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No description available.

The history, management and ecology of the European red mite, Panonvchus ulmi Koch, and two important phytoseiid predators, Typhiodromus caudiglans Schuster and Typhiodromus occidentalis Nesbitt were reviewed. The roles and interactions of dispersal, predation and weather in the orchard mite system were examined. Field experiments in an apple orchard with well-established phytoseiid and European red mite (ERM) populations showed that Typhiodromus rarely move among or between trees and the ground cover, either by air or via the trunk. They were incapable, within a single season, of repopulating trees from which phytoseiids had been removed by early-season carbaryl application, even though these trees supported high prey populations and were interspersed among unsprayed trees well-populated with Typhiodromus and the ERM. Large numbers of sticky traps captured very few aerially dispersing phytoseiids. In contrast, their ERM prey actively dispersed within trees and throughout the orchard. Mite densities were uncorrelated with leaf chlorophyll content; within-tree dispersal was not directly determined by leaf condition. Adult females were greatly over-represented in aerially-dispersing ERM emigrants in comparison with populations on the apple trees. No density threshold effect on ERM dispersal was discernible on a per-tree basis. Aerial dispersal was extensive and appeared to depend on the weather more mites disperse on warm and calm days than on cool or windy days. ERM dispersal via the tree trunk was minimal and the presence of weeds resulted in only a slight increase in ERM density on the trees. The phytoseiids affected the ERM by reducing population densities, by reducing the proportion of immatures, and by decreasing the degree of prey aggregation (as represented by frequency distribution of leaf counts). The consequences of low predator dispersal and high prey dispersal in a weather-dependent system are discussed. Results of computer simulation of the development, predation, and dispersal are presented. Dispersal (immigration and emigration) allow the phytoseiid populations in the single-tree model to persist and control the ERM. In simulations of the interaction of Typhlodromus with the ERM, the interaction of dispersal and temperature-related processes is strong and non-linear, and may operate through several processes. / Land and Food Systems, Faculty of / Graduate

Dissertation (Ph.D.)--Auburn University, 2009. / Abstract. Includes bibliographic references.

The citrus red mite, Panonychus citri (McGregor), is a relatively new pest to South African citriculture, the first recorded injury to citrus trees was from Rustenberg, Transvaal in 1950 (Smith 1953). In the U.S.A. the biology of this mite has been studied by Quayle (1938), Prendergast (1938), English and Turnipseed (1941), DeBach (1947), DeBach et al. (1950), Ebeling (1959) and Jeppson et al. (1957,1961). However, in South Africa little information is available concerning the ecolopy of the citrus red mite. The majority of the literature pertaining to P. citri in Republic, (Smith (1953), Mentz (1954), Stofberg (1959), Schwartz (1965) and Brodrick (1965) is of a descriptive nature, and mainly concerned with the chemical control of the mite. The only biological investigation on the development of P.citri, and the effect of insecticides and insect predators on its biology, under South African conditions, was made by van Rooyen (1966) at Zebediela, Transvaal. In the control of citrus pests, such as the citrus red mite, that need for a better understanding of their ecology has been well emphasised by DeBach (1951) and Griffiths (1951). DeBach (1951) in particular, stressed the danger of the continued reliance on insecticidal treatment as the only method of nest control, and has pointed out that persistent chemical applications may only serve to intensify the pest problem. He has suggested that a closer study of the environment of the pest species could provide a solution to the problems now encountered as a result of insecticidal control measures. Intro., p. 1-2.

