Includes bibliographical references (leaves 217-230). Details the biology and life history of the Quandong moth and investigates management strategies that would enable growers to manage the pest in an economically and environmentally sustainable program.

Includes bibliographical references (leaves 217-230). / 230 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Details the biology and life history of the Quandong moth and investigates management strategies that would enable growers to manage the pest in an economically and environmentally sustainable program. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001

Fruit and vegetables are often spoilt during storage, handling and transportation due to microorganisms. The common spoilage causes are fungi within the order Mucorales, the largest order of the class Zygomycetes. Such spoilage can result in reduced food supplies, poor quality and severe losses to producers and traders. The study was to investigate the type of Mucorales prevalent in various commodities and in a particular market than others. Fifty infected papaya, peaches and strawberries were collected at five occasions from large, medium and small markets. Isolation was done aseptically in a biosafety cabinet. Mucorales were identified morphologically, through culture based tests and molecular techniques. Mucorales isolated are Rhizopus stolonifer, Mucor circinelloides and Mucor racemosus. Mucorales were isolated at a higher rate in samples collected from the small market than other two markets. Spoilage in all three markets is assumed to be influenced by lack of modified temperatures in the storage room. / Life and Consumer Sciences / M. Sc. (Life Sciences)

Thesis (PhD (Conservation Ecology and Entomology))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Codling moth, Cydia pomonella, is a worldwide pest and of major economic importance to the South African pome fruit industry. Sterile insect release is applied as a component of area-wide integrated pest management and includes the mass-rearing, sterilization and the release of the sterile insects. For sterile insect release, the improvements of rearing methods in terms of the quality of the diet ingredients and the economical aspect of the rearing method are examined. The effect of genetically modified maize meal, containing the Bacillus thuringiensis gene, in an artificial medium for codling moth rearing, is determined. The use of even a small amount of Bacillus thuringiensis resulted in larval mortality and prolonged development. These results are detrimental to a mass-rearing facility and must be considered by any rearing facility that uses genetically modified maize meal if the insect is sensitive to the gene. An alternative to maize meal in the artificial medium was tested and whole wheat flour was considered to be a suitable replacement. Agar agar is an expensive gelling agent used in the artificial medium. An alternative for agar agar (Kelcogel, Elastigel and carrageenen) is tested and the biological effect on codling moth is determined. Factors such as mortality, pupal and moth weight, longevity, fecundity and development time were used as quality parameters. Results showed that Elastigel was a suitable replacement for agar agar, with bigger pupae and moths, higher fecundity and increased longevity. The economical advantage of the replacement is a 40.91% reduction of the diet cost. The other gelling agents tested also gave acceptable results and can be considered if shortages of agar agar or Elastigel occur. A new method of mass-rearing codling moth larvae in a closed rearing system using large trays placed in a ventilated box is designed. This method is more cost and space effective as a smaller area is needed to rear a large number of moths. The risk of diet contamination is less because of the closed environment and more economical and effective air handling. This is the first report of its kind to describe the mass-rearing of codling moth in a closed environment and the risks involved in using genetically modified maize meal in an artificial diet for the codling moth. These results should be incorporated into existing mass-rearing facilities or taking into consideration when designing new mass-rearing facilities. / AFRIKAANSE OPSOMMING: Die kodlingmot, Cydia