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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Effect of Lygus bugs (Hemiptera: Miridae) on field beans in Manitoba

NAGALINGAM, THARSHINIDEVY 04 1900 (has links)
Lygus lineolaris (Palisot de Beauvois), L. elisus (Van Duzee), L. borealis (Knight) and Adelphocoris lineolatus (Goeze) were the major species of plant bugs present in commercial field bean and soybean fields in 2008–2010. Lygus lineolaris comprised 78–95% of the mirid adults and <10% were A. lineolatus. Lygus lineolaris reproduced in field beans and completed a single generation. In field beans, adults entered the crop in late July, corresponding to growth stages from late vegetative to pod initiation, and females laid eggs in the crop. Nymphs hatched and developed and were most numerous at the seed development and seed filling stage. At seed maturity, late instar nymphs and adults were present. In soybeans, L. lineolaris reproduced but nymphs had poorer survival than in field beans. Late in the season, adult numbers greatly increased in field beans and soybeans, partly due to immigration of adult Lygus bugs from early‐maturing crops. Field beans and soybeans appeared to be a transient host for A. lineolatus. There were no effects on yield quality or quantity associated with the numbers of plant bugs seen in field surveys. In laboratory and field cages, the type of injury from L. lineolaris feeding differed among plant growth stages but not between nymphs and adults, although nymphs generally were more injurious. At flowering to pod initiation, abortion of buds, flowers or pods was the most common response to feeding injury; pod abortion did not occur when injury occurred at later growth stages. Sometimes abortions resulted in reduced yield quantity, but sometimes plants compensated for the injury. No loss of seed quality occurred from feeding at this stage. During seed development and filling, feeding injury most frequently affected the vascular supply to filling seeds, resulting in shriveled seeds and pods at harvest, and consequent reduced total harvested seed weight. At seed maturity, direct seed injury, involving penetration of the testa and loss of cotyledon tissue, was the most frequent injury and resulted in pits in the seed coat at harvest. There was no loss in yield quantity when feeding occurred at seed maturity, but seed pitting reduced yield quality. / May 2016
22

The resistance of sorghum varieties and hybrids to chinch buc Blissus leucopterus (Say)

Sifuentes, Juan Antonio. January 1958 (has links)
Call number: LD2668 .T4 1958 S54
23

The Reduviids and Nabids Associated with Arizona Crops

Werner, Floyd G., Butler, George D., Jr. 12 1900 (has links)
No description available.
24

Predicting NFL Games Using a Seasonal Dynamic Logistic Regression Model

Zimmer, Zachary 01 January 2006 (has links)
The article offers a dynamic approach for predicting the outcomes of NFL games using the NFL games from 2002-2005. A logistic regression model is used to predict the probability that one team defeats another. The parameters of this model are the strengths of the teams and a home field advantage factor. Since it assumed that a team's strength is time dependent, the strength parameters were assigned a seasonal time series process. The best model was selected using all the data from 2002 through the first seven weeks of 2005. The last weeks of 2005 were used for prediction estimates.
25

Ploštice čeledi Acanthosomatidae jako modelová skupina k demonstraci různého rozmnožovacího chování / Shield Bugs (Acanthosomatidae) as a Model Animals for the Demonstration of Various Reproductive Behaviour

Jiskrová, Martina January 2013 (has links)
This thesis deals with parental care of invertebrates. I focus on its types, forms and examples of species in which it occurs. I worked out in more detail the care of the offspring of true bugs (Heteroptera) family Acanthosomatidae and focused on the observation, collection and study of a particular kind Elasmucha grisea in insectarium and nature.
26

Invisible Scourge: What Bed Bugs and Propoxur Can Teach Us About Health and the Urban Environment

Nienaber, Sara 17 June 2014 (has links)
Bed bugs were once considered eliminated from the United States, so recent resurgence of this pest has been cause for concern. Presence of these troublesome insects has resulted in the proposal of controversial policies. For example, the state of Ohio petitioned the EPA for a FIFRA Section 18 emergency exemption to use the insecticide propoxur, a neurotoxin, to treat bed bug infestations in the state. In this thesis, I analyzed public comments for the exemption, task force reports, and media to examine how health and the urban indoor environment are framed in this decision-making process. Though bed bugs carry stigma, those who have them are not overtly blamed for the pest. However, an inability to eliminate them effectively is situated as a lack of personal responsibility. A political ecology of health analysis and healthism are used to understand how narratives of health and personal responsibility justify use of this pesticide.
27

Scanning Electron Microscopic (SEM) Studies on Range Grasses and Their Resistance to Black Grass Bugs

