vi, 128 leaves : photos, tables ; 30 cm / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Pathology, 1978

Com o crescimento populacional acelerado e a diminuição das áreas para cultivo, o aumento da produtividade de gêneros alimentícios de todos os tipos é essencial para o atendimento da população mundial, no entanto as perdas desde o momento de colheita até a chegada ao consumidor limita a oferta de frutas ao consumidor. Estas perdas na pós-colheita de maçã, morango e pêssego, são na sua maioria causadas por fitopatógenos causando podridões. Estas podridões são causadas por vários fungos, dentre estes estão o Colletotrichum sp., causador da podridão amarga em maçãs, Botrytis cinerea agente causador do mofo cinzento em morangos e Monilinia fructicola em pêssegos o qual causa a podridão parda. Usualmente o controle destes fungos é efetivado com a utilização de fungicidas, no entanto, a utilização de químicos neste processo preocupa os consumidores, pois, podem existir resíduos nas frutas e no ambiente. Desta forma métodos alternativos como a indução de resistência podem ser alternativas para o controle dos microrganismos causadores de doenças na pós-colheita de frutos. A indução de resistência consiste em estimular através de moléculas elicitoras (indutoras) as defesas vegetais, ou seja, a síntese de composto que atuem diretamente sobre o fitopatógeno como as proteínas-RPs, ou que promovam o reforço estrutural nos tecidos adjacentes ao sítio de infecção do fungo. A quitosana retirada da carapaça de crustáceos é uma alternativa de molécula elicitora de baixo custo e sem riscos ao consumidor que vem sendo utilizada na indução de resistência em frutos na pós-colheita. Esse biopolímero apresenta a capacidade de desencadear as respostas defensivas dos frutos; maçã, morango e pêssego contra os fungos, Colletotrichum sp., Botrytis cinerea e Monilinia fructicola respectivamente. Foram desenvolvidos experimentos na Universidade Tecnológica Fededral do Paraná durante os anos de 2013 e 2014, com objetivo de verificar a capacidade da quitosana de induzir as defesas dos frutos da maçãs, morangos e pêssegos em pós-colheita, bem como , a atividade fungistática sobre os fungos Colletotrichum sp., Botrytis cinerea e Monilinia fructicola em condições in vitro. Para os experimentos com os frutos o indutor foi aplicado nas concentrações 0,25; 0,5; 1,0 e 2,0% e a testemunha (água destilada), os tratamentos foram organizados em delineamento inteiramente casualizado com quatro repetições de 20 frutos de maçã, 20 frutos de morango e 15 frutos de pêssego. Os frutos foram selecionados e padronizados, sendo em seguida as maçãs e os pêssegos submetidos ao tratamento por imersão em soluções de quitosana, já os morangos foram tratados pulverizando a solução contendo quitosana diretamente sobre os frutos. Após 24horas, os frutos foram inoculados, com uma suspensão contendo conídios do patógeno Colletotrichum sp. nas maçãs, B. cinerea em morangos e M. fructicola em pêssegos na concentração 5.10-3 conídios/ml diretamente sobre os frutos com auxílio de um borrifador e de uma micropipeta. Após a realização dos tratamentos os frutos foram acondicionados em B.O.D. a 26 ± 1 °C para maçãs e pêssegos e a 10 ± 1 °C para os morangos. Foram realizadas avaliações periódicas após a implantação e no término dos experimentos para os seguintes parâmetros, físicoquímicas (perda de massa, sólidos e solúveis totais, acidez titulável, firmeza de polpa, incidência de podridões) e bioquímicas (proteínas, açúcares redutores, açúcares totais, antocianinas, flavonoides, e a atividade das enzimas fenilalanina mônia-liase(FAL), peroxidases, quitinases e β-glucanases). Nos experimentos in vitro avaliou-se o efeito da quitosana sobre os patógenos (Colletotrichum sp, B. cinerea e M. fructicola) Os fungos previamente cultivados em placas puras forma transferidos para placas contendo meio B.D.A. com as concentrações de quitosana (0; 0,25; 0,5, 1 e 2%). Sendo após 24 e 48 horas realizadas as medições perpendiculares do diâmetro da colônia pra verificar o crescimento micelial. Os dados dos experimentos foram submetidos à análises de normalidade e de variância e as médias comparadas pelo teste de Tukey e de regressão (p=0,05), com auxílio do software Assistat. Os resultados demonstraram a interferência da quitosana sobre a indução de resistência ao controle da incidência da podridão amarga em pós-colheita de maçãs Gala, ativando a PRPs B-1-3 Glucanase e no controle de Colletotrichum sp in vitro com ação fungistática. Já em morango o indutor controlou o mofo cinzento ativando as peroxidases e quitinases e β-1-3-Glucanase e diretamente o fungo B. cinerea in vitro. Em pêssegos a atuação foi sobre a manutenção da qualidade dos frutos, na indução ativando os genes da quitinase, β 1-3 Glucanase e da mesma forma em in vitro sobre M. fructicola. Conclui-se então que a quitosana apresenta um grande potencial na indução de resistência de frutos na pós-colheita, ativando as defesa contra fungos fitopatogênicos e diretamente sobre os mesmo com atividade fungistática e fungitóxica in vitro. Sendo que nos frutos de maçã cv. Gala atuou diretamente sobre os parâmetros físico-químicos reduzindo a perda de massa, mantendo a firmeza de polpa e reduzindo capacidade de esporulação de Colletotrichum sp. confirmando também o efeito indutor pela ativação da enzima β-1,3 glucanase e a atividade fungistática sobre Colletotrichum sp. in vitro com redução do crescimento micelial. Já em morangos cv. Camarosa, ativa a síntese