This study investigated the potential of companion planting as a strategy to aid in the management of Helicoverpa armigera in tomato and capsicum cropping systems. The investigaitons showed that a companion planting type system is unlikely to confer any benefits to the management of H. armigera in these crops. The project has contributed to the understanding of H. armigera host selection and how the pest responds to a diversified environment. Companion planting and vegetational diversity are strategies for reducing pest incidence on crops. Many theories have been devised to explain how introducing more than one plant species to a cropping space may reduce the incidence of a pest. Five ecological theories formed the basis of experiments in this study: The resource concentration hypothesis - Herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands (Root, 1973). Associational resistance/Plant apparency - Crop plants grown as monocultures are more apparent to herbivorous insects than plants in diverse natural systems (Tahvanainen and Root, 1972). Trap cropping – the use of plants within a cropping area to attract oviposition away from the main crop (Banks and Ekbom, 1999). The ability of H. armigera to learn in regard to host seleciton (Cunningham et al., 1998a). The natural enemies hypothesis - generalist and specialist natural enemies are expected to be more abundant in diverse rather than simple systems (Root, 1973) A tall variety of sorghum (the forage variety Chopper) was tested for its ability to disrupt host location. Sorghum was planted around plots of tomatoes to act as a screen to disrupt visual cues for host location by Helicoverpa spp. No difference was found in egg numbers on tomatoes with or without sorghum companions. However, significantly higher numbers of Helicoverpa spp. larvae were found in the sorghum at flowering than in the tomatoes. This suggested the sorghum was acting as a trap crop, diverting oviposition away from the tomato crop. However, due to a short period of flowering and therefore peak attractiveness to H. armigera, sorghum was not considered to be a suitable companion plant for inclusion in commercial tomato production systems. A host preference study was conducted to determine the preferences of H. armigera for crop plants and possible companions in the hope of finding a suitable trap crop species. Tomatoes were shown to be a highly preferred plant making it difficult to find a compatible trap crop species that would be more attractive than the main crop. However, capsicums were less prefered and therefore more suitable for this type of experimentation. Marigolds were also found to be a highly preferred plant and formed the basis for further investigations into trap cropping systems. Field experiments were conducted in successive years in two geographical locations to assess the suitability of marigolds as a trap crop for capsicums in a field situation. However, in both years H. armigera incidence was extremely and unusually low leading to inconclusive results. A glasshouse experiment was performed to assess if the ratio of capsicum plants to marigolds plants had an effect on which species H. armigera would choose for oviposition. It was found that as more capsicum plants were introduced, moths became less likely to oviposit on the supposedly more preferred marigold plant. The diminishing attractiveness of a more preferred host in the presence of other hosts is a new observation of H. armigera behaviour. This result suggests that marigolds would be unlikely to be a successful trap crop in a field situation. The ability of H. armigera to learn in regard to host selection and the influence of this on host selection in the field was investigated. No evidence of learning was found. This was the first study investigating the effect of learning in a field situation; previously the behaviour had only been investigated in a laboratory situation (Cunningham, et al. 1998a). The ability of the Australian assassin bug, Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) to predate H. armigera larvae on capsicum plants was investigated. This predator has been sucessfully been used for H. armigera management in cotton (Grundy, 2000b), but had not been investigated in horticultural crops. Significant reductions in larvae were achieved in treatments where assassin bugs were introduced. This predator warrants further investigation for inclusion in commercial integrated pest managment programs for capsicums. Pest repellent plants were also considered. Previous to this study, very little research work had been conducted on repellent plants for H. armigera. The herbs investigated were catnip (Nepta cataria), tansy (Tanacetum vulgare), basil (Ocium basilicum) and coriander (Coriander sativum). An olfactometer system was designed and built to test H. armigera moths’ responses to odours from the herbs. Glasshouse experiments were also conducted. No repellent activity was recorded with any of the herbs tested. The results of this study support the theory that Helicoverpa spp. employ a strategy of passive host selection as suggested by Firempong (1986). This means that all available plants in an area may be oviposited on with successful ovipostion and larval development leading to the future utilisation of a species as a host plant. The implication of this finding is that in-field trap cropping is unlikely to be a successful strategy for reducing H. armigera oviposition in tomato or capsicum production systems in Australia. In cotton crops in Australia, trap cropping is used as part of an area wide management strategy and aims to reduce the total Helicoverpa spp. population of a region. Such a strategy may also be successful in horticultural crops but only with the full participation of the growers of all crops that are attractive to H. armigera in a horticultural growing region. Due to the diverse nature of horticultural production this may be a difficult task.

