Adam S. Davis, George B. Frisvold, “Are herbicides a once in a century method of weed control?,” Pest Management Science, 2017, 73:11, DOI: 10.1002/ps.443.

ABSTRACT:

The efficacy of any pesticide is an exhaustible resource that can be depleted over time. For decades, the dominant paradigm – that weed mobility is low relative to insect pests and pathogens, that there is an ample stream of new weed control technologies in the commercial pipeline, and that technology suppliers have sufficient economic incentives and market power to delay resistance – supported a laissez faire approach to herbicide resistance management. Earlier market data bolstered the belief that private incentives and voluntary actions were sufficient to manage resistance. Yet, there has been a steady growth in resistant weeds, while no new commercial herbicide modes of action (MOAs) have been discovered in 30 years. Industry has introduced new herbicide tolerant crops to increase the applicability of older MOAs. Yet, many weed species are already resistant to these compounds. Recent trends suggest a paradigm shift whereby herbicide resistance may impose greater costs to farmers, the environment, and taxpayers than earlier believed. In developed countries, herbicides have been the dominant method of weed control for half a century. Over the next half-century, will widespread resistance to multiple MOAs render herbicides obsolete for many major cropping systems? We suggest it would be prudent to consider the implications of such a low-probability, but high-cost development.  FULL TEXT

Fred Gould, Zachary S. Brown, Jennifer Kuzma, “Wicked evolution: Can we address the sociobiological dilemma of pesticide resistance?,” Science, May 18, 2018, 360: 6390, DOI: 10.1126/science.aar3780.

ABSTRACT:

Resistance to insecticides and herbicides has cost billions of U.S. dollars in the agricultural sector and could result in millions of lives lost to insect-vectored diseases. We mostly continue to use pesticides as if resistance is a temporary issue that will be addressed by commercialization of new pesticides with novel modes of action. However, current evidence suggests that insect and weed evolution may outstrip our ability to replace outmoded chemicals and other control mechanisms. To avoid this outcome, we must address the mix of ecological, genetic, economic, and sociopolitical factors that prevent implementation of sustainable pest management practices. We offer an ambitious proposition.  FULL TEXT

Matt Liebman, Bàrbara Baraibar, Yvonne Buckley, Dylan Childs, Svend Christensen, Roger Cousens, Hanan Eizenberg, Sanne Heijting, Donato Loddo, Aldo Merotto Jr, Michael Renton, Marleen Riemens, “Ecologically sustainable weed management: How do we get from proof-of-concept to adoption?,” Ecological Applications, 26:5, 2016, DOI: 10.1002/15-0995

ABSTRACT:

Weed management is a critically important activity on both agricultural and non‐agricultural lands, but it is faced with a daunting set of challenges: environmental damage caused by control practices, weed resistance to herbicides, accelerated rates of weed dispersal through global trade, and greater weed impacts due to changes in climate and land use. Broad‐scale use of new approaches is needed if weed management is to be successful in the coming era. We examine three approaches likely to prove useful for addressing current and future challenges from weeds: diversifying weed management strategies with multiple complementary tactics, developing crop genotypes for enhanced weed suppression, and tailoring management strategies to better accommodate variability in weed spatial distributions. In all three cases, proof‐of‐concept has long been demonstrated and considerable scientific innovations have been made, but uptake by farmers and land managers has been extremely limited. Impediments to employing these and other ecologically based approaches include inadequate or inappropriate government policy instruments, a lack of market mechanisms, and a paucity of social infrastructure with which to influence learning, decision‐making, and actions by farmers and land managers. We offer examples of how these impediments are being addressed in different parts of the world, but note that there is no clear formula for determining which sets of policies, market mechanisms, and educational activities will be effective in various locations. Implementing new approaches for weed management will require multidisciplinary teams comprised of scientists, engineers, economists, sociologists, educators, farmers, land managers, industry personnel, policy makers, and others willing to focus on weeds within whole farming systems and land management units. FULL TEXT

Matt Liebman and Adam Davis, “Managing Weeds in Organic Farming Systems: An Ecological Approach,” In Organic Farming: The Ecological System, Ed: Charles Francis, 2009.

SUMMARY:

In this chapter, we describe major components of the weed management tool kit for organic farming, highlighting areas in which important advances have been made in the last decade. We then argue that instead of approaching the development of multitactic weed management strategies as a purely empirical, trial-and-error activity, the choice and deployment of weed management tactics should instead be informed by insights from ecological theory… Finally, we emphasize the need for ongoing dialog between empiricists and theoreticians and between scientists and farmers, so as to better direct scarce research resources and management time to where they are likely to be most beneficial. Multitactic weed management strategies informed by theory should be useful not just to organic farmers but also to conventional farmers who seek to reduce their reliance on herbicides due to concerns over herbicide resistance in weeds, rising production costs, and environmental and human health risks associated with herbicide exposure. FULL TEXT