Two field experimental trials were carried out in central Italy, in 2005 and 2006, on biomass sorghum [Sorghum bicolor (L.) Moench] in order to assess weed control efficacy and selectivity to the crop of some pre- and post-emergence herbicides applied at different doses and in different mixtures. All herbicides showed good selectivity to the crop, although postemergence treatments showed higher transitory phytotoxicity effects than pre-emergence treatments, especially when high temperatures occurred after treatments, decreasing the selectivity of leaf herbicides (i.e. MCPA, 2,4-D, bromoxynil and dicamba). Considering pre-emergence applications, terbuthylazine alone against broadleaves or in mixtures at low doses with s-metolachlor against mixed infestations (grasses + broadleaves), seemed to be the best options to obtain a good selectivity to the sorghum and a high weed control level. Aclonifen showed some limits in terms of weed spectrum and could be recommended only against simplified broadleaf weed infestations without the presence of less susceptible weeds, like Amaranthus retroflexus, Portulaca oleracea and Solanum nigrum. Propachlor seemed not to be advisable due to the low efficacy against all the major broadleaf warmseason weed species in the Mediterranean areas. Considering post-emergence applications, all treatments gave quite similar results in terms of weed control, although, the mixture of terbuthylazine + bromoxynil seemed to be the best option due to bromoxinil’s higher efficacy than other foliar herbicides, such as MCPA, 2,4-D and dicamba, which can increase the efficacy of terbuthylazine alone especially under dry weather conditions. There were no significant differences in sorghum biomass between herbicide treatments, although, the more selective pre-emergence treatments showed, on average, a higher biomass yield value than the less selective post-emergence treatments. For these reasons, biomass values seemed to be more related to herbicide selectivity than to herbicide efficacy, especially in cases of scarce competitiveness of weed flora.

This paper reports a study on genetic identification of Parthenium hysterophorus and the ability of P. hysterophorus crude extract (PHCE) to inhibit germination of weeds in palm oil plantations, particularly slender buttonweed ( Diodia ocimifolia). Parthenium hysterophorus is a noxious plant with invasive properties. It has become one of the world’s seven most devastating and hazardous weed‑s due to its allelopathic properties. However, a comprehensive study on its genetic identification and its herbicidal activity against weeds in palm oil plantations had never been carried out. In the present study, internal transcribes spacer (ITS) region-based analysis was used as a molecular marker to ascertain the local Rumput Miang Mexico (RMM) as a P. hysterophorus species. From the results, the DNA sequence obtained was 99% matched with P. hysterophorus species database. In the dose-response bioassay study, the phytotoxicity of PHCE on D. ocimifolia was simulated under laboratory conditions. Methanolic extract of P. hysterophorus significantly inhibited germination and growth of shoots and radicles of D. ocimifolia at low concentrations (1−5 g ∙ l−1). A study on the herbicidal activity of PHCE could be an additional management approach for this phytotoxic species and an alternative way to naturally control weeds on palm oil plantations.

Solanum elaeagnifolium Cav. is known to be one of the most invasive species worldwide. In this study, laboratory and greenhouse experiments were carried out to investigate the allelopathic properties of S. elaeagnifolium vegetative parts, root parts, fruit mucilage, and exudate extracts on plant communities and soil properties. In addition, the extract profiles of allelochemicals were quantified and their influence on soil properties and microorganisms was determined. Overall, the allelopathic performance of S. elaeagnifolium was established depending on the extract types, used concentrations, and target species. The doseresponse activity indicated that vegetative parts extract showed the greatest allelopathic potential followed by root parts extract. Subsequently, mucilage extract had a moderate inhibitory potential, while root exudates showed the least activity. The same trend with slight response was detected in soil properties of pH and EC properties. Polyphenols, in the range of 5.70–0.211 mg · g–1 and flavonols, in the range of 2.392–0.00 mg · g–1, were found in the analyzed samples extracted by ethyl acetate using LC-DAD-MS. The total phenol amount was 1.67 to 1.89 in the rhizosphere and 0.53 to 087 mg · g–1 in non-rhizosphere soils. Solanum elaeagnifolium exhibited a greater significant suppression of fungi count in both high and low-density areas than in rhizosphere bacteria. In conclusion, the strong and broadspectrum allelopathic potentials may enhance the ability of S. elaeagnifolium to impact seed germination and seedling growth of neighboring species. These biochemical weapons may play a critical role to facilitate their invasion and establishment in new agroecosystems.

Determination of interference periods, competitive ability and economic threshold level ( ETL) are important tools for integrated weed management (IWM) in barley. The objective of the work was to determine the periods of interference, the competitive ability and the ETL of weeds in barley ( Hordeum vulgare). Two field experiments were carried out, in a randomized block design, with four replications. In this study, the periods of coexistence and control for ryegrass ( Lolium multiflorum) and turnip ( Raphanus raphanistrum) infesting barley cultivar, cv. ANA 01 were evaluated. The coexistence periods and/or control were: 0, 7, 14, 21, 28, 35, 42 and 120 days after barley emergence (DAE). In experiment 2the treatments for determination of ETLs were composed by barley cultivars (BRS Suábia, ANA 01, BRS Korbel, BRS Manduri, BRS Cauê and BRS Greta), and turnip densities, from zero (0) to maximum densities of 816, 788, 948, 394, 584 and 618 plants · m−2, in competition with each cultivar. Control of turnip and ryegrass should be adopted in barley in the period between 12 to 22 DAE, which is described as a critical control period. The rectangular hyperbola adequately estimates losses in grain yield due to turnip infestation. There is an effect on the competitive ability of the cultivars in relation to turnip, which resulted in ETLs that ranged from 0.27 to 1.99 plants · m−2. The cultivars BRS Greta, BRS Suábia, ANA 01 and BRS Manduri were the most competitive in the presence of turnip.

The aim of this study was to investigate qualitative and quantitative chemical compounds of plant water extract (PWE), and the reduction potential of Corum herbicide (bentazone and imazamox) doses using PWE for weed control in faba bean fields. Chemical analysis revealed the presence of diverse allelochemicals including polyphenols, flavonoids, and terpenoids. The field experiment results showed clear differences between the measured traits in response to the applied treatments. The application of Corum at 1.5 l · ha ^–1, at 0.75 l · ha ^–1, and at 0.75 l · ha ^–1 + PWE significantly reduced weed density and biomass, with a weed control efficiency of 75.5–78.4, 57.4–53.3 and 68.2–56.9 % during the first-second cropping seasons, respectively. Meanwhile, Corum at 1.5 l · ha ^–1 and at 0.75 l · ha ^–1 + PWE treatments guaranteed approximately the same yield components and improved the faba bean yield (Q · ha ^–1) by 65 and 40% in 2018–2019 and by 91 and 85% in 2019–2020, respectively. Therefore, the results suggest that PWE in combination with a lower herbicide dose (up to 50%) could be used as a potential weed management strategy in faba bean. Further research is required to understand the phytotoxic mechanisms of the studied extract-herbicide mixtures and their modes of action.