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Rodriguez D.,University Militar Nueva Granada | Cure J.R.,University Militar Nueva Granada | Cotes J.M.,National University of Colombia | Gutierrez A.P.,Center for the Analysis of Sustainable Agricultural Systems Global | And 2 more authors.
Ecological Modelling | Year: 2011

This paper is the first of three on the coffee production system consisting of (1) the coffee plant, (2) coffee berry borer (CBB) and (3) the role of CBB parasitoids. A previous simulation model of the coffee plant was developed using data from Brazil where coffee phenology is characterized by distinct seasonal flowering (Gutierrez et al., 1998). In contrast, flowering in Colombia is continuous with low seasonality. To capture the differences in coffee phenology and growth in the two climatic regions, the Gutierrez et al. (1998) model was modified using new data from Colombia. The modifications to the model include:. (1)The effect of solar radiation on floral buds initiation;(2)An age structure population model to track the daily input and development of the floral buds;(3)The effect of leaf water potential on breaking dormancy in flower buds, and hence on the timing and intensity of flowering;(4)The incorporation of both the vegetative and the reproductive demands to predict the photosynthetic rate.(5)The effect of low temperature on photosynthesis and defoliation. Other aspects of the model were re-interpreted and refinements made to generalize its structure for use across coffee varieties and geographic areas. The model, without modification, realistically simulates field data from Brazil and two Colombian locations having different varieties, patterns of rainfall and hence flowering phenology. The model will be used as the base trophic level for incorporating CBB and high tropic levels effects, and for the analysis of management options in the coffee production system. © 2011 Elsevier B.V.

Gutierrez A.P.,University of California at Berkeley | Gutierrez A.P.,Center for the Analysis of Sustainable Agricultural Systems Global | Ponti L.,Center for the Analysis of Sustainable Agricultural Systems Global | Ponti L.,ENEA
Environmental Entomology | Year: 2013

Published bi- and tri-trophic physiologically based demographic system models having similar sub components are used to assess prospectively the geographic distributions and relative abundance (a measure of invasiveness) of six invasive herbivorous insect species across the United States and Mexico. The plant hosts and insect species included in the study are: 1) cotton/pink bollworm, 2) a fruit tree host/Mediterranean fruit fly, 3) olive/olive fly, 4) a perennial host/light brown apple moth, 5) grapevine/glassy-winged sharpshooter and its two egg parasitoids, and 6) grapevine/European grapevine moth. All of these species are currently or have been targets for eradication. The goal of the analyses is to predict and explain prospectively the disparate distributions of the six species as a basis for examining eradication or containment efforts against them. The eradication of the new world screwworm is also reviewed in the discussion section because of its pivotal role in the development of the eradication paradigm. The models used are mechanistic descriptions of the weather driven biology of the species. Observed daily weather data (i.e., max-min temperatures, solar radiation) from 1,221 locations across the United States and Mexico for the period 1983-2003 were used to drive the models. Soil moisture and nutrition were assumed nonlimiting. The simulation results were mapped using GRASS GIS. The mathematical underpinnings of the modeling approach are reviewed in the appendix and in the supplemental materials. © 2013 Entomological Society of America.

Gutierrez A.P.,Center for the Analysis of Sustainable Agricultural Systems Global | Gutierrez A.P.,University of California at Berkeley | Ponti L.,Center for the Analysis of Sustainable Agricultural Systems Global | Ponti L.,ENEA
Agricultural and Forest Entomology | Year: 2013

The control of insect pests and other taxa may be a result of many factors that are difficult to separate and quantify. Introduced parasitoids, host plant resistance, pathogens and native predators led to the successful control of the spotted alfalfa aphid (SAA; Therioaphis maculata Monell) in California and elsewhere, although the relative contribution of each factor remained largely unknown. The relative contribution of each control factor was estimated using a weather-driven physiologically-based demographic system model consisting of alfalfa, SAA, its three exotic parasitoids [Aphelinus semiflavus Howard, Praon palitans Muesebeck and Trioxys complanatus (Quilis)], a native coccinellid beetle [Hippodamia convergens (Guérin-Menéville)], a fungal pathogen [Erynia neoaphidis Remaudière & Hennebert (Zygomycetes: Entomophthorales)] and host plant resistance (HPR). Daily weather data for the period 1995-2006 from 142 locations in Arizona and California were used to drive the model. The factors were introduced to the model singly or in combination to assess their effects in suppressing simulated SAA populations using SAA-daysm-2year-1 (i.e. density) as the metric of control. Data from selected runs were mapped using the geographic information system grass (http://grass.osgeo.org). The simulation data across all factor combinations, years and locations were summarized using linear multiple regression, with the dependent variable being log10SAA-daysm-2year-1 and the independent variables being the presence-absence (0, 1) of the various factors and their interactions. Marginal analysis of the regression model (∂y/∂xi) enabled separation of the average effects of the different factors (xi) given the average effects of the other factors. Alone, each factor failed to control SAA, as did combinations of the parasitoids and coccinellid predation. Control was predicted across all ecological zones only when all mortality factors were included. The marginal analysis suggests that the order of importance of the mortality factors is HPR > coccinellid beetles > T. complanatus>P. palitans>A. semiflavus > the fungal pathogen. The variability of control by coccinellid beetles and the fungal pathogen was high and hence unreliable. © 2013 The Royal Entomological Society.

