Orientador: Silvia Renata Siciliano Wilcken / Coorientador: Luís Garrigós Leite / Banca: Regiane Cristina Oliveira de Freitas Bueno / Banca: Nádia Cristina de Oliveira / Banca: Solange Maria Bonaldo / Banca: Juliana Magrenelli Osorio Rosa / Resumo: Nematoides entomopatogênicos (NEPs) são promissores para o controle biológico de pragas. Os fatores abióticos, temperatura e os tipos de solos e substratos, influenciam a sobrevivência de juvenis infectantes em condições de armazenamento e a campo. Os objetivos do presente estudo foram: isolar e identificar espécies de NEPs coletadas em áreas de culturas florestais, anuais e frutíferas no Brasil; avaliar o período de mortalidade de lagartas de Galleria mellonella após a infecção de Heterorhabditis amazonensis IBCB 24, o período da emergência e JIs (juvenis infectantes) multiplicados durante o período de 30 dias em cinco temperaturas; avaliar a influência da temperatura na sobrevivência JIs de Steinernema carpocapsae IBCB 02 Heterorhabditis amazonensis IBCB 24 e Steinernema feltiae IBCB 47 em condições de armazenamento; avaliar a influência da luminosidade e do substrato na capacidade de infecção de juvenis dos isolados IBCB 06 Steinernema brazilense, IBCB 02 Steinernema carpocapsae, IBCB 47 Steinernema feltiae e IBCB 24 Heterorhabditis amazonensis em lagartas de G. mellonella e avaliar o uso de diferentes substratos para prolongar a sobrevivência de JIs de S. brazilense IBCB 06 e H. amazonensis IBCB 24 em condições de armazenamento. O presente estudo foi dividido em cinco capítulos. Após a coleta de dados, as espécies foram identificadas como H. amazonensis, S. rarum, M. rainai e O. tipulae. As temperaturas de 26°C e 30°C proporcionaram o menor período de tempo (três dias) para a mortalidade de lagartas de G. mellonella causadas por H. amazonensis. O menor período de tempo para a 2 emergência de JIs foi na temperatura 30°C, (9,4 dias). O número médio de JIs produzidos a 26°C (229.563) foi superior a todas as temperaturas estudadas, mas sem diferença estatística quando comparado aos JIs produzidos na temperatura de 30°C (127.157). A temperatura de 22°C (223.88 ... / Abstract: Entomopathogenic nematodes (EPNs) show promising for biological control of pests. The abiotic factors, temperature, soil types and substrates, may influence the survival of infective juveniles storage and field conditions. The objectives of this study were to isolate and identify species of EPNs collected in areas of forestry, annual and fruit crops in Brazil; assess the period of mortality of larvae Galleria mellonella after infection of Heterorhabditis amazonensis IBCB 24, the emergency period and IJs (infective juveniles) multiplied during the 30-day period in five temperatures; evaluate the influence of temperature on survival IJs of Steinernema carpocapsae IBCB 02 Heterorhabditis amazonensis IBCB 24 and Steinernema feltiae IBCB 47 storage conditions; evaluate the influence of light and substrate on juvenile infection capacity of isolates IBCB 06 Steinernema brazilense, IBCB 02 Steinernema carpocapsae, IBCB 47 Steinernema feltiae and IBCB 24 Heterorhabditis amazonensis in larvae G. mellonella and evaluate the use of different substrates to prolong the survival of IJs of S. brazilense IBCB 06 and H. amazonensis IBCB 24 storage conditions. This study was divided into five chapters. After collecting data, the species were identified as H. amazonensis, S. rarum, M. rainai and O. tipulae. The at temperatures of 26°C and 30°C gave the shortest time period (three days) for the crawler mortality caused by H. amazonensis in G. mellonella. The shortest duration for emergency IJs was found at 30°C temperature (9.4 days). The average number of IJs produced at 26°C (229.563) was higher at all temperatures studied, but no statistical difference when compared to 30°C IJs produced in the temperature (127.157). The temperature of 22°C (223.886) did not differ statistically from the lower temperature ... / Doutor

