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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.
41

Possible Limits to Range Expansion for Non-native Asian Shore Crabs in Maine: A Biogeographic-thermogeographic Approach

Stephenson, Elizabeth January 2007 (has links) (PDF)
No description available.
42

The role of colonisation of soil and wheat roots by Trichoderma koningii in biological control of Gaeumannomyces graminis var. tritici

Dyer, Sonya. January 1998 (has links) (PDF)
Bibliography: leaves 132-185.
43

Metarhizium pathogenesis of mosquito larvae

Greenfield, Bethany Patricia Jane January 2014 (has links)
No description available.
44

Seleção de substratos celulósicos atrativos para o cupim Coptotermes gestroi (Isoptera: Rhinotermitidae)

Lima, Juliana Toledo [UNESP] 23 November 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-11-23Bitstream added on 2014-06-13T21:00:39Z : No. of bitstreams: 1 lima_jt_me_rcla.pdf: 5130482 bytes, checksum: 457a7f5bbb943ed3bd6fdd756c357a36 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A espécie exótica de cupim Coptotermes gestroi (Família Rhinotermitidae) é considerada uma das pragas urbanas economicamente mais importantes no Brasil. O seu hábito críptico limita os estudos sobre sua biologia e comportamento, o que dificulta um controle realmente efetivo. Uma forma de controle biorracional é a tecnologia de iscas, já que leva em consideração o comportamento social desses insetos, além de preservar o meio ambiente. Seu princípio é a transmissão de agentes químicos ou biológicos diretamente para os cupins, visando atingir toda a colônia. A isca é composta por ingredientes ativos incorporados a substratos que contenham celulose. Para que o controle seja mais eficiente, esses substratos devem ser atrativos aos cupins, estimulando o recrutamento e a atividade de alimentação dos indivíduos. Em vista do exposto, a presente pesquisa propôs, por meio de testes laboratoriais e de campo, selecionar substratos celulósicos mais atrativos e adequados à incorporação de ingredientes ativos. Inicialmente foram testados 12 tipos de substratos, e a partir desses, selecionados 4 que foram utilizados nos bioensaios posteriores. O período de duração dos testes laboratoriais foi de 28 dias. Já para os testes de campo foram executados 8 ciclos experimentais, sendo que cada ciclo durou 7 dias. Todos os resultados foram analisados estatisticamente, com nível de significância (á) igual a 0,05. Os resultados obtidos evidenciaram que os substratos mais atrativos para C. gestroi foram papelão corrugado e colmo de milho. Tais fontes celulósicas... / The exotic species of termite Coptotermes gestroi (Family Rhinotermitidae) is considered one of the most important urban pests in Brazil. Its cryptic habit limits the studies about its biology and behavior, what difficult an effective control. A way to perform biorrational control of termites is the bait technology, since it considers the social behavior of these insects beyond preserving the environment. Its principle is the transmission of chemical or biological agents straightly for the termites, aiming to reach the whole colony. The bait is composed by active ingredients incorporated to substrates that contain cellulose. In order to improve the efficiency of the bait control, these substrates must be attractive to the termites, stimulating the recruitment and the feeding activity of the individuals. Based on the presented background, this research proposed, by means of laboratory and field tests, to select cellulosic substrates more attractive and suitable to adding the active ingredients. Initially, twelve types of substrates were tested, and four of them were selected, which had been used in the posterior bioassays. The laboratory tests were processed along 28 days, while the field tests demanded eight experimental cycles, each of them during 7 days. All the results were statistically analyzed, at a significance level (á) of 0.05. The results showed that the most attractive substrates for C. gestroi were corrugated cardboard and corn stem. Such cellulosic sources were clearly more consumed than the other materials; in addition they had recruited a large number of individuals to the baits. Some Abstract 4 factors must be considered in the matrix choice, such as their manipulation and viability to termiticid impregnation, aiming to the contribution for the development of more efficient baits in the termite control.
45

The potential of using insectivorous bats (Microchiroptera) as a means of insect pest control in agricultural areas

