Glyphosate is a non-selective broad-spectrum herbicide. Although the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC) have classified it as probably carcinogenic to humans, the indiscriminate use of this herbicide in agriculture continues today, as a consequence of its low cost and effectiveness, as well as of the large number of generic products available. In addition to the adverse health effects, the massive use of glyphosate has caused environmental problems which have direct and indirect effects on agroecosystems. With the introduction of resistant transgenic crops, the use of this herbicide has increased fifteenfold since 1996. Just in the last 26 years, 350 cases of glyphosate resistance among weeds have been reported worldwide; however, multiple resistance has been recorded in 23 weed species in 17 countries around the world. In the future, the dependence on this herbicide will result in multiple resistance among weeds, not only in Mexico, but in more parts of the world than those that have been reported to date.

La pudrición de raíz y tallo de plantas del melón, es un factor limitante en la producción del cultivo. El uso indiscriminado de fungicidas, ha causado problemas de resistencia y contaminación ambiental en las áreas agrícolas de México. Una alternativa es el uso de agentes microbianos como Trichoderma, Bacillus y Streptomyces, los cuales favorecen el manejo y control de la enfermedad, inducen el crecimiento y aumentó de la cosecha. Este trabajo se realize, con el objeto de aislar e identificar al agente causal de la pudrición radical del melón en la región de Paila, Municipio de Parras de la Fuente, Coahuila y su control con agentes microbianos. Se recuperaron seis aislamientos, de la misma cantidad de áreas de cultivo, identificados morfológicamente como especies distintas del Género Fusarium. Molecularmente y con base en las secuencias de nucleotidos de las regiones ITS1 e ITS4, se encontró porcentajes de identidad del 97-100 % correspondientes a Fusarium oxysporum y Fusarium solani. Bioensayos de antagonismo in vitro, mostraron que Trichoderma asperellum inhibió hasta un 74%, Bacillus subtillis 46 % y Streptomyces mutabilis 35 %, para las cepas de Fusarium. Los agentes microbianos representan un recurso para el biocontrol de la pudrición radical y del tallo del cultivo de melón.

Synthetic chemicals are mainly used for the control of fungal diseases in tomato, causing the phytopathogens to generate resistance to the chemical active ingredient, with a consequent risk to human health and the environment. The use of plant extracts is an option for the control of these diseases, which is why the main objective of this research was to study an alternative biocontrol strategy for the management of plant diseases caused by fungi through obtaining polyphenol extracts from mistletoe plants growing on three different tree species—mesquite (Prosopis glandulosa), cedar (Cedrus), and oak (Quercus), which contain flavones, anthocyanins, and luteolin. The overall chemical structure of the obtained plant extracts was investigated by RP-HPLC-ESI-MS liquid chromatography. The antifungal effect of these extracts was examined. The target phytopathogenic fungi were isolated from tomato plantations located in Altamira, Tamaulipas, Mexico. The microorganisms were characterized by classical and molecular methods and identified as Alternaria alternata, Fusarium oxysporum, Fusarium sp., and Rhizoctonia solani.

Fusarium oxysporum y Rhizoctonia solani son agentes causales de la marchitez del chile y provocan pérdidas hasta 80% en el cultivo en México. El uso inadecuado de fungicidas químicos ha generado problemas de resistencia, esto no se observó con agentes microbianos, por lo que se evaluaron en el biocontrol de la marchitez del chile en parcelas experimentales donde se identificó a F. oxysporum y R. solani como agentes causales de la enfermedad. Trichoderma spp., Bacillus spp., mezcla de fermento propagativo microbiano, Tiabendazol y testigo, fueron aplicados en una parcela de 800 m2 con seis variedades de chile. Los tratamientos Trichoderma y fermento propagativo mostraron bajos porcentajes de incidencia y severidad, altos rendimiento con Trichoderma en HS- 52 y Coloso (15.67 y 13.89 t ha-1). Los tratamientos Trichoderma y fermento propagativo promueven el biocontrol de la marchitez del chile provocada por F. oxysporum y R. solani e incrementar el rendimiento.

One of the phytopathogens that cause severe damage to jalapeño pepper is Leveillula taurica (Lév.) Arnaud, the causative agent of powdery mildew. Synthetic fungicides are currently employed for its control, contributing to adverse effects on human health and the environment. The main objective of this research was to identify the causal agent of powdery mildew and assess the efficacy of chitosan in powdery mildew control on jalapeño pepper. The following treatments were evaluated in laboratory and greenhouse conditions: T1 = 0.0125% chitosan, T2 = 0.0025% chitosan, T3 = 0.05% chitosan, T4 = 0.1% chitosan, T5 = 0.2% chitosan, T6 = tebuconazole 25% (1.8 mL/L water), and T7 = control (water). Symptomatology results indicated that L. taurica is indeed the causative agent of powdery mildew. Treatments T4 and T5 exhibited the lowest percentages of incidences and severity, hence achieving higher control efficacy in the laboratory (57.70 ± 3.85 and 65.39 ± 3.85) and greenhouse (56.67 ± 4.08 and 70 ± 8.16%) compared to T6 (control efficacy, 38.46 ± 0.00% in the laboratory and 50 ± 0.00% in the greenhouse). The chitosan derived from shrimp had a significant impact on the cell walls of L. taurica spores and mycelium. Consequently, chitosan emerges as a viable organic alternative to fungicides for controlling powdery mildew in jalapeño pepper.

The production of the pepper seedling (Capsicum annuum) is affected by the fungal complex that causes the ‘damping-off’, in which some species of the oomycete Pythium spp., stand out. The objective of the present study was to identify the causal agent of the death of pepper plants and evaluate its pathogenicity in pepper seeds and seedlings. A fast and aggressive growing oomycete was isolate from pepper plants, morphologically identified as P. aphanidermatum based on its sexual and asexual reproduction structures and, by molecular techniques. This isolate had a high degree of in vitro pathogenicity in pre-emergence and post-emergence in chile, showing 100% mortality. In addition, it presented a high rate of mycelial growth in different culture media (V8-Agar, Corn Agar, Corn Potato Agar, Potato Dextrose Agar, Czapek & Oat Agar), being in V8-Agar medium the only medium where it developed reproduction structures sexual and asexual. The isolation presented a mycelial growth rate of 58.3 ± 0.3 mm / day at 26 ± 2 °C in PDA medium. Due to its rapid growth and its high degree of pathogenicity in vitro, it is an unusual and aggressive isolate for pepper seedlings.