Este trabalho teve por objetivo verificar a seletividade de inseticidas alternativos ao parasitóide Telenomus podisi (Ashmead) (Hymenoptera: Scelionidae). Para isto foram utilizados os inseticidas alternativos Compostonat, Natuneem, Natualho, Óleo de Gerânio, Pironat e Rotenat. Foram pulverizados 0,2 mL de cada produto, na concentração recomendada pelo fabricante, sobre cartelas (1,0 × 5,0 cm) contendo ovos de Euschistus heros (Fabricius) (Hemiptera: Pentatomidae). A testemunha constou da pulverização de água destilada. Realizou-se teste com chance de escolha, confinando uma fêmea de T. podisi com duas cartelas, uma pulverizada com o inseticida alternativo e a outra com a testemunha, sendo avaliada a taxa de parasitismo, analisando a repelência provocada pelo inseticida alternativo em relação a sua respectiva testemunha. O teste sem chance de escolha consistiu em duas estratégias de pulverização, pulverização pré-parasitismo e pulverização pós-parasitismo. A pulverização pré-parasitismo consistiu em confinar uma fêmea com uma cartela pulverizada com o inseticida alternativo, ou confinada com uma cartela da testemunha, enquanto a pulverização pós-parasitismo consistiu em confinar uma fêmea com uma cartela não pulverizada, após 24 h retirou-se a fêmea e foi realizada a pulverização com o inseticida alternativo ou com água destilada, sendo esta a testemunha. Neste teste, avaliou-se o taxa de parasitismo, porcentagem de emergência, longevidade dos adultos, período ovo-adulto e razão sexual dos parasitóides emergidos. Verificou-se que no teste com chance de escolha os inseticidas alternativos Compostonat, Natualho e Óleo de Gerânio afetaram a taxa de parasitismo. No teste sem chance de escolha a taxa de parasitismo foi afetada pelos inseticidas alternativos Rotenat no pós-parasitismo, Natualho e Óleo de Gerânio no pré-parasitismo, enquanto a emergência foi reduzida por Compostonat e Óleo de Gerânio no pré-parasitismo. O parâmetro período ovo-adulto foi afetado pelos produtos Natualho no pré-parasitismo para fêmeas e Óleo de Gerânio no pós-parasitismo para macho, a razão sexual foi reduzida por Natualho e Óleo de Gerânio nos pós-parasitismo. A longevidade foi diminuída pelos inseticidas alternativos Rotenat e Óleo de Gerânio no pré-parasitismo, e aumentada pelo Óleo de Gerânio no pós-parasitismo. Assim, Natuneem foi o único produto a apresentar seletividade a T. podisi em todos os parâmetros avaliados, porém, os demais inseticidas alternativos não são seletivos, tomando por base os testes aqui realizados, pois afetaram a maioria dos parâmetros avaliados, comprometendo o controle do inseto-praga. / The aim of this study was to verify the selectivity of alternative insecticides to the egg parasitoid, Telenomus podisi (Ashmead) (Hymenoptera: Scelionidae). The following products were evaluated: Compostonat, Natuneem, Natualho, Geranium Oil, Pironat and Rotenat. A quantity of 0.2 ml of each product, at the manufacturer’s recommended concentration, was sprayed onto cards (1.0 × 5.0 cm) supporting the eggs of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae). The control was sprayed with distilled water. In this test, it was available the parasitism rate, emergency of percentage, adults longevity, period of adult-egg, sexual ration of the emerged parasitoids. It was verified that in the test with chance of choice, the alternative insecticides Compostonat, Natualho and Geranium oil affect the rate of parasitism. In the test with no-chance of parasitism choice the rate of parasitism was affected by the alternative insecticides Rotenat in the post-parasitism, Natualho and Geranium oil in the pre-parasitism, while the emergency was reduced by Compostonat and Geranium oil in the pre-parasitism. The parameter period adult-egg was affected by the products Natualho in pre-parasitism for females and Geranium oil in the post-parasitism for male, the sexual ration was reduced by Natualho and Geranium oil in the post-parasitism. The longevity was reduced by alternative insecticides Rotenat and Geranium oil in the pre-parasitism, and elevated by Geranium oil in the post-parasitism. Thus, Natuneem was the unique product to present selectivity to T. podisi in all the available parameters, although the other alternative insecticides are no selective, basing in the tests hear realized, because they affected the majority of the available parameters, compromising the control of prague- insect.

