Within-field variation in mortality of Colorado potato beetle, Leptinotarsa decemlineata (Say), in a filter-paper insecticide bioassay was determined in three Virginia potato fields in 1989 and five fields in 1990. Bioassays were performed for each of three different insecticides on Colorado potato beetle larvae collected from 12-16 different locations (equal sized blocks) per field. Comparisons of 95% mortality confidence intervals between all block combinations per field indicated that field size had no influence on variation in Colorado potato beetle mortality in the bioassay. No apparent relationship existed between the level of Colorado potato beetle insecticide susceptibility (LC₉₀ value) and percentage of mortality confidence interval overlap among field blocks. Bioassay data from the sample fields indicated that a single bioassay (of potato beetles from one location per field) will yield at least a 0.50 probability (> 0.90 in six of the eight fields) of estimating the mean mortality response (± 5%) of Colorado potato beetle in the entire field. The probability of sampling potato beetles from one location which differed in mean mortality (P ≤ 0.05) from individuals collected in another location within the same field decreased as the number of locations sampled increased (i.e., the probability is 0.12 if three locations are sampled). Filter paper insecticide bioassays were performed on Colorado potato beetles collected from three commercial potato fields to determine the most cost-effective number of bioassay sample units (filter paper disks, 10 larvae per disk). Relative net precision values from three different insecticide bioassays were used as an indication of sample size efficiency, and were based on variation in larval mortality and sample cost. Greatest sample size efficiency in all insecticide bioassays was achieved from a sample of two to five filter paper disk sample units (20-50 total larvae). Additional insecticide bioassays were performed on Colorado potato beetle larvae collected at different times during the potato growing season (from a commercial potato field and from experiment station plots) to determine whether the larval generation sampled or previous insecticide application affected results of the bioassay. Although trends in mortality were not always consistent among first generation larvae sampled on different dates (from insecticide-treated and untreated plots), first generation larvae exhibited significantly (P ≤0.05) greater mortality in the bioassay compared with second generation larvae. Based on these results, we recommend that bioassays to estimate the effectiveness of a particular insecticide against Colorado potato beetle be performed on the target generation immediately before the planned insecticide treatment. PIES (potato insect expert system) is a knowledge-based system for Colorado potato beetle insecticide management in commercial potato fields on the Eastern Shore of Virginia. PIES was written using VP-Expert, a rule-based expert system shell, and uses Colorado potato beetle lifestage, potato growth stage, percent defoliation, and other factors to decide if an insecticide application is necessary to prevent tuber yield loss due to Colorado potato beetle pressure. Field tests at the Eastern Shore Agricultural Experiment Station compared PIES with conventional spray thresholds based on the number of Colorado potato beetles per stem. Tuber yields were not significantly different (P ≤ 0.05) between the two methods, while PIES recommended, on average, 3.7 insecticide applications and conventional thresholds required six insecticide applications. An additional benefit of PIES is that scouting requirements are simpler and quicker than the conventional stem counts. Supercooling points determined for Colorado potato beetle populations from Maine, Washington, and Prince Edward Island, Canada, suggest these populations are freeze-tolerant, that is, they can sustain ice formation within their body fluids. Colorado potato beetles collected from Virginia supercooled at a significantly (P ≤ 0.05) lower temperature than the other Colorado potato beetle populations. The temperature at which Virginia Colorado potato beetle supercooled is indicative of freeze-sensitive species and may indicate divergence in the mechanisms Colorado potato beetle are using for cold tolerance. Two polyhydric alcohols (polyols) were isolated in the hemolymph of Colorado potato beetle using high performance thin layer chromatography. The polyols were tentatively identified as inositol and xylitol. / Ph. D.

Apple scab is the most important disease of apples in most of the world. The disease, caused by Venturia inaequalis, is controlled by numerous fungicide applications, regardless of the presence of inoculum in the orchard. Better timing of fungicide applications could be achieved if the airborne ascospore concentration (AAC) was considered in decision making. AAC can be measured in real time using spore traps. In this project, the relationship between AAC and lesions development was studied under controlled and natural conditions for five cultivars: Empire, McIntosh, Jonagold, Royal Gala, and Spartan. Potted trees were exposed to different airborne ascospore inoculum and the corresponding AAC were measured using spore traps. The spatial distribution of ascospores was studied in a commercial apple orchard plot. The potential ascospore dose (PAD) and the AAC were measured in 40 quadrats in the spring of 1999. (Abstract shortened by UMI.)

