Efficacy of rocket and mustard oils and their nano-emulsions as alternatives to chemical herbicides for controlling weeds associated faba bean

Weeds are one of the most well-known biotic environmental stresses in crop ecosystems. They negatively affect plant growth by competing for essential natural resources, leading to adverse impacts on physiological and biochemical processes. Chemical herbicides are also considered as abiotic stress and negatively affect on human and animal health as well as the surrounding environment. So, we shed light on natural products as rocket salad and mustard oils and their nano-emulsions as alternatives to chemical herbicides. Two pot experiments in greenhouse along the winter seasons of 2021/2022 and 2022/2023. Treatments involved foliar spray of rocket and mustard oils and their nano-emulsions at successive concentrations (2.5, 5.0 and 7.5%). Healthy uninfected faba bean plants and unweeded control treatments were applied for comparison. Recorded results revealed that all applied weed control treatments significantly decreased canary grass and cheeseweed growth parameters. Mustard oil was more efficient than rocket oil in suppressing both investigated weeds. This recorded reduction was directly proportional to concentration. Nano-emulsions applications recorded better results than pure oils (without nano-emulsions). Hence, Mustard oil nano-emulsions at 7.5% recorded notified inhibition for both weeds. The reduction of weeds' biotic stress is positively reflected in turn on faba bean plants. In this respect, rocket oil showed a stimulatory effect on faba bean plants higher than mustard oil. Meanly, rocket oil at 7.5% scored the highest growth traits and photosynthetic pigment at both growth ages. Rocket and mustard oils at the highest concentration (7.5%) progressed on healthy faba bean in scoring the high yield traits and seed quality as compared to the unweeded control. GC-mass fractionation of both oils identified eight fatty acids, namely: palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, behenic and erucic fatty acids. Inhibitory response of weeds and stimulatory response of faba bean plants may be attributed to these phenolic acids. Rocket and mustard oils and their nano-emulsions achieved our hypothesis in having herbicidal properties as they have a high phytotoxic effect on growth and physiological processes of the weeds.