The Experts below are selected from a list of 1410 Experts worldwide ranked by ideXlab platform
Clifford S Gold - One of the best experts on this subject based on the ideXlab platform.
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Effects of Temperature on Embryonic Development of Banana Weevil Cosmopolites Sordidus germar
African Crop Science Journal, 2011Co-Authors: L. Traore, Clifford S Gold, Jg Pilon, G BoivinAbstract:Developemental threshold and thermal requirements for eggs of banana weevil, Cosmopolites Sordidus Germar, were determined under laboratory conditions at constant temperatures of 15,18,25,27,30,32 and 34 °C and a photoperiod of 12:12 L/D. The duration of the egg stage decreased from 34.9 days at 15° C to 4.9 days at 30° C, then increased again to 5.3 days at 32° C. Eggs did not hatch above the latter temperature although signs of embryonic development, such as formation of the head capsule, could be observed. Simple linear regression revealed a developmental threshold of 12° C and a thermal requirement of 89 days-degrees average. Highest rates of eclosion occurred between 25° C and 30° C. Keywords: Banana weevil, Cosmopolites Sordidus, development, thermal requirements
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Components of resistance to banana weevil (Cosmopolites Sordidus) in Musa germplasm in Uganda
Entomologia Experimentalis Et Applicata, 2006Co-Authors: Andrew Kiggundu, Clifford S Gold, Maryke Labuschagne, Dirk Vuylsteke, Schalk LouwAbstract:A field screening trial undertaken in Uganda showed that a number of Musa L. (Musaceae) cultivars and hybrids displayed high levels of resistance to banana weevil, Cosmopolites Sordidus (Germar) (Coleoptera: Curculionidae), while most highland banana cultivars tended to be susceptible to weevil attack. In this study, research was undertaken to determine modalities of resistance to banana weevil. Laboratory studies suggested that all cultivars were attractive to the weevil and that females freely oviposited on all cultivars. While some differences were found between cultivars in attractivity and egg numbers, these were not related to subsequent damage. Therefore, antixenosis does not appear to play an important role in host-plant resistance to banana weevil. Larval survivorship rates in living corms were, for the most part, low on resistant cultivars, suggesting that antibiosis mechanisms offer the primary avenues of resistance. In the laboratory, development was slower on some resistant cultivars although survivorship rates on excised corm material were not as well related to levels of resistance as that on living material. Sap appeared to play a minor role in reducing egg eclosion rates on some resistant cultivars. Methanol extracts from Kayinja, a resistant cultivar, inhibited larval development on corms of susceptible cultivars in the laboratory.
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Factors influencing pheromone trap effectiveness in attracting the banana weevil, Cosmopolites Sordidus
International Journal of Pest Management, 2005Co-Authors: W. Tinzaara, Clifford S Gold, Marcel Dicke, A. Van Huis, P.e. RagamaAbstract:Studies were conducted in Uganda to evaluate the influence of distance, environmental factors, trap location and trap type on catches of Cosmopolites Sordidus (Germar) (Coleoptera: Curculionidae) in pheromone-baited traps. Marked weevils were released at recorded locations within plots. Trap efficiency was low and decreased with distance from the pheromone trap. When weevils were released in close vicinity to the trap, significantly more weevils were recaptured from 0.5 m compared to those recaptured from 4 m within 30 days of trap placement. Relative humidity showed a significant positive relationship to C. Sordidus catches, while wind speed, temperature and rainfall had no effect. Covering pheromone-baited traps with banana leaves increased capture rates. In one experiment, more weevils were captured in pheromone-baited traps placed in alleys than at the base of mats, while no differences were found in the second. This study provides information on how various factors influence the effectiveness of pheromone-baited traps that will assist in designing a pheromone-based mass trapping strategy for the control of C. Sordidus.
