasitica in an earlier greenhouse trial, their combined effect in the control of the pathogen was performed. Before carrying out a greenhouse trial, activities of the isolates to be combined were evaluated in vitro. This trial showed that Trichoderma Isolates AA16 and Eco-T®were compatible. Trichoderma isolates AA16 and Eco-T®were also found to be compatible with
Bacillus Isolates B77, B81 and PHP. As a result, further in vivo trials were conducted. The tunnel trials were carried out as two separate experiments:
In the first experiment, a combination of two Trichoderma Isolates A A 16 and Eco-T®was conducted assayed at 5 X 105 or 1 X 106 spores / ml, on rough lemon seedling, and cuttings and trifoliate orange and sour orange seedlings. A combination of Trichoderma isolate AA16 and Eco-T®at 5 X 105 spore / ml increased significantly the new flush biomass of rough lemon cuttings compared to AA16 alone, but was not different from Eco-TID alone. The combination of AA16 and Eco-T® achieved no change of biomass of rough lemon and trifoliate orange seedlings. The combination of AA16 and Eco-TID did not increase the root biomass of sour orange compared to AA16 or Eco-r® alone. The combination of AA16 and Eco-r® at higher doses (1 x 106 spores / ml) showed significantly better suppression of Phytophthora root rot of rough lemon cuttings but did not show disease suppression in all seedling species verities tested. In a second experiment, individual and combined effects of Trichoderma isolates (drenched at 5 X 105 spores / ml) with Bacillus isolate (drenched at 1 X 106 colony forming units (CFU) / ml) for suppression of Phytophthora root rot on rough lemon and trifoliate orange seedlings was performed. The combination of Trichoderma Isolate AA16 and Bacillus Isolate B81 increased root biomass on rough lemon seedlings compared to the combination of Trichoderma AAI6 or Bacillus PHP but was not significantly different to Trichoderma AA16 alone. Bacillus PHP combined with Trichoderma AA16 or singly had no effect on rough lemon seedlings. Combining Trichoderma Eco--r® and with Bacillus B8I or PHP did not increase biomass of rough lemon seedlings compared to Trichoderma Isolate Eco--r® alone. There was no statistically significant differences in the effects of the combinations of the Trichoderma and Bacillus isolates compared to their individual applications on the biomass of trifoliate oranges. This study established the antagonistic potential of several South African isolates of
Trichoderma and Bacillus as a viable alternative to agrochemicals for controlling Phytophthora parasitica. The growth stimulation capabilities of Trichoderma isolates in terms of seedling development was also demonstrated. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
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Extratos de brássicas e termoterapia no controle de podridão parda em pós-colheita de pêssegoPazolini, Kelly 18 December 2014 (has links)
CAPES / A podridão parda (Monilinia fructicola) é uma das principais doenças das frutas de caroço, causando perdas em pré e pós-colheita. Os objetivos deste estudo foram avaliar diferentes formas de extração dos extratos de canola e de mostarda-da-índia sobre a podridão parda, avaliar a melhor forma de aplicação dos extratos dessas plantas associados à termoterapia sobre podridão parda e comparar o melhor resultado desses estudos com o controle químico. Inicialmente foram realizados testes com diferentes formas de extração dos extratos de canola e mostarda-da-índia. Para isso, as espécies de brássicas foram cultivadas e coletadas em pleno florescimento, secas em estufa e trituradas, para obtenção de um pó. Para o modo de extração simples, o pó foi misturado à água e filtrado. Para extração por maceração, o extrato foi filtrado somente após um tempo de reserva de 8 horas. Para extração por infusão utilizou-se água aquecida a 100 °C e, após 20 minutos a solução foi filtrada. Os extratos simples de cada planta foram selecionados para serem testados em diferentes combinações de tratamentos com a termoterapia por imersão em água quente (50 °C por 30 s). Os tratamentos testados, para canola e mostarda-da-índia, foram: 1- Aplicação do respectivo extrato e inoculação dos frutos (EI); 2- Frutos inoculados e aplicação do respectivo extrato (IE); 3- Inoculação dos frutos e aplicação da termoterapia (IT); 4- Aplicação do