Made available in DSpace on 2014-06-11T19:22:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-28Bitstream added on 2014-06-13T20:10:09Z : No. of bitstreams: 1 delarco_m_me_sjrp.pdf: 172067 bytes, checksum: ff3cc84d9b26229bb4e0fa1f887bc9a0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esse trabalho teve como objetivo estudar o ciclo biológico de T. heveae em folíolos de seringueira dos clones RRIM 600, PB 235 e GT 1. Inicialmente foi estabelecida uma colônia de manutenção de T. heveae. As arenas de criação e para estudos da biologia foram confeccionadas a partir de folíolos de seringueira dos clones acima citados sendo mantidas sob condições controladas em câmara climatizada do tipo BOD com umidade relativa de 70+10%, fotoperíodo de 12 h, 28+0,1oC na fotofase e 25+0,1oC na escotofase. Três observações diárias foram realizadas, acompanhando-se o desenvolvimento de 60 ovos em folíolos de cada clone para verificação do estágio de desenvolvimento em que o ácaro se encontrava, assim como a oviposição das fêmeas. A fase mais longa registrada nos três clones foi a de ovo e o período mais curto foi o protoninfal. Em todos os clones estudados a fase de maior viabilidade foi a deutoninfal, e a menor, a larval. Quatorze fêmeas e quatro machos atingiram a fase adulta no clone PB 235, sendo observada uma taxa média de oviposição de 1,2 ovo/dia/fêmea. No clone RRIM 600, nove fêmeas e dois machos foram observados, sendo registrada a taxa de oviposição de 0,7 ovo/dia/fêmea. No clone GT 1, sete fêmeas chegaram à fase adulta com taxa média de 0,51 ovo/dia/fêmea. O ciclo completo da incubação do ovo até a morte do adulto durou 25 dias, em média, nos clones RRIM 600 e PB 235. A taxa intrínseca de crescimento populacional (rm) foi de 0,09; 0,08 e 0,02 nos clones PB 235, RRIM 600 e GT 1, respectivamente. O clone PB 235 possibilitou um melhor desenvolvimento de T. heveae, seguido pelo clone RRIM 600. O clone GT 1 foi o menos favorável ao desenvolvimento. / This work aims to study the biological cycle of T. heveae in rubber tree leaflets of clones RRIM 600, PB235 and GT 1. Initially, a maintenance colony was established. The breeding arenas and those for the study of the biology were created using leaflets of the aforementioned rubber tree clones, which had been kept under controlled conditions in a climatic chamber. Three daily observations were done, following the development of 60 eggs in each clone to check the developmental stage and female oviposition. The egg was the longest-lasting phase registered and the protonymph was the shortest period. The deutonymph was the most viable phase in all clones, whereas the least viable was the larval stage. Fourteen females and four males reached the adult stage in the clone PB 235, an average oviposition rate of 1.2 egg per day per female. In the RRIM 600 clone, nine females and two males were viable, and an oviposition rate of 0.70 egg per day per female was observed. In the GT 1 clone, seven females reached the adult stage, the average ovoposition rate was 0.51 egg per day per female. The complete cycle of incubation of the egg until the death of the adult lasted, on average, 25 days in RRIM 600 and PB 235 clones. The intrinsic rate of population increase (rm) was 0.09; 0.08 and 0.02 in clones PB 235, RRIM 600 and GT1, respectively. The clone PB 235 allowed a better development of T. heveae, followed by RRIM 600. The clone GT 1 was the least favourable for the development of that mite species.