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Effects of covering highland banana stumps with soil on banana weevil Cosmopolites Sordidus (Coleoptera: Curculionidae) oviposition
International Journal of Tropical Insect Science, 2005Co-Authors: M. Masanza, Clifford S Gold, A. Van Huis, P.e. RagamaAbstract:The effect of covering post-harvest banana stumps with soil on banana weevil Cosmopolites Sordidus (Germar) oviposition levels was investigated at three locations, Sendusu, Kawanda Agricultural Research Institute (KARI) and Ntungamo district of southwestern Uganda. In the first experiment oviposition levels were assessed in a banana system comprising growing plants and residues. Oviposition increased on sword suckers, reaching a peak 1?7 days after harvest and decreased thereafter. In the second experiment conducted on farmers' fields, corms received 70% of the eggs and pseudostems 30%. The area 5?10 cm below the collar received 27% of the eggs, the area 0?5 cm above the collar 30% and the area 5?10 cm above the collar 0.3%. The remaining eggs (43%) were laid 0?5 cm below the collar. The effect of stump height and covering the stumps was evaluated in both the wet and the dry seasons at Kawanda and Ntungamo. Cutting stumps to the ground level alone had no effect on oviposition. Covering post-harvest banana stumps reduced C. Sordidus oviposition in the wet but not in the dry season
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Effect of crop sanitation on banana weevil Cosmopolites Sordidus (Germar) (Coleoptera: Curculionidae) populations and crop damage in farmers’ fields in Uganda
Crop Protection, 2005Co-Authors: M. Masanza, Clifford S Gold, P.e. Ragama, A. Van Huis, S.h.o. OkechAbstract:An on-farm study of the effect of crop sanitation on the banana weevil Cosmopolites Sordidus (Germar) populations and corm damage was conducted through farmer participatory trials in Ntungamo district, Uganda. Farmers practiced sanitation levels that were broadly defined as low, moderate and high, with most farmers at the lower end. During the study, some farmers were asked to maintain their original level of management, while others were asked to increase sanitation levels. However, farmers did not strictly adhere to prescribed treatments so that an incomplete block design was used in the analysis of data. Increase in sanitation level from low to high significantly reduced C. Sordidus adult populations, lowered corm damage, increased plant maturation rates and increased yields. The data suggest that improved sanitation management can contribute to C. Sordidus control and improved banana productivity.
Anja Nühring - One of the best experts on this subject based on the ideXlab platform.
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First asymmetric synthesis of (+)-sordidin and (-)-7-epi-sordidin, aggregation pheromones of the banana weevil Cosmopolites Sordidus
European Journal of Organic Chemistry, 2005Co-Authors: Dieter Enders, Irene Breuer, Anja NühringAbstract:The asymmetric synthesis of (1S,3R,5R,7S)-(+)-sordidin and 7-epi-(1S,3R,5R,7R)-(–)-sordidin, both components of the natural male-produced aggregation pheromone of the banana weevil Cosmopolites Sordidus (Germar), starting from 2,2-dimethyl-1,3-dioxan-5-one is described. Two of the stereogenic centers were generated by three α-alkylations of the corresponding RAMP-hydrazone. Diastereoselective epoxide opening as another key step of the synthesis employing the aza-enolate of 3-pentanone SAEP-hydrazone as nucleophile and subsequent acidic intramolecular acetalisation furnished the sordidin C-7 epimers in good overall yield (39 %) as a 1.5:1 diastereomeric mixture. The epimers could be separated by preparative GC and thus, each of them could be obtained in high diastereomeric and enantiomeric purity (de ≥ 97 %, ee ≥ 98 %). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
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first asymmetric synthesis of sordidin and 7 epi sordidin aggregation pheromones of the banana weevil Cosmopolites Sordidus