The timing of weed emergence is of major importance for integrated weed management programs. If accurately forecasted, the timing of weed control operations could be optimized, enabling the implementation of more effective control strategies and consequently, the reduction of herbicide use. Little is known about weed emergence in Quebec. Weed emergence in the field results from the breaking of seed dormancy, seed germination and growth of the seedling to the soil surface. The purpose of this study was initially to review the environmental and cultural factors that affect these mechanisms, to determine which factors are mainly responsible for weed emergence in southwestern Quebec and, finally to develop a weed emergence model. This study focused primarily on common lambsquarters (Chenopodium album L.) and barnyardgrass (Echinochloa crus-galli [L.] Beauv.) since they were the most abundant weeds, representing 37 and 22%, respectively, of the total number of annual weeds in the experimental sites. A 3-year study established that the presence of corn did not affect the density and the pattern of emergence of these weeds. A 2-year experiment demonstrated that rainfall and irrigation had no or little influence on the pattern of weed emergence since soil water content was at or greater than field capacity in the spring. In Quebec, temperature was determined to be the most important factor regulating weed germination and emergence, meaning that weed germination is initiated by a minimal temperature in the spring and that this temperature is specific to each species. Thermo-gradient plate experiments established a base temperature for common lambsquarters, redroot pigweed (Amaranthus retroflexus L.), barnyardgrass, and green foxtail (Setaria viridis L.) of 4, 8, 11, 12 +/- 1 C and <3, >16, 12 and 12 +/- 1 C, respectively for seed lots originating from eastern and southwestern Quebec. These results served as a starting point for the calculation of thermal units for the

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Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: One of the most threatening factors to the biodiversity of the Cape Floristic Region is that of invasive alien organisms. A contestant for the most noxious of these fynbos threatening organisms is Hakea sericea. When left to grow uncontrolled, this small Australian tree forms impenetrable stands that out compete the natural vegetation. Due to the threat this plant poses, an extensive and integrated control programme was initiated to reduce its numbers to a level where it can no longer compete successfully with the indigenous flora. This control programme consists of a carefully devised slash and burn method, chemical herbicides and four biological control agents. Little literature surrounding the success of this control programme is available. Two data sets, Fugler (1979) and Protea Atlas Project 2001, recording the distribution and density of the plant at the height of its invasion and twenty two years later are compared to one another using Geographical Information System techniques. Success of control measures is reflected by: (1) a reduction of 340 135 ha in total invaded by H sericea, (2) a reduction in density and (3) shifts in patterns of average rainfall, altitude, slope and aspect of the areas associated with different density categories of this species. These data provide reward for all those involved in the control programme by justifying efforts associated with the control of the invader. Furthermore, the findings of this project also highlight the value of the control programme as well as indicate how future research should be concentrated in order to perfect the programme. / AFRIKAANSE OPSOMMING: Uitheemse indringerplante is een van die enkele belangrikste faktore wat die Kaapse Fynbos biodiversiteit bedreig. In hierdie geval is Hakea sericea een van die mees kompeterende spesies. Hierdie klein Australie boompie ontwikkel, indien ongekontroleerd gelaat, tot 'n ondeurdringbare digte woud wat natuurlikke plantegroei verdring. Dit is weens hierdie faktor dat ekstensiewe en geintegreerde kontroleringsprogramme ontwikkel is om die getalle van bome na die vlakke te verlaag waar dit geen bedreiging vir inheemse flora sal inhou nie. Die kontroleringsprogramme maak onder andere van chemiese onkruiddoders, vier biologiese beheermiddels, ontbossing en beheerde brande gebruik. Min literatuur is beskikbaar oor die sukses wat verkry word met die programme. Twee datastelle elk van Fugler (1979), bevattende data oor digtheid en verspreiding van die plante 22 jaar tevore en die Protea Atlas Projek (2001) word vergelyk met behulp van Geografiese Inligtingstelsel (GIS) tegnieke. Die sukses van die beheer maatreels word weerspieel in: (1) die totale afname van 531 229 ha to 340 135 ha ingedring deur H. sericea, (2) afname in die digtheid en (3) verskuiwing in die algemene reenval-, hoogte-, helling- en liggingspatrone wat geassosieer word met die verskillende digtheidskatogoriee van die spesie. Die resultate bied regverdiging vir die kontroleringsprogramme van indringerplante. Ook beklemtoon die projek die waarde van kontroleringsprogramme en dui aan waarop toekomstige navorsing moet konsentreer om die programme te vervolmaak.