pomonella, is van ekonomiese belang vir die Suid-Afrikaanse kernvrugte bedryf. Die steriele insek tegniek word gebruik as ‘n komponent in area-wye geïntegreerde plaagbeheer en sluit in die massa-aanteel, sterilisering en vrylaat van steriele insekte. Vir die steriele insek tegniek is die verbetering van die massa-aanteel van die kodlingmot in terme van kwaliteit van die dieet en die ekonomiese aspek van die aanteel metode ondersoek. Die effek van genetiese gemanipuleerde mieliemeel wat die Bacillus thuringiensis geen bevat, in ‘n kunsmatige voedselmedium vir die aanteel van kodlingmot, is bepaal. Daar is gevind dat die gebruik van selfs ‘n klein persentasie Bacillus thuringiensis in die mieliemeel, mortaliteit en ‘n verlengde lewenssiklus in kodlingmot veroorsaak. Die gevolge is nadelig vir ‘n massa-aanteel fasiliteit en behoort in ag geneem te word vir enige insek wat op ‘n kunsmatige medium, wat mieliemeel bevat, geteel word, mits die insek sensitief is vir Bacillus thuringiensis. ‘n Alternatiewe bestanddeel vir mieliemeel, volkoringmeel, word aanbeveel. Agar agar is ‘n duur verdikkingsagent wat in kunsmatige mediums gebruik word. ‘n Alternatief vir agar agar (Kelcogel, Elastigel en carrageenen) is getoets en die biologiese effek op die kodlingmot is bepaal. Faktore soos mortaliteit, papie en mot gewig, langlewendheid, vrugbaarheid en lengte van lewenssiklus was gebruik as kwaliteit parameters. Resultate het getoon dat Elastigel ‘n geskikte plaasvevanger is van agar agar, met groter papies en motte, groter vrugbaarheid en langlewendheid. Die ekonomiese gevolg van die plaasvervanger, is ‘n vermindering van 40.91% van die dieetkoste. Die ander verdikkingagente wat is getoets is, het aanvaarbare resultate gelewer wat noodsaaklik is indien daar ‘n tekort van Elastigel of agar agar ontwikkel. ‘n Nuwe metode van massa-aanteel van kodlingmot larwes is bepaal. Die metode behels ‘n geslote sisteem, waar groter aanteel bakke in ‘n geslote, geventileerde boks geplaas word. Die metode is koste en spasie effektief en ‘n kleiner area word benodig om ‘n groter aantal motte te lewer. Die risiko van kontaminasie van die dieet word verminder as gevolg van die geslote sisteem wat gebruik word en meer ekonomiese en effektiewe lugversorging word gebruik. Hierdie is die eerste verslag van sy soort wat die massa-aanteel van kodlingmot in ‘n geslote sisteem beskryf en wat die risiko aandui van geneties gemanipuleerde mieliemeel in ‘n kunsmatige medium vir die kodlingmot. Hierdie resultate behoort in ag geneem te word vir reeds bestaande massa-aanteel fasiliteite of met die ontwerp van nuwe massa-aanteel fasiliteite.

Thesis (MScAgric (Conservation Ecology and Entomology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The banded fruit weevil, Phlyctinus callosus (Schönherr), is a key pest of apples, nectarines and grapevines in the southern areas of the Western Cape. The control of P. callosus is not satisfactory and the insecticides used to control this insect have not proved to be effective since the development of tolerance to pyrethroids and acephate. A control method that can be used, despite it being very labour-intensive, is that of tree trunk barriers. The use of such a method will prevent the weevils from reaching the fruit, as they are unable to fly. Alternative control options, such as the use of entomopathogenic nematodes, are urgently needed for the control of P. callosus. Entomopathogenic nematodes belonging to the Steinernematidae and Heterorhabditidae are ideal biocontrol agents for incorporation into an integrated pest management programme. In order to develop control strategies for P. callosus, large numbers and a predictable quantity of different weevil stages are needed. Especially large numbers of larvae are needed, as this is the stage that will be targeted with nematodes. One of the aims of the current study was to assess various artificial diets for rearing larvae of P. callosus. Though adult weevils were easily collected from orchards, it was very difficult to obtain large numbers of larvae. Modified versions of an agar diet, as well as different carrot based diets, were tested at 21°C. The highest percentage survival obtained for the agar diet was 50% and 60% for one type of carrot diet. A better rearing method proved to be that