das proteínas-RPs quitinases e β-1-3 glucanases contra o mofo cinzento, mantém a firmeza de polpa em níveis mais elevados e interfere no metabolismo dos açúcares totais e redutores e das flavonoides. E ainda atua diretamente sobre B. cinerea diminuindo crescimento micelial in vitro em relação controle. Nos frutos de pêssego a quitosana atua na indução de resistência a podridão parda em pós-colheita de pêssegos “delicioso” ativando as enzimas FAL, quitinase e β-1-3-glucanases. E Atua sobre M. fructicola in vitro com ação fungistática. / With the rapid population growth and the reduction of areas for cultivation, the increased productivity of foods of all kinds is essential to meet the world's population demand. However post-harvest losses from the time of harvest until the arrival to the consumer, limits the supply of fruits to the consumer. The losses in the post-harvest of apples, strawberries and peaches, caused by the incidence of rot led by phytopathogenic fungi, is responsible for most of the losses. These rots are caused by various fungi, among these are the Colletotrichum sp., cause of bitter rot on apples, Botrytis cinerea causative agent of gray mold on strawberries and M. fructicola on peaches which causes brown rot. These phytopathogens are fungi with high ability to spread infection and therefore cause serious damage to fruits, generating losses in post-harvest. Usually the fungi control is conducted with the use of fungicides. However, the use of chemicals in the process concerns consumers, since there may be residues in fruits and the environment. Therefore, alternative methods like the resistance induction can be used to control the disease-causing microorganisms in the postharvest fruits. The induction consists on stimulating the plants defenses through (inducing) elicitor molecules, specifically the synthesis of compounds that act directly on the pathogen as phenols, protein-RPs, or producing structural reinforcement of tissues adjacent to the site of infection of the fungus. Currently, chitosan extracted from crustacean shells is an alternative elicitor molecule of low cost and no risk to the consumer that has been used in the induction of the resistance in postharvest fruits. This biopolymer has the ability to trigger the defensive responses of the fruits; apple, peach, and strawberry against fungi Colletotrichum sp., Botrytis cinerea and Monilinia fructicola, respectively. The inductor was applied at concentrations of 0.25, 0.5; 1.0 and 2.0% and on the control (distilled water). The treatments were arranged in a completely randomized design with four replications of 20 apple fruits, 20 strawberry fruits and 15 peach fruits. The fruits were selected and standardized, and subsequently the apples and peaches were subjected to treatment by immersion in solutions of chitosan, and strawberries were treated by spraying the chitosan-containing solution directly onto the fruits. After 24 hours, the fruits were inoculated with a solution containing conidia of the phytopathogen Colletotrichum sp. on apples, B. cinerea on strawberries and M. fructicola on peaches, in concentrations of [5.10]^(-3) conidia/ml directly on the fruit, with the help of a spray bottle or with a micropipette in the case of apples, directly inoculating the solution in an wound to the 2 mm bark. After completion of the treatments, the fruits were placed in BOD at 26 ± 1 ° C for apples and peaches, and 10 ± 1 ° C for strawberries, and evaluated after 24 hours to determine the following parameters; weight loss, physical and chemical analysis (solids and total soluble, titratable acidity, firmness, decay incidence) and biochemical (protein, reducing sugars, total sugars, anthocyanins, flavonoids, FAL, peroxidase, chitinase and β-glucanase). An initial sample of the fruits was taken to carry out the initial analyzes, using this data as comparative parameters. In a second experiment, the fungus (Colletotrichum sp, Botrytis cinerea and M. fructicola) were grown in the middle of culture containing the different concentrations of chitosan, to verify the existence of fungitoxic or fungistatic effect of the biomolecule in vitro. The fungi were previously cultivated in clean plates, and subsequently transferred to plates containing PDA medium with the chitosan concentrations (0, 0.25, 0.5, 1 and 2), and after 24 and 48 hours, were performed perpendicular measurements of the diameter of the colony to verify its mycelial growth. Data from experiments were submitted to analysis of normality and variance, and measures were compared by Tukey test and regression test (p = 0.05), with the assistance of Assistat software. The results demonstrated the interference of chitosan on the induction of resistance to control the incidence of bitter rot in postharvest Gala apple, activating the PRPs B-1-3 glucanase and control of Colletotrichum sp in vitro with fungistatic action. On strawberries, the inductor controlled the gray mold by activating the peroxidase, chitinase and β-1-3-glucanase, directly under the fungus B. cinerea in vitro. On peaches, the action was on the maintenance of fruit quality, on the induction, activating genes of chitinase, β 1-3 glucanase, and on the same way, on the in vitro of M. fructicola. Therefere, it has been concluded that chitosan has great potential in the induction of fruit resistance in post-harvest, activating the defense against pathogenic fungi, and directly over the latter with fungistatic activity and in vitro fungitoxic activity.