Orientador: Reinaldo José Fazzio Feres / Banca: Marineide Rosa Vieira / Banca: Marcel Ricardo Tanzini / Resumo: Esse trabalho teve como objetivo estudar o ciclo biológico de T. heveae em folíolos de seringueira dos clones RRIM 600, PB 235 e GT 1. Inicialmente foi estabelecida uma colônia de manutenção de T. heveae. As arenas de criação e para estudos da biologia foram confeccionadas a partir de folíolos de seringueira dos clones acima citados sendo mantidas sob condições controladas em câmara climatizada do tipo BOD com umidade relativa de 70+10%, fotoperíodo de 12 h, 28+0,1oC na fotofase e 25+0,1oC na escotofase. Três observações diárias foram realizadas, acompanhando-se o desenvolvimento de 60 ovos em folíolos de cada clone para verificação do estágio de desenvolvimento em que o ácaro se encontrava, assim como a oviposição das fêmeas. A fase mais longa registrada nos três clones foi a de ovo e o período mais curto foi o protoninfal. Em todos os clones estudados a fase de maior viabilidade foi a deutoninfal, e a menor, a larval. Quatorze fêmeas e quatro machos atingiram a fase adulta no clone PB 235, sendo observada uma taxa média de oviposição de 1,2 ovo/dia/fêmea. No clone RRIM 600, nove fêmeas e dois machos foram observados, sendo registrada a taxa de oviposição de 0,7 ovo/dia/fêmea. No clone GT 1, sete fêmeas chegaram à fase adulta com taxa média de 0,51 ovo/dia/fêmea. O ciclo completo da incubação do ovo até a morte do adulto durou 25 dias, em média, nos clones RRIM 600 e PB 235. A taxa intrínseca de crescimento populacional (rm) foi de 0,09; 0,08 e 0,02 nos clones PB 235, RRIM 600 e GT 1, respectivamente. O clone PB 235 possibilitou um melhor desenvolvimento de T. heveae, seguido pelo clone RRIM 600. O clone GT 1 foi o menos favorável ao desenvolvimento. / Abstract: This work aims to study the biological cycle of T. heveae in rubber tree leaflets of clones RRIM 600, PB235 and GT 1. Initially, a maintenance colony was established. The breeding arenas and those for the study of the biology were created using leaflets of the aforementioned rubber tree clones, which had been kept under controlled conditions in a climatic chamber. Three daily observations were done, following the development of 60 eggs in each clone to check the developmental stage and female oviposition. The egg was the longest-lasting phase registered and the protonymph was the shortest period. The deutonymph was the most viable phase in all clones, whereas the least viable was the larval stage. Fourteen females and four males reached the adult stage in the clone PB 235, an average oviposition rate of 1.2 egg per day per female. In the RRIM 600 clone, nine females and two males were viable, and an oviposition rate of 0.70 egg per day per female was observed. In the GT 1 clone, seven females reached the adult stage, the average ovoposition rate was 0.51 egg per day per female. The complete cycle of incubation of the egg until the death of the adult lasted, on average, 25 days in RRIM 600 and PB 235 clones. The intrinsic rate of population increase (rm) was 0.09; 0.08 and 0.02 in clones PB 235, RRIM 600 and GT1, respectively. The clone PB 235 allowed a better development of T. heveae, followed by RRIM 600. The clone GT 1 was the least favourable for the development of that mite species. / Mestre

Made available in DSpace on 2015-03-26T13:39:50Z (GMT). No. of bitstreams: 1 texto completo.pdf: 654247 bytes, checksum: d2c9ac5e28ba3e3ab366388eba9e7d9f (MD5) Previous issue date: 2012-07-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / To obtain plant cultivars resistant to pests it is important to search for sources of resistance, and determine its mechanisms and modes of expression, and furthermore, evaluate its persistence over time. Coffea canephora Pierre is known as conilon coffee and it is the second most widely cultivated species of coffee in the world. Among some of the major pests of C. canephora is the red mite Oligonychus ilicis (McGregor) (Acari: Tetranychidae). The main objectives of this study were: (i) select clones of C. canephora resistant to O. ilicis, (ii) determine the persistence of resistance when this mite reproduces over several generations on conilon coffee and (iii) correlate the concentration of proteins and serine protease inhibitors of the leaves with the the population growth of O. ilicis on C. canephora. In the bioassays, 14 clones of C. canephora cv Vitória were tested. The 14 clones of C. canephora showed no antixenosis resistance to O. ilicis. The clones 1, 4, 5, 6, 9, 10, 12, 13 and 501 of C. canephora exhibited an antibiosis effect upon the development of O. ilicis. Among all these clones, 1 and 10 showed resistence to the mites with the highest persistence over time. Nonetheless, the resistance in clones of C. canephora to O. ilicis was not correlated with neither the concentration of proteins nor the protease inhibitors in the leaves of these plants. / Na obtenção de cultivares resistentes às pragas é importante a seleção de fontes e a determinação dos mecanismos, modos de expressão, causas da resistência e a persistência da resistência ao longo do tempo. Coffea canephora Pierre é conhecida como café conilon e ela é a segunda