European Journal of Organic Chemistry, 2005Co-Authors: Dieter Enders, Irene Breuer, Anja NühringAbstract:The asymmetric synthesis of (1S,3R,5R,7S)-(+)-sordidin and 7-epi-(1S,3R,5R,7R)-(–)-sordidin, both components of the natural male-produced aggregation pheromone of the banana weevil Cosmopolites Sordidus (Germar), starting from 2,2-dimethyl-1,3-dioxan-5-one is described. Two of the stereogenic centers were generated by three α-alkylations of the corresponding RAMP-hydrazone. Diastereoselective epoxide opening as another key step of the synthesis employing the aza-enolate of 3-pentanone SAEP-hydrazone as nucleophile and subsequent acidic intramolecular acetalisation furnished the sordidin C-7 epimers in good overall yield (39 %) as a 1.5:1 diastereomeric mixture. The epimers could be separated by preparative GC and thus, each of them could be obtained in high diastereomeric and enantiomeric purity (de ≥ 97 %, ee ≥ 98 %). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
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Cover Picture: First Asymmetric Synthesis of (+)-Sordidin and (−)-7-epi-Sordidin, Aggregation Pheromones of the Banana Weevil Cosmopolites Sordidus (Eur. J. Org. Chem. 12/2005)
European Journal of Organic Chemistry, 2005Co-Authors: Dieter Enders, Irene Breuer, Anja NühringAbstract:The cover picture shows the most important worldwide insect pest of banana plants, the banana weevil Cosmopolites Sordidus (Germar). These long-lived weevils lay their eggs in the rhizome of the plant. The larvae hatch and then feed and tunnel in the rhizome of the plant, weakening it and leading to the snapping of the rhizome at the ground level before the bunch is ripe. The first evidence for the depicted volatile male-produced aggregation pheromones, sordidin and 7-epi-sordidin was supplied by Budenberg et al. in 1993. Details of the first asymmetric synthesis of the major pheromone compound, sordidin, and its C-7-epimer based on the SAMP/RAMP-hydrazone methodology are described in the article by D. Enders et al. on p. 2677 ff.
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cover picture first asymmetric synthesis of sordidin and 7 epi sordidin aggregation pheromones of the banana weevil Cosmopolites Sordidus eur j org chem 12 2005
European Journal of Organic Chemistry, 2005Co-Authors: Dieter Enders, Irene Breuer, Anja NühringAbstract:The cover picture shows the most important worldwide insect pest of banana plants, the banana weevil Cosmopolites Sordidus (Germar). These long-lived weevils lay their eggs in the rhizome of the plant. The larvae hatch and then feed and tunnel in the rhizome of the plant, weakening it and leading to the snapping of the rhizome at the ground level before the bunch is ripe. The first evidence for the depicted volatile male-produced aggregation pheromones, sordidin and 7-epi-sordidin was supplied by Budenberg et al. in 1993. Details of the first asymmetric synthesis of the major pheromone compound, sordidin, and its C-7-epimer based on the SAMP/RAMP-hydrazone methodology are described in the article by D. Enders et al. on p. 2677 ff.
Françoise Lescourret - One of the best experts on this subject based on the ideXlab platform.
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COSMOS, a spatially explicit model to simulate the epidemiology of Cosmopolites Sordidus in banana fields
Ecological Modelling, 2009Co-Authors: Fabrice Vinatier, Philippe Tixier, Pierre-françois Duyck, Christophe Le Page, Françoise LescourretAbstract:A stochastic individual-based model called COSMOS was developed to simulate the epidemiology of banana weevil Cosmopolites Sordidus, a major pest of banana fields. The model is based on simple rules of local movement of adults, egg laying of females, development and mortality, and infestation of larvae inside the banana plants. The biological parameters were estimated from the literature, and the model was validated at the small-plot scale. Simulated and observed distributions of attacks were similar except for five plots out of 18, using a Kolmogorov–Smirnov test. These exceptions may be explained by variation in predation of eggs and measurement error. An exhaustive sensitivity analysis using the Morris method showed that predation rate of eggs, demographic parameters of adults and mortality rate of larvae were the most influential parameters. COSMOS was therefore used to test different spatial arrangements of banana plants on the epidemiology of C. Sordidus. Planting bananas in groups increased the time required to colonise plots but also the percentage of banana plants with severe attacks. Spatial heterogeneity of banana stages had no effect on time required to colonise plots but increased the mean level of attacks. Our model helps explain key factors of population dynamics and the epidemiology of this tropical pest.