Com o crescimento populacional acelerado e a diminuição das áreas para cultivo, o aumento da produtividade de gêneros alimentícios de todos os tipos é essencial para o atendimento da população mundial, no entanto as perdas desde o momento de colheita até a chegada ao consumidor limita a oferta de frutas ao consumidor. Estas perdas na pós-colheita de maçã, morango e pêssego, são na sua maioria causadas por fitopatógenos causando podridões. Estas podridões são causadas por vários fungos, dentre estes estão o Colletotrichum sp., causador da podridão amarga em maçãs, Botrytis cinerea agente causador do mofo cinzento em morangos e Monilinia fructicola em pêssegos o qual causa a podridão parda. Usualmente o controle destes fungos é efetivado com a utilização de fungicidas, no entanto, a utilização de químicos neste processo preocupa os consumidores, pois, podem existir resíduos nas frutas e no ambiente. Desta forma métodos alternativos como a indução de resistência podem ser alternativas para o controle dos microrganismos causadores de doenças na pós-colheita de frutos. A indução de resistência consiste em estimular através de moléculas elicitoras (indutoras) as defesas vegetais, ou seja, a síntese de composto que atuem diretamente sobre o fitopatógeno como as proteínas-RPs, ou que promovam o reforço estrutural nos tecidos adjacentes ao sítio de infecção do fungo. A quitosana retirada da carapaça de crustáceos é uma alternativa de molécula elicitora de baixo custo e sem riscos ao consumidor que vem sendo utilizada na indução de resistência em frutos na pós-colheita. Esse biopolímero apresenta a capacidade de desencadear as respostas defensivas dos frutos; maçã, morango e pêssego contra os fungos, Colletotrichum sp., Botrytis cinerea e Monilinia fructicola respectivamente. Foram desenvolvidos experimentos na Universidade Tecnológica Fededral do Paraná durante os anos de 2013 e 2014, com objetivo de verificar a capacidade da quitosana de induzir as defesas dos frutos da maçãs, morangos e pêssegos em pós-colheita, bem como , a atividade fungistática sobre os fungos Colletotrichum sp., Botrytis cinerea e Monilinia fructicola em condições in vitro. Para os experimentos com os frutos o indutor foi aplicado nas concentrações 0,25; 0,5; 1,0 e 2,0% e a testemunha (água destilada), os tratamentos foram organizados em delineamento inteiramente casualizado com quatro repetições de 20 frutos de maçã, 20 frutos de morango e 15 frutos de pêssego. Os frutos foram selecionados e padronizados, sendo em seguida as maçãs e os pêssegos submetidos ao tratamento por imersão em soluções de quitosana, já os morangos foram tratados pulverizando a solução contendo quitosana diretamente sobre os frutos. Após 24horas, os frutos foram inoculados, com uma suspensão contendo conídios do patógeno Colletotrichum sp. nas maçãs, B. cinerea em morangos e M. fructicola em pêssegos na concentração 5.10-3 conídios/ml diretamente sobre os frutos com auxílio de um borrifador e de uma micropipeta. Após a realização dos tratamentos os frutos foram acondicionados em B.O.D. a 26 ± 1 °C para maçãs e pêssegos e a 10 ± 1 °C para os morangos. Foram realizadas avaliações periódicas após a implantação e no término dos experimentos para os seguintes parâmetros, físicoquímicas (perda de massa, sólidos e solúveis totais, acidez titulável, firmeza de polpa, incidência de podridões) e bioquímicas (proteínas, açúcares redutores, açúcares totais, antocianinas, flavonoides, e a atividade das enzimas fenilalanina mônia-liase(FAL), peroxidases, quitinases e β-glucanases). Nos experimentos in vitro avaliou-se o efeito da quitosana sobre os patógenos (Colletotrichum sp, B. cinerea e M. fructicola) Os fungos previamente cultivados em placas puras forma transferidos para placas contendo meio B.D.A. com as concentrações de quitosana (0; 0,25; 0,5, 1 e 2%). Sendo após 24 e 48 horas realizadas as medições perpendiculares do diâmetro da colônia pra verificar o crescimento micelial. Os dados dos experimentos foram submetidos à análises de normalidade e de variância e as médias comparadas pelo teste de Tukey e de regressão (p=0,05), com auxílio do software Assistat. Os resultados demonstraram a interferência da quitosana sobre a indução de resistência ao controle da incidência da podridão amarga em pós-colheita de maçãs Gala, ativando a PRPs B-1-3 Glucanase e no controle de Colletotrichum sp in vitro com ação fungistática. Já em morango o indutor controlou o mofo cinzento ativando as peroxidases e quitinases e β-1-3-Glucanase e diretamente o fungo B. cinerea in vitro. Em pêssegos a atuação foi sobre a manutenção da qualidade dos frutos, na indução ativando os genes da quitinase, β 1-3 Glucanase e da mesma forma em in vitro sobre M. fructicola. Conclui-se então que a quitosana apresenta um grande potencial na indução de resistência de frutos na pós-colheita, ativando as defesa contra fungos fitopatogênicos e diretamente sobre os mesmo com atividade fungistática e fungitóxica in vitro. Sendo que nos frutos de maçã cv. Gala atuou diretamente sobre os parâmetros físico-químicos reduzindo a perda de massa, mantendo a firmeza de polpa e reduzindo capacidade de esporulação de Colletotrichum sp. confirmando também o efeito indutor pela ativação da enzima β-1,3 glucanase e a atividade fungistática sobre Colletotrichum sp. in vitro com redução do crescimento micelial. Já em morangos cv. Camarosa, ativa a síntese das proteínas-RPs quitinases e β-1-3 glucanases contra o mofo cinzento, mantém a firmeza de polpa em níveis mais elevados e interfere no metabolismo dos açúcares totais e redutores e das flavonoides. E ainda atua diretamente sobre B. cinerea diminuindo crescimento micelial in vitro em relação controle. Nos frutos de pêssego a quitosana atua na indução de resistência a podridão parda em pós-colheita de pêssegos “delicioso” ativando as enzimas FAL, quitinase e β-1-3-glucanases. E Atua sobre M. fructicola in vitro com ação fungistática. / With the rapid population growth and the reduction of areas for cultivation, the increased productivity of foods of all kinds is essential to meet the world's population demand. However post-harvest losses from the time of harvest until the arrival to the consumer, limits the supply of fruits to the consumer. The losses in the post-harvest of apples, strawberries and peaches, caused by the incidence of rot led by phytopathogenic fungi, is responsible for most of the losses. These rots are caused by various fungi, among these are the Colletotrichum sp., cause of bitter rot on apples, Botrytis cinerea