Purpose: Considering that the field dodder is one of the most dangerous parasitic weeds that causes serious damage to cultivated crops, this study aimed to evaluate the efficiency of different control methods against field dodder and the damage caused by the field dodder to eggplant. As well, to determine the isothiocyanate content of turnip and broccoli plants using GC-MS analysis. Research Method: This study was conducted during 2020 and 2021. The experiment examined control methods involving turnip and broccoli as pre-cultivation plants, later both incorporated into the soil separately during specific growth stages, and then both covered and uncovered with black polyethylene mulch, and black polyethylene mulch alone. Controls included plots free of field dodder (Control 1) and plots totally infested with field dodder (Control 2). Finally, all plots were cultivated with eggplant seedlings on rows. Findings: The efficacy of control methods against field dodder in eggplant plots reached 95.81% in TM (turnip+BP mulch) , 92.30% in BM (broccoli+BP mulch), 91.25% in M (black polyethylene mulch alone), 68.26% in T (turnip alone), and 62.58% in B (broccoli alone) treatments. The highest eggplant yield of 8.396 tons/da was achieved in TM treatment. The field dodder caused a yield loss in eggplant by 82.16%, a decrease in eggplant height by 31.12%, and by 58.99% in the number of eggplant fruits in the Con 2 treatment, where the plots were fully infested with filed dodder. Originality/value: The efficiency of cruciferous plants against field dodder is attributed to their isothiocyanates content as the highest percentage of isothiocyanate compounds was found in turnip by 56.6% and the lowest in broccoli by 30.47%.
The widespread distribution of wolf poison (Stellera chamaejasme L.), spanning from southern Russia to southwestern China and the western Himalayas, contributes to its prevalence as an invasive species in grassland ecosystems. Its extensive range, coupled with its ability to thrive in harsh environments, enables it to rapidly colonize grasslands. Once established, it rapidly spreads and dominates large areas. This process inevitably leads to grassland degradation over time, thereby exerting significant impacts on both ecology and economy. In China, grasslands (26.45 million ha, 27.5% of land area) face severe degradation, with more than 90% impacted by overgrazing and climate change. Stellera chamaejasme infestations exceed 1.4 million ha in Qinghai, 546,700 ha in Gansu, and 133,000 ha in Inner Mongolia, causing annual forage losses of 137,500 Mg and economic damages of 15 to 20 million yuan in Gansu alone. These impacts threaten ecosystem stability and pastoral livelihoods. Therefore, research on the mechanisms of spread of invasive plants is crucial. In this comprehensive description, we investigated the effects of S. chamaejasme on plant communities and herbivore interactions. Our research showed how this species successfully invades grasslands and establishes itself as a dominant species. Stellera chamaejasme enhances its expansion by altering soil physicochemical properties, reducing nutrient cycling, and increasing pathogenic fungi abundance while enhancing microbial diversity, creating self-favoring soil conditions. With high genetic diversity, robust reproductive capacity, and potent allelopathic effects, it suppresses neighboring vegetation and escapes herbivory due to toxicity, accelerating invasion. These interrelated traits facilitate the rapid invasion and spread of S. chamaejasme on grasslands, ultimately leading to its dominance. This trend poses a significant threat to the health and stability of the grassland ecosystem. Future research should delve into the ecological adaptability and allelopathic mechanisms of S. chamaejasme, aiming to develop effective management strategies for controlling its spread and promoting grassland recovery and biodiversity conservation.
A field experiment replicated over two seasons examined allelopathic effects of eleven sorghum accessions with known sorgoleone content on sorghum growth and yield, weed density and biomass at Panmure Experiment Station, in Shamva, Zimbabwe in the 2017/2018 summer and in late winter to summer in 2018. The trial was a 2 x 11 factorial in a randomized complete block design plus two control treatments replicated thrice. Factor A was weeding regime with two levels: clean weeding and no weeding. Factor B were 11 sorghum accessions. There was a significant sorghum accession x weeding regime interaction effect (p 0.05) between sorgoleone content and weed density and biomass, suggesting that sorgoleone may not instantly cause allelopathic effects on weeds upon its release from root hairs because it is strongly sorbed in soil, and inhibition of density and biomass might have been caused by other allelopathic compounds. Future research should trace uptake and translocation of allelopathic compounds to target sites of receiver plants, and demonstrate that subsequent damage symptoms are caused by the allelopathic compounds.
