Thesis (Ph. D.)--Oregon State University, 1990. / Typescript (photocopy). Includes bibliographies. Also available on the World Wide Web.

The feasibility of managing codling moth, Cydia pomonella (L.), with mixtures of Bacillus thuringiensis-based microbial and selected chemical insecticides was studied under laboratory and field conditions. Joint actions (synergism, additivity and antagonism) of these mixtures were determined for both egg and larval stages. Higher rates of microbial control agents (MCAs), Dipel�� 2X and MVP��, combined with low to medium rates of chemical insecticides gave additive or synergistic egg and/or larval mortality. Esfenvalerate and permethrin synergised the effect of these MCAs, whereas carbaryl, azinphosmethyl, phosmet and diflubenzuron had an additive effects. For all chemical insecticides, often the interactions were better with Dipel than MVP. Generally, egg exposure to low rates of the chemical insecticides alone or in combination with MCAs, caused the larvae hatching from these eggs to be more susceptible to insecticides-MCA mixtures. Most mixtures produced better results when treated at the blackhead stage of egg development. Adult and larval exposure to sublethal rates of azinphosmethyl, phosmet, carbaryl, esfenvalerate and permethrin manifested short- and long-term effects. Adult exposure caused deleterious effects on the survival and oviposition, and the larval exposures affected survival and pupal formation. Carbaryl, esfenvalerate and permethrin affected the pupal survival and subsequent eclosion of adults. Only esfenvalerate and permethrin significantly extended the larval period and reduced pupal weight and subsequent egg deposition. The deleterious sublethal effects of pyrethroids observed in the present study may provide added control of codling moth in the field. Diflubenzuron and MCAs had neither adulticidal activity nor long-term effects on codling moth biology. Results of field efficacy tests indicate that utilization of mixtures of Dipel with low rates of pyrethroids (0.1-0.2X) or diflubenzuron (0.25-0.50X) in the codling moth management is possible and indeed might be beneficial. Dipel-diflubenzuron mixtures were only suitable when applied 3 times/generation. These mixtures were environmentally safe and did not cause any outbreak of phytophagous mites. Standard application rate (2 times/generation) and timing were found to be appropriate for Dipel-pyrethroid (esfenvalerate and permethrin) mixtures. These pyrethroids at all test rates (0.1-1.0X), applied alone or mixed with MCAs, were toxic to predatory phytoseiids, thus caused an outbreak of European red mite and yellow spider mites particularly at higher rates. However, mixtures of Dipel and 0.1X of esfenvalerate/permethrin were less disruptive than corresponding 0.2-1.0X standard rate. These mixtures were selective to most predatory insects, spiders and Zetzellia malt. Hence, use of these mixtures instead of full rate of pyrethroids may improve the prospects of biological control of insect and mite pests in apple orchards. / Graduation date: 1996

Thesis (Ph. D.)--University of Wisconsin--Madison, 1939. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 85-93).

