Macrophomina phaseolina and Rhizoctonia solani are considered two major soil-borne pathogens of Phaseolus vulgaris in Cuba. Their management is difficult, not only due to their intrinsic biology as soil-borne pathogens, but also because the lack of active ingredients available against these pathogens. Actinobacteria, a heterogeneous bacterial group traditionally known as actinomycetes have been reported as promising biological control agents (BCAs) in crop protection. Thus, the main objective of this study was to evaluate the effectiveness of 60 actinobacterial strains as BCAs against M. phaseolina and R. solani in vitro by dual culture assays. The most effective strains were characterized according to their cellulolytic, chitinolytic and proteolytic extracellular enzymatic activity, as well as by their morphological and biochemical characters in vitro. Forty and 25 out of the 60 actinobacteria strains inhibited the mycelial growth of M. phaseolina and R. solani, respectively, and 18 of them showed a common effect against both pathogens. Significant differences were observed on their enzymatic and biochemical activity. The morphological and biochemical characters allow us to identify all our strains as species belonging to the genus Streptomyces. Streptomyces strains CBQ-EA-2 and CBQ-B-8 showed the highest effectiveness in vitro. Finally, the effect of seed treatments by both strains was also evaluated against M. phaseolina and R. solani infections in P. vulgaris cv. Quivicán seedlings. Treatments combining the two Streptomyces strains (CBQ-EA-2 + CBQ-B-8) were able to reduce significantly the disease severity for both pathogen infections in comparison with the non-treated and inoculated control. Moreover, they showed similar effect than that observed for Trichoderma harzianum A-34 and with Celest^® Top 312 FS (Syngenta^®; Basilea, Switzerland) treatments, which were included for comparative purposes.

Verticillium wilt of olive (VWO) caused by Verticillium dahliae is considered a major olive (Olea europaea) disease in Mediterranean-type climate regions. The lack of effective chemical products against VWO makes it necessary to search for alternatives such as biological control. The main goal of this study was to evaluate the effect of six Streptomyces spp. strains as biological control agents (BCAs) against VWO. All of them were molecularly characterized by sequencing 16S or 23S rRNA genes and via phylogenetic analysis. Their effect was evaluated in vitro on the mycelial growth of V. dahliae (isolates V004 and V323) and on microsclerotia (MS) viability using naturally infested soils. Bioassays in olive plants inoculated with V. dahliae were also conducted to evaluate their effect against disease progress. In all the experiments, the reference BCAs Fusarium oxysporum FO12 and Aureobasidium pullulans AP08 were included for comparative purposes. The six strains were identified as Streptomyces spp., and they were considered as potential new species. All the BCAs, including Streptomyces strains, showed a significant effect on mycelial growth inhibition for both V. dahliae isolates compared to the positive control, with FO12 being the most effective, followed by AP08, while the Streptomyces spp. strains showed an intermediate effect. All the BCAs tested also showed a significant effect on the inhibition of germination of V. dahliae MS compared to the untreated control, with FO12 being the most effective treatment. Irrigation treatments with Streptomyces strain CBQ-EBa-21 or FO12 were significantly more effective in reducing disease severity and disease progress in olive plants inoculated with V. dahliae compared to the remaining treatments. This study represents the first approach to elucidating the potential effect of Streptomyces strains against VWO.

Given the importance of using endophytic bacteria for the control of cocoa diseases, the objective of this study was to build the phylogenetic tree and characterize the endophytic endospore-forming bacteria based on the cropping altitude, age and tissue of the cocoa plant in a producing area of the Esmeraldas province, in Ecuador. The isolation of bacteria was done from healthy pods and flower pedicels from cocoa Criollo Type Nacional cultivar. Forty-five endospore forming endophytic bacteria were recovered from healthy pods and flowers pedunculus, mainly from endocarp. No association was found between the number of bacterial isolates and the age of the fruit, although there was a slight tendency for the isolates to decrease towards the higher altitude sites.

Dada la importancia de las investigaciones relacionadas con el uso de Bacillus endófitos como agentes de control biológico de Moniliophthora roreri, el objetivo de este estudio fue evaluar el efecto de cuatro cepas de este género bacteriano en la protección de Theobroma cacao L. frente al agente causal de la moniliasis en una zona productora de la provincia de Esmeraldas, Ecuador. El experimento se realizó en una plantación establecida con el genotipo de cacao EET-103 tipo Nacional de 14 años de edad, con un marco de 3 x 3 m, sobre un suelo Andisol, bajo un diseño de bloques completos al azar, con seis tratamientos y cinco réplicas. Se hicieron tres aplicaciones con una frecuencia mensual. Se evaluó la incidencia y severidad externa en la mazorca durante los 90 días de desarrollo con una frecuencia quincenal. Cuando las mazorcas alcanzaron la madurez de cosecha se abrieron longitudinalmente y se determinó el porcentaje de severidad interna. Todas las cepas mostraron efecto de biocontrol sobre M. roreri en condiciones de campo, sobresaliendo Bacillus sp. 33 y B. amyloliquefaciens 24, aisladas del mesocarpio del fruto, con valores de incidencia promedio entre 4,4 y 7,6 %, severidad externa entre 3,6 y 6,2 % e interna entre 22-30 %, respectivamente. La aplicación de cepas de Bacillus endófitos constituye una alternativa biológica para reducir las afectaciones ocasionadas por la moniliasis en los agroecosistemas cacaoteros.

The present work aimed to evaluate the agro-productive response of bell pepper 'Robur F1' and 'Clair F1' hybrids. The experiment was conducted in a tropical sheltered production system at the "Valle del Yabú" Agricultural Enterprise. The experimental design was a randomized complete block with four replicates. The height and diameter of the main stem, length of internodes, and number of days to flowering were evaluated. Additionally, the number of fruits per plant, average fruit weight and yield, and fruit quality attributes (thickness of the pericarp, length, top width, color, shape, and number of lobes) were recorded. Results showed that 'Robur F1' reached a higher height (33.9 cm), the diameter of the main stem (12.9 mm) and the length of the internodes (9.84 cm). 'Clair F1' showed the highest number of fruits per plant (12), average fruit weight (273.60 g), and yield (3.87 kg/m2). A higher pericarp thickness and fruit width were observed in 'Clair F1', while the fruit was longer in 'Robur F1 (13 cm). Both hybrids had green bell peppers and fruits. With the knowledge of agro-productive characteristics of both pepper hybrids, Cuba may select the most remarkable genotype under a tropical sheltered production system. Keywords: agricultural yield, Capsicum annuum, fruit quality, morphological traits.