Marais, Werner Christiaan 03 June 2010 (has links)
M.Sc. / Members of the Suborder Microchiroptera consume large numbers of insects. When large enough numbers of these bats are present in agricultural areas, the need for insecticides can be reduced significantly. The ZZ2 Tomato Farms in Mooketsi and the Secrabje Farm in Waterpoort, in the Limpopo Province were chosen as study sites. Although ZZ2 focuses on the production of tomatoes, both farms produce a variety of vegetables and fruit. These farms were chosen because the management of both have shown a commitment to conservation and attempt to minimise their impact on the environment. Bat species indigenous to the study areas were captured by means of mist nets for identification purposes. Basic morphological data of captured specimens were collected and recorded. Their roosting behaviour and preferences were studied by visiting diurnal roosts in the two study sites. Microclimatic measurements were taken in roosts occupied by Chaerephon pumilus, Mops condylurus and Taedarida aegyptiaca. Microclimatic measurements were also done in bat houses designed for the housing of bats in agricultural areas. Results suggest that other factors, additional to temperature and relative humidity, contribute to the success and probability of bat house occupancy by bats. Existing roosts in man-made structures such as roofs, can successfully be enhanced to stimulate increase in colony size. Bat activities were determined in agricultural areas and adjacent natural habitats by means of recordings of the echolocation calls of the different bat Families. These were compared to the occurrence of nocturnal flying insect orders that were captured in light traps at the same localities. Of the bat species studied, a positive correlation between increased bat activity and higher number of insects, including pest species, was found. It seems as if the Molossidae has the greatest potential to be utilised in the control of insect pests of agricultural areas in the Limpopo of the bat species studied. A holistic approach favouring insectivorous bats on farms is recommended. This can be done i.a. through the conservation of abundant areas of natural vegetation adjacent to the agricultural areas which would provide foraging for bats during winter, periods of drought or when the lands lie fallow. The excessive and injudicious use of insecticides, which has a negative effect on bats, counteracts the beneficial and cheap alternative of natural insect pest control provided by insectivorous bats.
46

Development of genetic control methods in two lepidopteran species

Rosas Martins, Sara January 2011 (has links)
No description available.
47

Studies on the physical properties of insect bait materials

Portman, Roland Wagner January 1940 (has links)
Typescript, etc.
48

Predation, dispersal and weather in an orchard mite system

Johnson, Dan Lloyd January 1983 (has links)
The history, management and ecology of the European red mite, Panonvchus ulmi Koch, and two important phytoseiid predators, Typhiodromus caudiglans Schuster and Typhiodromus occidentalis Nesbitt were reviewed. The roles and interactions of dispersal, predation and weather in the orchard mite system were examined. Field experiments in an apple orchard with well-established phytoseiid and European red mite (ERM) populations showed that Typhiodromus rarely move among or between trees and the ground cover, either by air or via the trunk. They were incapable, within a single season, of repopulating trees from which phytoseiids had been removed by early-season carbaryl application, even though these trees supported high prey populations and were interspersed among unsprayed trees well-populated with Typhiodromus and the ERM. Large numbers of sticky traps captured very few aerially dispersing phytoseiids. In contrast, their ERM prey actively dispersed within trees and throughout the orchard. Mite densities were uncorrelated with leaf chlorophyll content; within-tree dispersal was not directly determined by leaf condition. Adult females were greatly over-represented in aerially-dispersing ERM emigrants in comparison with populations on the apple trees. No density threshold effect on ERM dispersal was discernible on a per-tree basis. Aerial dispersal was extensive and appeared to depend on the weather more mites disperse on warm and calm days than on cool or windy days. ERM dispersal via the tree trunk was minimal and the presence of weeds resulted in only a slight increase in ERM density on the trees. The phytoseiids affected the ERM by reducing population densities, by reducing the proportion of immatures, and by decreasing the degree of prey aggregation (as represented by frequency distribution of leaf counts). The consequences of low predator dispersal and high prey dispersal in a weather-dependent system are discussed. Results of computer simulation of the development, predation, and dispersal are presented. Dispersal (immigration and emigration) allow the phytoseiid populations in the single-tree model to persist and control the ERM. In simulations of the interaction of Typhlodromus with the ERM, the interaction of dispersal and temperature-related processes is strong and non-linear, and may operate through several processes. / Land and Food Systems, Faculty of / Graduate
49

Evaluation of a forecaster and establishment of action thresholds to begin fungicide applications against cercospora blight of carrot

Abraham, Varghese January 1993 (has links)
No description available.
50

Factors influencing the development of septoria blight in celery

Martinez Granja, Edgar. January 1992 (has links)
No description available.

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