Conhecer os efeitos dos produtos fitossanitários naturais (PFN) sobre insetos praga e organismos não alvo é fundamental no contexto do Manejo Integrado de Pragas. Esse trabalho objetivou avaliar a atividade de PFN sobre Anticarsia gemmatalis (Lepidoptera: Noctuidae), esporos e cristais de Bacillus thuringiensis subesp. kurstaki (Btk) e a seletividade sobre Apis mellifera L. (Hymenoptera: Apidae). Foram utilizados os extratos de pitanga (Eugenia uniflora), pimenta (Capsicum baccatum var. pendulum), trombeta (Brugmansia suaveolens) e uva-do-japão (Hovenia dulcis), à 5%, Natuneem®, Natualho®, Pironat®, Rotenat® e Calda Bordalesa (CB), na concentração recomendada pelo fabricante. Para esporos, os tratamentos Btk + PFN e Btk, isoladamente, foram incubados em agitador horizontal (150 rpm, 30 ± 2 ºC, 2 h) e, inoculados em meio de cultura ágar nutriente (AN), em placas de Petri. Foram preparadas quatro placas (repetições), acondicionadas em câmara climatizada (30 ± 2 ºC, 18 h), quantificando-se as unidades formadoras de colônias (UFC)/mL. Para cristais, os PFN e Btk, isoladamente, água destilada esterilizada (testemunha) e Btk + PFN, após incubação, nas condições descritas acima, foram aplicados sobre cubos de dieta artificial para A. gemmatalis, em placas de Petri, que receberam 20 lagartas de segundo ínstar, cada. Foram preparadas quatro placas (repetições), acondicionadas em câmara climatizada (26 ± 2 ºC, UR: 70%±10 % fotofase 14 h). Avaliou-se a mortalidade após, 24, 48, 72, 96 e 120 h, o percentual de empupamento e emergência e o período ovo-adulto. A seletividade sobre A. mellifera foi avaliada pulverizando-se os tratamentos sobre operárias e adicionando-os a pasta Cândi. Como testemunha utilizou-se respectivamente água destilada esterilizada e pasta Cândi pura. Em ambos os experimentos utilizou-se 30 operárias por tratamento (repetição), individualizadas em tubos de vidro (10 cm × 2,5 cm), acondicionados em câmara climatizada (25 ± 2 °C, U.R. 70% ± 10%, fotofase de 12 h) e a mortalidade, avaliada a uma; duas; três; quatro; cinco; seis; nove; 12; 15; 18; 21; 24; 30; 36; 42; 48; 60; 72 e 96 h. Verificou-se que os extratos de pitanga, pimenta e uva-do-japão reduziram significativamente as UFC/mL. O extrato de pitanga foi o único que afetou negativamente a toxicidade dos cristais de Btk. Nenhum extrato vegetal afetou a mortalidade, não havendo diferença entre os tempos de avaliação, nem o empupamento, emergência e período ovo-adulto. Na mistura com Btk o extrato de pitanga retardou a mortalidade e o extrato de pimenta acelerou a mortalidade. Nos experimentos com A. mellifera, houve redução significativa, apenas para o extrato de uva-do-japão, quando pulverizado. Os produtos Natuneem® e Rotenat® aumentaram significativamente as UFC/mL. Somente a CB afetou negativamente a toxicidade dos cristais de Btk. Nos demais parâmetros, observou-se redução significativa do percentual de empupamento para CB e Natualho®e percentual de emergência para CB e Natuneem®. Entre os tempos de avaliação, não houve influência dos produtos isolados, na mistura com Btk Natualho®, Pironat®, Rotenat® aceleraram a mortalidade e a CB influenciou negativamente. Não se verificou atividade dos produtos sobre o período