espécie de café mais cultivada no mundo. Dentre as principais pragas de C. canephora está o ácaro vermelho Oligonychus ilicis (McGregor) (Acari: Tetranychidae). Assim neste trabalho foram conduzidos bioensaios com o objetivo de: (i) selecionar clones de C. canephora resistentes a O. ilicis, (ii) verificar a persistência da resistência quando este ácaro se desenvolve por várias gerações no café conilon e (iii) relacionar a concentração de proteínas e inibidores de proteases das folhas com o desempenho demográfico de O. ilicis em clones de C. canephora. Nos bioensaios foram usados 14 clones de C. canephora da cultivar Vitória. Os 14 clones de C. canephora não apresentaram resistência por antixenose a O. ilicis. Os clones 1, 4, 5, 6, 9, 10, 12, 13 e 501 de C. canephora apresentaram resistência por antibiose a O. ilicis. Entre estes, os clones 1 e 10 apresentaram resistência com maior persistência ao longo do tempo. A resistência nos clones de C. canephora a O. ilicis não esteve correlacionada com a concentração de proteínas e inibidores de proteases nas folhas destas plantas.

The aim of this study was to investigate the usefulness of image analysis for studying mite behaviour. Image analysis was used to convert video recordings of mites' locomotory behaviour into a series of x,y coordinates that, when joined, closely resemble the paths of mites. The coordinates were also used to calculate walking speed, direction of travel, turning frequency, turn bias and tortuosity. Two experimental arenas were developed and used to study the movement of three mite species: 1) a leaf disc arena for two-spotted spider mite, Tetranychus urticae Koch and European red mite, Panonychus ulmi (Koch); and 2), a cover-slip/tack-trap arena for Typhlodromus pyri Scheuten. Two-spotted spider mite exhibited a change in locomotory behaviour through a 48 minute period. Mites exhibited a significant decline in distance travelled, whereas the mean stationary time (per four minute interval) more than doubled, and the duration of stationary events increased steadily over the same period. A reduction in sampling frequency of mite coordinates from one per second to one every two seconds and every four seconds produced a 5% and 12% 'loss' in path length respectively. Sample period length was shown to greatly influence the results produced for some of the mean parameters calculated, however, a reduction in sample length from 3000 to 1500 coordinates was not considered to cause a major loss in information. The influence of the inherent mite movement could not be ignored and made it difficult to make decisions on the 'best' sample length to use. Some strong correlations were found between parameters used to analyse mite locomotory behaviour. In particular, arithmetic mean vector length, speed, total stationary time and total distance travelled were significantly correlated with each other. Mean angular deviation and weighted mean vector length, which both measure the degree of clustering around the mean heading angle, were strongly negatively correlated. Parameters which differentiated between 'straight' and 'tortuous' mite movement were found to be mean meander, absolute mean turn and fractal dimensions. Mean meander was thought to be the most 'powerful', while coefficient of a straight line, a commonly used parameter for measuring tortuosity, did not significantly differentiate between the two different behaviours. Frequency distributions of turns and standard deviations of the three mite species were very similar. All three species had a slight bias to turning right (clockwise) rather than to the left (counter-clockwise) and for each species certain angles occurred more often than would be expected in a 'perfect' normal distribution. A similar pattern also occurred with the frequency distribution of two-spotted spider mite heading angles, in that angles which were expected to occur more often, did not, and vice versa. The potential to use saturated salt solutions to control relative humidity on the arena was` demonstrated and indicated that relative humidity is likely to have an important influence on mite behaviour. Two-spotted spider mites appeared to move more quickly in an attempt to escape the unfavourable, extreme (10% and 95% R.H. at 25°C) moisture conditions. All three mite species displayed a characteristic edge-walking behaviour around the arenas. However, when 'edge' and 'non-edge' behaviours were compared, mean meander was the only parameter (of the parameters tested) which gave a significant difference. Behavioural responses of European red mite and T. pyri to sub-lethal (field rate) esfenvalerate were investigated and the results indicated that these mites did not seek the unsprayed halves of the arenas during the first 48 minutes. However, significant differences in most behavioural parameters to esfenvalerate residues were found with European red mite when whole arenas were compared. Image analysis is an extremely useful research tool for studying mite behaviour because of its ability to measure many parameters quickly. Careful choice of the environmental conditions, the sampling framework, and interpretation of data is essential for meaningful results.