of planting full-grown carrots in pots, kept at 25°C, resulting in the attainment of the highest percentage survival rate of 90%. A study was undertaken to assess how long, and at what temperature, P. callosus eggs could be stored. A mean percentage hatch of 45.7% was obtained when eggs were stored at 4°C for 70 days. Eggs started hatching after 47 days and 10 days, when stored at temperatures of 11°C and 14°C, respectively. If the aim of the employment of such a method is only to delay egg hatching, the two temperatures (11°C and 14°C) will be suitable. For the following part of the study, several entomopathogenic nematode isolates were evaluated for their potential use as biological control agents against P. callosus. The susceptibility of P. callosus larvae and adults to nematode infection was assessed in the laboratory by screening for their mortality, using different nematode isolates. Larvae were found to be more susceptible to nematode infection than adults. Heterorhabditis isolates were found to cause higher levels of mortality than the Steinernema isolates during screening, when a concentration of 400 infective juveniles (IJ) per insect V was used. Biological characteristics, such as the effect of different temperatures on nematode activity and the minimum concentration of nematodes needed to obtain acceptable levels of control for P. callosus, were also investigated. The percentage mortality ranged from no infection to 75% after four days for the larvae, and the SF41 isolate of Heterohabditis zealandica was selected as the most promising isolate for further laboratory experiments. The vertical movement of nematodes in sand, compared with such movement in sandy loam soil, and the biology of H. zealandica in P. callosus larvae was also investigated in laboratory bioassays. After four days, the LD50 and LD90 values were 96 IJ/50 μl and 278 IJ/50 μl, respectively. Nematodes were found to be inactive at 11°C, with the highest mortality rate of P. callosus resulting from nematode infection being recorded at 25°C. A higher percentage mortality rate was obtained with the sandy loam soil (95.2%) than with the sand (77.5%). Heterorhabditis zealandica could successfully complete its life cycle in 6th instar P. callosus larvae. The study showed that P. callosus larvae are suitable hosts for H. zealandica, and that the control of P. callosus in the field by the selected isolate holds promise. The persistence of the SF41 isolate of H. zealandica at different concentrations was investigated in the last part of the study. The experiment took place in a blueberry orchard, subject to a high rate of infestation by P. callosus. Concentrations of 0, 20, 30 and 45 IJ/cm2 were topically applied, with persistence being evaluated for days 1, 35 and 84. Percentage persistence for 30 IJ/cm2 was calculated as 87.5% for days 35 and 84. The persistence of soil samples taken on day one, and kept in plastic containers at room temperature, was again evaluated on day 128, with the finding that both 30 IJ/cm2 and 45 IJ/cm2 caused 100% mortality of Tenebrio molitor (L.). Results indicated good persistence of H. zealandica after 84 days in field conditions, with a high maintenance of P. callosus populations. The study indicated the potential use of H. zealandica for the control of P. callosus, with the possibility of persistence for at least three months. Future research into the control of P. callosus with nematodes should aim to investigate the technical aspects of field application. The current study shows that entomopathogenic nematodes have potential for controlling the soil stages of P. callosus. The capacity to rear large numbers of P. callosus larvae in the laboratory, for later use in laboratory and field trials, is of key importance. / AFRIKAANSE OPSOMMING: Die gebande vrugtekalander, Phlyctinus callosus (Schönherr), is ʼn groot plaag in appel- en nektarienboorde sowel as wingerde in die suidelike gebiede van die Wes-Kaap. Phlyctinus callosus word nie voldoende beheer nie, en plaagdoders wat voorheen gebruik is om dié insek in toom te hou, het doeltreffendheid ingeboet weens weerstandontwikkeling teen piretroϊede en asefaat. ʼn Alternatiewe beheermetode is stamsperbande. Omdat die kalanders nie kan vlieg nie, moet hulle teen stamme uitklim om die vrugte te