causative agent of gray mold on strawberries and M. fructicola on peaches which causes brown rot. These phytopathogens are fungi with high ability to spread infection and therefore cause serious damage to fruits, generating losses in post-harvest. Usually the fungi control is conducted with the use of fungicides. However, the use of chemicals in the process concerns consumers, since there may be residues in fruits and the environment. Therefore, alternative methods like the resistance induction can be used to control the disease-causing microorganisms in the postharvest fruits. The induction consists on stimulating the plants defenses through (inducing) elicitor molecules, specifically the synthesis of compounds that act directly on the pathogen as phenols, protein-RPs, or producing structural reinforcement of tissues adjacent to the site of infection of the fungus. Currently, chitosan extracted from crustacean shells is an alternative elicitor molecule of low cost and no risk to the consumer that has been used in the induction of the resistance in postharvest fruits. This biopolymer has the ability to trigger the defensive responses of the fruits; apple, peach, and strawberry against fungi Colletotrichum sp., Botrytis cinerea and Monilinia fructicola, respectively. The inductor was applied at concentrations of 0.25, 0.5; 1.0 and 2.0% and on the control (distilled water). The treatments were arranged in a completely randomized design with four replications of 20 apple fruits, 20 strawberry fruits and 15 peach fruits. The fruits were selected and standardized, and subsequently the apples and peaches were subjected to treatment by immersion in solutions of chitosan, and strawberries were treated by spraying the chitosan-containing solution directly onto the fruits. After 24 hours, the fruits were inoculated with a solution containing conidia of the phytopathogen Colletotrichum sp. on apples, B. cinerea on strawberries and M. fructicola on peaches, in concentrations of [5.10]^(-3) conidia/ml directly on the fruit, with the help of a spray bottle or with a micropipette in the case of apples, directly inoculating the solution in an wound to the 2 mm bark. After completion of the treatments, the fruits were placed in BOD at 26 ± 1 ° C for apples and peaches, and 10 ± 1 ° C for strawberries, and evaluated after 24 hours to determine the following parameters; weight loss, physical and chemical analysis (solids and total soluble, titratable acidity, firmness, decay incidence) and biochemical (protein, reducing sugars, total sugars, anthocyanins, flavonoids, FAL, peroxidase, chitinase and β-glucanase). An initial sample of the fruits was taken to carry out the initial analyzes, using this data as comparative parameters. In a second experiment, the fungus (Colletotrichum sp, Botrytis cinerea and M. fructicola) were grown in the middle of culture containing the different concentrations of chitosan, to verify the existence of fungitoxic or fungistatic effect of the biomolecule in vitro. The fungi were previously cultivated in clean plates, and subsequently transferred to plates containing PDA medium with the chitosan concentrations (0, 0.25, 0.5, 1 and 2), and after 24 and 48 hours, were performed perpendicular measurements of the diameter of the colony to verify its mycelial growth. Data from experiments were submitted to analysis of normality and variance, and measures were compared by Tukey test and regression test (p = 0.05), with the assistance of Assistat software. The results demonstrated the interference of chitosan on the induction of resistance to control the incidence of bitter rot in postharvest Gala apple, activating the PRPs B-1-3 glucanase and control of Colletotrichum sp in vitro with fungistatic action. On strawberries, the inductor controlled the gray mold by activating the peroxidase, chitinase and β-1-3-glucanase, directly under the fungus B. cinerea in vitro. On peaches, the action was on the maintenance of fruit quality, on the induction, activating genes of chitinase, β 1-3 glucanase, and on the same way, on the in vitro of M. fructicola. Therefere, it has been concluded that chitosan has great potential in the induction of fruit resistance in post-harvest, activating the defense against pathogenic fungi, and directly over the latter with fungistatic activity and in vitro fungitoxic activity.

Predation by thrips was referred to as early as 1882 when Pergande discussed their habits. Later, Plank (1936) found Leptothrips mali (Fitch) to be predaceous on lepidopterous eggs, and Sharp (1938) cited it as a being a predator of the pecan nut caseborer, Acrobasis caryae Grote. Bailey (1939) stated that the six-spotted thrip, Scolothrips sexmaculatus (Pergande), is predaceous on Tetranychus telarius (L.), Tetranychus pacificus McG., Bryobia praetiosa Koch, Paratetranychus citri McG., Paratetranychus pilosus (C & F.), Paratetranychus indicus Hirst, Paratetranychus yothersi (McG.), Paratetranychus ilicis (McG.), and Phyllocoptes oleivorus Aschm. and in 1943 Bailey and Keifer noted that L. mali fed on tomato russet mite, Phyllocoptes desctructor (Keifer). Muma (1955) discussed the predation of S. sexmaculatus, L. mali, and Aleurodothrips fasciapennis (Franklin) on citrus insects and mites in Florida.

No description available.

Dissertation (PhD(Agric))--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The codling moth, Cydia pomonella (L.) has been a major pest of pome fruits since before the turn of the last century. However, despite its high economic profile little is known about the bionomics and . behaviour of this pest in apple orchards in South Africa, information required for the development of a sustainable integrated management programme. In field trials there was contingency between the time of year and the upper and lower half of the tree. First generation moths laid significantly more eggs in the bottom half of the tree while second and third generation moths laid significantly more eggs in the top half of the tree. The preferred oviposition sites on Granny Smith (GS) and Golden Delicious (GD) cultivars, in order of preference, were leaves, fruit and wood. More eggs were laid on the fruit ofGS spurs (35.6 %) than on those ofGD spurs (10.7 %). On fruit spurs there was a significant increase in the number of eggs on GD leaves and GS fruit over the season, whereas the number of eggs on GS leaves and GD fruit remained constant. On branches there was an increase in the number of eggs on GD and GS leaves, but not on the fruit or wood. The preferred