Positive-ion electrospray ionisation Fourier transform ion cyclotron resonance and ion trap mass spectrometry have been used to investigate the reactions of the flavonoids 3-hydroxyflavone, 5-hydroxyflavone, 5-methoxyflavoe, quercetin, quercitrin and rutin with monovalent Li+, Na+, K+ and Cs+, divalent Cu2+, Zn2+ and Pb2+ and trivalent La3+ and Eu3+ metal cations. The effect of capillary-skimmer potential difference and the ion residence time in the hexapole ion trap of the Fourier transform ion cyclotron resonance mass spectrometer are systematically investigated for the flavonoid-alkali and divalent metal ion experiment. It is observed that these variables impact significantly on the type of ions observed in the ESI experiments and hence the mass spectra. The binding selectivity of alkali metal ions towards 3-hydroxyflavone, 5-hydroxyflavone and 5-methoxyflavone are determined using the results from FTICR mass spectrometry experiments. The selectivity order follows the order Li+>Na+>K+ for individual flavonoids. Collision-induced dissociation experiments are carried out by Fourier transform ion cyclotron resonance and ion trap mass spectrometry to compare the fragmentation behaviour of metal-flavonoid complexes. Low energy collision-induced dissociation experiments of the [2L+M]+ for 3-hydroxyflavone, 5-hydroxyflavone and 5-methoxyflavone alkali metal complexes show the loss of ligand only. When the energy is increased only the lithiated dimer [2L+Li]+ for 5-methoxyflavone shows the loss of methyl radical along with the ligand. For quercitrin the predominant dissociation pathways are the loss of rhamnose for Li+, Na+ and K+ complexes although aglycone loss is also observed for the K+ complex. The favourable dissociation pathways for rutin are the loss of disaccharide, aglycone and rhamnose for the Na+ complex and the loss of disaccharide for the K+ complex. Collision-induced dissociation data are also used to determine the threshold dissociation energies for displacement of one flavonoid ligand from alkali metal flavonoid complexes. The threshold dissociation energies for loss of one ligand from [2L+M]+ of 5-methoxyflavone and quercitrin follow the order Li+ > Na+ > K+, rutin follows the order Na+ > K+ > Li+ , and 3-hydroxyflavone and 5-hydroxyflavone follow the order Li+ > Na+. For the same metal cation experiment, 5-methoxyflavone system has the highest dissociation energy compared to the 3-hydroxyflavone and 5-hydroxyflavone experiment. Preliminary DFT calculations show that the calculated dissociation energies follow the same trend as the experimental dissociation energies for the simple flavonoid alkali metal cation experiments. For 5-methoxyflavone-divalent metal cation (Zn2+, Cu2+ and Pb2+) complexes loss of methyl radical is the common process. CO loss is also observed for the Zn2+ complex whereas CHO and H2O losses are observed for Cu2+. For 3-hydroxyflavone and 5-hydroxyflavone divalent metal cation experiments loss of ligand is the dominant process. Zn2+ and Cu2+ complexes also show CO loss. La3+ and Er3+ with the same flavonoids show the ligand as the dominant product. For quercetin-divalent metal cation experiment, ligand loss is the dominant process. For quercitrin and rutin various dissociation products are observed where the dissociation occurs via the loss of the rhamnose and/or the disaccharide moieties. Similar dissociation patterns are also observed for La3+ and Er3+ complexes for quercitrin and rutin.

This study investigated the potential of companion planting as a strategy to aid in the management of Helicoverpa armigera in tomato and capsicum cropping systems. The investigaitons showed that a companion planting type system is unlikely to confer any benefits to the management of H. armigera in these crops. The project has contributed to the understanding of H. armigera host selection and how the pest responds to a diversified environment. Companion planting and vegetational diversity are strategies for reducing pest incidence on crops. Many theories have been devised to explain how introducing more than one plant species to a cropping space may reduce the incidence of a pest. Five ecological theories formed the basis of experiments in this study: The resource concentration hypothesis - Herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands (Root, 1973). Associational resistance/Plant apparency - Crop plants grown as monocultures are more apparent to herbivorous insects than plants in diverse natural systems (Tahvanainen and Root, 1972). Trap cropping – the use of plants within a cropping area to attract oviposition away from the main crop (Banks and Ekbom, 1999). The ability of H. armigera to learn in regard to host seleciton (Cunningham et al., 1998a). The natural enemies hypothesis - generalist and specialist natural enemies are expected to be more abundant in diverse rather than simple systems (Root, 1973) A tall variety of sorghum (the forage variety Chopper) was tested for its ability to disrupt host location. Sorghum was planted around plots of tomatoes to act as a screen to disrupt visual cues for host location by Helicoverpa spp. No difference was found in egg numbers on tomatoes with or without sorghum companions. However, significantly higher numbers of Helicoverpa spp. larvae were found in the sorghum at flowering than in the tomatoes. This suggested the sorghum was acting as a trap crop, diverting oviposition away from the tomato crop. However, due to a short period of flowering and therefore peak attractiveness to H. armigera, sorghum was not considered to be a suitable companion plant for inclusion in commercial tomato production systems. A host preference study was conducted to determine the preferences of H. armigera for crop plants and possible companions in the hope of finding a suitable trap crop species. Tomatoes were shown to be a highly preferred plant making it difficult to find a compatible trap crop species that would be more attractive than the main crop. However, capsicums were less prefered and therefore more suitable for this type of experimentation. Marigolds were also found to be a highly preferred plant and formed the basis for further investigations into trap cropping systems. Field experiments were conducted in successive years in two geographical locations to assess the suitability of marigolds as a trap crop for capsicums in a field situation. However, in both years H. armigera incidence was extremely and unusually low leading to inconclusive results. A glasshouse experiment was performed to assess if the ratio of capsicum plants to marigolds plants had an effect on which species H. armigera would choose for oviposition. It was found that as more capsicum plants were introduced, moths became less likely to oviposit on the supposedly more preferred marigold plant. The diminishing attractiveness of a more preferred host in the presence of other hosts is a new observation of H. armigera behaviour. This result suggests that marigolds would be unlikely to be a successful trap crop in a field situation. The ability of H. armigera to learn in regard to host selection and the influence of this on host selection in the field was investigated. No evidence of learning was found. This was the first study investigating the effect of learning in a field situation; previously the behaviour had only been investigated in a laboratory situation (Cunningham, et al. 1998a). The ability of the Australian assassin bug, Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) to predate H. armigera larvae on capsicum plants was investigated. This predator has been sucessfully been used for H. armigera management in cotton (Grundy, 2000b), but had