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The use of heartbeat as a potential screening technique for insect patholgesWare, Mildred G. 03 June 2011 (has links)
Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.
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The use of autoradiography in the indentification of selected bacteria in the European corn borerWarn, Beverly Jean 03 June 2011 (has links)
AbstractScientists trying to find biological controls for insect pests are hamperedd by the absence of rapid methods for screening organisms such as bacteria for potential pathogenicity. An organism must grow in the gut of the insect to be pathogenic. By using radioisotopes as tracers a quick method of screening potential insect pathogens may be developed.Escherichia coli and Sarcina flava were used as known nonpathogens and Bacillus thuringiensis was used as a known pathogen. In this work an attempt was made to verify the presence of bacteria in specific tissues of the insects.European corn borer larvae were fed 1-C14 palmitic acid and labeled E. coli, S. flava and B. thuringiensis. Parasaggital sections were made of the corn borers and radioautograms were made of the sections. Grain counts over a 2,000 u2 area were made of various tissues and compared.There was a statistically significant difference in the distribution of label in corn borer larvae fed labeled bacteria as compared to corn borers fed 1-C14 palmitic acid. Label tended to incorporate into fatty tissue in the corn borers.If this technique can be used to positively demonstrate the establishment of selected bacteria in the gut of the insect then it may be possible to use such methods to screen for potential insect pathogens and give insight into the mechanisms which result in the death of insects.Ball State UniversityMuncie, IN 47306
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Stink bugs on grain sorghum in Mississippi ecological relationships with host plants and crop planting dates and crop damage /Parada Jaco, Mario Ernesto, January 2007 (has links)
Thesis (Ph.D.)--Mississippi State University. Department of Entomology and Plant Pathology. / Title from title screen. Includes bibliographical references.
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Occurrence of diseases and insect pests in select soybean (Glycine max (L.) Merr.) and sorghum (Sorghum bicolor (L.) Moench) rotations in MississippiPichardo, Sergio Tomás, January 2007 (has links)
Thesis (Ph.D.)--Mississippi State University. Department of Entomology and Plant Pathology. / Title from title screen. Includes bibliographical references.
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Ecological interaction among natural enemies and its consequences for biological control /Chang, Gary C. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 121-139).
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Olfactory response of Lygus hesperus Knight to chemicals naturally found in alfalfaZaugg, Jerry Lynn, 1942- January 1971 (has links)
No description available.
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THE OPTIMAL CONTROL OF LYGUS HESPERUS ON COTTONWatson, Fred Lee, 1941- January 1973 (has links)
No description available.
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Control Garden PestsTate, Harvey F., Roney, J. N. 01 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
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Impact of insect growth regulators on non-target species, with an emphasis on Coccinellids on citrus, in Swaziland.Magagula, Cebisile N. N. 23 December 2013 (has links)
This study investigated effects of insect growth regulators (IGRs), recommended for use on
citrus in southern Africa, on non-target organisms, particularly species of Coccinellidae in and
around three citrus estates in the lowveld region of Swaziland, i.e. Tambuti, Tambankulu and
Tunzini estates. Some of the species are important predators of citrus pest insects. The
distribution of coccinellids within an agricultural land mosaic and factors affecting this
distribution pattern were also investigated. Results showed that coccinellid densities and
species diversity were lowest in the natural veld surrounding the orchards. In contrast, citrus
orchards had the highest coccinellid densities and diversity. River borders, along the Great
Usuthu river, had intermediate densities and diversity. While temperature, relative humidity and
ground insolation had no significant effect on coccinellid population densities, the presence /
absence of prey (host plant), on the other hand, was an important factor. This was the case
both for phytophagous and predatory coccinellid species. These showed close patterns of
distribution with their respective host plants or prey species. Economically important species,
such as Rodolia spp., were restricted to the orchards, while other species, especially those
whose economic role is uncertain, such as Cheilomenes lunata and Scymnus spp., were found
in most habitat types.
Coccinellid population densities were assessed during four treatment programmes: 1) an
integrated pest management (IPM) programme where no IGRs were used, 2) a programme
where any of the recommended IGRs were to be applied, 3) conventional pesticide
programme, and 4) an orchard which did not receive any chemically treatment over the last
four years (at Tambankulu estate only). Significant differences between treatment programmes
were observed at all three estates, when only economically important coccinellid species were
assessed. Orchards under an IPM programme (with no IGRs) were found to have significantly
higher population densities compared to those in IGR-treated or under a conventional pesticide
regime. The untreated orchard at Tambankulu, however, had significantly higher coccinellid
densities of economically important species and higher overall population densities than any
of the managed orchards. Of the three estates assessed, Tunzini had significantly higher
population densities of all beneficial coccinellids, (excluding the untreated orchard at Tambankulu). Natural vegetation around Tunzini and Tambuti contributed to the higher
coccinellid densities compared to Tambankulu, which was surrounded by other agricultural
land.