oviposition site on the fruit was the fovea of the stalk insertion and the rounded cheek area surrounding the fovea. The distribution within different fruit bearing classes (1 - 4 fruit per spur) was random only for one fruit per spur, while on the other spur classes clustering occurred. In laboratory studies of the embryonic and immature stages there was a linear relationship between rate of development and constant temperatures of 15, 17,20,25 and 30·C ± l·C. The lower threshold temperatures for embryonic, larval and pupal development were 11.1, 7.9, 9.9°C respectively. The degree-days required to complete embryonic, larval and pupal development were 80.5, 345, and 279 respectively. The response of the different stages to constant temperatures was similar to that under fluctuating temperatures. At temperatures below 16°C or abouve 27°C moths did not mate and few eggs were laid. Moth longevity decreased with increasing temperature. There was seasonal variation in longevity and oviposition at constant and fluctuating temperatures. Summer adults produced significantly more eggs than spring adults at constant temperatures. At a constant temperature of2S·C and fluctuating temperatures there were five distinct larval instars. The similarity between the mean head capsule width and ranges for each instar reared on fruit of different stages of development at fluctuating temperatures indicates that fruit development and temperature have little influence on mean head capsule width. From sleeve-cage studies in the orchard there was no significant difference in the fecundity of spring and summer moths. In the beginning of October spring moths produced significantly fewer eggs than in November. Egg mortality increased from 8.2 %in spring to 21.2 %in summer. Failure of 1st instar larvae to penetrate the fruit ranged from 4.9 % to 19.5 %, while mortality oflarvae from egg hatch to emergence from the fruit ranged from 29.7 % to 42.9 %. Mortality of 5th instar larvae after emerging from the apples ranged from 0 % to 8.7 % and pupal mortality from 0 % to 3.5 %. On large 27-year old trees more overwintering larvaewere found on Golden Delicious (13.9) than on Granny Smith trees (5.7), with over 70 % oflarvae being found in pruning wounds on both cultivars. On small 7-year old Golden Delicious and Granny Smith trees the mean number oflarvae was 0.5 and 2.0 per tree. A combined mating disruption and insecticide control programme reduced codling moth resistant populations to levels requiring a minimum to no insecticide intervention for several seasons. The efficacy of a pheromone based strategy, number of pheromone treatments, number of dispenserslha and level of insecticide intervention required are strongly influenced by prevailing weather conditions. Fruit infestation in orchards under a mating disruption programme and under an insecticide programme were greater along the borders compared to the interior. The presence of horticultural mineral oil on the leaves and branches did not have a detrimental effect on oviposition nor was there any significant ovicidal effect. A significant ovicidal effect was obtained when applied after oviposition. In field trials, insecticides with lower levels of efficacy than the primary insecticide, azinphos-methyl, provided acceptable control when successfully incorporated into a spray programme which followed a policy of alternation of insecticides across generations. The least variation in the number of degree-days between biofix and first egg hatch of the spring flight was when the second trap catch (Biofix 2) was used as the biofix. A biofix based on the first evening when the temperature reached or exceeded 1TC at 18:00 after first trap catch also showed less variation than when the biofix was based on first trap catch. The mean number of degree-days accumulated between Biofix 2 and first egg hatch was found to be 139.1 ° D. The number of degreedays between the first and second flight biofixes varied between 531.2 and 488.87°D with a mean of 508.1°D. / AFRIKAANSE OPSOMMING: Kodlingmot (Cydia pomonella) is reeds sedert die vorige eeu 'n sleutelplaag van kemvrugte. Ten spyte van die hoë ekonomiese profiel, is daar min kennis betreffende die bionomie en gedrag van hierdie plaag in appelboorde in Suid-Afrika. Hierdie inligting is noodsaaklik vir die ontwikkeling van 'n volhoubare geïntegreerde bestuursprogram. Tydens veldproewe is 'n korrelasie tussen die tyd van die jaar en eierlegging in die boonste of onderste helfte van bome gevind. Eerste-generasie motte het betekenisvol meer eiers in die onderste helfte van die bome gelê, terwyl tweede- en derde-generasie motte meer eiers in die boonste helfte van die bome gelê het. In toenemende volgorde was die voorkeur eierleggingsposisies op Granny Smith (GS) en Golden Delicious (GD) appels die blare, vrugte en hout. Meer eiers is op vrugte van GS spore (35.6%) as op dié van GD spore (10.7%) gelê. Op vrugspore was daar 'n betekenisvolle toename in aantal eiers op GD blare en GS vrugte deur die seisoen, terwyl die getal eiers op GS blare en GD vrugte konstant gebly het. Op takke was daar 'n toename in aantal eiers op GD en GS blare, maar nie op vrugte of hout nie. Die voorkeur eierleggingsposisie op vrugte was die fovea van die steelaanhegting en die wang rondom die fovea. Die verspreiding tussen verskillende vrugdraende klasse (1 - 4 vrugte per spoor) was slegs in die een-Vrug-per-spoorklas ewekansig, terwyl daar in die ander spoorklasse groepering voorgekom het. In laboratoriumstudies van embrioniese en onvolwasse stadia is 'n lineêre verband tussen ontwikkelingskoers en konstante temperature van 15, 17,20,25 en 30°C±I°C gevind. Die onderste drempel-temperature vir embrioniese, larwale en papie-ontwikkeling was onderskeidelik II. 1°C, 7.f?C en 9.9°C. Graaddae benodig vir voltooiing van embrioniese, larwale en papie-ontwikkeling was onderskeidelik 80.5,345 en 279. Die respons van verskillende stadia by konstante temperature het ooreengestem met hul respons onder wisselende temperature. Motte het nie gepaar nie en min eiers is gelê by temperature onder 16°C of bo 27°C. Die lewensverwagting van motte het afgeneem met toename in temperatuur. Seisoenale variasie in . lewensverwagting en eierlegging het voorgekom by konstante sowel as wisselende temperature. By konstante temperature het somer-volwassenes betekenisvol meer eiers as lente-volwassenes geproduseer. By 'n konstante temperatuur van 25°C, sowel as by wisselende temperature, het vyf duidelik onderskeibare larwale instars voorgekom. Die ooreenkoms tussen