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COSMOS, a spatially explicit model to simulate the epidemiology of Cosmopolites Sordidus in banana fields
Ecological Modelling, 2009Co-Authors: Fabrice Vinatier, Philippe Tixier, Pierre-françois Duyck, Christophe Le Page, Françoise LescourretAbstract:A stochastic individual-based model called COSMOS was developed to simulate the epidemiology of banana weevil Cosmopolites Sordidus, a major pest of banana fields. The model is based on simple rules of local movement of adults, egg laying of females, development and mortality, and infestation of larvae inside the banana plants. The biological parameters were estimated from the literature, and the model was validated at the small-plot scale. Simulated and observed distributions of attacks were similar except for five plots out of 18, using a Kolmogorov-Smirnov test. These exceptions may be explained by variation in predation of eggs and measurement error. An exhaustive sensitivity analysis using the Morris method showed that predation rate of eggs, demographic parameters of adults and mortality rate of larvae were the most influential parameters. COSMOS was therefore used to test different spatial arrangements of banana plants on the epidemiology of C. Sordidus. Planting bananas in groups increased the time required to colonise plots but also the percentage of banana plants with severe attacks. Spatial heterogeneity of banana stages had no effect on time required to colonise plots but increased the mean level of attacks. Our model helps explain key factors of population dynamics and the epidemiology of this tropical pest. (C) 2009 Elsevier B.V. All rights reserved.
Pierre-françois Duyck - One of the best experts on this subject based on the ideXlab platform.
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Effect of environment and fallow period on Cosmopolites Sordidus population dynamics at the landscape scale
Bulletin of Entomological Research, 2012Co-Authors: Pierre-françois Duyck, Dominique Carval, Fabrice Vinatier, Emmanuelle Dortel, E. Gaujoux, Philippe TixierAbstract:Understanding how the population dynamics of insect pests are affected by environmental factors and agricultural practices is important for pest management. To investigate how the abundance of the banana weevil, Cosmopolites Sordidus (Coleoptera: Curculionidae), is related to environmental factors and the length of the fallow period in Martinique, we developed an extensive data set (18,130 observations of weevil abundance obtained with pheromone traps plus associated environmental data) and analysed it with generalized mixed-effects models. At the island scale, C. Sordidus abundance was positively related to mean temperature and negatively related to mean rainfall but was not related to soil type. The number of insects trapped was highest during the driest months of the year. Abundance of C. Sordidus decreased as the duration of the preceding fallow period increased. The latter finding is inconsistent with the view that fallow-generated decomposing banana tissue is an important resource for larvae that leads to an increase in the pest population. The results are consistent with the view that fallows, in association with pheromone traps, are effective for the control of the banana weevil.
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Cosmodrome': an experimental design to study movements and behavior of the banana weevil, Cosmopolites Sordidus, using RFID
2011Co-Authors: Dominique Carval, Philippe Tixier, Pierre-françois DuyckAbstract:The banana weevil Cosmopolites Sordidus (Germar) is an important pest of banana crops. Radio-tracking and capture-recapture studies at the scale of the field have revealed a limited capacity of dispersion of the banana weevil. However, for a better understanding of the epidemiological process more information on the movement at a finer scale is needed. To analyze the behavioral response of individuals, we use the Cosmodrome, an experimental design composed of two patches whose quality may vary (bare soil, banana rhizome). The patches are connected by a tunnel of one meter of length at the ends of which RFID tag readers are placed. We analyzed the behavioral response of individuals to variation in patch density. The statistical analysis of results using generalized linear model revealed that the individuals shows a non-linear response of movement to the density in patches. The banana weevil tends to move at a higher rate at intermediate density than at low and high density. The movement response to patch density differs also according to the sex, with a higher activity of females than males at low and intermediate patch density. These preliminary results on the effect of density may reflect the individual strategies of colonization of banana fields by Cosmopolites Sordidus that maximize the individual fitness (mating, oviposition). The information on movement and behavior of the banana weevil at the plant level is of great importance for the understanding of the dynamic of the epidemiological front during the colonization process.