Dissertation (PhD)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: A survey was conducted in the Western Cape Province during the 1999/2000 and 2000/2001 seasons on mealybugs occurring in vineyards. P/anococcus ficus (Signoret) was the dominant mealybug in vineyards during this time. During this study P. ficus was recorded for the first time on roots of grapevines, which has far reaching implications for the control of this important vine leafroll virus vector as control actions were focused on above ground control. Other mealybugs presently recorded in local vineyards included Pseudococcus /ongispinus (Targioni) and Ferrisia ma/vastra (McDaniel). Pseudococcus viburni (Maskell) and Ps. so/ani Ferris were found on weeds in vineyards. Natural enemies of P. ficus recorded most frequently were species of Nephus predatory beetles, and the parasitaids Coccidoxenoides peregrinus (Timberlake), Anagyrus sp. and Leptomastix dacty/opii (Howard). Developmental studies on P. ficus and C. peregrinus indicated that the intrinsic rate of increase (rm) was similar, peaking at 25°C (rm = 0.169 for P. ficus; rm = 0.149 for C. peregrinus). The net replacement rate (Ra) was higher for P. ficus than for C. peregrinus at all five temperatures tested. The Ra for P. ficus reached a maximum at 21°C (308.87) and C. peregrinus at 25°C for C. peregrinus (69.94). The lower and upper thresholds for development of P. ficus were estimated at 16.59 and 35.61°C respectively. The lower threshold for development of C. peregrinus was 8.85°C. These parameters indicated that both insects were well adapted to temperatures in the Western Cape Province. The lower minimum threshold temperature of C. peregrinus in relation to that of P. ficus suggests that C. peregrinus should be more active during winter and early spring than P. ficus. A central systematic presence-absence sampling system was developed for P. ficus. Monitoring three different plant parts on the vine indicated that new growth areas on vines adjacent to the main stem could serve as an early warning system for pending P. ficus bunch infestations. Intervention should be planned when 2 % of the stems are infested with P. ficus when using this system. Seasonal population studies of P. ficus and its natural enemies showed that stem infestation by P. ficus reached peak levels during January in Robertson and Stellenbosch and during February in the Hex River Valley. Vine mealybugs colonised new growth early in the season, followed by the leaves and eventually the bunches towards the end of the season. High stem infestations early in the season resulted in high bunch infestation levels at harvest. A density dependent relationship was evident between P. ficus populations and parasitoid populations, suggesting that the parasitoids played a mayor role in the biological control of P. ficus populations. Biological control was however only achieved towards the end of the season when damage to the crop had already occurred. Mass releases of C. peregrinus on P. ficus populations were done in order to augment biological control as an alternative to chemical control. Between five and six releases of 20 000 C. peregrinus per release were done at monthly intervals in three grapegrowing areas. Mass released C. peregrinus controlled P. ficus adequately in the Hex River Valley. Control of P. ficus using this approach was no worse than using chemical control in Robertson and Stellenbosch. C. peregrinus is commercially available and can therefore be used as an alternative to chemical control by producers. Degree day estimation was used to predict development of P. ficus populations. This information was used as an input in a P. ficus pest management model. Data acquired from P. ficus and ant monitoring were used as components to construct a decision chart. This chart can be used by producers to optimise the control of P. ficus populations using either chemical control or mass releases of C. peregrinus. / AFRIKAANSE OPSOMMING: "n Studie is gedurende die 1999/2000 en 2000/2001 