bereik. Stamsperbande versper dus die insekte se toegang tot die vrugte, maar is baie arbeidsintensief. Meer haalbare metodes vir die beheer van P. callosus is daarom dringend nodig, en die gebruik van entomopatogeniese nematodes blyk ʼn besliste moontlikheid te wees. Entomopatogeniese nematodes, wat tot die Steinernematidae en Heterorhabditidae behoort, is uitstekende biobeheermiddels vir insluiting by geϊntegreerde plaagbeheerprogramme. Om doeltreffende beheerstrategieë vir P. callosus te bedink, is groot en voorspelbare hoeveelhede kalanders nodig veral groot hoeveelhede larwes, aangesien nematodes op hierdie ontwikkelingstadium gemik sal wees. Die eerste doel met die studie was dus om ʼn kunsmatige dieet vir die teling van P. callosus larwes te ontwikkel. Volwasse kalanders kon maklik in vrugteboorde ingesamel word, maar groot hoeveelhede larwes was moeiliker bekombaar. Aangepaste weergawes van ʼn agardieet sowel as verskillende worteldiëte is by 21°C beproef. Die hoogste persentasie larwale groei en -oorlewing op die agardieet was 50%, en 60% op een bepaalde soort worteldieet. Die beste teelmetode blyk egter volgroeide wortels te wees wat in potte geplant is en by 25°C gehou word. Dié metode het ʼn oorlewingspersentasie van 90% opgelewer. ʼn Studie is onderneem om te bepaal hoe lank en by watter temperature P. callosus eiers vir toekomstige gebruik geberg kan word. ʼn Gemiddelde uitbroeipersentasie van 45.7% is verkry toe eiers vir 70 dae by 4°C geberg is. Eiers wat onderskeidelik by 11°C en 14°C geberg is, het ná 47 en 10 dae onderskeidelik begin uitbroei. Indien die doel is om die eiers slegs stadiger te laat uitbroei, sal hierdie twee temperature dus geskik wees. VII Hierna is verskeie entomopatogeniese nematode-isolate vir moontlike gebruik as biologiese beheermiddels vir P. callosus beoordeel. Phlyctinus callosus larwes en volwassenes se vatbaarheid vir nematode infeksie is in die laboratorium bepaal deur dit met behulp van verskillende nematodeisolate vir mortaliteit te toets. Dié toetse het getoon dat larwes meer vatbaar is vir nematode infeksie as volwassenes. In die proefnemings het die Heterorhabditis-isolate hoër mortaliteit as die Steinernema-isolate veroorsaak teen ʼn konsentrasie van 400 infektiewe larwes (IJ) per insek. Biologiese eienskappe, soos die uitwerking van verskillende temperature op nematode aktiwiteit, sowel as die minimum konsentrasie nematodes om aanvaarbare vlakke van beheer uit te oefen, is ondersoek. Die persentasie mortaliteit vir die larwes het ná vier dae tussen 0% en 75% gewissel, en die SF41-isolaat van Heterohabditis zealandica is as die belowendste isolaat vir die res van die proefnemings gekies. Die vertikale beweging van nematodes in sand teenoor leemgrond, sowel as die biologie van H. zealandica in P. callosus larwes, is ook bestudeer. Ná vier dae was die LD50- en LD90-waardes onderskeidelik 96 en 278 IJ/50 μl. Wat temperatuur betref, is daar bevind dat nematodes onaktief is by 15°C, terwyl die hoogste mortaliteit van P. callosus larwes as gevolg van nematode infeksie by 25°C aangeteken is. Die mortaliteit was hoër in die leemgrond (95.2%) as in die sandgrond (77.5%). Heterorhabditis zealandica kon sy lewensiklus suksesvol in 6de instar P. callosus larwes voltooi. Die studie het derhalwe getoon dat P. callosus larwes geskikte gashere is vir H. zealandica, en dat hierdie isolaat dus in die praktyk ʼn doeltreffende beheermiddel vir P. callosus kan wees. Die oorlewing van verskillende konsentrasies H. zealandica is ten slotte bestudeer. Die proefneming is in ʼn bloubessieboord met ʼn groot populasie P. callosus uitgevoer. Konsentrasies van 0, 20, 30 en 45 IJ/cm2 is op die grond (uitwendig) toegedien, en oorlewing is op dag 1, 35 en 84 gemeet. Die persentasie oorlewing vir die 30 IJ/ cm2 konsentrasie was 87.5% op sowel dag 35 as 84. Oorlewing in grondmonsters wat op dag een ingesamel en by kamertemperatuur in plastiekhouers geberg is, is weer op dag 128 beoordeel. Daar is bevind dat sowel die 30 IJ/cm2 as die 45 IJ/cm2 konsentrasie 100% mortaliteit by T. molitor veroorsaak het. Heterorhabditis zealandica blyk ʼn goeie oorlewing te hê ná 84 dae in veld kondisies wat erg met P. callosus besmet is, en is dus ʼn moontlike beheermiddel vir P. callosus, met potensiële oorlewing vir minstens drie maande.