Toxicological studies were carried out to evaluate the susceptibility of codling moth, Cydia pomonella L. to different insecticides. Bioassay procedures for adults and larvae were standardized in terms of posttreatment holding and temperature, age and sex of insects, insecticide formulations and selection of a reference strain. This study detected a low level of resistance to azinphosmethyl in codling moth from Oregon. The LD50 value of the most susceptible strain was 0.038 ug AI/moth, while that of the most resistant population was approximately 4.3 times higher as determined by the topical application method on pheromone traps. The adult topical bioassay using moths reared in the laboratory showed that two of the seven strains tested (Crippens and Medford) had 4-5 fold higher LD50 values than reference (Saint Cloud) strain. In the topical and residual studies with first instar larvae, similar but slightly lower differences were observed among the different populations. There was a strong indication of low levels of resistance in populations to diazinon and fenvalerate in topical tests applied to both males and females. However, there was no significant difference for carbaryl or endosulfan. Larval topical bioassays showed a significant difference only to diazinon. Correlation analysis suggests that a degree of cross-resistance exists between azinphosmethyl and diazinon and to some extent to fenvalerate. Codling moths exposed to the residues of diflubenzuron showed a maximum of 2-fold difference between the susceptible and resistant populations. The differences were visible in terms of egg hatch and first instar larval entries. The pupal and adult stages emerging from the treated apples exposed to ovipositing females showed insignificant sublethal effects. A strong positive correlation between the resistance to azinphosmethyl and resistance to diflubenzuron was noticed. Selection of codling moths for resistance to diflubenzuron for six generations in the laboratory decreased susceptibility by 5-fold. Application of synergists such as PBO and DEF, combined with azinphosmethyl and diflubenzuron, showed slightly different effects on all strains of codling moth. Use of PBO (a P-450 inhibiting compound) with azinphosmethyl and diflubenzuron did not change toxicity of either of the compounds. However, the combination of DEF (an esterase inhibiting compound) with the insecticides significantly increased the toxicity of azinphosmethyl and to some extent diflubenzuron. The maximum synergistic ratios obtained were 8 and 2 for azinphosmethyl and diflubenzuron, respectively. These results indicate a possible involvement of esterases in development of resistance in codling moth to azinphosmethyl and maybe to diflubenzuron. The optimal synergistic ratio determined on a resistant strain of codling moth to various combinations of azinphosmethyl and DEF was 1:4 (50 ppm of azinphosmethyl 200 ppm of DEF). The phytotoxicity studies on young apple trees showed that DEF should be used at or below 500 ppm to avoid phytotoxicity while maintaining effective control of codling moth with a reduced dose of azinphosmethyl. / Graduation date: 1997

Thesis (MScAgric)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 140-159). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 140-159). Also available on the Internet.

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.