Ling, Yun-Hwa 01 May 1982 (has links)
Large populations o+ black grass bugs, Labops hesperius Uhler, have been observed on extensive acreages o+ range lands. These bugs cause severe damage to the range grasses, lowering their palatability and productivity. This study was to determine whether morphological differences among breeding lines o+ grass species or interspecific hybrids could be correlated with the feeding behavior o+ black grass bugs. I+ so, plant breeders should be able to develop resistant cultivars. To explore this possibility, cultivars and synthetics o+ range grasses, representing the genera, Agropyron, Dactylis, Phalaris and Poa, were exposed to di++erent instar stages was examined under a scanning electron microscope. Leaf pubescence (trichomes) varied in density and size and appeared to be associated with resistance of plants in the genera, Agropyron, to the Labops nymphs (instar stages II and III> but had no relation with the feeding behavior of adult black grass bugs. Plant leaves of the general, Dactylis and Phalaris, were smooth (few and small if any trichomes> and were the least preferred of any of the grasses by all stages of the bugs. Trichomes on leaves of other genera were varied in density and size. Based on percent damage, preference by the nymphs was for the species with intermediate sized trichomes. The adult bugs showed no discrimination in their feeding behavior. Field grown plants developed more trichomes per unit leaf area and appeared to have thicker surface waxes than the same species grown in the greenhouse. For this reason, nymph feeding habits may be different in the field than in the greenhouse. Future studies should perhaps investigate (1) first stage nymph activity on field plants and (2) palatability and/or chemical differences of the grasses.
28

Insect pests of cultivated and wild olives, and some of their natural enemies, in the Eastern Cape, South Africa /

Mkize, Nolwazi. January 2008 (has links)
Thesis (Ph.D. (Zoology & Entomology)) - Rhodes University, 2009.
29

Ecology of Veliidae and Mesoveliidae (Heteroptera: Gerromorpha)in Central Europe / Ecology of Veliidae and Mesoveliidae (Heteroptera: Gerromorpha)in Central Europe

DITRICH, Tomáš January 2010 (has links)
Ecology of Veliidae and Mesoveliidae (Hemiptera: Heteroptera: Gerromorpha) was studied in selected European species. The research of these non-gerrid semiaquatic bugs was especially focused on voltinism, overwintering with physiological consequences and wing polymorphism with dispersal pattern. Hypotheses based on data from field surveys were tested by laboratory, mesocosm and field experiments. New data on life history traits and their ecophysiological consequences are discussed in seven original research papers (four published journal papers, two submitted papers and one communication in conference proceedings), creating core of this thesis.
30

Life History of the Common Bed Bug Cimex lectularius L. in the U.S.

Polanco, Andrea M. 15 April 2011 (has links)
This study quantifies the rate of bed bug nymphal development, mortality, fecundity and survivorship during starvation for wild caught resistant populations. I then compare some of these characteristics with two susceptible strains. I found that resistant populations develop faster and exhibit less mortality per life stage than susceptible populations. However, there were no significant differences in the total number of eggs produced by the resistant females from the field strains during the 13 feedings/oviposistion cycles (P = 0.106). On average, resistant females from the field strains produced 0.74 eggs per day. Susceptible strains survived a significantly longer time without feeding (89.2 d and 81.4 d) than the resistant strains (RR, ER). The mean duration of adult life (from the day the female becomes an adult until the day she dies) for (RR) strains was 118.7 d ° 11.8 SE. The intrinsic rate of increase r or average daily output of daughter eggs by female was 0.42. The net reproductive rate Rₒ, indicated that one live female egg would, on the average, be replaced by approximately 35 females. Resistant and susceptible populations were found to be different in terms of development, survivorship, and fecundity. The differences between susceptible and resistant strains could be explained by a trade-off between the alleles that confer resistance and the fitness in the population. When compare the stable age distribution of a pyrethroid susceptible strain (HS) and a resistant strain (RR) there were not significant differences (?°= 9.0066, df = 6, P = 0.1732) in the stable age distribution, basically both strains were dominated by the egg stage. No significant difference was found in the expected reproductive contribution of the various life stages to future population size between the two strains (?°= 1.5458, df = 6, P = 0.9564). Despite this, the reproductive contributions of life stages other than eggs were generally higher for the HS strain than for the RR strain. For both strains changes in P? for the adult stage are expected to have the greatest impact on?? compared with changes in P? for the other life stages. The key to the reduction of the populations of bed bugs lies with the reduction of survival of the adults. / Master of Science in Life Sciences

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