• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 15
  • 11
  • 8
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 47
  • 47
  • 20
  • 12
  • 11
  • 11
  • 10
  • 10
  • 10
  • 10
  • 7
  • 6
  • 6
  • 5
  • 5
  • 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.
11

Control of Early Woolly Whiteflies Infestations with Foliar Insecticides

Kerns, David L. January 2003 (has links)
Five foliar insecticide treatments (Esteem, Provado, Applaud, Assail, and Danitol + Lorsban) were evaluated for their control of early woolly whitefly infestations in lemons. Esteem and Applaud are insect growth regulators that should have little impact on whitefly parasitoids. The impact of Provado and Assail on whitefly parasitoids is not certain, but at high rates may be detrimental, while Danitol + Lorsban will be especially harmful to parasitoids. The impact of these insecticides on woolly whitefly could not be fully determined in this trial due to the effectiveness of parasitoids, Eretmocerus comperei or E. dozieri (exact species not certain), on controlling the whiteflies in this test. However, other research (not reported here) has indicated that all of the insecticide treatments evaluated have good activity against woolly whitefly. Because parasitoids can be extremely effective in mitigating woolly whiteflies populations during the early phases of colonization, it is recommended that chemical control not be utilized until woolly whitefly colonies are common. However, previous experiences suggest that allowing woolly whitefly populations develop extremely high populations should be avoided.
12

Assessing the Risk of Insecticide Resistance in Citrus Thrips in Arizona

Kerns, David L. January 2004 (has links)
Bioassay with Dimethoate, Carzol, Danitol, Baythroid and Success were conducted on citrus thrips collected from the Yuma Mesa to determine if insecticide resistance to these insecticides occurred. Low to moderate levels of resistance were detected for Dimethoate, Carzol and Danitol, and one population exhibited a high level of resistance to Baythroid. No resistance was evident for Success. Susceptibility to Success was much higher for the Yuma populations relative to populations previously reported in California.
13

Integrated Pest Management of Citrus Mealybug

Kerns, David L. January 2004 (has links)
Foliar-applied insecticides and the soil-applied insecticide, Admire, were evaluated for their ability to control citrus mealybug on lemons while having a minimal impact on parasitoids. All of the foliar-applied insecticide exhibited activity towards citrus mealybug. The standard insecticide, Lorsban, performed very well, but since this product is especially harmful to parasitoids it is not considered to have a good fit in IPM programs where parasitoid conservation is emphasized. The currently labeled alternative, Applaud, was an effective treatment and should be considered for citrus mealybug control to avoid destruction of parasitoids. Several experimental insecticides showed promise: NNI-850, NNI-750C and NNI-010. However, NNI-0101 at the lower rate of 0.24 lbs-ai/ac appeared to be weak. The addition of narrow range crop oil, NR-415 at 1.0 gal/ac, appeared to be beneficial for initial mealybug knock-down, especially for the slower acting insecticides such as Applaud. Soil injection of Admire at 16 and 32 oz/ac appeared to have very good activity, but due to variability in the mealybug population, more data should be collected to confirm this finding.
14

Using Feeding Stimulants to Increase Insecticidal Control of Citrus Thrips

Kerns, David L. January 2004 (has links)
Carzol and Success with and without the addition of the feeding stimulants molasses and bee-collected pollen were evaluated for their control of citrus thrips on lemons on the Yuma Mesa. Although normal use rate of Carzol and Success were efficacious toward citrus thrips, the addition of either molasses or pollen to these insecticides as a means of increasing efficacy at low rates was not encouraging. At no point did the feeding stimulants appear to increase the efficacy of the same rate of Carzol when used alone, and it appeared that the additives may have actually decreased the efficacy of Success.
15

Chemical Control and Integrated Pest Management of Woolly Whitefly

Kerns, David L. January 2004 (has links)
Five foliar insecticide treatments (Esteem, two rates of Provado, two rates of Applaud, Prev-am, and Danitol + Lorsban) were evaluated for their control of woolly whitefly infestations in grapefruit. All of these products demonstrated efficacy in mitigating woolly whitefly populations. Danitol + Lorsban was the best knock-down treatment evaluated, but for sustained control, Esteem appeared to be most effective. Applaud demonstrated good activity, but the rate we tested may be a little low; the 1.0 lb/ac rate should be evaluated. Provado at 19 oz/ac was a good treatment, while the 10 oz/ac rate appears to be sub-par. Prev-am is a oil based contact material and demonstrated good initial activity. Soil injections of 16 and 32 oz/ac of Admire were very effective against WWF, and there were no detectable differences between the two rates. Previous experiments with soil injections of Admire in citrus suggested that as much as six weeks needs to pass before the trees have enough time to adequately take up the Admire from the soil. However, these data suggest that smaller trees, about 10 ft tall, may require as little as two weeks to pick up the material.
16

