Evaluating the Antifungal Potential of Botanical Compounds to Control Botryotinia fuckeliana and Rhizoctonia solani

The European Union is promoting regulatory changes to ban fungicides because of the impact their use has on the ecosystem and the adverse effects they can pose for humans. An ecofriendly alternative to these chemicals to fight against fungal species with low toxicity is essential oils and their compounds extracted from aromatic plants. The purpose of this study was to evaluate the in vitro antifungal capacity of the botanical compounds eugenol, carvacrol, thymol, and cinnamaldehyde, and the synergy or antagonism of their mixtures, against Botryotinia fuckeliana and Rhizoctonia solani. Different bioassays were performed at doses of 300, 200, 150, and 100 µg/mL using pure commercial compounds and their combination in potato dextrose agar culture medium. Growth rate and the mycelium growth inhibition parameters were calculated. Phenolic compounds and their combination inhibited the development of species at the different concentrations, with fungicidal or fungistatic activity shown under almost all the tested conditions. When comparing the growth rates of the species in the control plates and treatments, the statistical analysis showed that there were statistically significant differences. The mixture of compounds improved fungicidal activity against the studied species and at a lower concentration of monoterpenes.

Phenotypic and Genetic Characterization of Botrytis cinerea Population from Kiwifruit in Sichuan Province, China

Botrytis cinerea (anamorph of Botryotinia fuckeliana) causes gray mold on numerous plants, including kiwifruit. The primary aim of this study was to investigate the phenotypic and genetic characteristics of the Botrytis cinerea population from kiwifruit in Sichuan Province, China. In all, 176 isolates were collected from kiwifruit orchards from eight geographic regions in Sichuan. All isolates were identified as B. cinerea sensu stricto based on the combined datasets, including morphological criteria, determination of the Bc-hch allele, and phylogenetic analysis of the genes RPB2, G3PDH, and HSP60. Three colony types (i.e., sclerotial, mycelial, and conidial) were observed on potato dextrose agar after 2 weeks, with sclerotial isolates, the predominant category, accounting for 40.91%. No obvious differences in microscopic characteristics were observed among the three types. Three genotypes of transposable elements were identified in the B. cinerea population: boty, flipper, and transposa types. The most prevalent genotype from different geographic populations of B. cinerea was transposa; in contrast, the flipper genotype accounted for only 3.98% of the total population, whereas the vacuma genotype was absent. According to MAT locus amplification, 87 and 89 isolates are MAT1-1 and MAT1-2 type, respectively, and the two mating types were found to be balanced overall in the population. Forty-eight representative isolates were all able to cause gray mold to some extent, and disease severities were significantly different between the cultivars Hongyang and Hort16A (P < 0.01). Disease severity was significantly greater on young leaves than on mature leaves (P < 0.01). No significant relationship was found between pathogenicity and geographical region, colony type, or transposon distribution. The results obtained in the present study suggest a relatively uniform species diversity of Botrytis but rich phenotypic and genetic differentiation within the B. cinerea population on kiwifruit in China. Utilizing resistant cultivars and rain-shelter cultivation instead of fungicides may be an effective approach to delaying pathogen variability.

Arreglo espacial de cultivares de crisantemo (Dendrathema grandiflora) para disminuir daño por Botrytis

<p><em>Botrytis cinerea</em> (Teleomorfo: <em>Botryotinia fuckeliana)</em> es el agente causal de la pudrición gris en crisantemo (<em>Dendrathema grandiflora</em>), uno de los cultivos más importantes de flor de corte en México. Chena (Ch), cultivar de mayor demanda comercial, es más susceptible a dicho hongo respecto de cultivares como Flamingo (F) y Moreliana (M). En ésta investigación, se evaluó la incidencia de <em>B. cinerea</em> y la calidad del tallo floral en el cultivar Chena, bajo tres arreglos espaciales: A1, Chena flanqueada por Flamingo (F-Ch-F); A2, Chena flanqueada por Moreliana (M-Ch-M) y A3 solamente Chena (Ch-Ch-Ch). Al corte del capítulo floral, <em>B. cinerea</em> se presentó solamente en A3 (22 %) y en vida de florero a los 16 días, Chena en A3 mostró 100 % de infección, seguido de A1 y A2 con 15 y 0 %, respectivamente. La calidad del tallo floral de Chena (altura, diámetro del capítulo, grosor del tallo) en los arreglos A1 y A2 fue significativamente mayor (<em>P?0.05</em>) respecto a A3. La baja incidencia de <em>B. cinerea</em> en Chena en A1 y A2 indica que Flamingo y Moreliana actuaron como barreras laterales que pueden ser útiles para disminuir la incidencia de la enfermedad y el uso de fungicidas.</p>