GIS / Modeling Analysis

Bioeconomic analysis of olive in the Mediterranean Basin

The Mediterranean Basin is a climate change and biodiversity hot spot, and climate change threatens its agroecosystems including olive, an ancient drought-tolerant crop of considerable ecological and socio-economic importance. Climate change will impact the interactions of olive and the obligate olive fruit fly (Bactrocera oleae) and affect the economics of olive culture across the Basin. … Continue reading Bioeconomic analysis of olive in the Mediterranean Basin →

Bt cotton

Transgenic cotton expressing the genes for the production of protoxin of the bacterium Bacillus thuringiensis (Bt) is used to control lepidopterous pests. Among the most successful applications is for control pink bollworm (Pectinophora gossypiella Saunders (i.e. PBW)) in irrigated cotton of the southwestern United States. A major threat to this technology is the development of … Continue reading Bt cotton →

New World Screwworm Analysis

The new world screwworm (Cochliomyia hominivorax (Coquerel)) was eradicated in North America, Libya and other locations using the sterile insect technique (SIT).  A physiologically-based demographic model (PBDM) was developed and used to characterize its range of year-round persistence and to examine the role of weather in its eradication. Published data on developmental times, fecundity and … Continue reading New World Screwworm Analysis →

Mediterranean Fruit Fly Analysis

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 … Continue reading Mediterranean Fruit Fly Analysis →

Alfalfa Agro-ecosystem Analysis

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 … Continue reading Alfalfa Agro-ecosystem Analysis →

Climate Change Effects on Olive Fly

Climate change is expected to alter the geographic distribution and abundance of many species. Here we examine the potential effects of climate warming on olive (Olea europaea) and olive fly (Bactrocera oleae) across the ecological zones of Arizona–California (AZ–CA) and Italy. A weather-driven physiologically-based demographicmodel was developed from the extensive literature and used to simulate … Continue reading Climate Change Effects on Olive Fly →

East African Agro-pastoral Systems with Multiple Disease Constraints

The effectiveness of international research and development efforts in Africa has been questioned on scientific, administrative and social grounds, and for the lack of conceptual models to place observed eco-social change in interpretive dimensions. To illustrate how the latter problem may be addressed, we examine the ongoing suppression of trypanosomiasis disease affecting cattle in an … Continue reading East African Agro-pastoral Systems with Multiple Disease Constraints →

Rice /Fish System in South East Asia

A modular, object oriented, multitrophic model of the mass dynamics of a tropical rice/fish pond is reported. The model includes the interactions of bacteria, blue_/green algae, small and large phytoplankton in the first trophic level; heterotrophic nanoflagellates (HNF), ciliates rotifers and cladocerans in the second; phytoplankton grazing fish (Nile tilapia, Oreochromis niloticus L.) in the … Continue reading Rice /Fish System in South East Asia →

Analysis of the Biological Control of Noxious Weeds: Yellow starthistle

The invasive weed yellow starthistle (YST) (Centaurea solstitialis) and its interactions with annual grasses and herbivorous biological control agents is used to demonstrate the utility of the PBDM approach for analyzing complex invasive species problems. The PBDM model accurately predicts the distribution and relative abundance of YST across the western USA, and the results are … Continue reading Analysis of the Biological Control of Noxious Weeds: Yellow starthistle →

Coffee/Coffee Borer System

The coffee production system consisting of models for coffee growth and development, coffee/coffee berry borer (CBB) dynamics, and the role of the CBB parasitoids and complementary strategies for control of CBB have been modeled and analyzed. The CBB model is based on a prior model by Gutierrez et al. (1998) with the following modifications: Refinements … Continue reading Coffee/Coffee Borer System →

Analysis of the Biological Control of Cassava Pests In SubSaharan Africa (with IITA Nigeria)

Models for cassava (Manihot esculenta Crantz) growth, development and yields as modified by weather, soil water and nitrogen, and natural enemies were developed. Rainfall-induced mortality and plant carbohydrate stress were the major determinants of P. manihoti population patterns prior to the introduction of exotic natural enemies. The cassava model was the basis for examining  the … Continue reading Analysis of the Biological Control of Cassava Pests In SubSaharan Africa (with IITA Nigeria) →