Background Use of phytopathogenic fungi for the biocontrol of weeds represents a promising path in the search for new management alternatives that allow reducing negative effects on the environment and the generation of biotypes having resistance to herbicides. The first step in developing weed biological control programs is to determine the plants and their natural enemies with the highest affinity and potential to achieve effective biocontrol. The objective of the present study was to evaluate the phytopathogenic potential of fungal isolates on four economically important weeds including: Rumex crispus L., Digitaria horizontalis Willd, Persicaria nepalensis (Meisn.) Miyabe, and Thunbergia alata Bojer ex Sims, as a possible biocontrol agent. Results Morphological and molecular identification of nine phytopathogenic isolates of weeds was achieved, according to the sequencing of the ITS, β-Tub2, and TEF1-α regions. Pathogenicity of the following species on original hosts was confirmed: Colletotrichum cigarro, Epicoccum draconis, and Didymella rumicicola on R. crispus; Bipolaris sp., on D. horizontalis; Bipolaris zeicola, Phialemoniopsis curvata, and Stemphylium beticola on P. nepalensis and, Alternaria thunbergiae and Nigrospora sphaerica on T. alata. These could be, fairly, considered the first worldwide reports of such interactions, except for A. thunbergiae and Bipolaris sp. The most virulent interactions according to the AUDPC value corresponded to (R. crispus × D. rumicicola), (D. horizontalis × Bipolaris sp.), (P. nepalensis × S. beticola) and (T. alata × A. thunbergiae), with an incidence of 100%. Conclusion These strains were proposed for future research as potential biocontrol agents, which represented a great resource for the possible generation of new bio-herbicides.

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Este artículo muestra las aproximaciones interdisciplinarias que integran conocimientos respecto a los suelos de cementerios contemporáneos y antiguos e inhumaciones clandestinas que producen interés científico bio-geo-arqueológico, forense reciente, lo anterior es lo que compila el estudio de los Necrosoles. Las investigaciones al respecto, plantean interrogantes pedogenéticos, antropogénicos, morfológicos, de características físico-químicas y microbiológicas. Así los Necrosoles se definen con precisión e incluyen en propuestas para sistemas taxonómicos locales y mundiales. Los suelos de los cementerios tienen propiedades físico-químicas y microbiológicas variables, antrópicas, temporalidades e insumos orgánicos e inorgánicos exógenos y predominancia de procesos de cambio ambiental. Actualmente, las necrópolis en las urbes y la proximidad a fuentes de agua e impactos de estos suelos en la salud pública y ambiente, se evalúan en investigaciones científicas. También aumenta el interés por las características de entierros ilegales de cuerpos humanos e integración de herramientas pedológicas y forenses. Revisamos los estudios de Necrosoles y el desarrollo de la investigación científica experimental ligada a efectos e implicaciones de entierros humanos

Pteridium aquilinum (L.) Kuhn is a cosmopolitan plant with great competitive abilities, including allelopathy. The search for plants with negative allelopathic effects on other undesirable plants has led to the discovery of new useful substances for weed control. The objective of this research was to evaluate the allelopathic effect of P. aquilinum on seed germination and growth of four economically important weeds: Bidens pilosa L., Brachiaria decumbens Stapf, Emilia sonchifolia (L.) DC. ex DC and Rumex crispus L. Two experiments were conducted under laboratory and greenhouse conditions using extracts and dried plant residues of P. aquilinum, respectively. For the first experiment, extracts of bracken were obtained using four different solvents (hexane, dichloromethane, ethyl acetate, and methanol) and applied to the test seeds; germination rates were determined. For the second experiment, dry residues of bracken were applied to the soil at concentrations of 2, 5, and 10% and their effect on weed growth variables was determined; a control treatment (no appliacation) was also included. In addition, the presence of some chemical groups associated with each type of extract was qualitatively detected. The extracts inhibited seed germination by 52 -97% in all the studied species. Dichloromethane and methanol were the most efficient solvents, while E. sonchifolia was the most sensitive species. The dry residues of bracken reduced germination by 18 -44% of all the weeds, as well as root length of Bidens pilosa (-30%) and Brachiaria decumbens (-82%). The phytochemical analysis showed the presence of flavonoids, tannins, and polyphenols in the extracts. These results suggest that P. aquilinum can be a good alternative for the biocontrol of the weeds under study and provide knowledge for the development of bioherbicides.