seisoene gedoen met die doelom die witluisspesies wat in wingerde voorkom, te identifiseer. Planococcus ficus (Signoret) is tans die dominante witluisspesie in wingerde in die Wes Kaap Provinsie. P. ficus kolonies is op wingerdwortels gevind. Dié bevinding kan verreikende gevolge hê vir die beheer van dié plaag as "n belangrike rolbladvirus vektor aangesien beheer tot dusver gefokus het op bogrondse gedeeltes. Ander witluisspesies wat in wingerde gevind is, sluit in Pseudococcus /ongispinus (Targioni) en Ferrisia malvastra (McDaniel). Pseudococcus vibumi (Maskell) en Ps. so/ani Ferris is op onkruide in wingerde gevind. Dominante natuurlike vyande van P. ficus sluit predatoriese kewertjies van verskeie Nephus spp. en die parasitoïede Coccidoxenoides peregrinus (Timberlake), Anagyrus sp. en Leptomastix dacty/opii (Howard) in. Ontwikkelingstudies op P. ficus en C. peregrinus het aangetoon dat die inhirente voortplantingstempo (rm) soortgelyk was vir beide insekte met "n maksimum by 25°C (0.169 vir P. ficus, 0.149 vir C. peregrinus). Die netto vervangingstempo (Ra) was in vergelyking met C. peregrinus hoër vir P. ficus by al vyf temperature getoets. Die Ra van P. ficus het "n maksimum bereik teen 21°C (308.87) en die van e. peregrinus by 25°C (69.94). Die teoretiese hoër en laer drempels vir ontwikkeling van P. ficus was onderskeidelik 16.59 en 35.61 oe. Die teoretiese laer drempelwaarde van ontwikkeling vir e. peregrinus was 8.85°e. Hierdie parameters dui aan dat beide insekte goed aangepas is by temperature in die Wes Kaap Provinsie. Die laer minimum drempel vir ontwikkeling van C. peregrinus in verhouding tot P. ficus impliseer dat C. peregrinus in die winter en vroeë lente meer aktief sal wees as P. ficus. 'n Sentrale sistematiese aan-afwesig moniteringsisteem met bekende vlakke van steekproefnemingsfout is ontwikkel in kommersiële wingerde vir P. ficus. Monitering van drie verskillende dele op die wingerdstok het aangedui dat die nuwe groei areas kan dien as 'n vroeë waarskuwing vir latere P. ficus trosinfestasies. Dié sisteem sal produsente in staat stelom te bepaal wanneer optrede noodsaaklik is. Daar word voorgestel dat optrede noodsaaklik is by 'n P. ficus besmettingsvlak van 2 % op die nuwe groei areas op stokke. Stambesmetting deur P. ficus het in Januarie piekvlakke bereik in Stellenbosch en Robertson, en in Februarie in die Hex Rivier Vallei. P. ficus koloniseer nuwe groei vroeg in die seisoen waarna blare en trosse aan die einde van die seisoen gekoloniseer word. Dié data dui aan dat P. ficus besmetting op nuwe groei vroeg in die seisoen 'n aanduiding kan gee van hoë trosbesmetting aan die einde van die seisoen. 'n Digtheidsafhanklike verwantskap was waarneembaar tussen P. ficus plaagpopulasies en parasitoïed populasies. Dié verwantskap dui aan dat parasitoïede die belangrikste rol speel in biologiese beheer van P. ficus populasies. Biologiese beheer van witluis is egter eers aan die einde van die seisoen bereik toe die oes reeds beskadig was. Massavrylatings van C. peregrinus is in P. ficus besmette blokke gedoen om biologiese beheer aan te help en sodoende as alternatief tot chemiese beheer te dien. Tussen vyf en ses vrylatings met 20 000 C. peregrinus is een keer per maand gedurende die seisoen gedoen. Die vrygelate C. peregrinus het P. ficus populasies voldoende beheer in die Hex Rivier Vallei. Beheer van P. ficus deur massavrylatings van C. peregrinus was soortgelyk as chemiese beheer in Robertson en Stellenbosch. C. peregrinus is kommersieel beskikbaar en kan om hierdie rede as alternatief tot chemiese beheer gebruik word. Graaddag bepaling is gebruik om die ontwikkeling van P. ficus populasies te voorspel. Hierdie inligting is gebruik as 'n verdere hulpmiddel in die P. ficus plaagbeheermodel. Inligting verkry vanuit P. ficus en mier monitering is gebruik as komponente in die opstel van 'n besluitnemingstabel. Hierdie tabel kan gebruik word deur produsente om beheer van P. ficus plaagpopulasies te optimaliseer deur chemiese beheer of massavrylatings van C. peregrinus.