not been investigated in horticultural crops. Significant reductions in larvae were achieved in treatments where assassin bugs were introduced. This predator warrants further investigation for inclusion in commercial integrated pest managment programs for capsicums. Pest repellent plants were also considered. Previous to this study, very little research work had been conducted on repellent plants for H. armigera. The herbs investigated were catnip (Nepta cataria), tansy (Tanacetum vulgare), basil (Ocium basilicum) and coriander (Coriander sativum). An olfactometer system was designed and built to test H. armigera moths’ responses to odours from the herbs. Glasshouse experiments were also conducted. No repellent activity was recorded with any of the herbs tested. The results of this study support the theory that Helicoverpa spp. employ a strategy of passive host selection as suggested by Firempong (1986). This means that all available plants in an area may be oviposited on with successful ovipostion and larval development leading to the future utilisation of a species as a host plant. The implication of this finding is that in-field trap cropping is unlikely to be a successful strategy for reducing H. armigera oviposition in tomato or capsicum production systems in Australia. In cotton crops in Australia, trap cropping is used as part of an area wide management strategy and aims to reduce the total Helicoverpa spp. population of a region. Such a strategy may also be successful in horticultural crops but only with the full participation of the growers of all crops that are attractive to H. armigera in a horticultural growing region. Due to the diverse nature of horticultural production this may be a difficult task.

This study investigated the potential of companion planting as a strategy to aid in the management of Helicoverpa armigera in tomato and capsicum cropping systems. The investigaitons showed that a companion planting type system is unlikely to confer any benefits to the management of H. armigera in these crops. The project has contributed to the understanding of H. armigera host selection and how the pest responds to a diversified environment. Companion planting and vegetational diversity are strategies for reducing pest incidence on crops. Many theories have been devised to explain how introducing more than one plant species to a cropping space may reduce the incidence of a pest. Five ecological theories formed the basis of experiments in this study: The resource concentration hypothesis - Herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands (Root, 1973). Associational resistance/Plant apparency - Crop plants grown as monocultures are more apparent to herbivorous insects than plants in diverse natural systems (Tahvanainen and Root, 1972). Trap cropping – the use of plants within a cropping area to attract oviposition away from the main crop (Banks and Ekbom, 1999). The ability of H. armigera to learn in regard to host seleciton (Cunningham et al., 1998a). The natural enemies hypothesis - generalist and specialist natural enemies are expected to be more abundant in diverse rather than simple systems (Root, 1973) A tall variety of sorghum (the forage variety Chopper) was tested for its ability to disrupt host location. Sorghum was planted around plots of tomatoes to act as a screen to disrupt visual cues for host location by Helicoverpa spp. No difference was found in egg numbers on tomatoes with or without sorghum companions. However, significantly higher numbers of Helicoverpa spp. larvae were found in the sorghum at flowering than in the tomatoes. This suggested the sorghum was acting as a trap crop, diverting oviposition away from the tomato crop. However, due to a short period of flowering and therefore peak attractiveness to H. armigera, sorghum was not considered to be a suitable companion plant for inclusion in commercial tomato production systems. A host preference study was conducted to determine the preferences of H. armigera for crop plants and possible companions in the hope of finding a suitable trap crop species. Tomatoes were shown to be a highly preferred plant making it difficult to find a compatible trap crop species that would be more attractive than the main crop. However, capsicums were less prefered and therefore more suitable for this type of experimentation. Marigolds were also found to be a highly preferred plant and formed the basis for further investigations into trap cropping systems. Field experiments were conducted in successive years in two geographical locations to assess the suitability of marigolds as a trap crop for capsicums in a field situation. However, in both years H. armigera incidence was extremely and unusually low leading to inconclusive results. A glasshouse experiment was performed to assess if the ratio of capsicum plants to marigolds plants had an effect on which species H. armigera would choose for oviposition. It was found that as more capsicum plants were introduced, moths became less likely to oviposit on the supposedly more preferred marigold plant. The diminishing attractiveness of a more preferred host in the presence of other hosts is a new observation of H. armigera behaviour. This result suggests that marigolds would be unlikely to be a successful trap crop in a field situation. The ability of H. armigera to learn in regard to host selection and the influence of this on host selection in the field was investigated. No evidence of learning was found. This was the first study investigating the effect of learning in a field situation; previously the behaviour had only been investigated in a laboratory situation (Cunningham, et al. 1998a). The ability of the Australian assassin bug, Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) to predate H. armigera larvae on capsicum plants was investigated. This predator has been sucessfully been used for H. armigera management in cotton (Grundy, 2000b), but had not been investigated in horticultural crops. Significant reductions in larvae were achieved in treatments where assassin bugs were introduced. This predator warrants further investigation for inclusion in commercial integrated pest managment programs for capsicums. Pest repellent plants were also considered. Previous to this study, very little research work had been conducted on repellent plants for H. armigera. The herbs investigated were catnip (Nepta cataria), tansy (Tanacetum vulgare), basil (Ocium basilicum) and coriander (Coriander sativum). An olfactometer system was designed and built to test H. armigera moths’ responses to odours from the herbs. Glasshouse experiments were also conducted. No repellent activity was recorded with any of the herbs tested. The results of this study support the theory that Helicoverpa spp. employ a strategy of passive host selection as suggested by Firempong (1986). This means that all available plants in an area may be oviposited on with successful ovipostion and larval development leading to the future utilisation of a species as a host plant. The implication of this finding is that in-field trap cropping is unlikely to be a successful strategy for reducing H. armigera oviposition in tomato or capsicum production systems in Australia. In cotton crops in Australia, trap cropping is used as part of an area wide management strategy and aims to reduce the total Helicoverpa spp. population of a region. Such a strategy may also be successful in horticultural crops but only with the full participation of the growers of all crops that are attractive to H. armigera in a horticultural growing region. Due to the diverse nature of horticultural production this may be a difficult task.