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"Cosmodrome": an experimental design to study movements and behavior of the banana weevil, Cosmopolites Sordidus, using RFID
2011Co-Authors: Dominique Carval, Philippe Tixier, Pierre-françois DuyckAbstract:The banana weevil Cosmopolites Sordidus (Germar) is an important pest of banana crops. Radio-tracking and capture-recapture studies at the scale of the field have revealed a limited capacity of dispersion of the banana weevil. However, for a better understanding of the epidemiological process more information on the movement at a finer scale is needed. To analyze the behavioral response of individuals, we use the Cosmodrome, an experimental design composed of two patches whose quality may vary (bare soil, Quels outils pour un changement d'echelle dans la gestion des insectes d?interet economique ? Montpellier, 4-5 Octobre 2011 9 banana rhizome). The patches are connected by a tunnel of one meter of length at the ends of which RFID tag readers are placed. We analyzed the behavioral response of individuals to variation in patch density. The statistical analysis of results using generalized linear model revealed that the individuals shows a non-linear response of movement to the density in patches. The banana weevil tends to move at a higher rate at intermediate density than at low and high density. The movement response to patch density differs also according to the sex, with a higher activity of females than males at low and intermediate patch density. These preliminary results on the effect of density may reflect the individual strategies of colonization of banana fields by Cosmopolites Sordidus that maximize the individual fitness (mating, oviposition). The information on movement and behavior of the banana weevil at the plant level is of great importance for the understanding of the dynamic of the epidemiological front during the colonization process. (Texte integral)
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COSMOS, a spatially explicit model to simulate the epidemiology of Cosmopolites Sordidus in banana fields
Ecological Modelling, 2009Co-Authors: Fabrice Vinatier, Philippe Tixier, Pierre-françois Duyck, Christophe Le Page, Françoise LescourretAbstract:A stochastic individual-based model called COSMOS was developed to simulate the epidemiology of banana weevil Cosmopolites Sordidus, a major pest of banana fields. The model is based on simple rules of local movement of adults, egg laying of females, development and mortality, and infestation of larvae inside the banana plants. The biological parameters were estimated from the literature, and the model was validated at the small-plot scale. Simulated and observed distributions of attacks were similar except for five plots out of 18, using a Kolmogorov–Smirnov test. These exceptions may be explained by variation in predation of eggs and measurement error. An exhaustive sensitivity analysis using the Morris method showed that predation rate of eggs, demographic parameters of adults and mortality rate of larvae were the most influential parameters. COSMOS was therefore used to test different spatial arrangements of banana plants on the epidemiology of C. Sordidus. Planting bananas in groups increased the time required to colonise plots but also the percentage of banana plants with severe attacks. Spatial heterogeneity of banana stages had no effect on time required to colonise plots but increased the mean level of attacks. Our model helps explain key factors of population dynamics and the epidemiology of this tropical pest.
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COSMOS, a spatially explicit model to simulate the epidemiology of Cosmopolites Sordidus in banana fields
Ecological Modelling, 2009Co-Authors: Fabrice Vinatier, Philippe Tixier, Pierre-françois Duyck, Christophe Le Page, Françoise LescourretAbstract:A stochastic individual-based model called COSMOS was developed to simulate the epidemiology of banana weevil Cosmopolites Sordidus, a major pest of banana fields. The model is based on simple rules of local movement of adults, egg laying of females, development and mortality, and infestation of larvae inside the banana plants. The biological parameters were estimated from the literature, and the model was validated at the small-plot scale. Simulated and observed distributions of attacks were similar except for five plots out of 18, using a Kolmogorov-Smirnov test. These exceptions may be explained by variation in predation of eggs and measurement error. An exhaustive sensitivity analysis using the Morris method showed that predation rate of eggs, demographic parameters of adults and mortality rate of larvae were the most influential parameters. COSMOS was therefore used to test different spatial arrangements of banana plants on the epidemiology of C. Sordidus. Planting bananas in groups increased the time required to colonise plots but also the percentage of banana plants with severe attacks. Spatial heterogeneity of banana stages had no effect on time required to colonise plots but increased the mean level of attacks. Our model helps explain key factors of population dynamics and the epidemiology of this tropical pest. (C) 2009 Elsevier B.V. All rights reserved.
