Incorporating biological control into ecologically based weed management.

2009 ◽  
pp. 211-228
Author(s):  
R. L. Sheley ◽  
M. J. Rinella
Keyword(s):  
Biological Control ◽  
Weed Management

Integrated Management of Scotch Broom (Cytisus scoparius) Using Biological Control

2012 ◽  
Vol 5 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Angelica M. Herrera-Reddy ◽  
Raymond I. Carruthers ◽  
Nicholas J. Mills
Keyword(s):  
Biological Control ◽  
Seed Production ◽  
Seed Bank ◽  
Weed Management ◽  
Biological Control Agent ◽  
Integrated Management ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
Scotch Broom ◽  
Mature Seeds

AbstractIntegrated weed management strategies (IWM) are being advocated and employed to control invasive plants species. In this study, we compared three management strategies (biological control alone [BC], BC with fire [BC + F], and BC with mowing [BC + M]) to determine if physical controls reduce seed production by Scotch broom and interfere with the action of the biological control agent—the Scotch broom seed weevil. We measured seed production and seed predation by the weevil at both pod and plant scale, and seed bank density over two field seasons. We found no difference in the number of seeds per pod among management strategies. However, combining management strategies (BC + M and BC + F) resulted in significant reductions in pods per plant, mature seeds per plant, and seed bank density relative to biological control alone. We did not find differences among management strategies in number of weevils per pod or proportion of seeds predated by the weevil at either pod or whole-plant scale. However, combining management strategies (BC + M and BC + F) resulted in a significant reduction in healthy mature seeds per plant relative to biological control alone. Although both integrated strategies outperformed biological control alone in reducing seed production and the seed bank, with no statistical difference between them, we propose that short-rotation prescribed fire could prove to be a more effective strategy for long-term management of Scotch broom due to its potential for slightly greater depletion of the seed bank.

Sustainability, conservation tillage and weeds in Canada

1996 ◽  
Vol 76 (4) ◽  
pp. 651-659 ◽  
Author(s):  
D. A. Derksen ◽  
R. E. Blackshaw ◽  
S. M. Boyetchko
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Conservation Tillage ◽  
The United States ◽  
Integrated Weed Management ◽  
Biological Weed Control ◽  
Plant Residues ◽  
Tillage Systems ◽  
Weed Communities ◽  
Inundative Biological Control

The sustainability of conservation tillage is dependent on the extent of changes in weed community composition, the usage of herbicides, and the development of integrated weed management (IWM) strategies, including biological weed control. The objective of this paper is to review research on conservation tillage and weed management in light of these factors. Recent Canadian research has found that changes in weed communities due to the adoption of conservation tillage are not necessarily those expected and were not consistant by species, location, or year. Changes reflected the use of different selection pressures, such as different crop rotations and herbicides, within the studies to a greater extent than weed life cycle groupings. Therefore, research that determines the reasons for change or the lack of change in weed communities is required to provide the scientific basis for the development of IWM strategies. Documented herbicide usage in conservation tillage varies from less than to more than conventional-tillage systems. Potential to reduce herbicide usage in conservation-tillage systems exists. Furthermore, the herbicides used in western Canada are different from those causing ground water contamination in the United States, are less volatile, and are used at lower rates. The presence of surface crop residues in conservation tillage may provide a unique environment for classical and inundative biological control agents. Some insects, fungi, and bacteria have the potential to survive to a greater extent in undisturbed plant residues. Residue management and conservation tillage systems are evolving in Canada. Research must keep pace by providing weed management strategies that enchance the sustainability of these systems. Key words: Biological control, zero tillage, integrated weed management, residues, herbicides, rhizobacteria.

scholarly journals Principles of Biological Weed Control

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 750D-750
Author(s):  
Susan M. Boyetchko
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Fungal Pathogens ◽  
The United States ◽  
Reproductive Capacity ◽  
Biological Weed Control ◽  
Weed Biocontrol ◽  
Weed Growth ◽  
Inundative Biological Control ◽  
High Concentrations