This study investigated the potential of companion planting as a strategy to aid in the management of Helicoverpa armigera in tomato and capsicum cropping systems. The investigaitons showed that a companion planting type system is unlikely to confer any benefits to the management of H. armigera in these crops. The project has contributed to the understanding of H. armigera host selection and how the pest responds to a diversified environment. Companion planting and vegetational diversity are strategies for reducing pest incidence on crops. Many theories have been devised to explain how introducing more than one plant species to a cropping space may reduce the incidence of a pest. Five ecological theories formed the basis of experiments in this study: The resource concentration hypothesis - Herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands (Root, 1973). Associational resistance/Plant apparency - Crop plants grown as monocultures are more apparent to herbivorous insects than plants in diverse natural systems (Tahvanainen and Root, 1972). Trap cropping – the use of plants within a cropping area to attract oviposition away from the main crop (Banks and Ekbom, 1999). The ability of H. armigera to learn in regard to host seleciton (Cunningham et al., 1998a). The natural enemies hypothesis - generalist and specialist natural enemies are expected to be more abundant in diverse rather than simple systems (Root, 1973) A tall variety of sorghum (the forage variety Chopper) was tested for its ability to disrupt host location. Sorghum was planted around plots of tomatoes to act as a screen to disrupt visual cues for host location by Helicoverpa spp. No difference was found in egg numbers on tomatoes with or without sorghum companions. However, significantly higher numbers of Helicoverpa spp. larvae were found in the sorghum at flowering than in the tomatoes. This suggested the sorghum was acting as a trap crop, diverting oviposition away from the tomato crop. However, due to a short period of flowering and therefore peak attractiveness to H. armigera, sorghum was not considered to be a suitable companion plant for inclusion in commercial tomato production systems. A host preference study was conducted to determine the preferences of H. armigera for crop plants and possible companions in the hope of finding a suitable trap crop species. Tomatoes were shown to be a highly preferred plant making it difficult to find a compatible trap crop species that would be more attractive than the main crop. However, capsicums were less prefered and therefore more suitable for this type of experimentation. Marigolds were also found to be a highly preferred plant and formed the basis for further investigations into trap cropping systems. Field experiments were conducted in successive years in two geographical locations to assess the suitability of marigolds as a trap crop for capsicums in a field situation. However, in both years H. armigera incidence was extremely and unusually low leading to inconclusive results. A glasshouse experiment was performed to assess if the ratio of capsicum plants to marigolds plants had an effect on which species H. armigera would choose for oviposition. It was found that as more capsicum plants were introduced, moths became less likely to oviposit on the supposedly more preferred marigold plant. The diminishing attractiveness of a more preferred host in the presence of other hosts is a new observation of H. armigera behaviour. This result suggests that marigolds would be unlikely to be a successful trap crop in a field situation. The ability of H. armigera to learn in regard to host selection and the influence of this on host selection in the field was investigated. No evidence of learning was found. This was the first study investigating the effect of learning in a field situation; previously the behaviour had only been investigated in a laboratory situation (Cunningham, et al. 1998a). The ability of the Australian assassin bug, Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) to predate H. armigera larvae on capsicum plants was investigated. This predator has been sucessfully been used for H. armigera management in cotton (Grundy, 2000b), but had not been investigated in horticultural crops. Significant reductions in larvae were achieved in treatments where assassin bugs were introduced. This predator warrants further investigation for inclusion in commercial integrated pest managment programs for capsicums. Pest repellent plants were also considered. Previous to this study, very little research work had been conducted on repellent plants for H. armigera. The herbs investigated were catnip (Nepta cataria), tansy (Tanacetum vulgare), basil (Ocium basilicum) and coriander (Coriander sativum). An olfactometer system was designed and built to test H. armigera moths’ responses to odours from the herbs. Glasshouse experiments were also conducted. No repellent activity was recorded with any of the herbs tested. The results of this study support the theory that Helicoverpa spp. employ a strategy of passive host selection as suggested by Firempong (1986). This means that all available plants in an area may be oviposited on with successful ovipostion and larval development leading to the future utilisation of a species as a host plant. The implication of this finding is that in-field trap cropping is unlikely to be a successful strategy for reducing H. armigera oviposition in tomato or capsicum production systems in Australia. In cotton crops in Australia, trap cropping is used as part of an area wide management strategy and aims to reduce the total Helicoverpa spp. population of a region. Such a strategy may also be successful in horticultural crops but only with the full participation of the growers of all crops that are attractive to H. armigera in a horticultural growing region. Due to the diverse nature of horticultural production this may be a difficult task.