die gemiddelde kopkapsulewydte en wydte-reeks vir elke instar wat op vrugte van verskillende stadiums van ontwikkeling by wisselende temperature geteel is, dui daarop dat vrugontwikkeling en temperatuur weinig invloed op gemiddelde kopkapsule-wydte het. Tydens mou-hok studies in die boord is geen betekenisvolle verskil in die fekunditeit van lente- en somer-motte waargeneem nie. Vroeg in Oktober het lente-motte betekenisvol meer eiers as in November geproduseer. Eiermortaliteit het van 8.2% in die lente tot 21.2% in die somer toegeneem. Faling van 1ste instar larwes om vrugte te penetreer het van 4.9% tot 19.5% gewissel, terwyl mortaliteit van larwes vanaf uitbroei tot uitkoms uit die vrug van 29.7% tot 42.9% gewissel het. Mortaliteit van Sde instar larwes na uitkoms uit die vrug het van 0% tot 8.7% gewissel, en papie-mortaliteit van 0% tot 3.5%. Op groot, 27-jaar oue bome is meer oorwinterende larwes op Golden Delicious (13.9) as op Granny Smith (5.7) gevind, en meer as 70% van die larwes op beide kultivars is op snoeiwonde gevind. Op klein, 7-jaar oue bome was die gemiddelde aantallarwes op Golden Delicious en Granny Smithbome 0.5 en 2.0 onderskeidelik. 'n Gekombineerde paringsontwrigting- en insekdoder beheerprogram het weerstandbiedende kodlingmot-populasies verminder tot 'n vlak waar minimum tot geen insekdoder-toedienings vir verskeie seisoene gemaak is. Die effektiwiteit van 'n feromoon-gebaseerde strategie, aantal feromoonbehandelings, aantal vrystellers/ha en vlak van insekdoder-toediening word sterk deur heersende weersomstandighede beïnvloed. Die rande het hoër vruginfestasie as die middel getoon in boorde onder paringsontwrigting sowel as boorde onder insekdoder-programme. Die teenwoordigheid van minerale olie op blare en takke het geen nadelige effek op eierlegging gehad nie en dit het geen betekenisvolle eierdodende effek gehad nie. Indien die olie ná eierlegging toegedien is, is daar wel 'n betekenisvolle eierdodende effek waargeneem. Tydens veldproewe het insekdoders met laer effektiwiteit as die primêre insekdoder, azinfos-metiel, aanvaarbare beheer verskaf indien dit suksesvol geïnkorporeer is in 'n spuitprogram deur 'n beleid van afwisseling van insekdoders oor generasies. Die kleinste variasie tussen die aantal graaddae tussen biofix en eerste uitbroei van eiers is gevind indien die tweede lokvalvangs as biofix gebruik is. 'n Biofix gebaseer op die eerste aand na die eerste lokval vangste wat die temperatuur 17°Cofhoër was teen 18:00, het ook 'n kleiner variasie getoon as die eerste lokvalvangs. Die aantal graaddae tussen die tweede en derde vlug biofix het tussen 531.2 en 488.87°D gewissel, met 'n gemiddelde van 508.1°D.

Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Cydia pomonella (codling moth), Thaumatotibia leucotreta (False codling moth), Thaumatotibia batrachopa (Macadamia nut borer), Grapholita molesta (Oriental fruit moth), Cryptophlebia peltastica (Litchi moth), Epichoristodes acerbella (Pear leafroller/Carnation worm) and Lozotaenia capensana (Apple leafroller) are the most economically important tortricids affecting various crops in South Africa. The correct identification of these species, especially of the larval stage, is of great importance in pest management. Using available literature, augmented by additional morphological studies, an interactive identification key (Lucid key) for larval and adult stages of the seven species was developed. The colour and markings of the head, characteristics of the prothoracic and anal shields, the position of the prespiracular setae (L-group) relative to the spiracle on the prothoracic segment, the position of the spiracle on the eighth abdominal segment and L-group on the ninth abdominal segment, as well as the presence or absence of the anal comb are key characteristics for larval identification. For adult identification, wing pattern and genitalia are the most important features. However, the use of genitalia for moth identification might be difficult for the lay user, as the dissection and mounting of these structures requires certain skills and specialized equipment. Thus, genitalia have not been included in the Lucid Key. Differences in the morphological characteristics of most pupae were so minute that this stage was also not included in the Lucid key. However, the pupae of E. acerbella and L. capensana are easily distinguished from those of the other species by the presence of acremaster. This study also included the first morphological description of the pupa of L. capensana, which can be distinguished from that of E. acerbella by various features of the cremaster, antennae, spiracle shape, number of setae on abdominal segments A5-7, the size of spines on A3-7, and the presence/absence of spines on A9. A previous study by Timm (2005) indicated that geographically isolated populations of T. leucotreta tend to be genetically distinct. This raised the question of whether speciation/subspeciation has occurred or is occurring. Male moth genitalia are thought to evolve rapidly and are often the only features that can reliably distinguish similar species. Hence, variation in the shape of the valvae of T. leucotreta was used to determine whether divergence has occurred between populations of T. leucotreta. Elliptical Fourier analysis was used to analyze the valvar variation in three different populations. Although some variation in valvar shape was detected among mean population values for certain traits, no clear pattern emerged. Principle component analysis also showed no distinct clustering of valvae shape among populations, providing no evidence for divergence in male genitalia and therefore no morphological evidence of incipient speciation. / AFRIKAANSE OPSOMMING: Cydia pomonella (Kodlingmot), Thaumatotibia leucotreta (Valskodlingmot), T. batrachopa (Makadamianeutboorder), Grapholita molesta (Oosterse vrugtemot), Cryptophlebia peltastica (Lietsjiemot), Epichoristodes acerbella (Peerbladroller/Angelierrusper) en Lozotaenia capensana (Appelbladroller) is die mees ekonomies belangrike tortrisiede van die vrugtebedryf in Suid-Afrika. Die juiste identifikasie van hierdie spesies, veral van hulle larwale stadium, is van groot belang by plaagbestuur. Deur gebruik te maak van beskikbare literatuur, aangevul deur bykomstige morfologiese studies, is ‗n interaktiewe uitkenningssleutel (―Lucid key‖) vir die larwale en volwasse stadia van die sewe spesies ontwikkel. Die kleur en tekening van die kop, kenmerke van die prothorakale en anale skild, die ligging van die prespirakulêre