Pantoea agglomerans has been reported as the cause of chlorotic streaks on maize leaves in the Central High Valleys of México (CVHM), but there are no current data of how the infection of this new pathogen in Mexico affects production and yield of the crop. To understand the development of the disease in the crop, two experiments with a split-plot design and three replications were established during spring-summer 2010 in different microenvironments: Ayapango and Temamatla. Three cultivars of maize (a tri-linear HS2 hybrid, the single-cross hybrid Triunfo and the native Cacahuacintle) were evaluated with three P. agglomerans isolates. In the three maize cultivars, chlorotic streaks appeared on new leaves; at the ripening stage, the symptoms were less perceptible. The average incidence of plants with chlorotic streaks was higher in the town of Temamatla than in Ayapango, and in both microenvironments, the average degree of severity was less than 40%. Isolate A was the most virulent (P < 0.0001) on the three cultivars evaluated. These results will provide the basis for effective management of the disease under environmental conditions similar to those evaluated in this research.
The species<em> Opuntia ficus-indica</em> is affected by pests and diseases, one of the most important of these being golden spot. The latter has been reported in various countries, including Mexico. Symptoms similar to those of golden spot in <em>O. ficus-indica</em> have been observed in the xoconostle crop (<em>Opuntia matudae</em> Scheinvar, cv. Rosa). The objective of this study was to isolate and identify the causative agent that causes the symptoms, which resembled those of the disease described as golden spot in <em>O. ficus-indica</em>. Simple random sampling in the field (10 plots) was carried out on xoconostle plants that presented the described symptoms. Slices of diseased plant tissue were cut and placed in Petri plates with PDA medium. Compliance with Koch’s postulates showed that the isolated (one aislated) of <em>Alternaria</em> sp. obtained from the field samples colonized the cladodes after inoculations in the greenhouse. Through taxonomic keys, <em>Alternaria</em> sp. was identified as the causative microorganism. Molecular characterization of the isolated <em>Alternaria</em> sp. was identified as <em>Alternaria</em> <em>alternata</em>. This is the first report worldwide of <em>Alternaria alternata</em> as the causal agent of golden spot in a xoconostle crop.
El objetivo de la presente revisión es dar a conocer el estatus epidemiológico de Phytophthora cinnamomi Rands en interacción con Persea americana Mill. y las alternativas de manejo fitosanitario autorizadas. El ensayo se realizó con base en reportes de instancias oficiales y científicas en materia de sanidad vegetal, de brotes epidemiológicos de la enfermedad tristeza del aguacate causada por P. cinnamomi. A nivel mundial, la pérdida de árboles de aguacate fue exponencial, debido a la enfermedad causada por el oomiceto P. cinnamomi quien presentó comportamiento epidemiológico a nivel nacional e internacional. En 1942, en Puerto Rico el patógeno fue aislado por primera vez por Tucker en plantas de aguacate. En México, el primer brote epidemiológico por este patógeno fue en 1952, con pérdidas de 90% de la producción de aguacate, la distribución de la enfermedad se expandió a diferentes partes del mundo. En condiciones favorables afecta la raíz y base de la corona, invade haces vasculares y toma los nutrientes para su desarrollo. La patogénesis es influenciada por la temperatura, precipitación, humedad, pH, disponibilidad de nutrientes y textura del suelo. En campo, la efectividad biológica de las moléculas, para el control del oomiceto, puede presentar limitantes que impactan en la microbiota, flora y fauna; además, de los efectos que se reflejan en la calidad e inocuidad de frutos por la acumulación de moléculas de plaguicidas sintéticos. Dada la situación fitosanitaria que expresa la producción de aguacate es necesario implementar alternativas de manejo sustentable, como la endoterapia, a través de la inyección de productos selectivos en dosis específicas, que controlen a la enfermedad sin afectar la calidad e inocuidad del fruto.
Mexico has 159 species of Agave spp. In the agri-food industry stand out are Agave tequilana, A. angustifolia, and A. salmiana. A limitation to producing maguey seedlings is the low availability of organic substrates that favor plant adaptation in the field. The objective was to evaluate the effect of nitrogen (N), phosphorus (P) and potassium (K) found in substrates in response to vegetative and root growth of A. salmiana in agricultural areas of Huichapan, Hidalgo, Mexico. The treatment consisted of earthworm humus (EH) and leaf compost (LC) substrates with materials from the region with different percentages of EH (100, 75, 50%), LC (5, 10%), and sand (20, 40%). The treatments were applied with 14 random replications in two phases in seeds and 40-day-seedlings. The variables evaluated were NPK amount and pH in substrates. The physiological variables measured were plant height, leaf number, stem diameter, root length, and volume. Significant differences (P?0.05) were observed in seedling physiology due to the effect of the treatment. The best agronomic responses (plant growth and root length/weight) of Agave seedlings were T5 (75% earthworm humus + 20% sand + 5% leaf-soil) and T6 (50% earthworm humus + 40% sand + 10% leaf-soil); in both treatments, the NPK percentages were different from the control (Haplic Phaeozem soil) group. The final concentration of NPK in T6 was N = 0.04%, P = 398.13 mg Kg-1 and K = 11.88 meq 100g-1. The results infer that NPK availability in soil and progressive acidification (initial pH = 8.6, final pH = 7.4) of the substrate can favorably influence the plant response. The interactions between NPK availability in the substrate and their use for a better response in maguey seedling adaptability open up new lines of research on the productive systems in the region of Huichapan, Hidalgo, Mexico.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.