This study investigated the potential of companion planting as a strategy to aid in the management of Helicoverpa armigera in tomato and capsicum cropping systems. The investigaitons showed that a companion planting type system is unlikely to confer any benefits to the management of H. armigera in these crops. The project has contributed to the understanding of H. armigera host selection and how the pest responds to a diversified environment. Companion planting and vegetational diversity are strategies for reducing pest incidence on crops. Many theories have been devised to explain how introducing more than one plant species to a cropping space may reduce the incidence of a pest. Five ecological theories formed the basis of experiments in this study: The resource concentration hypothesis - Herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands (Root, 1973). Associational resistance/Plant apparency - Crop plants grown as monocultures are more apparent to herbivorous insects than plants in diverse natural systems (Tahvanainen and Root, 1972). Trap cropping – the use of plants within a cropping area to attract oviposition away from the main crop (Banks and Ekbom, 1999). The ability of H. armigera to learn in regard to host seleciton (Cunningham et al., 1998a). The natural enemies hypothesis - generalist and specialist natural enemies are expected to be more abundant in diverse rather than simple systems (Root, 1973) A tall variety of sorghum (the forage variety Chopper) was tested for its ability to disrupt host location. Sorghum was planted around plots of tomatoes to act as a screen to disrupt visual cues for host location by Helicoverpa spp. No difference was found in egg numbers on tomatoes with or without sorghum companions. However, significantly higher numbers of Helicoverpa spp. larvae were found in the sorghum at flowering than in the tomatoes. This suggested the sorghum was acting as a trap crop, diverting oviposition away from the tomato crop. However, due to a short period of flowering and therefore peak attractiveness to H. armigera, sorghum was not considered to be a suitable companion plant for inclusion in commercial tomato production systems. A host preference study was conducted to determine the preferences of H. armigera for crop plants and possible companions in the hope of finding a suitable trap crop species. Tomatoes were shown to be a highly preferred plant making it difficult to find a compatible trap crop species that would be more attractive than the main crop. However, capsicums were less prefered and therefore more suitable for this type of experimentation. Marigolds were also found to be a highly preferred plant and formed the basis for further investigations into trap cropping systems. Field experiments were conducted in successive years in two geographical locations to assess the suitability of marigolds as a trap crop for capsicums in a field situation. However, in both years H. armigera incidence was extremely and unusually low leading to inconclusive results. A glasshouse experiment was performed to assess if the ratio of capsicum plants to marigolds plants had an effect on which species H. armigera would choose for oviposition. It was found that as more capsicum plants were introduced, moths became less likely to oviposit on the supposedly more preferred marigold plant. The diminishing attractiveness of a more preferred host in the presence of other hosts is a new observation of H. armigera behaviour. This result suggests that marigolds would be unlikely to be a successful trap crop in a field situation. The ability of H. armigera to learn in regard to host selection and the influence of this on host selection in the field was investigated. No evidence of learning was found. This was the first study investigating the effect of learning in a field situation; previously the behaviour had only been investigated in a laboratory situation (Cunningham, et al. 1998a). The ability of the Australian assassin bug, Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) to predate H. armigera larvae on capsicum plants was investigated. This predator has been sucessfully been used for H. armigera management in cotton (Grundy, 2000b), but had not been investigated in horticultural crops. Significant reductions in larvae were achieved in treatments where assassin bugs were introduced. This predator warrants further investigation for inclusion in commercial integrated pest managment programs for capsicums. Pest repellent plants were also considered. Previous to this study, very little research work had been conducted on repellent plants for H. armigera. The herbs investigated were catnip (Nepta cataria), tansy (Tanacetum vulgare), basil (Ocium basilicum) and coriander (Coriander sativum). An olfactometer system was designed and built to test H. armigera moths’ responses to odours from the herbs. Glasshouse experiments were also conducted. No repellent activity was recorded with any of the herbs tested. The results of this study support the theory that Helicoverpa spp. employ a strategy of passive host selection as suggested by Firempong (1986). This means that all available plants in an area may be oviposited on with successful ovipostion and larval development leading to the future utilisation of a species as a host plant. The implication of this finding is that in-field trap cropping is unlikely to be a successful strategy for reducing H. armigera oviposition in tomato or capsicum production systems in Australia. In cotton crops in Australia, trap cropping is used as part of an area wide management strategy and aims to reduce the total Helicoverpa spp. population of a region. Such a strategy may also be successful in horticultural crops but only with the full participation of the growers of all crops that are attractive to H. armigera in a horticultural growing region. Due to the diverse nature of horticultural production this may be a difficult task.