ovo-adulto. Para A. mellifera, em ambos os experimentos, os produtos não afetaram significativamente a longevidade. / Knowing the effects of natural products phytosanitary (NPP) on pests and organisms target is not essential in the context of Integrated Pest Management. This study aimed to evaluate the activity of PFN on Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae), spores and crystals of Bacillus thuringiensis subsp. kurstaki (Btk) and selectivity of Apis mellifera L. (Hymenoptera: Apidae). We used extracts of cherry (Eugenia uniflora), pepper (Capsicum baccatum var. pendulum), trumpet (Brugmansia suaveolens) and Blueberry japan (Hovenia dulcis), to 5%, Natuneem®, Natualho®, Pironat®, Rotenat® Bordeaux and Syrup (SB), the concentration recommended by the manufacturer. For spores, the treatments Btk + NFP and Btk alone were incubated on horizontal shaker (150 rpm, 30 ± 2 ° C, 2 h) and inoculated onto nutrient agar plates (NA), in petri dishes. We prepared four plates (repetitions), placed in a climatic chamber (30 ± 2 º C, 18 h), quantifying the colony forming units (CFU) / mL. To crystals, the PFN and Btk alone sterilized distilled water (control) and Btk + NFP after incubation under the conditions described above were applied on artificial diet cubes for A. gemmatalis, in Petri dishes, which received 20 second instar larvae of each. We prepared four plates (repetitions), placed in a climatic chamber (26 ± 2 º C, RH 70% ± 10% photophase 14 h), evaluating mortality after 24, 48, 72, 96 and 120 h, the percentage empupament and the emergence and egg-adult period. The selectivity of A. mellifera was evaluated by spraying treatments on workers and adding them to pasta Candi. As a control we used respectively sterile distilled water and paste Candi pure. In both experiments, we used 30 workers per treatment (repeat), individually in glass tubes (10 cm × 2.5 cm), packed in a climatic chamber (25 ± 2 ° C, RH 70% ± 10%, photophase 12 h) mortality, assessed by one, two, three, four, five, six, nine, 12, 15, 18, 21, 24, 30, 36, 42, 48, 60, 72 and 96 h. It was found that the extracts of cherry, pepper and Blueberry japan significantly reduced CFU / mL. The cherry extract was the only negatively affecting toxicity of Btk crystals. No plant extract affected the mortality, there was no difference between the time of evaluation, nor empupament, emergence and egg-adult period. In mixture with Btk cherry extract delayed the mortality and pepper extract accelerated mortality. In experiments with A. mellifera, was significantly reduced only to extract Blueberry japan, when sprayed. Natuneem® products and Rotenat® were the only ones who have significantly increased CFU / mL. Only the SB negatively affected the toxicity of Btk crystals. Ns other parameters, there was significant reduction in the percentage of empupament for SB and Natualho® and percentage of emergency and SB Natuneem®. Between the time of evaluation, no influence of individual products, the mix with Btk Natualho®, Pironat®, Rotenat® accelerated mortality and SB negatively influenced. There was no activity of the products on the egg-adult period. To A. mellifera, in both experiments, the products did not significantly affect longevity.