Laboratory and field experiments on two non-target species, the ladybird Chilocorus nigritus
(Fabricius) (all stages) and the moth Bombyx mori (Linnaeus) (larval stage) assessed specific
IGR effects, if any. Three IGRs, buprofezin, teflubenzuron (both chitin synthesis inhibitors) and
pyriproxyfen (a juvenile hormone analogue) were used. All three pesticides are currently
recommended for use on citrus in southern Africa and were tested at the recommended
dosages. Laboratory experiments showed that all three IGRs have a negative impact on both
non-target species. When B. mori received direct applications, there was larval mortality as a
result of the failing to complete moulting or dying immediately after moulting. In addition, no
larvae were able to pupate after having fed on contaminated leaves. In the case of C. nigritus,
larvae fed IGR-treated scale or sprayed with buprofezin suffered significantly higher mortality
than controls, while IGR effects on those sprayed with, or fed scale-treated with, pyriproxyfen
or teflubenzuron were not significant. No adults however, emerged from any pupae in any of
the treatment groups. All three IGRs had ovicidal activity on C.nigritus eggs. Adult fecundity
in both field and laboratory experiments was not affected significantly after exposure to any
of the three IGRs. In field experiments, the proportion of larvae of the moth and ladybird that
developed up to the reproductive adult stage, after exposure to buprofezin, was not
significantly different from the control. This was not the case for pyriproxyfen and
teflubenzuron. Buprofezin was therefore found to be the least detrimental of the three IGRs
tested.
Minimal drift was observed when a knapsack sprayer was used. However, there was spray drift
up to 32m (the furthest distance assessed here) where commercial sprayers were used. This
suggests that pesticide drift from orchards to adjacent areas would have serious implications
for biological diversity in the river borders and rivers adjacent to the estates. The sensitivity
of the non-target species to the IGRs tested needs serious consideration, as it indicates a
broader spectrum of activity for the compounds than what is promoted. Additionally, natural
control may be affected. This is because the timing of IGR applications and increasing coccinellid populations coincide, resulting in a reduced pool of coccinellid predators.
This study emphasised the importance of an appropriately heterogenous landscape to maximise
habitat availability for the coccinellids. Although the economic role of the multihabitat
coccinellid species recorded here is unknown, they nevertheless clearly contribute to citrus pest
control. Such a mosaic landscape, in conjunction with IPM, with no IGR use, promotes
ecological diversity and controls pests with minimum disruption to biodiversity. The use of
IGRs in citrus thus needs carefiil reconsideration in light of the non-target effects observed on
the two species, especially the valuable predatory species, C. nigritus. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1998.
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Antixenosis and antibiosis as resistance mechanisms of South African sugarcane varieties against early instar larvae of Eldana saccharina Walker (Lepidoptera: Pyralidae)Mabulu, Linda Yolanda. 13 December 2013 (has links)
The complexity of the behaviour of neonate Eldana saccharina Walker
(Lepidoptera: Pyralidae) larvae and the limited information on their response to the morphological characteristics of South African sugarcane varieties was the primary justification to study antixenotic/antibiotic effects on larval behaviour. Laboratory experiments were conducted with stalk segments in plastic jars inoculated with larvae and in a metal cage covered with gauze. In jars, the larvae were observed until they penetrated the stalks. After 14 days, the stalks were dissected and larvae weighed. In all
varieties, larvae moved directly to the node after inoculation and penetrated the stalk through leaf scars and buds. No significant differences in larval mass were observed among varieties. In cage experiments different parts of the node, namely the rind below the wax band; the bud; and the root primordia were tested. There was a clear indication that rind hardness and the budscale properties are associated with varietal resistance and only affect early instars. The experiments were repeated using whole cane plants in a glasshouse. The results were similar to those of laboratory experiments. In the Insect Rearing Unit, scraped waxes from different varieties were incorporated into the diet. Larval masses from different diets showed significant differences among varieties, but they did not conform to the known resistance ratings, as cane varieties N12 and N21 showed high susceptibility, instead of resistance. Dispersal behaviour of neonates shortly after hatching was investigated in 'mobility experiments' conducted on live cane plants. Mobility is important because the more time neonates spend wandering around on the stalk surface or on exposed parts of the plant, the more vulnerable they are to predation and other adverse factors that may reduce their survival. Experiments to test stalk penetration by larvae on the node showed that neonates required a softer food source before attacking the hard nodal parts. Second
and third instar larvae were used subsequently to the mortality of all neonates fed on the rind, which in turn resulted in non-significant differences, suggesting that feeding on debris and/or leaves is critical to the survival and penetration of larvae into the sugarcane stalk.
Incorporation of the characteristics tested in these experiments aims to reduce the number of larvae that penetrate the stalk and to expose them for longer on the surface where their numbers may be controlled by predators and insecticides. The resistant varieties used in these experiments have high fibre and less sugar, but newer varieties, such as N29 and N33 incorporate both high resistance and high sucrose yield, which are the two key elements for optimised sugar production. Chemical characteristics of the plants need to be taken into consideration as high sucrose is seldom found in fibrous varieties. Leaf sheath tightness is another characteristic that would go well with leaf sheath hairiness, because though not tested in this work-would make it difficult for the
larvae to get to the smooth adaxial surface of the leaf. The hardness of trichomes is another feature that needs to be investigated, because a variety may have dense, but soft pubescence that does not repel even the most sensitive larvae, neonates. At present, integrating plant resistance with cultural control, i.e. field hygiene etc. is cost-beneficial for the sugar industry. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.
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