SIMULATION MODEL OF EUROPEAN RED MITE POPULATION DYNAMICS DEVELOPED FOR A MINI-COMPUTER

1979 ◽  
Vol 111 (4) ◽  
pp. 499-507 ◽  
Author(s):  
D. C. Herne ◽  
C. T. Lund
Keyword(s):  
Population Dynamics ◽  
Simulation Model ◽  
Control Strategies ◽  
Panonychus Ulmi ◽  
Factors Affecting ◽  
European Red Mite ◽  
Dynamics And Control ◽  
Population Component ◽  
Normal Probability Distribution ◽  
Log Normal

AbstractA simulation model is described for the population dynamics of the European red mite, Panonychus ulmi (Koch). The model incorporates the following features: (a) development rate is dependent on effective daily temperature; (b) division of each population component into distinct daily age classes; (c) emergence of individuals from each population component is dependent on a log-normal probability distribution, and a temperature related development vector to accumulate a measure of the temperature effect on development. Validation runs on a mini-computer in 1976 and 1977 adequately described actual population curves determined from daily orchard sampling. A model of this type which can be used with small computers should prove useful in investigating the main factors affecting the population dynamics, and control strategies for this and other pests.

Factors Affecting Spotted Knapweed (Centaurea stoebe) Seedling Survival Rates

2013 ◽  
Vol 6 (4) ◽  
pp. 568-576 ◽  
Author(s):  
Anastasia P. Maines ◽  
David G. Knochel ◽  
Timothy R. Seastedt
Keyword(s):  
Population Dynamics ◽  
Seedling Survival ◽  
Control Strategies ◽  
Plant Competition ◽  
Survival Rates ◽  
Field Studies ◽  
Spotted Knapweed ◽  
Factors Affecting ◽  
Precipitation Regimes ◽  
Wide Range

AbstractPredicting site vulnerability to nonnative plant establishment remains a difficult goal. Seedling survival is an important component of population dynamics and can affect the success of control strategies. Field manipulations allow potential causal mechanisms of site vulnerability to be evaluated under realistic environmental conditions. We conducted field studies to determine the effects of plant competition and differing precipitation regimes on spotted knapweed seedling survival. We also examined the effect of herbivory on rosette survival and growth. Seeds were sown into plots with vegetation intact or removed at three sites. Seeds were also sown into plots where plant competition and precipitation were manipulated in a factorial design at a single site. Field studies demonstrated that site accounted for much of the variation in emergence rate, while herbivory and plant competition affected seedling survival rates. We observed a wide range in emergence rates, with site averages ranging from 13.1 to 42.5%. Survival the following year ranged from 0.5 to 9.4% of sown seeds. Rosette survival was significantly higher when herbivores were excluded from plots. Below average precipitation reduced seedling survival; however, even with supplemental water, dry-down of exposed sites resulted in low seedling survival. Of the 8,000 seeds added to plots in one study, by autumn, only eight plants resulted, seven of which survived in watered plots with intact vegetation. Collectively, these results show that seedling survival is a critical phase in spotted knapweed population dynamics and can vary among habitats on the basis of plant competition and precipitation. Furthermore, herbivory affects all stages of the lifecycle from the seedling onward. The observed differences help explain the reported variability in seedling survival in the literature and inform efforts to control spotted knapweed using plant competition and biological controls.

Research on springback characteristic in flexible multi-points 3D stretch-bending process

2021 ◽  
pp. 095440542110284
Author(s):  
Song Gao ◽  
Tonggui He ◽  
Qihan Li ◽  
Yingli Sun ◽  
Jicai Liang
Keyword(s):  
Simulation Model ◽  
High Efficiency ◽  
Vertical Direction ◽  
Factors Affecting ◽  
Stretch Bending ◽  
Element Simulation ◽  
Bending Process ◽  
Bending Radius ◽  
Aluminum Profiles ◽  
Bending Sequence

The problem of springback is one of the most significant factors affecting the forming accuracy for aluminum 3D stretch-bending parts. In order to achieve high-efficiency and high-quality forming of such kind of structural components, the springback behaviors of the AA6082 aluminum profiles are investigated based on the flexible multi-points 3D stretch-bending process (3D FSB). Firstly, a finite element simulation model for the 3D FSB process was developed to analyze the forming procedure and the springback procedure. The forming experiments were carried out for the rectangle-section profile to verify the effectiveness of the simulation model. Secondly, the influence of tension on springback was studied, which include the pre-stretching and the post-stretching. Furthermore, the influences of the bending radius and bending sequence are revealed. The results show that: (1) The numerical model can be used to evaluate the effects of bending radius and process parameters on springback in the 3D FSB process effectively. (2) The pre-stretching has little effect on the horizontal springback reduction, but it plays a prominent role in reducing the springback in the vertical direction. (3) The increase of bending deformation in any direction will lead to an increase of springback in its direction and reduce the springback in the other direction. Besides, it reduces the relative error in both directions simultaneously. This research established a foundation to achieve the precise forming of the 3D stretch-bending parts with closed symmetrical cross-section.

Simulating the impact of four control strategies on the population dynamics of Neospora caninum infection in Swiss dairy cattle

2006 ◽  
Vol 77 (3-4) ◽  
pp. 254-283 ◽  
Author(s):  
Barbara Häsler ◽  
Katharina D.C. Stärk ◽  
Heinz Sager ◽  
Bruno Gottstein ◽  
Martin Reist
Keyword(s):  
Population Dynamics ◽  
Dairy Cattle ◽  
Neospora Caninum ◽  
Control Strategies ◽  
Caninum Infection ◽  
The Impact

scholarly journals Pathogenicity of Isaria fumosorosea to European red mite in the laboratory

Biotemas ◽  
2017 ◽  
Vol 30 (1) ◽  
pp. 73
Author(s):  
Cláudia Andréia Gräff ◽  
Liana Johann ◽  
Cláucia Fernanda Volken de Souza ◽  
Noeli Juarez Ferla
Keyword(s):  
Rio Grande ◽  
Panonychus Ulmi ◽  
Rio Grande Do Sul ◽  
Isaria Fumosorosea ◽  
European Red Mite

http://dx.doi.org/10.5007/2175-7925.2017v30n1p73A vitivinicultura no estado do Rio Grande do Sul tem sofrido infestações significativas de ácaros praga, destacando-se recentemente Panonychus ulmi (Koch). Há relatos sobre a capacidade de controle de ácaros fitófagos com Isaria fumosorosea. O objetivo deste trabalho foi avaliar em laboratório a ação patogênica de I. fumosorosea sobre o ácaro P. ulmi. As criações de P. ulmi foram estabelecidas a partir de coleta realizadas em videiras da Serra Gaúcha. Sobre os ovos de P. ulmi, as aplicações de suspensões de esporos foram feitas em diferentes concentrações. As triplicatas das fêmeas de 12 a 15 dias foram tratadas com suspensão a 108 esporos x mL-1. As testemunhas foram tratadas com água destilada. Após sete dias da aplicação, observaram-se 55,6% de ovos não eclodidos tratados com suspensão 106 esporos x mL-1 e com fêmeas tratadas obteve-se uma mortalidade total entre 85-90% e mortalidade confirmada entre 50-55%. A mortalidade máxima dos controles no tratamento dos ovos e das fêmeas foi, em média, de 12,8 e 15,5%, respectivamente. Conclui-se que o isolado I. fumosorosea possui habilidade para infectar ovos e fêmeas adultas de P. ulmi e portanto mostra-se como uma alternativa viável para ser experimentada no campo.

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