336 Chapters
Medium 9781780644370

4 Resistance of Busseola fusca to Cry1Ab Bt Maize Plants in South Africa and Challenges to Insect Resistance Management in Africa

Soberon, M.; Gao, Y.; Bravo, A. CABI PDF

4

Resistance of Busseola fusca to

Cry1Ab Bt Maize Plants in South

Africa and Challenges to Insect

Resistance Management in Africa

Johnnie Van den Berg1* and Pascal Campagne2

1Unit

for Environmental Sciences and Management, North-West

University, Potchefstroom, South Africa; 2Institute of Integrative

Biology, University of Liverpool, Liverpool, UK

Summary

The evolution of resistance to Bacillus thuringiensis (Bt) maize by the African stem borer, Busseola fusca, in South Africa highlighted the importance of the development of appropriate integrated resistance management (IRM) strategies for stem borers in Africa. Landscape heterogeneity is characteristic of African agroecosystems.

This heterogeneity, in addition to betweenfield and within-field spatial mosaics resulting from variable gene expression in

Bt maize, will provide challenges to managing resistance evolution of the lepidopteran stem borers that attack maize. Adding to this landscape heterogeneity is the cultivation of open-pollinated maize varieties

See All Chapters
Medium 9781845938178

6: Control Methods: Chemical

Buckle, A.P.; Smith, R.H. CABI PDF

6 

1

Control Methods: Chemical

A.P. Buckle1 and C.T. Eason2

School of Biological Sciences, University of Reading, Reading,

UK; 2Centre of Wildlife Management and Conservation,

Lincoln University, Lincoln, New Zealand

Introduction

The benefits of non-chemical methods of

­rodent control are increasingly recognized

(Chapter 5). In particular, the role of environmental characteristics, and their possible modification, in the prevention of rodent infestation is well established (Lambert et al.,

2008). Nonetheless, lethal chemical agents – rodenticides – are presently the mainstay of all practical rodent-control programmes that involve the removal of extant infestations. This is true in both urban and agricultural environments and in conservation

(Chapter 18), and this situation will r­ emain for the foreseeable future. The reasons for this are the great strides towards the i­ ncreased safety of rodenticides made with the introduction of the anticoagulants  in the  early

1950s, and the excellent cost-effectiveness of currently available compounds (Hadler and Buckle, 1992).

See All Chapters
Medium 9781780644233

10: Preferences for Conservation Agriculture in Developing Countries: a Case Study on the Tribal Societies of India and Nepal

Chan, C.; Fantle-Lepczyk, J. CABI PDF

10

Preferences for Conservation

Agriculture in Developing

Countries: a Case Study on the

Tribal Societies of India and

Nepal

Cynthia Lai,* Catherine Chan, Aliza Pradhan,

Bikash Paudel, Brinton Foy Reed and

Jacqueline Halbrendt

University of Hawaiʽi at Ma¯noa, Honolulu, Hawaii, USA

10.1  Introduction

In many agricultural regions of the world, farmers are experiencing the effects of climate change and its subsequent effects on soil productivity, which lead to reduced agricultural productivity (FAO, 2012). For smallholder subsistence farmers who reside in developing countries, the effects of climate change coupled with population pressures are of even greater impact, due to existing marginalized land conditions (i.e. poor soil fertility, moisture retention, and erosion), as well as lack of capital, institutional support, and access to resources and information (Lai et al., 2012a). With increasing population and decreasing land fertility, agricultural research in the 1960s and 1970s focused on agricultural intensification and increasing per capita food production (Conway and Barbier, 1990). The new technologies, innovations, and increased agricultural productivity that emerged from this period are recognized as the “Green Revolution”. Although the resulting chemical fertilizers, pesticides, and breeding programs for high-yielding varieties provided increased yields, the successes were short-lived, as they failed to provide sustainable solutions to existing land degradation and soil fertility problems, particularly for the smallholder subsistence farmer (Conway and Barbier, 1990).

See All Chapters
Medium 9781780643373

24: Reflections

Kirby, K.J.; Watkins, C. CABI PDF

24 Reflections

1

Charles Watkins1* and Keith J. Kirby2

School of Geography, University of Nottingham, Nottingham, UK;

2

Department of Plant Sciences, University of Oxford, Oxford, UK

24.1  Introduction

We are more aware than ever before of the variety of forms that landscapes with trees, woods and forests can take across Europe, thanks to easier travel and the way that images, data and opinions can be easily found across the Web.

This spatial heterogeneity is matched by temporal variety. People have valued and used trees and woods in different ways in different places, and at different times in the same place.

Indeed, Europe’s woods and forests have been providing ecosystem goods and services by different names throughout the last 10,000 years.

The wide range of potential benefits provided by woodland, including the production of timber, firewood and a range of non-timber forest products, as well as carbon sequestration, landscape and culture, wildlife and game conservation, public access and shelter make it a complex land use to understand and manage.

See All Chapters
Medium 9781780644370

6 Different Models of the Mode of Action of Bt 3d-Cry Toxins

Soberon, M.; Gao, Y.; Bravo, A. CABI PDF

6

Different Models of the Mode of

Action of Bt 3d-Cry Toxins

Alejandra Bravo,* Isabel Gómez, Gretel Mendoza,

Meztlli Gaytán and Mario Soberón

Instituto de Biotecnología, Universidad Nacional Autónoma de

México, Cuernavaca, Morelos, Mexico

Summary

Bacillus thuringiensis (Bt) produces insecticidal proteins that are active against different insect orders. In particular, the family of the three domain-Cry toxins (3dCry) have important applications in controlling insect pests as spray products or in transgenic Bt plants. At least three different models account for the mode of action of these proteins. Two of them are based on the pore formation activity of the toxin and propose that larvae are killed by osmotic shock to their midgut cells.

Differences in these models are related to the processes of receptor interactions and membrane insertion. The third model proposes that midgut cells are killed through a signal transduction mechanism that is triggered after the binding of 3d-Cry toxins to a cadherin receptor. In this chapter, we will review these models in light of the different resistance mechanisms to Cry toxins that have been documented so far in several insect species.

See All Chapters

See All Chapters