The aim of this study was to investigate the usefulness of image analysis for studying mite behaviour. Image analysis was used to convert video recordings of mites' locomotory behaviour into a series of x,y coordinates that, when joined, closely resemble the paths of mites. The coordinates were also used to calculate walking speed, direction of travel, turning frequency, turn bias and tortuosity. Two experimental arenas were developed and used to study the movement of three mite species: 1) a leaf disc arena for two-spotted spider mite, Tetranychus urticae Koch and European red mite, Panonychus ulmi (Koch); and 2), a cover-slip/tack-trap arena for Typhlodromus pyri Scheuten. Two-spotted spider mite exhibited a change in locomotory behaviour through a 48 minute period. Mites exhibited a significant decline in distance travelled, whereas the mean stationary time (per four minute interval) more than doubled, and the duration of stationary events increased steadily over the same period. A reduction in sampling frequency of mite coordinates from one per second to one every two seconds and every four seconds produced a 5% and 12% 'loss' in path length respectively. Sample period length was shown to greatly influence the results produced for some of the mean parameters calculated, however, a reduction in sample length from 3000 to 1500 coordinates was not considered to cause a major loss in information. The influence of the inherent mite movement could not be ignored and made it difficult to make decisions on the 'best' sample length to use. Some strong correlations were found between parameters used to analyse mite locomotory behaviour. In particular, arithmetic mean vector length, speed, total stationary time and total distance travelled were significantly correlated with each other. Mean angular deviation and weighted mean vector length, which both measure the degree of clustering around the mean heading angle, were strongly negatively correlated. Parameters which differentiated between 'straight' and 'tortuous' mite movement were found to be mean meander, absolute mean turn and fractal dimensions. Mean meander was thought to be the most 'powerful', while coefficient of a straight line, a commonly used parameter for measuring tortuosity, did not significantly differentiate between the two different behaviours. Frequency distributions of turns and standard deviations of the three mite species were very similar. All three species had a slight bias to turning right (clockwise) rather than to the left (counter-clockwise) and for each species certain angles occurred more often than would be expected in a 'perfect' normal distribution. A similar pattern also occurred with the frequency distribution of two-spotted spider mite heading angles, in that angles which were expected to occur more often, did not, and vice versa. The potential to use saturated salt solutions to control relative humidity on the arena was` demonstrated and indicated that relative humidity is likely to have an important influence on mite behaviour. Two-spotted spider mites appeared to move more quickly in an attempt to escape the unfavourable, extreme (10% and 95% R.H. at 25°C) moisture conditions. All three mite species displayed a characteristic edge-walking behaviour around the arenas. However, when 'edge' and 'non-edge' behaviours were compared, mean meander was the only parameter (of the parameters tested) which gave a significant difference. Behavioural responses of European red mite and T. pyri to sub-lethal (field rate) esfenvalerate were investigated and the results indicated that these mites did not seek the unsprayed halves of the arenas during the first 48 minutes. However, significant differences in most behavioural parameters to esfenvalerate residues were found with European red mite when whole arenas were compared. Image analysis is an extremely useful research tool for studying mite behaviour because of its ability to measure many parameters quickly. Careful choice of the environmental conditions, the sampling framework, and interpretation of data is essential for meaningful results.