This study investigated the potential of companion planting as a strategy to aid in the management of Helicoverpa armigera in tomato and capsicum cropping systems. The investigaitons showed that a companion planting type system is unlikely to confer any benefits to the management of H. armigera in these crops. The project has contributed to the understanding of H. armigera host selection and how the pest responds to a diversified environment. Companion planting and vegetational diversity are strategies for reducing pest incidence on crops. Many theories have been devised to explain how introducing more than one plant species to a cropping space may reduce the incidence of a pest. Five ecological theories formed the basis of experiments in this study: The resource concentration hypothesis - Herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands (Root, 1973). Associational resistance/Plant apparency - Crop plants grown as monocultures are more apparent to herbivorous insects than plants in diverse natural systems (Tahvanainen and Root, 1972). Trap cropping – the use of plants within a cropping area to attract oviposition away from the main crop (Banks and Ekbom, 1999). The ability of H. armigera to learn in regard to host seleciton (Cunningham et al., 1998a). The natural enemies hypothesis - generalist and specialist natural enemies are expected to be more abundant in diverse rather than simple systems (Root, 1973) A tall variety of sorghum (the forage variety Chopper) was tested for its ability to disrupt host location. Sorghum was planted around plots of tomatoes to act as a screen to disrupt visual cues for host location by Helicoverpa spp. No difference was found in egg numbers on tomatoes with or without sorghum companions. However, significantly higher numbers of Helicoverpa spp. larvae were found in the sorghum at flowering than in the tomatoes. This suggested the sorghum was acting as a trap crop, diverting oviposition away from the tomato crop. However, due to a short period of flowering and therefore peak attractiveness to H. armigera, sorghum was not considered to be a suitable companion plant for inclusion in commercial tomato production systems. A host preference study was conducted to determine the preferences of H. armigera for crop plants and possible companions in the hope of finding a suitable trap crop species. Tomatoes were shown to be a highly preferred plant making it difficult to find a compatible trap crop species that would be more attractive than the main crop. However, capsicums were less prefered and therefore more suitable for this type of experimentation. Marigolds were also found to be a highly preferred plant and formed the basis for further investigations into trap cropping systems. Field experiments were conducted in successive years in two geographical locations to assess the suitability of marigolds as a trap crop for capsicums in a field situation. However, in both years H. armigera incidence was extremely and unusually low leading to inconclusive results. A glasshouse experiment was performed to assess if the ratio of capsicum plants to marigolds plants had an effect on which species H. armigera would choose for oviposition. It was found that as more capsicum plants were introduced, moths became less likely to oviposit on the supposedly more preferred marigold plant. The diminishing attractiveness of a more preferred host in the presence of other hosts is a new observation of H. armigera behaviour. This result suggests that marigolds would be unlikely to be a successful trap crop in a field situation. The ability of H. armigera to learn in regard to host selection and the influence of this on host selection in the field was investigated. No evidence of learning was found. This was the first study investigating the effect of learning in a field situation; previously the behaviour had only been investigated in a laboratory situation (Cunningham, et al. 1998a). The ability of the Australian assassin bug, Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) to predate H. armigera larvae on capsicum plants was investigated. This predator has been sucessfully been used for H. armigera management in cotton (Grundy, 2000b), but had not been investigated in horticultural crops. Significant reductions in larvae were achieved in treatments where assassin bugs were introduced. This predator warrants further investigation for inclusion in commercial integrated pest managment programs for capsicums. Pest repellent plants were also considered. Previous to this study, very little research work had been conducted on repellent plants for H. armigera. The herbs investigated were catnip (Nepta cataria), tansy (Tanacetum vulgare), basil (Ocium basilicum) and coriander (Coriander sativum). An olfactometer system was designed and built to test H. armigera moths’ responses to odours from the herbs. Glasshouse experiments were also conducted. No repellent activity was recorded with any of the herbs tested. The results of this study support the theory that Helicoverpa spp. employ a strategy of passive host selection as suggested by Firempong (1986). This means that all available plants in an area may be oviposited on with successful ovipostion and larval development leading to the future utilisation of a species as a host plant. The implication of this finding is that in-field trap cropping is unlikely to be a successful strategy for reducing H. armigera oviposition in tomato or capsicum production systems in Australia. In cotton crops in Australia, trap cropping is used as part of an area wide management strategy and aims to reduce the total Helicoverpa spp. population of a region. Such a strategy may also be successful in horticultural crops but only with the full participation of the growers of all crops that are attractive to H. armigera in a horticultural growing region. Due to the diverse nature of horticultural production this may be a difficult task.