setae (L-groep) relatief tot die spiraculum op die prothorakale segment, die ligging van die spirakulum op die agste abdominale segment en L-groep op die negende abdominale segment, asook die aan- of afwesigheid van die anale kam is sleutel kenmerke vir larwale uitkenning. Vir die volwassenes is die vlerktekening en genitalia die mees belangrike kenmerke. Die gebruik van die genitalia vir motuitkenning kan egter vir die leek gebruiker moeilik wees omdat die disseksie en montering van hierdie strukture bepaalde vaardighede en gespesialiseerde toerusting vereis. Vir die rede is die genitalia nie in die Lucid-sleutel ingesluit nie. Verskille in die morfologiese kenmerke van meeste papies is klein en die stadium is gevolglik ook nie in die sleutel ingesluit nie. Die papies van E. acerbella en L. capensana kan egter maklik van die ander spesies onderskei word deur die aanwesigheid van ‗n cremaster. Hierdie studie sluit ook die eerste morfologiese beskrywing van die papie van L. capensana in, wat van dié van E. acerbella onderskei kan word deur gebruik te maak van kenmerke van die cremaster, antennae, spirakulêre vorm, aantal setae op abdominale segmente A5-7, die grootte van stekels op A3-7, en die aan- of afwesigheid van stekels op A9. ‗n Vroeëre studie (Timm 2005) het aangedui dat geografies geïsoleerde bevolkings van T. leucotreta neig om geneties verskillend te wees. Dit het die vraag laat ontstaan of spesiasie/subspesiasie moontlik plaasgevind het of steeds plaasvind. Manlike mot genitalië word geag om vinnig te ontwikkel en is dikwels die enigste kenmerke wat betroubaar tussen soortgelyke spesies kan onderskei. Dus is die variasie in die vorm van die valvae van T. leucotreta gebruik om te bepaal of divergensie wel tussen bevolkings van T. leucotreta plaasgevind het. Elliptiese Fourier ontleding is gebruik om die valvae se variasie by drie verskillende bevolkings te ontleed. Alhoewel enkele variasie in die vorm van die valvae bespeur is by die gemiddelde bevolkingswaardes vir bepaalde eienskappe, kon geen duidelike patroon bespeur word nie. Hoofkomponentontleding het ook geen duidelike groepering van valvae se vorm tussen bevolkings getoon nie, wat geen bewys lewer van divergensie in die manlike genitalia en dus geen morfologiese bewys van beginnende spesiasie.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Thaumatotibia leucotreta, the false codling moth (FCM), is a phytosanitary pest in South Africa posing a substantial threat to many of the country’s international export markets. Its pest status is of high importance because it has a wide ecological range and has been reported in all areas where citrus is produced in South Africa. Many methods of control have been implemented, such as chemical and cultural control, mating disruption and sterile insect releases. There was a need to obtain a more accurate understanding of FCM biology on deciduous fruit in South Africa and this then us to pose the questions described in the chapters to follow. The first aim was focused on the possibility of FCM diapause during winter. If FCM were to undergo diapause this could pose further problems for control methods, but knowledge thereof could also assist in more accurate and timely control methods. Considering past research on other Lepidoptera species, four physiological traits were chosen as indicative of a diapause state. Water loss rate, metabolic rate and the supercooling points should be lower if the individuals were in a diapause state, with a higher fat content expected for these individuals. Diapause induction was attempted through a gradual lowering of the environmental temperature in combination with longer nights to simulate overwintering conditions. Diapause was not observed in these experimental individuals. The second aim was to better understand the field biology of FCM. This was studied through in-field flight ability studies and damage assessments on four fruit kinds. Six release dates were used to measure the flight ability. The highest recapture rates were at minimum temperatures above 16°C and maximum temperatures averaging above 30°C, although the recapture rates were not significant in relation to the amount released. The recapture rates in the different fruit kinds were not significantly different, with the amount recaptured at the closest distance of 30 m being significantly more than that of the other distances. This was also only for the last release at the warmest temperatures. Fruit damage assessments were conducted and we were able to rear wild FCM from Granny smith apples, Forelle pears, Larry Ann plums and Satsuma and Clementine citrus cultivars. Citrus infestations had the highest count and a prolonged occurrence compared to the other varieties, due to its later harvest period. The third aim was to study the developmental parameters of FCM in different fruit kinds and an artificial medium. Firstly, FCM did not infest apples, Royal Gala and Pink lady’s, under laboratory conditions. Results were obtained using Forelle pears, Clementines and Thompson seedless grapes. On average the grapes had the shortest FCM developmental time from egg to adult stage, followed by oranges and then pears. Pears had the lowest developmental success rate, with that of oranges and grapes being much higher. Infestations took place at the stalk end of the fruit for the grapes and oranges, with the pears being infested at the calyx end. Future research should include an in-field life cycle, to determine the life cycle of FCM on different economically important fruit kinds under field conditions. The focus could also be shifted to where FCM overwinter, leading to better preventative control leading to lower infestation pressure during harvest periods. This is of utmost importance in an environment where maximum residue levels for pesticides dictate market access. / AFRIKAANSE OPSOMMING: Thaumatotibia leucotreta, die vals kodling mot (VKM) is ‘n fitosanitere pes in Suid Afrika, wat kan lei tot groot finansiele verliese. Die VKM se wye gasheerreeks en die feit dat dit al in al die sitrus verbouings-areas in Suid Afrika opgelet is, maak dit ‘n ernstige pes. Daar word van verskeie beheer metodes gebruik gemaak, insluitend chemiese en kulturele metodes. In sommige areas word daar ook van paaringsontwrigting en steriele insek vrylatings gebruik gemaak en hierdie metodes word gewoonlik met ander gekombineer. Daar is ‘n groot behoefte vir meer inligting omtrent die status van VKM in sagtevrugte in Suid Afrika en het gelei tot die vrae wat in hierdie studie aangespreuk