W. Tinzaara - One of the best experts on this subject based on the ideXlab platform.
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Factors influencing pheromone trap effectiveness in attracting the banana weevil, Cosmopolites Sordidus
International Journal of Pest Management, 2005Co-Authors: W. Tinzaara, Clifford S Gold, Marcel Dicke, A. Van Huis, P.e. RagamaAbstract:Studies were conducted in Uganda to evaluate the influence of distance, environmental factors, trap location and trap type on catches of Cosmopolites Sordidus (Germar) (Coleoptera: Curculionidae) in pheromone-baited traps. Marked weevils were released at recorded locations within plots. Trap efficiency was low and decreased with distance from the pheromone trap. When weevils were released in close vicinity to the trap, significantly more weevils were recaptured from 0.5 m compared to those recaptured from 4 m within 30 days of trap placement. Relative humidity showed a significant positive relationship to C. Sordidus catches, while wind speed, temperature and rainfall had no effect. Covering pheromone-baited traps with banana leaves increased capture rates. In one experiment, more weevils were captured in pheromone-baited traps placed in alleys than at the base of mats, while no differences were found in the second. This study provides information on how various factors influence the effectiveness of pheromone-baited traps that will assist in designing a pheromone-based mass trapping strategy for the control of C. Sordidus.
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Chemical ecology and integrated management of the banana weevil Cosmopolites Sordidus in Uganda
2005Co-Authors: W. TinzaaraAbstract:Infochemicals (pheromones and kairomones) may potentially be used for control of the banana weevil Cosmopolites Sordidus (Germar) (Coleoptera: Curculionidae) . Cosmopolites Sordidus is a major pest of East African highland banana and plantains in most banana growing regions of the world. The weevil produces an aggregation pheromone that attracts both males and females. The attractive isomer sordidin has been identified and synthesized, and is commercially available. The objective of the research project described in this thesis was to investigate whether an infochemical-based trapping system can be used to control C. Sordidus under Ugandan conditions. In laboratory and field experiments, C. Sordidus responded in an additive way to the combination of the fermented plant tissue and the aggregation pheromone. The effect was, however, more pronounced in laboratory than field experiments. Several factors such as the pest biology, pheromone efficacy, trap parameters, cropping system and environmental factors were found to variously influence the effectiveness of the pheromone-baited traps. The effects of doubling pheromone trap densities from 4 to 8 per ha on C. Sordidus population density and plant damage were negligible in an on-farm experiment . T he pheromone-trapping system on farmers' fields was therefore not effective at the trap density recommended by the supplier (4 traps per ha). Olfactory responses of the banana weevil predators Dactylosternum abdominale (Coleoptera: Hydrophilidae) and Pheidole megacephala (Hymenoptera: Formicidae) towards volatiles from banana pseudostem tissue (kairomones) and the synthetic banana weevil pheromone were evaluated in a two-choice olfactometer. Both predators discriminated between fermenting banana pseudostem tissue and clean air. There was no evidence that the pheromone influences predator distribution around the trap in the field. In experiments to investigate whether pheromone trapping can be integrated with use of entomopathogenic fungi, Beauveria bassiana to control C. Sordidus, we observed that weevils can be aggregated on banana mats on which pheromone-baited traps are placed and on adjacent mats. Infected weevils were also observed to transmit the fungal pathogen to healthy individuals in the field. Weevil mortality due to pathogen infection was significantly higher in plots where aggregation pheromone was used in combination with B. bassiana compared to when the pathogen was applied without the pheromone. The data demonstrate that the banana weevil aggregation pheromone could be used to enhance the dissemination of B. bassiana for the control of C. Sordidus. This project provides experimental evidence to further develop the application of the synthetic aggregation pheromone to control C. Sordidus in Ugandan banana production by small scale farmers. The aggregation pheromone should be considered to be a good component of an IPM system in which it may not be effective by itself but stimulate several mortality factors for the control of the banana weevil. The next major strategy for use of pheromones is therefore to further exploit the potential to integrate entomopathogenic fungi and nematodes in the trapping system.