respectivo extrato, inoculação dos frutos e aplicação da termoterapia (EIT); 5- Inoculação dos frutos, aplicação da termoterapia e aplicação do extrato (ITE); 6- Aplicação do respectivo extrato, inoculação dos frutos, aplicação da termoterapia e aplicação do extrato novamente (EITE) e 7- Pêssegos inoculados e tratados com água esterilizada (testemunha). Os tratamentos EITE de canola e mostarda-daíndia foram selecionados para serem comparados com o tratamento químico (azoxystrobin®, 2 g L-1). Todas as formas de extração testadas, das duas espécies de brássica, reduziram significativamente o crescimento micelial e germinação de conídios de M. fructicola, e a área da lesão de podridão parda e produção de conídios in vivo, exceto o extrato de mostarda-daíndia por infusão que não reduziu a área da lesão de podridão parda. Os tratamentos EITE de canola e mostarda-da-índia foram mais eficientes no controle da podridão parda em pêssego, reduzindo a doença, em média, 58 e 51%, respectivamente. Quando os tratamentos foram comparados entre si e com o controle químico, observou-se que o tratamento EITE de canola foi superior ao tratamento EITE de mostarda-da-índia e não diferiu do controle químico sobre a produção de conídios nas lesões de podridão parda em pêssego, diminuindo a área da lesão em mais de 84%, e a esporulação em mais de 90%. A aplicação de extrato simples de canola, seja aplicado sozinho ou na tática EITE, se apresenta como uma alternativa eficiente e práticas no controle da podridão parda em pós-colheita de pêssego. / Brown rot (Monilinia fructicola) is the major disease of stone fruits, causing pre and postharvest losses. The objectives of this study were to evaluate different forms of extraction of canola and indian mustard extracts to control brown rot, assess the best way of application of extracts of these plants associated with thermotherapy to control brown rot and compare the best result of these studies with chemical control. Initially, tests were made with different forms of extraction of canola and indian mustard extracts. For this, brassica species were collected in full bloom, oven dried and ground to obtain a powder. For the simple extraction mode, the powder was mixed with water and filtered. For maceration extraction, the extract was filtered only after a time of 8 hours of booking. To infusion extract, was used water heated to 100 °C and after 20 min the solution was filtered. Simple extracts from each plant were selected to be tested in different combinations with the thermotherapy treatment by immersion in hot water (50 °C for 30 s). The treatments tested for canola and indian mustard were: 1- Application of the respective extract and inoculation of fruits (EI); 2- inoculated fruits and implementation of its extract (IE); 3- Inoculation of fruit and application of thermotherapy (IT); 4- Application of the respective extract, inoculation of fruits and application of thermotherapy (EIT); 5- Inoculation of fruit, application of thermotherapy and application of the extract (ITE); 6- Application of the respective extract, inoculation of fruits, application of thermotherapy and application of the extract again (EITE) and 7- inoculated peaches and treated with sterile water (control). The EITE with treatments canola and indian mustard were selected for comparison with chemical treatment (azoxystrobin®, 2 g L-1). All tested extraction, of the two species of brassica, significantly reduced the mycelial growth and conidial germination of M. fructicola, and the area of brown rot injury and conidia production in vivo, except the extraction infusion of indian mustard, that did not reduce the area of brown rot injury. The EITE treatments of canola and indian mustard were more efficient in controlling brown rot in peach, reducing the disease, on average, 58 and 51%, respectively. When the treatments were compared with chemical control, were observed that canola EITE treatment was superior to indian mustard EITE treatment, and did not differ from chemical control on the production of conidia in brown rot lesions in peach, reducing the area of the lesion in more than 84% and sporulation in more than 90%. The application of simple canola extract, whether used alone or in EITE tactic, is an efficient alternative in the control of brown rot in peach postharvest. / 5000
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