Fruit and vegetables are often spoilt during storage, handling and transportation due to microorganisms. The common spoilage causes are fungi within the order Mucorales, the largest order of the class Zygomycetes. Such spoilage can result in reduced food supplies, poor quality and severe losses to producers and traders. The study was to investigate the type of Mucorales prevalent in various commodities and in a particular market than others. Fifty infected papaya, peaches and strawberries were collected at five occasions from large, medium and small markets. Isolation was done aseptically in a biosafety cabinet. Mucorales were identified morphologically, through culture based tests and molecular techniques. Mucorales isolated are Rhizopus stolonifer, Mucor circinelloides and Mucor racemosus. Mucorales were isolated at a higher rate in samples collected from the small market than other two markets. Spoilage in all three markets is assumed to be influenced by lack of modified temperatures in the storage room. / Life and Consumer Sciences / M. Sc. (Life Sciences)

O Brasil é o maior produtor de citros, sendo um dos seus principais produtos de exportação da cadeia agroindustrial. Um dos fatores que afetam a qualidade e a produção do produto final obtido é a Mancha Marrom de Alternaria, causado pelo fungo Alternaria alternata. A doença provoca desfolha, seca de ramos e queda de frutos em tangerinas e seus híbridos. Para controle dessa doença são utilizados fungicidas, porém, a mancha marrom é uma doença de difícil controle podendo ser necessárias de 7 a 10 aplicações do fungicida, aparecimento de resistência dos fungos, intoxicação nas pessoas e contaminação do meio ambiente devido ao emprego de fungicidas. Métodos alternativos como o controle biológico com aplicações de micro-organismos antagonistas e a nutrição das plantas são opções de menor impacto ao meio ambiente. Sendo assim, o objetivo deste trabalho foi avaliar o potencial de Trichoderma spp., Bacillus subtilis e fertilizante organomineral, no controle da Mancha Marrom de Alternaria em plantas cítricas de tangerina Ponkan. O experimento foi realizado com delineamento casualizado, constituído de oito tratamentos com quatro repetições. Os experimentos foram avaliados quanto a incidência da doença. Os dados mostraram que o melhor controle foi o tratamento químico, porém os tratamentos com Trichoderma spp., Trichoderma spp. + fertilizante e Trichoderma spp. + Bacillus subtilis apresentaram ótimas taxas de controle, podendo inclusive substituir o tratamento químico no controle desta doença. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-06-13T14:28:19Z No. of bitstreams: 1 Dissertacao Bianca Luzardo Porto.pdf: 1070166 bytes, checksum: 4e890666fce3c2b0d8ce25ef2c71241f (MD5) / Made available in DSpace on 2017-06-13T14:28:19Z (GMT). No. of bitstreams: 1 Dissertacao Bianca Luzardo Porto.pdf: 1070166 bytes, checksum: 4e890666fce3c2b0d8ce25ef2c71241f (MD5) Previous issue date: 2017-06-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES. / Brazil is the largest citrus producer, being one of its main exports of agro-industrial chain. One of the factors that affect the quality and production of the final product is the Brown Spot Alternaria, caused by the fungus Alternaria alternata. The disease causes leaf drop, dry branches and fruit drop in tangerines and their hybrids. To control this disease fungicides are used, however, the brown spot is a difficult to control disease, may be required from 7 to 10 applications of fungicide, appearance of resistance of fungi, intoxication in people and environment contamination owing the application of fungicides. Alternative methods such as biological control with applications antagonistic microorganisms and plant nutrition are options of smaller impact to the environment. Therefore, the objective of this work was to evaluate the potential of Trichoderma spp., Bacillus subtilis and fertilizer, in control of Alternaria Brown Spot in citrus plants Ponkan tangerine. The experiment was carried out in a randomized design, consisting of eight treatments with four replicates. The experiments were evaluated for the incidence of the disease. The data showed that the best control was the chemical treatment, but the treatments with Trichoderma spp., Trichoderma spp. + Fertilizer and Trichoderma spp. + Bacillus subtilis presented excellent control rates, and may even replace chemical treatment in the control of this disease.

