Monday, March 13, 2017

Bt cotton in India: critique of a macro analysis

This paper is a critique of Srivastava and Kolady (Current Science, 2016; 110: 3-10) who reported a macro analysis of the benefits of Bt cotton in India using statewide average data. The analysis is in error with respect to the economic benefits, biological underpinnings, and the effects of Bt cotton technology adoption on resource-poor farmers growing rainfed cotton. Viable non-GMO high-density cotton alternatives that increase yields, reduce cost of production, and give higher net average returns were ignored. The authors argue for biotechnology adoption in other crops in India without providing data or analysis

Gutierrez A.P., Ponti L., Baumg√§rtner, J., 2017. A critique on the paper ‘Agricultural biotechnology and crop productivity: macro-level evidences on contribution of Bt cotton in India’. Current Science, 112: 690-693. Full text free to download

Trends for cotton yield, pesticide use and the percentage of total cotton growing area planted to Bt cotton.

Friday, December 23, 2016

Impact of the rosette weevil on yellow starthistle

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, https://doi.org/10.1111/afe.12205

The rosette weevil Ceratapion basicorne.

Thursday, November 17, 2016

Earth observation: bridging the gap to crop-pest systems

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).

Friday, September 30, 2016

Crop-pest dynamics in the Mediterranean Basin

Climate change will make assessing and managing crop-pest systems in the Mediterranean Basin more difficult than elsewhere on the globe. The Basin is in many ways a hot spot of global change, as higher than average projected climate change threatens an extremely rich and intertwined biological and cultural diversity, and increases its vulnerability to biological invasions. As a consequence, pest problems in this hot spot will require a holistic approach to deconstruct the elusive complex interactions that are the underpinning basis for sound decision making at the field level. Building on 30+ years of multidisciplinary progress inspired by pioneering work at University of California, the ENEA GlobalChangeBiology project in collaboration with CASAS Global is developing an interdisciplinary tool to mechanistically describe (i.e., model), analyze and manage agro-ecological problems based on the unifying paradigm that all organisms including humans acquire and allocate resources by analogous processes – the paradigm of ecological analogies that is holistic by design. Recent analyses using this approach show how the tool provided and will continue to provide governmental agencies with the scientific basis for building eco-social resilience to climate warming into agricultural systems across the Mediterranean Basin and elsewhere.

Ponti L., Gutierrez A.P., Iannetta M., 2016. Climate change and crop-pest dynamics in the Mediterranean Basin. ENEA Technical Report, 27: 18 pp., http://hdl.handle.net/10840/8042 | Open access

Growth rates of a crop, pest and natural enemy plotted on temperature to intuitively illustrate how an increase in average temperature from T0 to T+2°C may affect the physiological basis of trophic interactions. With temperature warming, biological control of the pest may decrease due to the narrower temperature tolerance of the natural enemy compared to the pest.