Archive for the ‘GIS’ Category

Impact of the rosette weevil on yellow starthistle

March 13, 2017 Leave a comment

Yellow starthistle (Centaurea solstitialis L.) (YST) is an invasive weed native to the Mediterranean region with a geographical centre of diversity in Turkey. It is widely established in Chile, Australia, and western North America. It arrived in California as a contaminant in alfalfa seed in 1859 and, by 2002, had infested more than 7.7 million hectares in the U.S.A. Biological control of YST using capitula feeding weevils, picture wing flies and a foliar rust pathogen has been ongoing in the western U.S.A. for more than three decades with limited success. Modelling and field research suggest natural enemies that kill whole plants and/or reduce seed production of survivors are good candidates for successful biological control. A candidate species with some of these attributes is the rosette weevil Ceratapion basicorne (Illiger). In the present study, a model of the rosette weevil is added to an extant system model of YST and its capitula feeding natural enemies and, in a GIS context, is used to assess YST control in the Palearctic region and the weevil’s potential impact on YST in western U.S.A. The results obtained suggest densities of mature YST plants in western U.S.A. would be reduced by 70–80% in many areas.

Gutierrez A.P., Ponti L., Cristofaro M., Smith L., Pitcairn M.J., 2016. Assessing the biological control of yellow starthistle (Centaurea solstitialis L.): prospective analysis of the impact of the rosette weevil (Ceratapion basicorne (Illiger)). Agricultural and Forest Entomology,

The rosette weevil Ceratapion basicorne.

Earth observation: bridging the gap to crop-pest systems

November 16, 2016 Leave a comment

The workshop “When Space Meets Agriculture” aimed at promoting a better understanding of the significance and potential of Europe’s space systems (EGNOS/Galileo and Copernicus) for the agricultural sector. While introducing Rural Development Programmes of selected regions and exploring opportunities to set synergies for the development of space applications for the agriculture sector, it will present the main strands of the European Agriculture Policy and more generally link the space community to the agriculture community. Our contribution identified recent and prospective holistic analyses of climate change effects on crop-pest systems in the Mediterranean Basin. The approach used in the analyses involves using physiologically based demographic modeling (PBDM) of crop-pest-natural enemy interactions in the context of a geographic information system (GIS). A major goal is to link the PBDM/GIS technology with increasingly available biophysical datasets from global modeling and satellite observations, and use them to bridge the gap between bottom-up (primarily physiological and population dynamics) and top-down (climatological) GIS approaches for assessing on ground ecosystem level problems, such as agricultural pests.

Ponti L., Gutierrez A.P., Iannetta M., 2016. Climate change and crop-pest dynamics in the Mediterranean Basin. When Space Meets Agriculture: Fostering Interregional collaborations, investments and definition of user requirements. Workshop organized by NEREUS, the Network of European Regions Using Space Technologies, Matera, Italy, 14‐15 November 2016. | Presentation freely available online

Conceptual diagram representing how physiologically-based demographic models bridge the gap between bottom-up (primarily physiological and population dynamics) and top-down (climatological, remote sensing, and ecological niche modeling) GIS approaches for assessing on-ground ecosystem-level problems such as agricultural pests (see Rocchini et al. 2015).

Invasiveness of spotted wing Drosophila

September 10, 2016 Leave a comment

The polyphagous Asian vinegar fly Drosophila suzukii (spotted wing Drosophila) is a native of Eastern and Southeastern Asia. It emerged as an important invasive insect pest of berries and stone fruits in the Americas and Europe beginning in 2008. Species distribution models are commonly used for analyzing the extant and potential range expansion of invasive species. Previous modeling efforts for D. suzukii include a degree-day model, a MaxEnt ecological niche model, a demographic model incorporating the effects of temperature, and a preliminary mechanistic physiologically-based demographic model (PBDM). In the present analysis, we refine the PBDM for D. suzukii based on biological data reported in the literature. The PBDM is used to assess the effects of temperature and relative humidity from a recently published global climate dataset (AgMERRA) on the prospective geographic distribution and relative abundance of the pest in the USA and Mexico, and in Europe and the Mediterranean Basin. Our focus is on areas of recent invasion and of predicted higher invasiveness in these areas. Although the species is native to Asia and is of putative temperate origins, it has established in subtropical to north temperate zones worldwide where it infests a wide range of wild and domesticated berries and stone fruits. The model captures the observed phenology of D. suzukii at specific locations, as well as the potential geographic distribution and relative favorability across larger regions. The main limiting factor is cold winter temperature in northern areas, though high temperatures and low relative humidity may be limiting in arid areas. The effect of greater cold tolerance in winter morph adults is explored.

Gutierrez A.P., Ponti L., Dalton D.T., 2016. Analysis of the invasiveness of spotted wing Drosophila (Drosophila suzukii) in North America, Europe, and the Mediterranean Basin. Biological Invasions, | Full text free to view

Geographic distribution of  Drosophila suzukii in Europe.

