Management of black pod rot in cacao (Theobroma cacao L.): a review.

No abstract

This study provides a theoretical basis for the potential use of Ps. chlororaphis CP07 as a biocontrol agent for the protection of cacao plants from P. palmivora infection.

The capacity to solubilize phosphate and to produce indole compounds Indole Acetic Acid type, was evaluated in 15 strains isolated from castor bean lignocellulosic residues (Ricinus communis). To determine the solubilizing activity of phosphates a qualitative test by using Pikovskaya culture medium was employed and for the evaluation of the production of indole compounds (IAA) a Salkowsky colorimetric analysis technique was applied. Among the microorganisms tested, the Bacillus pumilus GIBI 206 demonstrated capacity to solubilize phosphates and Bacillus subtilis GIBI 200 showed of capacity to solubilize phosphates and to produce Indoleacetic Acid (IAA). To determine the effect of the Bacillus subtilis strain on germination and growth promotion, tomato seeds (Solanum lycopersicum 'Santa Clara') were inoculated; the inoculation of the seeds along with the microorganism revealed statistically significant differences, during the germination stage compared to the control treatment. Nevertheless, it revealed a positive influence on the development of tomato plants, originating a significant increase on the mass and length of its stem and root. The results of this research offer the possibility of using the Bacillus subtilis as a growth promoter in tomato seedlings and in the formulation of bio-products.

No abstract

The saprophytic bacterium Burkholderia cepacia has been shown to play an active role as plant growth promoting bacteria (PGPB). In this study, the ability of cell-free culture medium (CFCM) of B. cepacia to improve early developmental stages of plants has been assessed on two agronomically important crops, maize (Zea mays) and rice (Oryza sativa). Treating maize and rice seeds for 45 min before germination significantly improved seed germination and consequent seedling growth. The effect of CFCM was confirmed by the increased biomass of the shoot and, mainly, the root systems of treated seedlings. Chromatographic characterization of the CFCM revealed that the spent culture medium of B. cepacia is a complex mix of different classes of metabolites including, among others, salicylic acid, indole-3-acetic acid (IAA) and several unidentified phenolic compounds. Fractionation of the CFCM components revealed that the impressive development of the root system of CFCM-treated seedlings is due to the synergistic action of several groups of components rather than IAA alone. The data presented here suggest that a CFCM of B. cepacia can be used to improve crop germination.

The aerobiology can play a key role in protecting the rice crop since many fungi can cause serious damage to agricultural areas. In this way, the ideal time to implement different security measures can be identified. To determine the presence of potentially pathogenic fungi in the air of the rice agroecosystem, a weekly monitoring of viable fungi was carried out using a volumetric sampler. Collected fungi were quantified, isolated, and identified based on their morphological characteristics. The results obtained demonstrated that the annual average concentration of filamentous fungi in the atmosphere of rice agroecosystem studied was 1,225 cfu m -3 levels ranging between 115 cfu m -3 (April) and 2,865 cfu m -3 (August). Pyricularia grisea was detected in the air for 5 months, since the second week of June until the first week of October, and highest average concentration (25 cfu m -3 ) was observed in August. Of the meteorological factors evaluated, temperature and relative air humidity influence the concentration of propagules of P. grisea in the air. Besides, other fungi were detected such as Curvularia, Bipolaris, Alternaria, and Cercospora, all with relevance to rice cultivation. This is the first characterization of aeromycological biodiversity in the studied region.

No abstract