Black root rot, caused by Macrophomina phaseolina (Tass.) Goid., is the most common root disease in soybean fields. This study aimed to determine the in vitro mycelial sensitivity, measured by the IC50 (concentration to inhibit 50% of the fungus mycelial growth) of a M. phaseolina isolate obtained from soybean, to different fungicides (thiram, iprodione, carbendazim, pyraclostrobin, fluquinconazol, tolyfluanid, metalaxyl and penflufen + trifloxystrobin), at six concentrations (0.01 mg L-1, 0.10 mg L-1, 1.00 mg L-1, 10.00 mg L-1, 20.00 mg L-1 and 40.00 mg L-1 of the active ingredient). The 0.00 mg L-1 concentration represented the control, without fungicide addition. The mycelial growth evaluation was performed with the aid of a digital pachymeter, by measuring the colonies diameter, when the fungus growth in the control treatment reached the Petri dish edge. The experimental design was completely randomized, with four replications. Concerning the fungitoxicity of active ingredients, a variation from non-toxic to highly fungitoxic was observed to the M. phaseolina isolate, with IC50 values ranging from 0.23 mg L-1 to > 40.00 mg L-1, being carbendazim the most efficient one (IC50 = 0.23 mg L-1). The fungus showed insensitivity to the active ingredients of fluquinconazole, metalaxyl, thiram and tolyfluanid.

No abstract

No abstract

El cacao (Theobroma cacao L.) es uno de los principales cultivos de importancia económica en el Ecuador, principalmente para los pequeños y medianos agricultores del litoral. Sin embargo, las enfermedades fungosas reducen el rendimiento de este cultivo. Durante los años 2008 a 2011 se evaluó en las localidades Quevedo y Tenguel, el comportamiento de 10 clones experimentales de cacao tipo Nacional con el objetivo de seleccionar los de mayor productividad y tolerancia a dos enfermedades: moniliasis (Moniliophthora roreri) y escoba de bruja (Moniliophthora perniciosa), en comparación con dos testigos comerciales (EET-103 y CCN-51). El diseño experimental fue de bloques completos al azar con arreglos factorial, con cuatro repeticiones. Se registró el número de escobas de bruja vegetativas, porcentaje de mazorcas enfermas, número de mazorcas sanas y totales, así como el rendimiento de almendras secas de cacao. El clon comercial CCN-51 presentó la menor incidencia de enfermedades, así como la mayor producción de mazorcas sanas y rendimiento promedio de almendras (1047.7 kg ha-1). Cuatro clones experimentales presentaron características deseables: L46-H57 con una mayor producción de mazorcas sanas y totales, L21-H43, L46-H57 y L46-H88 con un rendimiento de almendras superior a 550 kg ha-1, L18-H58 con el menor número de escoba de bruja (7.3), y L21-H43 con la menor incidencia de mazorcas enfermas (37.0 %). Estos clones pueden ser utilizados en programas de mejoramiento y conservación. La incidencia de enfermedades fúngicas y el rendimiento de almendras secas de cacao fueron mayores en Quevedo que en Tenguel.

Vegetable crops are exposed to constant infection by numerous diseases, including those caused by the oomycete Phytophthora capsici. This microorganism is a polyphagous plant pathogen, capable of infecting dozens of plant species, including cultivated plants and weeds. The aim of this review is to address topics related to etiology and symptoms of the diseases caused by this oomycete (leaf blight, root rot, crown rot and fruit rot), as well as the integration and application of different control alternatives, such as genetics, cultural, physical, biological, and chemical. Crops such as sweet pepper (Capsicum annuum), chili pepper (Capsicum spp.), tomato (Solanum lycopersicum), eggplant (S. melongena), cucurbits (Cucumis sativus, Cucurbita spp.), among others, are subject to considerable economic losses induced by this pathogen. High soil humidity, high temperatures, resistance structures of the pathogen (oospores), scarce availability of resistant cultivars and a reduced range of effective fungicides are conditions that difficult the management of diseases caused by P. capsici in the field. Despite the irrefutable importance of this pathogen, the existing information regarding its integrated management is limited. Therefore, a successful management will depend to a great extent on its knowledge and its control. Thus, the joint application of different control strategies seeks to maintain the pathogen at low population levels and also keeping the epidemics under the threshold of economic loss. At the end, an integrated pest management approach for P. capsici could result in higher economic returns, long-term sustainable harvests, reduction of the environment impact and better quality products for consumers.