This study investigated the potential of companion planting as a strategy to aid in the management of Helicoverpa armigera in tomato and capsicum cropping systems. The investigaitons showed that a companion planting type system is unlikely to confer any benefits to the management of H. armigera in these crops. The project has contributed to the understanding of H. armigera host selection and how the pest responds to a diversified environment. Companion planting and vegetational diversity are strategies for reducing pest incidence on crops. Many theories have been devised to explain how introducing more than one plant species to a cropping space may reduce the incidence of a pest. Five ecological theories formed the basis of experiments in this study: The resource concentration hypothesis - Herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands (Root, 1973). Associational resistance/Plant apparency - Crop plants grown as monocultures are more apparent to herbivorous insects than plants in diverse natural systems (Tahvanainen and Root, 1972). Trap cropping – the use of plants within a cropping area to attract oviposition away from the main crop (Banks and Ekbom, 1999). The ability of H. armigera to learn in regard to host seleciton (Cunningham et al., 1998a). The natural enemies hypothesis - generalist and specialist natural enemies are expected to be more abundant in diverse rather than simple systems (Root, 1973) A tall variety of sorghum (the forage variety Chopper) was tested for its ability to disrupt host location. Sorghum was planted around plots of tomatoes to act as a screen to disrupt visual cues for host location by Helicoverpa spp. No difference was found in egg numbers on tomatoes with or without sorghum companions. However, significantly higher numbers of Helicoverpa spp. larvae were found in the sorghum at flowering than in the tomatoes. This suggested the sorghum was acting as a trap crop, diverting oviposition away from the tomato crop. However, due to a short period of flowering and therefore peak attractiveness to H. armigera, sorghum was not considered to be a suitable companion plant for inclusion in commercial tomato production systems. A host preference study was conducted to determine the preferences of H. armigera for crop plants and possible companions in the hope of finding a suitable trap crop species. Tomatoes were shown to be a highly preferred plant making it difficult to find a compatible trap crop species that would be more attractive than the main crop. However, capsicums were less prefered and therefore more suitable for this type of experimentation. Marigolds were also found to be a highly preferred plant and formed the basis for further investigations into trap cropping systems. Field experiments were conducted in successive years in two geographical locations to assess the suitability of marigolds as a trap crop for capsicums in a field situation. However, in both years H. armigera incidence was extremely and unusually low leading to inconclusive results. A glasshouse experiment was performed to assess if the ratio of capsicum plants to marigolds plants had an effect on which species H. armigera would choose for oviposition. It was found that as more capsicum plants were introduced, moths became less likely to oviposit on the supposedly more preferred marigold plant. The diminishing attractiveness of a more preferred host in the presence of other hosts is a new observation of H. armigera behaviour. This result suggests that marigolds would be unlikely to be a successful trap crop in a field situation. The ability of H. armigera to learn in regard to host selection and the influence of this on host selection in the field was investigated. No evidence of learning was found. This was the first study investigating the effect of learning in a field situation; previously the behaviour had only been investigated in a laboratory situation (Cunningham, et al. 1998a). The ability of the Australian assassin bug, Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) to predate H. armigera larvae on capsicum plants was investigated. This predator has been sucessfully been used for H. armigera management in cotton (Grundy, 2000b), but had not been investigated in horticultural crops. Significant reductions in larvae were achieved in treatments where assassin bugs were introduced. This predator warrants further investigation for inclusion in commercial integrated pest managment programs for capsicums. Pest repellent plants were also considered. Previous to this study, very little research work had been conducted on repellent plants for H. armigera. The herbs investigated were catnip (Nepta cataria), tansy (Tanacetum vulgare), basil (Ocium basilicum) and coriander (Coriander sativum). An olfactometer system was designed and built to test H. armigera moths’ responses to odours from the herbs. Glasshouse experiments were also conducted. No repellent activity was recorded with any of the herbs tested. The results of this study support the theory that Helicoverpa spp. employ a strategy of passive host selection as suggested by Firempong (1986). This means that all available plants in an area may be oviposited on with successful ovipostion and larval development leading to the future utilisation of a species as a host plant. The implication of this finding is that in-field trap cropping is unlikely to be a successful strategy for reducing H. armigera oviposition in tomato or capsicum production systems in Australia. In cotton crops in Australia, trap cropping is used as part of an area wide management strategy and aims to reduce the total Helicoverpa spp. population of a region. Such a strategy may also be successful in horticultural crops but only with the full participation of the growers of all crops that are attractive to H. armigera in a horticultural growing region. Due to the diverse nature of horticultural production this may be a difficult task.