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Field distribution of banana weevil Cosmopolites Sordidus (Germar) adults in cooking banana stands in Uganda
International Journal of Tropical Insect Science, 2004Co-Authors: C S Gold, G.h. Kagezi, P.e. Ragama, W. Tinzaara, G. Night, A. M. K. AberaAbstract:The banana weevil, Cosmopolites Sordidus (Germar), is a nocturnal insect that is not readily observed in banana fields. Knowledge on its distribution is essential for the design of management strategies that target the adult stage. Marked weevils were released into seven-year-old banana plots. Ten days later the plots were systematically sampled for adult weevils by first removing the banana leaf mulch and residues, searching subsections of the soil to depths of 3 and 25 cm and, finally, removal and dissection of the banana mats. Of the marked weevils, 62, 56 and 82% respectively, were recovered in three trials. Most weevils were found in close association with either the banana mat (46–66%) or with cut residues lying on the ground between the mats (24–31%). Lesser numbers were found in the leaf mulch and in the top 3 cm of soil away from the mat. The distribution of weevils is likely to be influenced by crop management practices and the availability of residues and by the presence of mulch. Implications for banana weevil IPM are discussed. Le charançon du bananier, Cosmopolites Sordidus (Germar), est un insecte nocturne qui n’est pas facilement observé dans les plantations de bananiers. La connaissance de sa distribution est essentielle pour élaborer des stratégies de lutte contre le stade adulte. Des adultes marqués ont été lâchés dans trois plantations de bananiers âgées de 7 ans. Un échantillonnage systématique des adultes a été réalisé 10 jours plus tard dans les résidus de feuilles au pied des troncs, dans le sol jusqu’à une profondeur de 25 cm ainsi que dans les gaines foliaires; 62,56 et 82% des adultes marqués ont été retrouvés dans les trois essais. La plupart des charançons ont été retrouvés dans la gaine foliaire (46–66%) ou dans les débris de gaines foliaires reposant sur le sol (24–31%). Peu d’adultes ont été retrouvés dans les débris de feuilles ou dans les 3 premiers centimètres de sol. Il apparaît que la distribution des charançons est influencée par les pratiques culturales et la disponibilité en résidus ainsi que par le paillage. Les conséquences de ces observations sur la lutte intégrée contre le charançon du bananier sont discutées.
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Field distribution of banana weevil Cosmopolites Sordidus (Germar) adults in cooking banana stands in Uganda
International Journal of Tropical Insect Science, 2004Co-Authors: Clifford S Gold, G.h. Kagezi, P.e. Ragama, W. Tinzaara, G. Night, A. M. K. AberaAbstract:The banana weevil, Cosmopolites Sordidus (Germar), is a nocturnal insect that is not readily observed in banana fields. Knowledge on its distribution is essential for the design of management strategies that target the adult stage. Marked weevils were released into seven-year-old banana plots. Ten days later the plots were systematically sampled for adult weevils by first removing the banana leaf mulch and residues, searching subsections of the soil to depths of 3 and 25 cm and, finally, removal and dissection of the banana mats. Of the marked weevils, 62, 56 and 82% respectively, were recovered in three trials. Most weevils were found in close association with either the banana mat (46–66%) or with cut residues lying on the ground between the mats (24–31%). Lesser numbers were found in the leaf mulch and in the top 3 cm of soil away from the mat. The distribution of weevils is likely to be influenced by crop management practices and the availability of residues and by the presence of mulch. Implications for banana weevil IPM are discussed.
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Different bioassays for investigating orientation responses of the banana weevil, Cosmopolites Sordidus, show additive effects of host plant volatiles and a synthetic male-produced aggregation pheromone
Entomologia Experimentalis Et Applicata, 2003Co-Authors: W. Tinzaara, Marcel Dicke, Arnold Van Huis, Joop J. A. Van Loon, Clifford S GoldAbstract:Three different bioassay methods to investigate the orientation behaviour of the banana weevil, Cosmopolites Sordidus (Germar) (Coleoptera: Curculionidae), to host plant volatiles and a synthetic pheromone (cosmolure+) were compared. A locomotion compensator was used to separately record walking tracks in response to three odour sources. The data show that C. Sordidus uses odour-conditioned anemotaxis in its orientation to the odour sources tested. Of the two olfactometers tested, a dual port olfactometer using a continuous airflow showed stronger discrimination by C. Sordidus to the different odours compared with a double pitfall olfactometer. The results of all three bioassays indicate that C. Sordidus responds in an additive way to the combination of fermentation plant volatiles and the synthetic pheromone.