Este trabalho teve por objetivo verificar a seletividade de inseticidas alternativos ao parasitóide Telenomus podisi (Ashmead) (Hymenoptera: Scelionidae). Para isto foram utilizados os inseticidas alternativos Compostonat, Natuneem, Natualho, Óleo de Gerânio, Pironat e Rotenat. Foram pulverizados 0,2 mL de cada produto, na concentração recomendada pelo fabricante, sobre cartelas (1,0 × 5,0 cm) contendo ovos de Euschistus heros (Fabricius) (Hemiptera: Pentatomidae). A testemunha constou da pulverização de água destilada. Realizou-se teste com chance de escolha, confinando uma fêmea de T. podisi com duas cartelas, uma pulverizada com o inseticida alternativo e a outra com a testemunha, sendo avaliada a taxa de parasitismo, analisando a repelência provocada pelo inseticida alternativo em relação a sua respectiva testemunha. O teste sem chance de escolha consistiu em duas estratégias de pulverização, pulverização pré-parasitismo e pulverização pós-parasitismo. A pulverização pré-parasitismo consistiu em confinar uma fêmea com uma cartela pulverizada com o inseticida alternativo, ou confinada com uma cartela da testemunha, enquanto a pulverização pós-parasitismo consistiu em confinar uma fêmea com uma cartela não pulverizada, após 24 h retirou-se a fêmea e foi realizada a pulverização com o inseticida alternativo ou com água destilada, sendo esta a testemunha. Neste teste, avaliou-se o taxa de parasitismo, porcentagem de emergência, longevidade dos adultos, período ovo-adulto e razão sexual dos parasitóides emergidos. Verificou-se que no teste com chance de escolha os inseticidas alternativos Compostonat, Natualho e Óleo de Gerânio afetaram a taxa de parasitismo. No teste sem chance de escolha a taxa de parasitismo foi afetada pelos inseticidas alternativos Rotenat no pós-parasitismo, Natualho e Óleo de Gerânio no pré-parasitismo, enquanto a emergência foi reduzida por Compostonat e Óleo de Gerânio no pré-parasitismo. O parâmetro período ovo-adulto foi afetado pelos produtos Natualho no pré-parasitismo para fêmeas e Óleo de Gerânio no pós-parasitismo para macho, a razão sexual foi reduzida por Natualho e Óleo de Gerânio nos pós-parasitismo. A longevidade foi diminuída pelos inseticidas alternativos Rotenat e Óleo de Gerânio no pré-parasitismo, e aumentada pelo Óleo de Gerânio no pós-parasitismo. Assim, Natuneem foi o único produto a apresentar seletividade a T. podisi em todos os parâmetros avaliados, porém, os demais inseticidas alternativos não são seletivos, tomando por base os testes aqui realizados, pois afetaram a maioria dos parâmetros avaliados, comprometendo o controle do inseto-praga. / The aim of this study was to verify the selectivity of alternative insecticides to the egg parasitoid, Telenomus podisi (Ashmead) (Hymenoptera: Scelionidae). The following products were evaluated: Compostonat, Natuneem, Natualho, Geranium Oil, Pironat and Rotenat. A quantity of 0.2 ml of each product, at the manufacturer’s recommended concentration, was sprayed onto cards (1.0 × 5.0 cm) supporting the eggs of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae). The control was sprayed with distilled water. In this test, it was available the parasitism rate, emergency of percentage, adults longevity, period of adult-egg, sexual ration of the emerged parasitoids. It was verified that in the test with chance of choice, the alternative insecticides Compostonat, Natualho and Geranium oil affect the rate of parasitism. In the test with no-chance of parasitism choice the rate of parasitism was affected by the alternative insecticides Rotenat in the post-parasitism, Natualho and Geranium oil in the pre-parasitism, while the emergency was reduced by Compostonat and Geranium oil in the pre-parasitism. The parameter period adult-egg was affected by the products Natualho in pre-parasitism for females and Geranium oil in the post-parasitism for male, the sexual ration was reduced by Natualho and Geranium oil in the post-parasitism. The longevity was reduced by alternative insecticides Rotenat and Geranium oil in the pre-parasitism, and elevated by Geranium oil in the post-parasitism. Thus, Natuneem was the unique product to present selectivity to T. podisi in all the available parameters, although the other alternative insecticides are no selective, basing in the tests hear realized, because they affected the majority of the available parameters, compromising the control of prague- insect.