Web-based IPM Resources for Arizona's Citrus Growers Final Report

Jones, Jennifer S., Kerns, David L., Matheron, Michael E., McCloskey, William B., Fournier, Al January 2004 (has links)
We proposed creating a user-friendly web site that would provide independent, research-based, integrated pest management information to Arizona’s citrus growers and PCAs. This citrus IPM website, located at http://cals.arizona.edu/crops/citrus/ was created and integrated within an existing web site, the Arizona Crop Information Site (ACIS) http://cals.arizona.edu/crops. The Citrus IPM web site was launched on April 15, 2004.
17

Chemical Control and Integrated Pest Management of Woolly Whitefly

Kerns, David L. 10 1900 (has links)
Eight foliar insecticide treatment regimes (single applications of Esteem, Danitol + Lorsban, Applaud, Provado and Prev-am, and two applications of Applaud, Provado, and Prev-Am) were evaluated for management of woolly whitefly infestations in grapefruit. All of these products demonstrated efficacy in mitigating woolly whitefly populations. Danitol + Lorsban appeared to be the best knock-down treatment evaluated, but Provado and Prev-Am also demonstrated good activity. For sustained control, all of the treatments were effective; however, Prev-Am required an additional application to achieve equivalent control. Soil injections of 16 and 32 fl-oz/ac of Admire were very effective against WWF, and there were no detectable differences between the two rates. The Admire appeared to require about 27 days after injection to demonstrate consistent activity.
18

The optimal control of dynamic pest populations

Hackett, Sean January 2018 (has links)
In the management of agricultural insect pests, short-term costs must be balanced against long-term benefits. Controls should be selected to account for both their immediate and downstream effects upon the demography and genetics of the pest, enabling suppression today without threatening suppression tomorrow. The iterative, algorithmic method of dynamic programming can provide optimal solutions to problems of this type, in which actions are taken sequentially and each action may influence those which follow it. However, this approach is fundamentally constrained with regards to the magnitude of the problems it may solve. As questions of insect pest management can be subject to ecological and evolutionary complexities, this may place them beyond the scope of dynamic programming. When it is the intricacies of a problem that are of interest, it may be more productive to utilise approximate dynamic programming (ADP) methods which can attempt problems of arbitrary complexity, although at the expense of no longer guaranteeing optimality. In this thesis I first challenge a dynamic programming algorithm with the management of a hypothetical insect pest feeding upon a transgenic insecticidal crop. The model explores how different realisations of fitness costs to resistance influence the algorithms suggested actions. I then apply a brute-force variant of ADP, a lookahead policy, to the management of a stage-structured, continuously reproducing pest population. This was to explore the extent to which an algorithm with a limited temporal perspective is able to balance the timetable of pest demography against the timescale over which insecticidal sprays and bisex-lethal sterile insect releases unfold. This same decision framework is then applied to a modified problem in which resistance to insecticidal toxins may evolve and releases are now male-selecting. This was used to assess the efficacy with which simple lookahead policies utilise a control with delayed benefits (the male-selecting releases) and possible constraints on their capacity to respond to resistance evolution. Dynamic programming and ADP methods offer a versatile toolbox for accounting for the potential impacts of the evolutionary and ecological peculiarities of particular pests upon control decisions.
19

Distribuição espacial de posturas e ninfas de quesada gigas (olivier, 1790) (hemiptera : cicadidae) na cultura do cafeeiro /