Indian cotton: weather, yields and suicides

August 28, 2015 Leave a comment

Cotton with coevolving pests has been grown in India for more than 5000 years. Hybrid cotton was introduced in the 1970s with increases in fertilizer and in insecticide use against pink bollworm that caused outbreaks of bollworm. Hybrid Bt cotton, introduced in 2002 to control bollworm and other lepidopteran pests, is grown on more than 90 % of the cotton area. Despite initial declines, year 2013 insecticide use is at 2000 levels, yields plateaued nationally, and farmer suicides increased in some areas. Biological modeling of the pre-1970s cotton/pink bollworm system was used to examine the need for Bt cotton, conditions for its economic viability, and linkage to farmer suicides. Yields in rainfed cotton depend on timing, distribution, and quantity of monsoon rains. Pink bollworm causes damage in irrigated cotton, but not in rainfed cotton unless infested from irrigated fields. Use of Bt cotton seed and insecticide in rainfed cotton is questionable. Bt cotton may be economic in irrigated cotton, whereas costs of Bt seed and insecticide increase the risk of farmer bankruptcy in low-yield rainfed cotton. Inability to use saved seed and inadequate agronomic information trap cotton farmers on biotechnology and insecticide treadmills. Annual suicide rates in rainfed areas are inversely related to farm size and yield, and directly related to increases in Bt cotton adoption (i.e., costs). High-density short-season cottons could increase yields and reduce input costs in irrigated and rainfed cotton. Policy makers need holistic analysis before new technologies are implemented in agricultural development.

Gutierrez A.P., Ponti L., Herren H.R., Baumgärtner J., Kenmore P.E.. 2015. Deconstructing Indian cotton: weather, yields, and suicides. Environmental Sciences Europe, 27: 12. | Open access

Simulated phenology of cotton fruiting and pink bollworm in irrigated and rainfed cotton during 2005. The movement of adults to rainfed cotton during late summer is indicated by the broad arrow.

Holistic approach in invasive species research

December 15, 2014 Leave a comment

The Mediterranean Basin is a climate change and biological invasion hotspot where recent warming is facilitating the establishment and spread of invasive species, one of which is the highly destructive South American tomato leafminer (Tuta absoluta). This pest recently invaded the Mediterranean Basin where it threatens solanaceous crops. Holistic approaches are required to project the potential geographic distribution and relative abundance of invasive species and hence are pivotal to developing sound policy for their management. This need is increasing dramatically in the face of a surge in biological invasions and climate change. However, while holistic analyses of invasive species are often advocated, they are rarely implemented. We propose that physiologically-based demographic models (PBDMs) in the context of a geographic information system (GIS) can provide the appropriate level of synthesis required to capture the complex interactions basic to manage invasive species such as T. absoluta. We review the PBDMs for two invasive flies, and use them as a basis for assessing the biological data available for the development of a PBDM for T. absoluta, and in the process identify large data gaps that using the PBDM as a guide can be easily filled. Other components for an ecologically-based management program for this pest (habitat modification, natural and classical biocontrol, pheromones, and others) are also reviewed. The development of a PBDM for T. absoluta would provide the basis for an interdisciplinary agroecological synthesis of the problem and the role different control tactics would play in region-specific control of the pest.

Ponti L., Gutierrez A.P., Altieri M.A., 2015. Holistic approach in invasive species research: the case of the tomato leaf miner in the Mediterranean Basin. Agroecology and Sustainable Food Systems, | Get a free reprint

PBDM sub-models used for all species in all trophic levels.

The new world screwworm: distribution and eradication

February 11, 2014 Leave a comment

The new world screwworm Cochliomyia hominivorax (Coquerel) was eradicated in North America, Libya and other locations using the sterile insect technique (SIT). To examine the role of weather in its eradication, a physiologically-based demographic model (PBDM) was developed and used to characterize its range of year-round persistence. Winter temperature and rainfall are shown to have a strong influence on screwworm outbreaks and in facilitating eradication in North America and Libya. Prospective analysis for the Mediterranean Basin suggests eastern areas are most favorable for screwworm establishment (e.g., the Nile River area of Egypt). The SIT eradication programme and its possible extension into South America are discussed. Expected +2°C climate warming is predicted to increase the potential year-round range of screwworm in the SE USA.

Gutierrez A.P., Ponti L., 2014. The new world screwworm: prospective distribution and role of weather in eradication. Agricultural and Forest Entomology,

Asian citrus psyllid and citrus greening disease

December 2, 2013 Leave a comment

The invasive Asian citrus psyllid Diaphorina citri Kuwayama vectors 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 is developed that summarizes the available data in the literature, and used to assess prospectively the geographic distribution and relative abundance of citrus, the psyllid, its parasitoid (Tamarixia radiata Waterston), and citrus greening disease in North America and the Mediterranean Basin. The potential for natural and biological control of citrus psyllid is examined prospectively.

Gutierrez A.P., Ponti L., 2013. Prospective analysis of the geographic distribution and relative abundance of Asian citrus psyllid (Hemiptera: Liviidae) and citrus greening disease in North America and the Mediterranean Basin. Florida Entomologist, 96:1375-1391.