A THESIS PRESENTED TO CAPE PENINSULA UNIVERSITY OF TECHNOLOGY IN FULFILMENT OF THE REQUIREMENTS FOR THE MASTERS OF TECHNOLOGY DEGREE IN HORTICULTURE. IN THE FACULTY OF APPLIED SCIENCES 2014 / Codling moth ([Cydia pomonella (Lepidoptera: Tortricidae]) infest pomes resulting in high production losses to fruit farmers in South Africa and globally. Many farmers are adopting biocontrol methods including the use of entomopathogens as alternatives to synthetic insecticides for sustainable management of Arthropod pests. Research activities on screening and application of entomopathogenic fungi (EPF) have intensified in recent years. This study was carried out to isolate and identify virulent indigenous entomopathogenic fungal strains from soils of selected locations in the Western Cape region of South Africa that are pathogenic against codling moth (Cydia pomonella (Linn) [Lepidoptera: Totricidae]) and to evaluate the possiblility of combining semiochemicals and fungal inoculums in a simulated attract-and-fungus contamination system for codling moth control. Soil samples were collected from 10 locations in the Western Cape, South Africa for the isolation of entomopathogenic fungi (EPF) by baiting the soil samples with 5th instar larvae of codling moths. Fungal strains were identified and characterized using light microscopy and DNA analysis (internal transcribed spacer region) and elongation factor 1-α (EF 1-α) genes of fungal cultures. Thirty-nine (39) isolates belonging to six species were obtained; Purpureocillium lilacinum (8 isolates), Fusarium oxysporum (five isolates), Fusarium polyphialidicum (two isolates), Beauveria pseudo-bassiana (one isolate), Aspergillus flavus (three isolates) and Metarhizium robertii (20 isolates). Generally, M. robertsii was the most frequently encountered species representing 51% of the total number of isolates collected from the soil samples. This is the first report of the isolation of M. robertsii in southern Africa. A screening test to identify the most virulent fungal strains against codling moth was carried out on 39 isolates by immersing 5th instar larvae of C. pomonella into aqueous spore suspension 1 x 108 conidia ml-1. Mortality data from the immersion bioassay indicated that the 39 fungal isolates were pathogenic against fifth instar larvae of codling moth inducing 47-85% insect mortality at an infective concentration of 1 x108 spores’ ml-1, 5 days post-treatment. Two fungal strains MTL151 and GW461 induced over 85% larval mortality and were selected for further evaluations. The effect of MTL151 and GW461 on egg hatchability of 0-day old eggs was evaluated by exposing freshly laid eggs on wax papers that were pre-treated with fungal spores ranging from 103 -108 spores/ml. Egg hatchability reduced significantly from 93-71% (GW461) and 95-66% (MTL151) as spore concentration increases from1 x 103 to 1 x 108 spores ml-1, respectively. The highest spore concentration significantly inhibited egg hatchability resulting in lower egg hatchability compared to that obtained with the cypermethrin containing commercial insecticide (Fruitfly [registered by Kombat (PTY) Ltd] ) tested at the recommended dose of 0.25 ml/250 ml of water. The potential of the two M. robertsii strains to protect apples from infestation by codling moth neonates was assessed in an apple fruit bioassay under laboratory and field bioassay. Codling moth neonates were exposed to apples that were sprayed topically with varied conidia concentrations (103 - 108 sporesml-1). The mean number of participating apple fruits having developing/developed larvae in the core/flesh significantly reduced from 5.3 to 1 and 7.6 to 1 for MTL151 and GW461, respectively as spore concentrations increased from 1 x103 to 1x 108 spores/ml-1. A concurrent decrease in apple fruit rot as conidia concentration increased was observed. Up to 90% of apples treated with 1 x 108 spores/ml-1 had no larva present in their cores and this result compared favourably with the commercial pesticide (Fruitfly) used at a recommended dose of 0.25g/250 ml of water. No significant difference was found between the EC50 values of 1.2 x 103 (CI=1.2 x 102 -1 x 105) (MTL151) and 1.1 x 105 (CI =7 x103 – 5.6x105) (GW461) spores ml-1. However, neither the two M. robertsii strains nor the insecticide deterred the neonates from feeding on the surface of the fruits. The attraction responses of male and female adult codling moths to butyl hexanoate and codlemone blend; butyl hexanoate (0.025 mg / ml of hexane) and codlemone (0.1 mg / ml of hexane) in a ratio of 1:1 (0.5 ml: 0.5 ml from both solutions) were assessed in a one-choice wind tunnel olfactory bioassay during scoto-phase in the absence of fungal spores. The blend attracted more females (69%) than males (66.7%), however these responses were not significantly different (P > 0.5). The prospect of integrated use of entomopathogenic fungal conidia and semiochemical blend for control of C. pomonella adults was assessed in a wind tunnel containing the combo lure and M. robertsii (MTL151) spores formulated as a powder (250 mg) or aqueous spore suspension (3.1 x 108 spores m-1 ± 7 x 102 sporesml-1). Insect attraction, mean number of spores picked per insect and insect mortality was assessed. No significant difference (P > 0.5) was observed in the number of inoculi picked by unsexed adult moths in the two conidial formulations tested; spore powder (3.1 x 103 ± 1 x 103 spores ml-1) and aqueous spore suspension (3.1 x 103 ± 7 x 102 spores ml-1). No mortality was recorded among fungus or control-treated moths. Both M. robertsii (MTL151) spore formulations did not significantly (P > 0.05) affect the attraction responses of the insects to the combo lure; powder (73.3 ± 3.3%) and aqueous (68.6 ± 2.9%) compared to the control treatment (without the fungal spores) (70 ± 0.5 %). These results suggest that the fungus did not inhibit the attraction of moths by semiochemicals. Despite the successful autoinoculation of moths with fungal spores, the level of contamination was too low to induce mortality among adult moths. This study opens up opportunities for research in attract-and-fungus contamination delivery systems. This is the first report of the occurrence of M. robertsii in the southern Africa. Further, results from this study indicates that C. pomonella is susceptible to indigenous South African entomopathogenic fungi and 2 indigenous M. anisopliae strains, MTL151 and GW461 provided adequate protections against codling moth larval infestations of apple fruits. Future research endeavours to improve adherence of conidia to adult moth cuticle is recommended. Key words: Entomopathogenic fungi (EPF), codling moth, B. pseudobassiana, M. robertsii, larvae, pathogenicity and biological control, coddlemone, butyl hexanoate, attraction, semiochemicals.

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 26, 2007) Includes bibliographical references.