In rural inland, south-eastern Australia, allergy to the fungus Alternaria is prevalent and an important risk factor for asthma. The aim of the thesis was to investigate the distribution and factors influencing allergens of Alternaria in the air. As airborne allergenic spores were thought to arise from harvesting of nearby crops, two towns with different agricultural practices were studied. Moree has two crop harvesting periods in summer and autumn whilst Wagga Wagga has one harvesting period in summer. Over two years, air was sampled daily in Wagga Wagga and Moree using Burkard traps. The reliability of measurements from a single site to represent the distribution of airborne concentrations of spores across each town was examined using data from three traps simultaneously, sited 2.0 to 4.9 km apart, over four weeks. Substantial intra-class correlation coefficients (ICC) were observed between the three sampling sites across both towns (ICC=0.52, 95% CI 0.30-0.71 to 0.76, 95% CI 0.61-0.87) when counts of Alternaria spores were relatively high. The correlation was poor when counts were low. Of more than 365 trap tapes examined, the two microscopic traverses strongly correlated for counts of Alternaria spores (ICC=0.95, 95% CI 0.94-0.96). Alternaria was detected in both towns throughout the two year period with peaks in spore concentrations reflecting the season of crop harvesting in each region. Individual exposure to spores was examined. Thirty three subjects (adults and children from nine families) wore nasal air samplers and personal air samplers both inside and outside their homes. The effects of activity, location, age on the inhalation of Alternaria spores and variation between individuals in the same environment were determined. Every subject inhaled Alternaria spores. Personal exposure to Alternaria in the home environment varied substantially between subjects. Levels of fungal spores inhaled were higher during periods of activity than during rest, and higher while subjects were outdoors than indoors. During outdoor activity, the number of Alternaria spores inhaled ranged from 4 to 794 (median 11) spores/hr. Sources of airborne spores was investigated by sampling air above wheat and cotton crops near the towns during harvesting and non-harvesting periods, in a grain and cotton seed storage shed, and a cotton gin. Substantially higher concentrations were detected above crops during harvesting periods compared to non-harvesting periods. Peaks were associated with harvesting and other activities where plants were manipulated. By regression analysis spore concentrations in both towns were modelled against those detected above crops and with weather variables. Only one crop sampling period (cotton harvest) independently correlated with concentrations in town. Analysis combining all data showed concentrations of spores above crops correlated with spore concentrations in the town when lagged by one day. Variables of rainfall and maximum temperature influenced concentrations in both towns, and wind direction in Wagga Wagga alone. Parents of asthmatic children were asked by questionnaire in which locations symptoms were provoked. Asthma was reported to be exacerbated at grain farms and with disturbance of local vegetation in town and home gardens. Nasal sampling confirmed that activities that disturbed dust or vegetation increased the inhalation of spores. The factors that release allergen from spores were determined in a modified Halogen immunoassay. Approximately 60% of spores released allergen, and the proportion was influenced by isolate, nutrient availability, viability, and not influenced by sunlight or culture age up to 21 days. Germinating the spores significantly increased the proportion that released total allergen and Alt a 1 (p<0.0001). Alt a 1 appears to be a minor contributor to the total allergen released from spores except when spores have germinated. Conclusions: People living in inland rural regions of Australia are exposed to substantial quantities of allergenic spores of Alternaria. Exposure is a highly personal event and is largely determined by disturbance of local vegetation releasing spores such as from nearby crops by wind, harvesting, slashing, transport and processing of produce, and from within town and home gardens. Most spores inhaled are likely to be allergenic, with potency potentially increasing with viability.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This project targeted the development of a new tracking collar, trap telemetry system and supporting infrastructure, to aid researchers from the Cape Leopard Trust. Previously used collar products had all proven insu cient in some capacity and remote monitoring of trap sites was also required. Tracking collars are used to identify the movement patterns of the leopards and through the resulting research, assist in protecting this threatened species. In the development of the tracking collar and trap telemetry system, a high level system design was rst formulated, identifying major components that would be required. Alternative methods for implementation were then considered and the most optimal chosen. Two di erent modes of communication with the collar were envisioned and designed for. These would be used to transmit logged coordinates obtained from a GPS receiver back to researchers. A VHF terrestrial radio link was investigated, but an Iridium Satellite based solution was ultimately selected. An Iridium Satellite communications system was also used for transfer of trap state data. Ultimately, a working trap telemetry system was delivered for use by researchers. The tracking collar system had progressed to a working prototype, requiring miniaturisation and packaging before deployment. A possible packaging solution was also identi ed. The trap telemetry system, although displaying certain de ciencies, provided a capability previously unavailable to researchers. With further development, there is potential for the tracking collar to provide accurate satellite tracking and communications in a mass and price combination not previously available. / AFRIKAANSE OPSOMMING: Hierdie projek het as doel die ontwikkeling van 'n nuwe opsporingshalsband, 'n lokval telemetriese stelsel en die nodige ondersteunende infrastruktuur daarvoor. As hulpmiddels vir navorsers van Cape Leopard Trust. Geen van die halsband produkte wat tot nou toe gebruik is, het voldoen aan al die nodige behoeftes nie, en dit was ook nodig om die lokvalterreine van 'n afstand te kan monitor. Die opsporingshalsbande word gebruik om die bewegingspatrone van luiperds vas te stel en die navorsing wat daarop volg, help dat 'n bedreigde spesie bewaar word. Die ontwikkeling van die opsporingshalsband en lokval telemetriese stelsel het begin met die formulering van 'n ho evlak stelselontwerp waarin die hoofkomponente wat benodig sou wees ge denti seer is. Alternatiewe metodes van bewerkstelling is daarna oorweeg en die optimale hiervan is gekies. Twee verskillende metodes van kommunikasie met die halsband is voorgestel en ontwerp. Hierdie sou gebruik word om die vasgelegte koordinate wat van 'n GPS ontvanger verkry is, na navorsers terug te versend. 'n Terrestriale radioverbinding is ondersoek, maar 'n Iridium Satelliet-baseerde oplossing is uiteindelik verkies. 'n Iridium Satelliet kommunikasie stelsel is ook gebruik vir die oordrag van data aangaande die lokvaltoestand. Uitendelik is 'n werkende lokval telemetriese stelsel gelewer vir dir gebruik van navorsers. Die opsporingshalsband stelsel was nou 'n werkende prototipe, wat slegs verklein en toepaslik verpak moes word voor dit in gebruik geneem kon word. 'n Moontlike oplossing tot die verpakkingsprobleem is ook identi seer. Die lokval telemetriese stelsel, hoewel dit steeds tekorte toon, voorsien die navorsers van voorheen onbekombare inligting. Met verder ontwikkeling is daar potensiaal vir die opsporingshalsband om akkurate satellietopsporing en kommunikasie te voorsien in 'n kombinasie van laer massa, sowel as prys, soos nog nooit voorheen beskikbaar nie.