O Brasil é o maior produtor de citros, sendo um dos seus principais produtos de exportação da cadeia agroindustrial. Um dos fatores que afetam a qualidade e a produção do produto final obtido é a Mancha Marrom de Alternaria, causado pelo fungo Alternaria alternata. A doença provoca desfolha, seca de ramos e queda de frutos em tangerinas e seus híbridos. Para controle dessa doença são utilizados fungicidas, porém, a mancha marrom é uma doença de difícil controle podendo ser necessárias de 7 a 10 aplicações do fungicida, aparecimento de resistência dos fungos, intoxicação nas pessoas e contaminação do meio ambiente devido ao emprego de fungicidas. Métodos alternativos como o controle biológico com aplicações de micro-organismos antagonistas e a nutrição das plantas são opções de menor impacto ao meio ambiente. Sendo assim, o objetivo deste trabalho foi avaliar o potencial de Trichoderma spp., Bacillus subtilis e fertilizante organomineral, no controle da Mancha Marrom de Alternaria em plantas cítricas de tangerina Ponkan. O experimento foi realizado com delineamento casualizado, constituído de oito tratamentos com quatro repetições. Os experimentos foram avaliados quanto a incidência da doença. Os dados mostraram que o melhor controle foi o tratamento químico, porém os tratamentos com Trichoderma spp., Trichoderma spp. + fertilizante e Trichoderma spp. + Bacillus subtilis apresentaram ótimas taxas de controle, podendo inclusive substituir o tratamento químico no controle desta doença. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES. / Brazil is the largest citrus producer, being one of its main exports of agro-industrial chain. One of the factors that affect the quality and production of the final product is the Brown Spot Alternaria, caused by the fungus Alternaria alternata. The disease causes leaf drop, dry branches and fruit drop in tangerines and their hybrids. To control this disease fungicides are used, however, the brown spot is a difficult to control disease, may be required from 7 to 10 applications of fungicide, appearance of resistance of fungi, intoxication in people and environment contamination owing the application of fungicides. Alternative methods such as biological control with applications antagonistic microorganisms and plant nutrition are options of smaller impact to the environment. Therefore, the objective of this work was to evaluate the potential of Trichoderma spp., Bacillus subtilis and fertilizer, in control of Alternaria Brown Spot in citrus plants Ponkan tangerine. The experiment was carried out in a randomized design, consisting of eight treatments with four replicates. The experiments were evaluated for the incidence of the disease. The data showed that the best control was the chemical treatment, but the treatments with Trichoderma spp., Trichoderma spp. + Fertilizer and Trichoderma spp. + Bacillus subtilis presented excellent control rates, and may even replace chemical treatment in the control of this disease.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The grain chinch bug, Macchiademus diplopterus, is an endemic pest of cultivated grain crops and wild grasses in the south-western Cape region of South Africa. In early summer when host plants dry out, adult grain chinch bugs aggregate in large numbers in shelter sites in surrounding areas and enter into aestivation. These shelter sites sometimes include the stalk or calyx ends of fruit, and shelter-seeking bugs can also contaminate export fruit cartons, consequently posing a phytosanitary/quarantine risk to importing countries. Presently, there are no feasible pre- or post-harvest control measures to manage this quarantine risk. The aggregating behaviour of grain chinch bugs suggests the involvement of pheromones. Therefore, investigating the chemical ecology of grain chinch bugs for potential use in control measures is the focus of the first research chapter of this study. Gas chromatography-mass spectrometry (GC-MS) was used to identify headspace volatiles collected from aggregating bugs. Olfactometer bioassays were conducted to assess the attractiveness of each gender to separate sexes, individual compounds and a mixture of the compounds as a formulated lure. The lure was tested in field trapping trials with delta and bucket traps. In