The essential oils of plants of the genus Piper have secondary metabolites that have antimicrobial activity related to their chemical composition. The objective of our work was to determine the chemical composition and evaluate the antifungal activity of the aerial part essential oil of P. auritum obtained by hydrodistillation on Fusarium oxysporum and Fusarium equiseti isolated from Capsicum chinense. The antifungal activity was evaluated by direct contact and poisoned food tests, and the minimum inhibitory concentration (MIC50) and maximum radial growth inhibition (MGI) were determined. The identification of oil metabolites was carried out by direct analysis in real time mass spectrometry (DART-MS). By direct contact, the essential oil reached an inhibition of over 40% on Fusarium spp. The 8.4 mg/mL concentration showed the highest inhibition on F. oxysporum (40–60%) and F. equiseti (>50%). The MIC50 was 6 mg/mL for F. oxysporum FCHA-T7 and 9 mg/mL for F. oxysporum FCHJ-T6 and F. equiseti FCHE-T8. DART-MS chemical analysis of the essential oil showed [2M-H]− and [M-H]− adducts of high relative intensity that were mainly attributed to eugenol and thymol/p-cimen-8-ol. The findings found in this study show a fungistatic effect of the essential oil of P. auritum on Fusarium spp.

The present study aimed to identify the phytochemicals of methanolic extract from Baccharis glutinosa (chilca) roots (MEBg) and to evaluate its antifungal activity on two major fungal pathogens of agricultural importance. The antifungal activity was evaluated by inhibition halo, minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and % sporulation against A. ochraceus and F. moniliforme. As-1 a preliminary test, inhibition halo was tested using 1, 10, 100 and 270 mg ml of MEBg. Different concentrations of MEBg were applied for MIC and MFC tests. Ketoconazole was used as positive control. The treatments were applied in triplicate. The phytochemical compounds of MEBg were determined by GC-MS analysis. The MEBg produced an inhibition zone of 2 to 4 mm in the inhibition halo test, with concentrations-1 of 100 and 270 mg ml for A. ochraceus and F. moniliforme, respectively. Reduction in % sporulation above-1 50 was shown in concentrations over 8 mg ml. MEBg were reported to exhibit antifungal activities against A.-1 ochraceus and F. moniliforme with the MIC values ranging from 2 to 5.6 mg•ml and the MFC from 12 to 15-1 mg ml. GC-MS analysis of Chilca extracts revealed that the most abundant metabolites were furfural compounds and organic acids. The most abundant furfural compounds were 5-(hydroxymethyl) furan-2carbaldehyde (38.59%), furan-2-carbaldehyde (4.103%) and 5-methylfuran-2-carbaldehyde (2.1%). The MEBg revealed efficient antifungal activity, likely due to the presence of bioactive compounds, which could be used as an alternative for biological control of pathogenic fungi in maize and coffee crops.

La jamaica (<em>Hibiscus</em> <em>sabdariffa</em>) es afectada por severas enfermedades como tizón y manchado del cáliz (MCJ). El objetivo fue estudiar las relaciones entre fluctuación estacional de esporas de <em>Corynespora</em> y <em>Coniella</em> patógenos del manchado y tizón de cálices y hojas, las condiciones de clima y severidad (MCJ) en Ayutla, Gro., México. Las esporas fueron monitoreadas en dos ciclos, se aislaron los hongos y se realizó la identificación morfológica y molecular de <em>Coniella</em> el estudio se centró en patógenos reportados en México. Las pruebas de patogenicidad con <em>C. diplodiella</em> y <em>C. cassiicola</em> confirmaron la sintomatología muy similar entre ambos hongos. <em>Coniella</em> fue el más abundante (48%) y con menos cantidad <em>Corynespora</em> (8.7%). La dinámica de esporas tuvo una fluctuación mensual y relacionada con el clima. Las temperaturas máximas y medias (°C) y promedio de radiación global (W/m2) mostraron correlaciones positivas significativas con la abundancia de esporas de <em>Coniella</em> y el total de esporas, mientras que la precipitación (mm), temperatura mínima, velocidad del viento máxima (Km h-1) y horas de radiación solar, sus relaciones fueron negativas con las fluctuaciones de esporas de <em>Corynespora</em>. La severidad del manchado de hojas y cálices fue correlacionada positiva y significativa con el número de esporas capturadas.

Black Sigatoka is the main constraint to banana production worldwide, and epidemic outbreaks are continuously causing huge losses. Successful management of diseases requires a profound knowledge of the epidemiological factors that influence disease dynamics. Information regarding alternative hosts of Pseudocercospora fijiensis, the causal agent, is still very scarce. To date, only Heliconia psittacorum has been reported as an alternative plant host, and we hypothesized that other plants can house P. fijiensis. In the present report, ten plant species with suspicious leaf spots were collected inside and around commercial banana crops in Mexico. Diagnostic PCR gave positive amplification for six of these plant species, and DNA sequencing confirmed the presence of the pathogen in four. This is the first report of the presence of P. fijiensis in unrelated plants and it represents a breakthrough in the current knowledge of black Sigatoka. This finding is very important given the polycyclic nature of this disease whose successful management requires the control of initial inoculum to minimize epidemic outbreaks. The results presented herein can be used to introduce innovations in integrated black Sigatoka management programs to reduce initial inoculum, and help the international initiative to reduce the use of fungicides in banana production.

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