Shifting the paradigm: An ecological systems approach to weed management

Abstract

Weeds have been historically, and are still today, the primary and most economically important pest in agriculture. Several selection pressures associated with weed management, such as an overreliance on herbicides, have promoted the rapid evolution of herbicide-resistant weeds. Integrated Weed Management (IWM) is promoted as an ecological systems approach, through the combination of biological, chemical, cultural, ecological, and mechanical control methods. The concept of a systems approach is defined as managing weeds by combining practice and knowledge with the goals of increasing yield and minimizing economic loss, minimizing risks to human health and the environment, and reducing energy requirements and off-target impacts. The reliance on herbicides in modern cropping systems has shifted the management focus from requiring intimate knowledge of biology, ecology, and ecological systems to herbicide chemistry, mixes, and rotations, application technology, and herbicide-tolerant crop traits. Here, an ecological systems approach is considered, examining new trends and technologies in relation to IWM and weed ecology. Prevention of spread, seedbank management, crop rotations, tillage, cover crops, competitive cultivars, biological weed control, and future solutions in concept-only are presented, and knowledge gaps are identified where research advancements may be possible. An ecological systems approach will provide improved stewardship of new herbicide technologies and reduce herbicide resistance evolution through diversification of selection pressures. Agroecological interactions should be studied in light of new, developing weed control technologies. The science of weed management needs to refocus on the foundations of weed biology and ecology to enable an ecological systems approach and promote agricultural sustainability.