Pereira, Nirélcio Aparecido. January 2017 (has links)
Orientador: Nilza Maria Martinelli / Resumo: A cigarra da espécie Quesada gigas é considerada praga-chave na cultura do café, principalmente nos Estados de São Paulo e Minas Gerais. Atualmente, essa espécie de cigarra é a principal e a mais prejudicial ao cafeeiro. O objetivo trabalho foi determinar a distribuição espacial de posturas e ninfas de Q. gigas em três talhões de café com histórico de infestação. O experimento foi realizado utilizando as cultivares Mundo Novo, Icatu 2939 e Icatu 2944, com idades de trinta, dezessete e quinze anos, respectivamente, pertencente à Fazenda São Judas Thadeu, localizada no município de São Sebastião do Paraíso-MG. O espaçamento entre as plantas foi de 4,0 x 1,0 m entrelinhas e na linha respectivamente, totalizando cada talhão 10.000 m2. Os talhões foram divididos em 100 parcelas de 10 x 10 m, e uma planta por parcela foi marcada com o auxílio de GPS (Global Positioning System). Foram coletados quinzenalmente três ramos secos do terço superior da planta marcada com aproximadamente 20 cm, totalizando 300 ramos por talhão, nos meses de outubro, novembro e dezembro de 2014 e outubro e novembro de 2015. Esses ramos para a avaliaç foram acondicionados em saco de papel e levados ao Departamento de Fitossanidade da UNESP/FCAV. Para o estudo de ninfas foi realizado através da abertura de trincheiras realizadas no período de dezembro de 2015. A abertura de trincheira com dimensões de 0,50 x 0,50 x 0,50m, foram realizadas a partir da base do tronco e as ninfas coletadas foram acondicionadas e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Quesada gigas cicada is considered a key pest in coffee growing, mainly in the States of São Paulo and Minas Gerais. Currently, these cicadas are the main and most damaging species to coffee and mainly infest the planting of these two States. The objective was to characterize the spatial distribution of Q. gigas postures and nymphs in the coffee crop. The experiment was carried out using the cultivars Mundo Novo, Icatu 2939 and Icatu 2944, aged thirty, seventeen and fifteen, respectively, belonging to Fazenda São Judas Thadeu, located in the municipality of São Sebastião do Paraíso-MG. The spacing between the plants was 4.0 x 1.0 m between lines and in the line respectively, totalizing each field 10,000 m2. The plots were divided into 100 plots of 10 x 10 m, and one plot per plot was marked with the aid of GPS (Global Positioning System). Three dry branches were collected biweekly from the upper third of the plant with approximately 20 cm, totaling 300 branches per plot, between October, November, and December 2014 and in the year 2015. These branches were packed in paper bags and taken To the Phytosanitary Department of FCAV / UNESP. For the study of nymphs was carried out through the opening of trenches held in the period of December 2015. The trench opening with dimensions of 0.50 x 0.50 x 0.50m, were carried out from the base of the trunk and the nymphs Were collected in glass containers with 70% alcohol solution for later counting. The identification of the nymphal i... (Complete abstract click electronic access below) / Doutor
20

Improving attractiveness of an insect pest through value-addition : A possible insect management strategy

Shadung, Kagiso Given January 2012 (has links)
Thesis (M.Sc. (Plant Protection)) --University of Limpopo, 2012 / Attractiveness of insect pest for use as sources of food may be improved by providing information on preservation and relevant nutritional value. Nutritional composition in edible insects may depend on drying method and/or vegetation (location). Influence of drying method and location on nutritional composition of the African metallic wood boring beetle (Sternocera orissa), widely consumed in certain rural communities of Limpopo Province, South Africa, was investigated. Randomised complete block design in a 3 x 3 factorial arrangement was used with three drying methods (oven-drying, freeze drying, cooking method) and three locations (Khureng, Magatle, Ga-Masemola), with three replicates. Nutritional composition data were subjected to a two-way analysis of variance (ANOVA) and means were separated using Turkey Honestly Significant Differences (HSD) at 5 % level of significance. Relative to freeze-drying, oven-drying and cooking methods increased protein, carbohydrates, fat, energy, ash and dry matter content with the exception of cooking method, which decreased the moisture content. Compared to other locations, Ga-Masemola significantly increased fat and energy of the test beetle. Relative to the freeze-drying method, oven-drying and cooking increased (P ≤ 0.05) essential and non-essential amino acids. Location did not have significant effect on the essential and non-essential amino acids of S. orissa across all the villages. Similarly, oven-drying and cooking increased K, P, Fe, Zn and Mg. Compared to locations, Ga-Masemola increased (P ≤ 0.05) Fe of the test beetle. Results of the study suggested that oven-drying and cooking methods improved the nutritional composition of S. orissa, which has the potential of enhancing nutrition in marginal rural communities of Limpopo Province. Providing results of this study to rural communities through extension services has the potential of improving the attractiveness of this beetle to marginal communities, and thus, increasing harvesting and therefore, reduce insects population densities. / the Technology Innovation Agency (TIA) and the National Research Foundation

Page generated in 0.049 seconds