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Widespread resistance in Phalaris minor is a major challenge for sustainable wheat production. Recently, multiple resistance and cross resistance in this weed increased the concerns of wheat growers. The use of potential integrated resistance management strategies including allelopathic crop mulches and herbicide mixtures is crucial in assuring sustainable production. A two-year field trial was conducted during 2014–15 and 2015–16 in wheat to evaluate the efficacy of allelopathic mulches of sunflower, rice, maize, and sorghum alone and in combination with three types of herbicide mixtures. Post-emergence herbicide mixtures used in this study were clodinafop –propargyl plus metribuzin, sulfosulfuron plus clodinafop-propargyl, and pinoxaden plus sulfosulfuron at 50% of recommended doses. Integrated use of allelopathic crop mulches and herbicide mixtures provided effective control of P. minor in wheat. However, application of allelopathic mulches and herbicide mixtures alone did not provide a satisfactory control of P. minor. In addition, the application of allelopathic mulches caused a significant decay (23–52%) of soil weed seed bank. The integrated use of mulches and herbicide mixtures consistently enhanced the wheat yield by 23–39% and 24–35% during 2014–15 and 2015–16, respectively. These findings, as the first indication of the potential integration of allelopathic mulches and post-emergence herbicide mixtures to manage P. minor in wheat fields, would help control resistant P. minor and delay further herbicide resistance in this weed.

A great deal of work has been done to explore the hormetic potential of various herbicides to enhance crop growth and yield. However, the growth stimulatory potential of plant-released phytotoxins at low rates to enhance crop yield has not yet been realized, as most of the research has focused on the herbicidal potential of these phytotoxins. However, hormesis of plant-released phytotoxins is a more practical aspect, as these are present at low concentrations in field conditions. These phytotoxins are biodegradable and safe for the environment, and have the potential for crop enhancement both under controlled and field conditions. Low doses of plant-released phytotoxins have been reported to enhance crop growth by up to 50% under controlled conditions, and crop yield by up to 42% under field conditions. In this review, we have discussed hormesis of plant-released phytotoxins with examples. In addition, we discuss the potential for crop enhancement, the influence of different factors on the expression of hormesis, as well as the potential for both undesirable (in weeds) and desirable hormesis (in crop plants). The use of plant-released phytotoxins as growth regulators is also discussed, focusing on sustainable crop production. In future, phytotoxins may be utilized as a crop stimulator to enhance crop yield, especially in organic crop production systems.

Weed management has become increasingly important in the backdrop of sustainable crop production, uncertain climatic patterns and food security concerns in Pakistan. Due to diverse agro-climatic conditions, 267 weed species have been identified to be responsible for causing monetary loss worth 3 billion USD annually. Weed competition for resources, interference with crops, weed-related increased incidence of pests and diseases in different crops, and high management costs incurred in controlling weeds make weed management a critical task for the farmers. Moreover, herbicide resistant weeds, labor shortage, higher wages, weed population shifts, changing climatic optima, unavailability of proper and timely inputs, ever increasing threats of invasive weeds, lack of knowledge and training regarding herbicides, and the poor financial resources of the small land holders are major hurdles towards effective weed management in Pakistan. These multi-dimensional problems need holistic line of action with multi-disciplinary collaboration. Improved knowledge of weed ecology, biology, genetics and molecular biology is essential for developing sustainable weed control practices. Some advances are already commercialized, and others are in the process of development. Advancements like vision guided machines for site-specific weed management, recognition and application modules, development of air inclusion nozzles, nanoherbicides, water based formulations with fewer hydrocarbons, herbicide-resistant transgenic crops, robotics to monitor and spray weeds, decision support systems and predictive modeling can be adopted to foster modern weed management in the country. Various conventional weed management approaches like narrow row spacing, row orientation, increased crop density, use of cover crops, intercropping, development of weed-competitive crop cultivars, and their integration can help reduce herbicide input under a given scenario. There is dire need to establish regional weed research institutes under various cropping systems to carry out strategic and applied research in weed science. Innovative teaching and training practices are needed to tackle complex weed management challenges. Effective linkages between academia-research-industry-extension services could play a pivotal role to reframe technological advancements and legislation and to advocate innovations to the farmers. Capacity building, more research fund allocation, and reorienting educational system seem indispensable. Here, we have presented a broad review to summarize the current state of knowledge about the problems and prospects of sustainable weed management approaches in Pakistan. Advanced weed management approaches keeping in view the local agro-ecological conditions have also been discussed in this review to improve the scientific knowledge so that the discipline gets stronger and more focused than ever before.