The intrusion of weeds into fertile areas has resulted in significant global economic and environmental impacts on agricultural production systems and native ecosystems, hence without ongoing and repeated management actions, the maintenance or restoration of these systems will become increasingly challenging. The establishment of herbicide resistance in many species and unwanted pollution caused by synthetic herbicides has ushered in the need for alternative, eco-friendly sustainable management strategies, such as the use of bioherbicides. Of the array of bioherbicides currently available, the most successful products appear to be sourced from fungi (mycoherbicides), with at least 16 products being developed for commercial use globally. Over the last few decades, bioherbicides sourced from bacteria and plant extracts (such as allelochemicals and essential oils), together with viruses, have also shown marked success in controlling various weeds. Despite this encouraging trend, ongoing research is still required for these compounds to be economically viable and successful in the long term. It is apparent that more focused research is required for (i) the improvement of the commercialisation processes, including the cost-effectiveness and scale of production of these materials; (ii) the discovery of new production sources, such as bacteria, fungi, plants or viruses and (iii) the understanding of the environmental influence on the efficacy of these compounds, such as atmospheric CO2, humidity, soil water stress, temperature and UV radiation.
Populations of invasive alien plants create disruptive plant communities that are extremely adaptable, imposing severe ecological impacts on agriculture, biodiversity and human activities. To minimise these impacts, prevention and effective weed management strategies are urgently required, including the identification of satellite populations before they invade new areas. This is a critical element that allows weed management practices to become both successful and cost-effective. Mimosa pigra L. (Giant sensitive plant) is an invasive weed that has spread across various environments around the world and is considered one of the world’s top 100 most invasive plant species. Being adaptable to a wide range of soil types, in addition to its woody protective prickles and low palatability, M. pigra has quickly spread and established itself in a range of habitats. Current control methods of this species include biological, chemical and physical methods, together with attempts of integrated application. Reports suggest that integrated management appears to be the most effective means of controlling M. pigra since the use of any single method has not yet proved suitable. In this regard, this review synthesises and explores the available global literature and current research gaps relating to the biology, distribution, impacts and management of M. pigra. The contribution of this work will help guide land managers to design appropriate and sustainable management programs to control M. pigra.
Blue heliotrope (Heliotropium amplexicaule Vahl) is an extremely drought-hardy perennial weed that is often problematic within agricultural production systems and natural environments in some parts of the world. It has the capacity to outcompete and displace desirable plant species and it contains various biochemical compounds that are toxic to grazing livestock and humans. Heliotropium amplexicaule plants can grow within a range of climatic and environmental conditions and produce seeds that remain dormant for several years within the soil which exhibit staggered emergence long after the original parent plants have expired. While control options, including biological, chemical, cultural, and physical methods, are available, many are not suitable as a single-use approach for the long-term management of this species. Therefore, an integrated weed management (IWM) program is necessary for the confident and long-term management of H. amplexicaule, particularly within dryland ecosystems. This review explores the biology, ecology, distribution, and suitable management options currently available for H. amplexicaule, while identifying research gaps that can be addressed to assist in its future management. While particular emphasis is placed on the Australian experience, information from a global perspective is included, providing valuable insights for the long-term management of H. amplexicaule worldwide.