Broad infestations of invasive, non-native vegetation have transformed wetlands around the world. Ludwigia hexapetala is a widespread, amphibious invasive plant with a creeping growth habit in open water and an erect growth habit in terrestrial habitats. In the upper San Francisco Estuary of California, L. hexapetala is increasingly terrestrializing into marshes and this expansion may be facilitated by allelopathy. We conducted the first field-based study on L. hexapetala allelopathy to determine whether (1) three allelochemicals known to be exuded by L. hexapetala are expressed in situ, (2) the allelochemicals are detectable in leaves, soil, and water, and (3) allelopathic expression varies by season, salinity, and growth habit (open water patch vs. terrestrial marsh interface locations). Water, soil, and L. hexapetala leaves were collected in two freshwater sites and two oligohaline sites in the upper San Francisco Estuary in summer 2021, fall 2021, and spring 2022. Myricitrin and quercitrin, known allelochemicals, and salipurposid, a newly identified polyphenol, were detected in water, soil, and leaves. There were significant differences in allelochemical concentrations under fresh versus oligohaline conditions in water and soil, but not leaves. All three allelochemicals generally had higher concentrations in patch versus interface locations, suggesting that L. hexapetala allelopathy plays a greater competitive role in open water than terrestrial habitats. Leaf concentrations of each allelochemical varied seasonally; however, both myricitrin and salipurposid had heightened concentrations in spring. These results suggest that herbicide application in early spring may be most effective in controlling L. hexapetala terrestrialization from open water to marshes.
Weed infestation is one of the most damaging biotic factors to limit crop production by competing with the crop for space, water, and nutrients. Different conventional approaches are being used to cope with weed infestation, including labor intensive manual removal and the use of soil-degrading, crop-damaging, and environment-deteriorating chemical herbicides. The use of chemicals for weed control has increased 2-fold after the green revolution and their non-judicious use is posing serious threats to mankind, animals, and biodiversity. The detrimental effects of these approaches have shifted the researchers' attention from the last two decades towards alternate, sustainable, and eco-friendly approaches to cope with weed infestation. The recent approaches of weed control, including plant and microbial allelopathy have gained popularity during last decade. Farmers still use conventional methods, but the majority of farmers are very passionate about organic agriculture and describe it as a slogan in the developed world. The effectiveness of these approaches lies in host specificity by selective bacteria and differential response towards weeds and crops. Moreover, the crop growth promoting effect of microorganisms (allelopathic bacteria) possessing various growth promoting traits, that is, mineral solubilization, phytohormone production, and beneficial enzymatic activity, provide additional benefits. The significance of this review lies in the provision of a comprehensive comparison of the conventional approaches along with their potential limitations with advanced/biological weed control approaches in sustainable production. In addition, the knowledge imparted about weed control will contribute to a better understanding of biological control methods.
Beyond ecological and health impacts, invasive alien plant species can generate indirect and direct costs, notably through reduced agricultural yields, restoration, and management of the invaded environment. Acacia dealbata and Ailanthus altissima are invasive plant species that cause particularly significant damage to the railway network in the Mediterranean area. The allelopathic properties of Mediterranean plant species could be used as nature-based solutions to slow down the spread of such invasive plant species along railway borders. In this context, a mesocosm experiment was set-up: (i) to test the potential allelopathic effects of Cistus ladanifer, Cistus albidus, and Cotinus coggygria leaf aqueous extracts on seed germination and seedling growth of A. dealbata and A. altissima; (ii) to evaluate whether these effects depend on the extract dose; and finally, (iii) to estimate whether these effects are modified by soil amendment. Leaf aqueous extracts of the three native plant species showed negative effects on both seed germination and seedling growth of the two invasive species. Our results show that the presence of allelochemicals induces a delay in seed germination (e.g., A. dealbata germination lasted up to 269% longer in the presence of high-dose leaf aqueous extracts of C. coggygria), which can lead to a decrease in individual recruitment. They also highlight a decrease in seedling growth (e.g., high-dose C. coggygria leaf aqueous extracts induced a 26% decrease in A. dealbata radicle growth), which can alter the competitiveness of invasive species for resource access. Our results also highlight that compost addition limits the inhibitory effect of native Mediterranean plants on the germination of invasive alien plants, suggesting that soil organic matter content can counteract allelopathic effects on invasive alien plants. Thus, our findings revealed that the allelopathic potential of certain Mediterranean plant species could be a useful tool to manage invasive plant species.