Phthorimaea operculella, commonly known as the Potato Tuber Moth, is an economically important agricultural pest worldwide. The baculovirus, Phthorimaea operculella granulovirus (PhoGV) has been considered as a means of control alternative to chemical control because of its host specificity and harmless impact on other organisms and ecosystems. An isolate of PhoGV obtained from a South African PTM population would be beneficial in the production of a biopesticide, which is not yet available. An efficient and cost-effective rearing method would be advantageous for potential commercial production. Commercial table and seed potato plantations and storage facilities located in Patensie, Bathurst, Howick and Ivanhoe were surveyed for PTM infestations. Patensie was the only site where milky discoloured larvae were found, a potential symptom of PhoGV infection. TEM analysis revealed no virus in these samples. Since no virus was found in the field-collected samples, PTM insects were collected to initiate rearing in the laboratory. PTM was raised by three different methods in the laboratory. A cost/benefit analysis, survival rate, fertility and sex ratio were recorded for each rearing method. Rearing method one was deemed unsuccessful for efficient commercial rearing, as survival percentage and fertility were low. Rearing methods two and three had high survival rates and high fertility, and were efficient and less labour intensive than rearing method one. Rearing method three was the most productive technique, but for commercial production rearing method two was considered the most manageable and efficient. The sex ratio was 1:1 for all three cultures. The cost analysis revealed that rearing methods two and three were less expensive than rearing method one because less labour was required to monitor insects. The success of rearing PTM for 19 months will enable these cultures to be up-scaled to a large production facility for mass rearing. Virus was not found in the field surveys or in laboratory cultures, therefore chemical, temperature, humidity and carbon dioxide stressors were used in an attempt to initiate a baculoviral infection. Symptoms were exhibited in larvae subjected to chemical, temperature and humidity treatments, but these were confirmed by TEM analysis not to be a result of PhoGV infection. The success of rearing PTM in the laboratory suggests that the method could be used in the commercial rearing of the insects in a large mass-rearing facility. The data obtained from induction protocols have allowed for better understanding for future induction for PhoGV and other baculoviruses in other insect species. The failure to isolate a South African PhoGV strain for developing a biopesticide against PTM has motivated further studies in obtaining a baculovirus in order for South Africa to develop a commercial product against this pest.

Please read the abstract in the section 00front of this document / Thesis (DPhil (Entomology))--University of Pretoria, 2005. / Zoology and Entomology / unrestricted

No description available.

Please read the abstract in the section 00front of this document / Dissertation (M Inst Agrar (Sustainable Insect Management))--University of Pretoria, 2005. / Zoology and Entomology / unrestricted

Thesis (MScAgric (Plant Pathology))--University of Stellenbosch, 2005. / The genus Rhizoctonia includes important soilborne plant pathogens that can cause severe economic losses on a wide range of crops including cereal, canola, pasture and grain legume crops. Limited information is available on specific anastomosis groups (AGs), nuclear status, pathogenicity and cross-pathogenicity of Rhizoctonia isolates associated with each of these crops in the Western Cape province. Therefore, these aspects were investigated in this study, since information in this regard is crucial for the development of Rhizoctonia disease management practices.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT:Chapter 1 - Mealybugs are tiny, soft-bodied insects which constitute the second largest scale insect family Pseudococcidae (Downie & Gullan 2004). The family comprises approximately 2000 species in 300 genera (Ben-Dov 1994), of which 20 species are pests of cultivated plants in South Africa (Annecke & Moran 1982). In South Africa, approximately 109 species of mealybugs have been recorded from 50 genera (Millar 2002). Chapter 2 - The effect of constant temperatures on the development, survival and fecundity of the oleander mealybug, Paracoccus burnerae on citrus was determined. Developmental time, rate of development, fecundity and survival were investigated at five constant temperatures and a 16L: 8D light: darkness regime. The rate of development increased linearly with an increase in temperature for the egg, 1st nymphal