Gutierrez A.P.,Center for the Analysis of Sustainable Agricultural Systems Global | Gutierrez A.P.,University of California at Berkeley | Ponti L.,Center for the Analysis of Sustainable Agricultural Systems Global | Ponti L.,ENEA
Florida Entomologist | Year: 2013

The invasive Asian citrus psyllid (Diaphorina citri Kuwayama) is the vector of the bacterial pathogen ('Candidatus Liberibacter asiaticus') that is the putative causal agent of citrus greening disease (Huanglongbing disease) in citrus in many areas of the world. The capacity to predict the potential geographic distribution, phenology and relative abundance of the pest and disease is pivotal to developing sound policy for their management. A weather-driven physiologically based demographic model (PBDM) system was developed to summarize the available data in the literature, and used to assess prospectively the geographic distribution and relative yield of citrus, the relative densities of the psyllid, its parasitoid (Tamarixia radiata Waterston), and the potential severity of citrus greening disease in North America and the Mediterranean Basin. The potential for natural and biological control of citrus psyllid was examined prospectively.

Gutierrez A.P.,Center for the Analysis of Sustainable Agricultural Systems Global | Gutierrez A.P.,University of California at Berkeley | Ponti L.,Center for the Analysis of Sustainable Agricultural Systems Global | Ponti L.,ENEA
Biological Invasions | Year: 2011

The polyphagous tropical Mediterranean fruit fly (Ceratitis capitata Weid. (medfly)) was detected in California in 1975, and a large-scale detection/eradication campaign was begun in the absence of sound knowledge of the fly's potential invasiveness and geographic distribution. Persistent measurable populations of the fly have not been found in California, but a scientific explanation for this has not developed. A physiologically based demographic system model (CASAS) was developed to examine the effects of temperature on medfly's potential distribution across the ecological zones of Arizona-California (AZ-CA), and in Italy where the fly is established. The system model simulates the daily age-mass structured dynamics of a tree host composed of sub-unit populations of leaves, stem, roots and fruit, as well as the age-structured dynamics of medfly life stages. Total pupae tree-1year-1 was used as the metric of favorability for medfly at 151 locations in AZ-CA during 1995-2006, and at 84 locations in Italy during 1999-2005. The results were mapped using GRASS GIS. AZ and the southern desert areas of CA are unfavorable for medfly because of high summer temperatures, while much of CA, including many frost-free areas, is too cold. Only the area of south coastal CA (San Diego, Orange and Los Angeles Counties) is potentially favorable for medfly, but in the absence of measurable populations, we cannot say whether it is established there. The majority of medfly discoveries over the past 35 years have occurred in south coastal CA, but discoveries also occurred in Santa Clara County in northern CA, mostly during 1975 and 1980-1981. Santa Clara County, just south of San Francisco Bay, is generally marginal for medfly, but favorability increased approximately 10% during the period 1979-1981. Medfly has been established in Italy for decades, and our model predicts its wide distribution in the southern and western regions of the country. The fly is restricted in northern areas and at higher elevations of Italy by winter temperatures. Temperature is expected to increase in CA and the Mediterranean Basin. We used two scenarios consisting of increasing observed daily temperatures +2 and +3°C to examine the effects on the potential distribution of the fly in CA and Italy. Increasing temperatures expand the favorable range for medfly northward along the coast of CA, but decrease it in the southern reaches of current favorability. A similar but greater increase in geographic range is predicted for Italy. We examine critically some ongoing eradication programs in CA, and question the scientific basis for them. We also review some climate matching approaches used to assess the potential geographic distribution of invasive species. © 2011 The Author(s).

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