the bioassays with the live insects the response of each gender to live females was greater than the responses of each gender to live males, suggesting that females may disseminate the pheromones more efficiently than males. The following eight volatile compounds were indentified from the GC-MS analysis: hexanal, (E)-2-hexenal, (E)-2-hexenol, (E)-2-hexenyl acetate, (E)-2-octenal, (E)-2-octenol, (E)-2-octenyl acetate and tridecane. In the bioassays with individual compounds, three of these eight compounds, hexanal, (E)-2-hexenal, and tridecane, elicited attraction of both females and males. The formulated lure was attractive to both males and females in the laboratory bioassay, but this attraction was not evident in the field. In the field, there was only one occasion when a significantly higher number of bugs were caught in baited traps compared to unbaited traps. Trap catches were very low compared to the actual level of infestation in the field which was evident from corrugated cardboard bands tied around tree trunks which contained many sheltering bugs. The low trap catches seen in the field were partly due to competition between the synthetic pheromone lure and the natural pheromones emitted by aggregating live insects. Also, the characteristic shelter-seeking behaviour of grain chinch bugs influenced trap catches, as more bugs were found in places that provide shelter, like cardboard bands and walls of the delta traps. This behavior of aestivating bugs could be used to the advantage of trapping bugs by integrating sheltering sites into traps in future trials. Also, the lure needs to be improved for optimum efficiency in the field. The second research chapter also addresses the quarantine risk posed by grain chinch bugs, by investigating the thermal biology of bugs to ultimately facilitate the development of effective post-harvest treatments. Critical thermal minimum and maximum temperatures (CTmin and CTmax) of both active and aestivating bugs were subjected to critical thermal limits analysis. The CTmin and CTmax of aestivating bugs were not affected by gender (p > 0.05). There was a decrease in CTmin from the active period into aestivation for both males (2.8°C to 1.0°C (± 0.1)) and females (2.1°C to 0.6°C (± 0.1)). Also, for CTmax there was an increase in tolerance from the active period into the aestivation period for both males (49.9°C to 51.0°C (± 0.1)) and females (49.9°C to 51.5°C (± 0.1)). To determine the plasticity of grain chinch bug thermal tolerance, aestivating bugs at 27 weeks into aestivation, were acclimated at different temperatures and photoperiods [18°C (10L:14D) and 26°C (16L:8D)] for a period of seven days. Both low (18°C) and high (26°C) acclimation temperatures and photoperiods increased CTmin of aestivating grain chinch bugs at 14 weeks from 0.8°C to -1.2°C and -0.1°C (± 0.1) respectively. However, CTmax was not altered by acclimation temperatures (p > 0.82). Field temperatures at collection sites were recorded to compare to grain chinch bugs thermal tolerance levels exhibited in the laboratory. These results, as well as the effects of acclimation treatments on the CTmin of bugs, have implications for post-harvest treatments, and understanding the quarantine risk posed to importing countries. The information generated from this study can be used to further advance the development of both effective pre-harvest and post-harvest control measures to reduce grain chinch bug quarantine risk. / AFRIKAANSE OPSOMMING: Die graanstinkluis, Macchiademus diplopterus, is 'n endemiese plaag van aangeplante graangewasse en wilde grasse in die Suidwes Kaap-provinsie van Suid-Afrika. In die vroeë somer wanneer gasheerplante uitdroog, soek groot getalle volwasse graanstinkluise skuiling in die omliggende gebiede en gaan in ʼn somerrusperiode. Hierdie skuilplekke sluit soms die stam of kelk eindes van vrugte in en graanstinkluise kan ook uitvoer-vrugte kartonne kontamineer. Gevolglik word lande wat vrugte uit Suid-Afrika invoer, aan die fitosanitêre kwarantynrisiko van stinkluisbesmetting blootgestel. Tans is daar nie haalbare voor- of na-oes beheermaatreëls om hierdie kwarantyn risiko te bestuur nie. Die aggregasiegedrag van graanstinkluise dui op die betrokkenheid van ʼn feromoon. ‘n Ondersoek van die chemiese ekologie van die