and pupal stages as well as the entire biological cycle (egg – adult), but was nonlinear for the 2nd and 3rd nymphal stages. Survival decreased with an increase in temperature. P. burnerae required 666.7 degree-days above a lower threshold of 8.7°C to complete one generation. The highest mean number of 68 eggs per female was reached at 22°C. A sex ratio of 0.52:0.48 (male:female) was obtained from the life table. The net reproductive rate (Ro) was >1 at all five temperatures, an indication that it is capable of increasing its population numbers despite the high mortality experienced in the 1st and 2nd nymphal stages. Chapter 3 - The oleander mealybug, Paracoccus burnerae (Brain) is a pest of citrus in South Africa. This study was carried out to determine the effect of temperature on development rate of P. burnerae and to investigate whether development rate is the reason why P. burnerae is out competing the citrus mealybug, Planococcus citri (Risso), in the Eastern and Western Cape Provinces of South Africa. The influence of temperature on life history traits of P. burnerae was determined at 20, 22, 25 and 27°C and compared with corresponding data for P. citri. The rate of development increased linearly with an increase in rearing temperature in the embryonic, first nymphal and pupal stages but reached a climax at 26.13 and 28.6°C in the second nymphal stage of both species, respectively. P. citri exhibited lower developmental thresholds except in first instar, shorter degree-days and higher developmental rates than P. burnerae. Results of the current study indicated that the dominance of oleander mealybug over the citrus mealybug is neither linked to developmental rates nor sum of effective temperatures. Chapter 4 - The importance of Paracoccus burnerae has risen over the years to an extent where it is now regarded as a quarantine pest for citrus fruit from South Africa. The field biology of P. burnerae on citrus in the Western Cape Province of South Africa was studied through periodic sampling of leaves from twigs enclosed in sleeve cages. The species composition and abundance of natural enemies was investigated. Both adult and immature stages attained maximum population peaks in March and P. burnerae had four generations. The highest level of mortality was experienced in the immature stages. Climate and an unidentified fungus were the key mortality factors. The level of abundance of the two observed predators, the harlequin beetle, Harmonia axyridis and the green lacewing, Chrysoperla sp. was relatively low. Although parasitism occurred in some cages, the level was low ranging between 1.62 to 9.43%. If biocontrol is the preferred method of controlling P. burnerae, suitable candidate parasitoids for inoculative biocontrol are Acerophagus sp., Leptomastix sp. and Microterys nietneri. The oleander mealybug does not share the same parasitoids with Planococcus citri, Pseudococcus calceolariae and Pseudococcus longispinus except the parasitoid Coccophagus sp. The most popular species of parasitoids used in the biolological control of mealybugs, Anagyrus sp. and Coccixenoides sp. were insignificant in the case of P. burnerae. Chapetr 5 - Biological control programs of mealybug species have relied on sprouting potatoes, pumpkins and butternut for rearing of both mealybugs and their natural enemies. In this study, the suitability of sprouting potatoes, butternuts and citrus as mass rearing substrates for the oleander mealybug, Paracoccus burnerae was investigated. Developmental times, rate and fecundity on each substrate were determined and compared at three different temperatures. The developmental time on sprouting potatoes was shorter than on citrus. P. burnerae was unable to complete its life cycle on butternut. The rate of development increased linearly with an increase in temperature on both sprouting potatoes and citrus. P. burnerae required 666.7 degree-days on citrus and 434.8 degree-days on sprouting potatoes above lower developmental thresholds of 7.6°C and 10.4°C respectively to complete one generation. The mean number of eggs per female was higher on sprouting potatoes (121.3) than on citrus (68), but declined with an increase in temperature from 22 to 27°C. Despite the shorter shelf life, sprouting potatoes are the preferred host for mass rearing of the oleander mealybug. Chapter 6 - general conclusions Chapter 7 - Researchers often present impressive results of their studies on the biology of the Coccoidea without mentioning the problems they came across and had to solve. In this paper the practical problems encountered during a study of the biology of the oleander mealybug, Paracoccus burnerae (Brain), an endemic pest of citrus in South Africa, are discussed. / AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.