Weeds continue to have a tremendous impact on crop yield losses in Canada and the United States, despite efforts to control them with chemicals. Biological control offers an additional means for reducing weed populations while reducing the reliance of the agri-food industry on chemical pesticides. Effective biological strategies that are compatible with good soil conservation practices would benefit farmers while maintaining environmental quality and a sustained production for the future. Inundative biological control of weeds with microbial agents involves the mass production and application of high concentrations of a plant pathogen to a target weed. Historically, biocontrol agents used on weeds have been foliar fungal pathogens. More recently, the soil has become a source for microorganisms, such as rhizobacteria, for development as biological control agents. Several naturally occurring rhizobacteria have weed suppressive properties, where growth and development of weeds such as downy brome, wild oats, leafy spurge, and green foxtail are significantly inhibited. Although the focus in weed biocontrol has been on the eradication of weeds, rhizobacteria may be used to improve seedling establishment of the crop by reducing the weed competition. This can be achieved through a reduction in weed growth, vigor, and reproductive capacity and improvement in the ability of the crop to compete with the weed. Current research in weed biocontrol with microorganisms and its application to weed management systems will be discussed.

scholarly journals Impact of soil microorganisms on weed biology and ecology

2005 ◽  
Vol 77 (1) ◽  
pp. 41-56 ◽  
Author(s):  
S.M. Boyetchko
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Mycorrhizal Fungi ◽  
Soil Microorganisms ◽  
Arbuscular Mycorrhizal ◽  
Management Tool ◽  
Mycorrhizal Dependency ◽  
Cultural Methods ◽  
Weed Growth ◽  
Inundative Biological Control

While weed populations have traditionally been controlled by chemical and cultural methods, inundative biological control with microbial agents offers an additional strategy for managing weeds. Foliar pathogens have long been sought after as potential biocontrol agents, but rhizosphere microorganisms and their influence on weed growth and development have been ignored until recently. Rhizosphere soil is replete with a variety of microorganisms such as rhizobacteria, pathogenic soil-borne fungi, and arbuscular mycorrhizal fungi, all of which have a direct or indirect impact on weeds and their competitive ability. In some cases, specific microbes have a detrimental effect on the weeds and can be exploited as biological control agents. The ubiquitous mycorrhizal fungi are beneficial symbionts that can impart a competitive ad vantage to their plant hosts, particularly if mycorrhizal dependency is exhibited in weeds as opposed to crops. It may be possible to exploit various soil microbes by directly or indirectly reducing weed competition and tipping the competitive advantage in favor of the crop. However, information available on microbial/weed/crop relationships is limited and research efforts are required to explore the use of soil microorganisms as another weed management tool.

scholarly journals Weed management practices in natural ecosystems: a critical overview

Koedoe ◽  
2000 ◽  
Vol 43 (1) ◽  
Author(s):  
C.F. Reinhardt
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Management Practice ◽  
Management Tool ◽  
Natural Ecosystems ◽  
Basic Biology ◽  
Herbicide Use

Increasing public pressure against the use of pesticides and other agricultural inputs has placed increased emphasis on the development of ecologically based pest management. One distinct reaction of the Weed Science discipline has been the swing away from herbicide research to increased research on the basic biology and ecology of weeds in hopes of reduced reliance on "technological crutches" such as herbicides and other practices that are potentially harmful to the environment. Biological control is the long-standing alternative to the use of herbicides and interest in the former practice has been boosted by the realization that the use of herbicides may lead to the development of herbicide resistance in weed populations, and that herbicide residues occur in surface and groundwater. Supporters of herbicide use would point out that biological control is generally not effective in crop production systems, and is basically slow-acting. Debates between protagonists for the exclusive use of one or the other weed management practice tend to obscure the benefits that integration of different techniques are likely to have. For natural ecosystems it is proposed that integration of the more subtle practice of biological control with the use of herbicides, which relatively quickly overwhelm a biological system with mortality, is likely to be the most effective weed management tool. Different weed management practices that could be considered in natural ecosystems are discussed in terms of three key performance rating criteria, viz. activity, selec- tivity and persistence In this concise review, general discussion is focussed on the fundamentals of weed management practices, with the view to promote concept-based approaches that are critical for the development of effective weed management strate- gies.

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