word. Die eerste doelwit was om te bepaal of die VKM wel diapouse ondergaan. Dit sal verskeie beheermetodes belemmer, maar kennis hiervan kan meer gefokusde en gevolglik meer effektiewe beheermaatreels tot gevolg hê. Daar is gekyk na vier fisiologiese eienskappe wat beduidend tot diapouse van ander Lepidoptera spesies is. Daar word verwag dat VKM wat diapouse ondervind ‘n hoër vetinhoud sal he, terwyl die metabolise tempo, “supercooling’ punte en tempo van waterverlies laer sal wees. Hierdie eienskappe kon egter nie by die individue geidentifiseer word nie. Ons het diapouse probeer induseer deur gebruik te maak van ‘n gesimuleerde oorgang na winterstoestande in die laboratorium. Die toestande het toegelaat vir korter dae en laer gemiddelde temperature gedurende beide die dag en nag. Die tweede doelwit waarna gekyk is, is die bepaling van VKM se beweging in die boorde en die vrugskade op verskillende vrugsoorte. Daar kon ‘n duidelike tendens geidentifiseer word in die toename van VKM hervangs by temperature bo ‘n minimum van 16°C en gemiddelde maksimum bo 30°C. Daar was 6 vrylatings periodes, met geen betekenisvolle getalle van hervangs nie. Daar was geen betekenisvolle verskille tussen die hervangsgetalle in die verskillende vrugsoorte nie, alhoewel die 30m lokval ‘n betekenisvol hoër gemiddelde hervangs gehad het, in vergelyking met lokvalle by 60m en 90m. Die hoeveelheid vrugskade is ook gemonitor op Granny smith appels, Forelle pere, Larry Ann pruime en Satsuma en Clementine sitrus kultivars. Die vrugte is na die laboratorium geneem waar die VKM tyd gegee is om uit te broei. Al die vrugsoorte het VKM volwassenes opgelewer, maar die eksperiment kon nie op appels in die laboratorium herhaal word tydens die toets van verkillende onwikkeling stadiums nie. Ons glo dus die VKM wat hier vanaf appels uitgebroei het, is weens sekondere infeksies in die boorde. Die hoogste skadetelling is in die sitrusboord gevind. Die derde doelwit was om die duur van onderskeie ontwikkeling stadiums te bepaal op vier vrugsoorte, sowel as op ‘n kunsmatige medium. Ons het ondervind dat die VKM nie Royal Gala of Pink lady kultivars kan infesteer onder laboratorium toestande nie. Die vrugsoorte wat dus ontwikkeling kon onderhou was Forelle pere, Clementines en Thompson pitlose druiwe. Die ontwikkeling vanaf eier na volwasse stadium was die kortste op druiwe, gevolg deur lemoene en pere. Die pere het die minste VKM onderhou in vergelyking met die lemoene en druiwe. Al die vrugte is binnegedring naby die aansluiting van die stingel aan die vrugte, behalwe die pere wat nader aan die kelk binnegedring is. Toekomstige navorsing sal gefokus moet word op die lewenssiklus in die veld, vir die verskillende vrugsoorte. Daar sal ook gekyk moet word na die spesifieke alternatiewe gashere of plekke waar die VKM kan oorwinter sodat beheer meer voorkomend plaas kan vind. Dit sal infestasie vlakke onderdruk, om veral laer druk tydens oesperiodes te verseker. Dit is uiters belangrik om beheer stategieë te kombineer met die hoeveelheid druk vanaf uitvoermarkte oor maksimum residu vlakke van chemiese middels.

Thesis (PhD (Agric) (Conservation Ecology and Entomology))--University of Stellenbosch, 2005. / Six tortricid species are of major economic importance to the South African fruit industry. They are the codling moth Cydia pomonella, the oriental fruit moth Grapholita molesta, the false codling moth Thaumatotibia leucotreta, the macadamia nut borer T. batrachopa, the litchi moth Cryptophlebia peltastica and the carnation worm Epichoristodes acerbella. For phytosanitary purposes and to aid the management of population levels of the aforementioned species, their identities at species and population level were investigated using morphological and molecular genetic techniques. Morphological characteristics were used to distinguish and differentiate between the final instar larvae and pupae of the six species. For this purpose the morphology of the final instar larvae and pupae of the Afrotropical species T. leucotreta, T. batrachopa, Cr. peltastica and E. acerbella was described and illustrated using line drawings and scanning electron micrographs. Taxonomic characters found to be useful for the identification of the larvae were the presence and structure of the anal comb and the number and arrangement of crochets on the prolegs. The pupae could be distinguished based on the presence or absence of a distinct cremaster, the shape of the spiracle, the position of the setae on the anal rise, the structure of the mouthparts and the length of the procoxa in relation to that of the protarsus. These characters were used to develop keys to distinguish between the tortricid species occurring on tropical and subtropical fruit (T. leucotreta, T. batrachopa and Cr. peltastica) and deciduous fruit (E. acerbella, C. pomonella, G. molesta and T. leucotreta). At population level, molecular techniques were employed to compare geographic populations of each of the six species. Amplified fragment length polymorphism (AFLP) analysis with five selective primer pairs was used to investigate genetic diversity. In addition, host populations of species were compared where relevant. No evidence was found to suggest that populations from different hosts were genetically differentiated. However, geographic populations were found to be genetically distinct in each of the six species, with extensive genetic divergence apparent over local geographic scales and significantly high estimates of population differentiation ranging between Gst = 0.2625 and 0.3778. Factors influencing the genetic population structure of the six species were investigated by comparing the amount and distribution of genetic variation between oligophagous and polyphagous species as well as introduced and native species. Results indicated that host range and population history did not have a major effect on population genetic structure. It was therefore suggested that other factors such as limited dispersal were responsible for the extensive genetic divergence observed between geographic populations of each of the six tortricid species. These results should be incorporated into existing pest management programs and taken into consideration when designing new control strategies. This is the first report of its kind to identify, with a high level of accuracy, the aforementioned tortricids and the first to determine the population genetic structure of these species.

published_or_final_version / abstract / toc / Ecology and Biodiversity / Master / Master of Philosophy