graanstinkluis vir moontlike gebruik in beheermaatreëls is die fokus van die eerste gedeelte van hierdie studie. Gaschromatografie-massaspektrometrie (GC-MS) is gebruik om die vlugtige organiese verbindings in die bodamp van die saamgetrosde stinkluise te identifiseer. Olfaktometriese biotoetse is uitgevoer om die aantreklikheid van die insekte vir die teenoorgestelde geslag te bepaal, asook van die individuele verbindings en 'n mengsel van die verbindings as 'n geformuleerde lokmiddel in lokvalle. Die lokmiddel is getoets in veldproewe met deltatipe en emmertipe lokvalle. In die olfaktometriese biotoetse met die lewende insekte is die reaksie van beide geslagte teenoor lewende wyfies groter as die reaksie van die geslagte teenoor mannetjies, wat daarop dui dat wyfies die feromoon meer doeltreffend as mannetjies versprei. Die volgende agt verbindings is geïdentifiseer met behulp van GC-MS-analise: heksanaal, (E)-2-heksenaal, (E)-2-heksenol, (E)-2-heksenielasetaat, (E)-2-oktenaal, (E)-2-oktenol, (E)-2-oktenielasetaat en tridekaan. In die biotoetse met individuele verbindings het drie van die agt verbindings, hexanal, (E)-2-hexenal, en tridecane, lokaktiwiteit vir beide geslagte getoon. Die geformuleerde lokmiddel was aantreklik vir beide geslagte in laboratorium toetse, maar soortgelyke lok is nie in die veld gevind nie, waar daar net een keer 'n aansienlike groter getal graanstinkluise met lokmiddel gevang is in vergelyking met lokvalle sonder lokmiddel. Die getal graanstinkluise in lokvalle was baie laag in vergelyking met die werklike vlak van besmetting in die veld, wat duidelik geblyk het uit die getalle graanstinkluise wat skuiling gesoek het in die geriffelde karton bande wat om boomstamme vasgemaak was. Die lae lokvalvangste in die veld was deels te wyte aan die kompetisie tussen sintetiese feromoon en die natuurlike feromoon van saamgetrosde insekte. Die kenmerkende aggregasiegedrag van graanstinkluise het lokvalvangste beïnvloed, aangesien meer stinkluise gevind is in plekke wat skuiling bied, soos die kartonbande en die binnekant van die delta-lokvalle. Hierdie skuilings van graanstinkluise kan in toekomstige proewe uitgebuit word deur vir meer skuilplek in lokvalle voorsiening te maak. Die formulering en die aanbieding van die lokmiddle moet ook verbeter word vir 'n optimale doeltreffendheid in die veld. In die tweede hoofstuk word die kwarantynrisiko van die graanstinkluis aangespreek deur die ondersoek van die termiese biologie van stinkluise om uiteindelik die ontwikkeling van doeltreffende na-oes behandelings te fasiliteer. Kritiese termiese minimum en maksimum temperature (CTmin en CTmax) van beide aktiewe en rustende graanstinkluise is bepaal deur analise van die kritiese termiese beperkings van die insek. Die CTmin en CTmax van rustende graanstinkluise is nie geraak deur geslag nie (p > 0.05). Daar was 'n afname in CTmin van die aktiewe tydperk tot in rus, vir beide manlike (2.8°C tot 1.0°C (± 0.1)) en vroulike insekte (2.1°C tot 0.6°C (± 0.1)). Ook vir die CTmax was daar 'n verbetering in toleransie vanaf die aktiewe tydperk tot in die rusperiode vir beide manlike (49.9°C tot 51.0°C (± 0.1)) en vroulike insekte (49.9°C tot 51.5°C (± 0.1)). Om die aanpasbaarheid van die termiese toleransie van die graanstinkluis te bepaal, is graanstinkluise 27 weke na aanvang van die rusperiode geakklimatiseer by verskillende temperature en fotoperiodes [18°C (10L: 14D) en 26°C (16L: 8D)] vir 'n tydperk van sewe dae. Beide lae (18°C) en hoë (26°C) akklimatiseringstemperature en fotoperiodes het onderskeidelik die CTmin van rustende graanstinkluise op 14 weke verhoog van 0.8°C tot -1.2°C en -0.1°C (± 0.1). Daar is egter geen effek op CTmax deur akklimasie temperature nie (p > 0.82). Veldtemperature is ook bepaal om te vergelyk met graanstinkluis termiese toleransie vlakke wat in die laboratorium bepaal is. Hierdie resultate, sowel as die gevolge van die akklimasie behandelings op die CTmin van graanstinkluise, het implikasies vir na-oes behandelings, en begrip van die kwarantyngevaar wat dit inhou vir vrugte-invoerlande. Die inligting wat uit hierdie studie voortvloei, kan gebruik word om die ontwikkeling van beide effektiewe voor-oes en na-oes beheermaatreëls te bevorder en om die kwarantynrisiko wat graanstinkluise inhou, te verminder.