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International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / Deutsche Telekom has been operating different flight models for several years. A Satellite Control Center (SCC) was designed and installed to support the operation of the satellite systems DFS Kopernikus and TV-Sat. The DFS Kopernikus system is composed of three flight models and the satellite system TV-Sat has one flight model. The aim was to design an SCC and ground stations in a way, enabling the operation of satellites and groundstations by only two operators at the main control room. The operators are well trained but not scientifically educated. The high integrated SCC supports the operators with a state of the art man-machine-interface. Software executes all necessary tasks for spacecraft- and ground station control. Interaction in front of communication equipment is not necessary. The operation of satellites is a business with a high risk potential. This paper presents the design of a Satellite Control Center with high system availability.

Introdução: Após alguns anos possivelmente ausente do Brasil, o Ae. aegypti, principal transmissor dos vírus da dengue volta a ser encontrado, sendo este fato comprovado no Estado de São Paulo desde 1985. No município de Santos focos de Ae. aegypti foram assinalados em 1980, todavia a sua infestação foi comprovada em 1994 (SUCEN). Os primeiros casos de dengue autóctones (contraídos no município de Santos) emergiram no início de 1997. O objeto de estudo desse trabalho é a dengue no município de Santos e sua transmissão que parece ininterrupta. Objetivo: estudar a ocorrência da dengue no município de Santos no período de 1997 a 2008 em alguns de seus aspectos epidemiológicos, clínicos e vetoriais e possíveis causas da flutuação das epidemias1 consecutivas permeadas por períodos de surtos epidêmicos2. Método: Estudo descritivo com análise comparativa entre os índices de infestação do Aedes com a incidência3 da dengue no mesmo período para avaliar se houve impacto das ações de controle. As variáveis para a análise de incidência serão somente os casos notificados, confirmados e residentes em Santos nos anos de 1997 a 2008, por faixa etária, sexo, ano e mês de ocorrência. Resultados: A incidência acumulada da doença de aproximadamente 84% pode apontar para uma possível diminuição de suscetíveis para os três sorotipos (1, 2 e 3), e o risco de novas epidemias é possível, seja com a introdução do sorotipo 4, onde toda a população é suscetível, aumentando o risco dos casos de dengue hemorrágica, ou epidemias infantis, atingindo em maior número lactantes e crianças até 14 anos, uma vez que a prevalência é menor. Conclusões: O comportamento da incidência da dengue durante esses doze anos consecutivos de autoctonia no município de Santos mostrou como característica principal a ciclotimia, anos epidêmicos intercalados com surtos, possível esgotamento de suscetíveis adultos para cada novo vírus introduzido, e os métodos utilizados no controle da doença mostraram que não foram suficientes, embora legitimamente embasados, faltou a integração das ações, com planejamento, acompanhamento e avaliação / Introduction: After a few years away from possibly Brazil, Ae. aegypti, the main transmitter of the dengue virus is again found, and this was proven in the State of São Paulo since 1985. In the city of Santos foci of Ae. aegypti was reported in 1980, but its infestation was confirmed in 1994 (SUCEN). The first cases of indigenous dengue fever (contracted in the city of Santos) re-emerged in early 1997. The object of this paper is to study dengue in the city of Santos and its transmission that seems unbroken. Objective: To study the incidence of dengue in the city of Santos in the period 1997 to 2008 in some of its epidemiological, clinical and vector and possible causes of fluctuations in consecutive epidemics1 interspersed by periods of epidemic outbreaks2. Method: A descriptive and comparative analysis between the infestation levels of Aedes with the incidence3 of dengue in the same period to assess whether there was impact of control measures. The variables for the incidence analysis will only be notified cases confirmed and living in Santos in 1997 and 2008, by age, sex, year and month of occurrence. Results: The prevalence of the disease approximately 84% can point to a possible reduction of susceptibility to the three serotypes (1, 2 and 3), and the risk of new epidemics are possible, either with the introduction of serotype 4, where the entire population is susceptible, increasing the risk of cases of dengue hemorrhagic fever, epidemic or \"childish\", reaching in many infants and children up to 14 years, since the prevalence is lower. Conclusions: The behavior of the incidence of dengue during these twelve consecutive years of autochthony the city of Santos showed the main characteristic of cyclothymia, interspersed with years epidemic outbreaks, depletion of susceptible adults for each new virus introduced, and the methods used to control the disease showed that there were sufficient, although legitimately grounded, lacked the integration of action, with planning, monitoring and evaluation