ABSTRACT
The objective of this work was to evaluate the effectiveness of the putative biocontrol agents (PBA) Bacillus paralicheniformis and Trichoderma asperelloides in vitro and in vivo to control two of the most important tomato plant diseases: vascular wilt (Fusarium oxysporum) and early blight (Alternaria alternata). The assessment of the in vitro interactions between the PBA and the phytopathogenic fungi was performed by dual confrontation assays. The biocontrol effectiveness of the individual and combined PBA treatments towards individual phytopathogen inoculations was evaluated in tomato plants. T. asperelloides was able to exert an outstanding mycoparasitic effect on both phytopathogenic fungi in the in vitro tests by hyphal strangulation and penetration. In addition, the individual PBA treatments were effective in the biocontrol of A. alternata and F. oxysporum in tomato plants reducing the plant disease severity in more than 53.8 and 66.7% for each of the pathogens, respectively. On the other hand, the combined use of the tested strains showed similar effectiveness in the biocontrol of A. alternata, but no synergism was observed. In addition, it was concluded that B. paralicheniformis protected the plants from the attack of A. alternata through the induction of the systemic resistance of the plant. This study demonstrated the effectiveness of the individual and combined use of the strains tested for the biocontrol of A. alternata and F. oxysporum in tomato plants.
Subject(s)
Alternaria/pathogenicity , Bacillus/physiology , Biological Control Agents , Fusarium/pathogenicity , Hypocreales/physiology , Plant Diseases/microbiology , Solanum lycopersicum/microbiology , Microbial Interactions , Plant Diseases/prevention & controlABSTRACT
Fifteen plant species from a protected cloud forest (CF) in Veracruz, Mexico, were screened for their inâ vitro capacity to inhibit the growth of the phytopathogenic bacteria Chryseobacterium sp., Pseudomonas cichorii, Pectobacterium carotovorum and Pantoea stewartii, causal agents of damage to crops like 'chayote', lettuce, potato and corn. As a result, the bioactivity of Turpinia insignis and Leandra cornoides is reported for the first time against Chryseobacterium sp. and P. cichorii. In addition, 24 and 18 compounds not described for these species were dereplicated by an UPLC/MS-MS method, respectively. The identified compounds included simple phenols, hydroxycinnamic acids, flavonoids and coumarins. The antibacterial assay of 12 of them demonstrated the bacteriostatic effect of vanillin, trans-cinnamic acid, scopoletin and umbelliferone against Chryseobacterium sp. These findings confirm for the first time the value of the CF plants from Veracruz as sources of bioactive natural products with antimicrobial properties against phytopathogenic bacteria.
Subject(s)
Anti-Bacterial Agents/pharmacology , Magnoliopsida/chemistry , Melastomataceae/chemistry , Phenols/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Chryseobacterium/drug effects , Dose-Response Relationship, Drug , Mass Spectrometry , Mexico , Microbial Sensitivity Tests , Molecular Structure , Pantoea/drug effects , Pectobacterium/drug effects , Phenols/chemistry , Phenols/isolation & purification , Pseudomonas/drug effects , Species Specificity , Structure-Activity RelationshipABSTRACT
An unusual food plant for Cydia pomonella (Linnaeus) (Lepidoptera, Tortricidae) in Mexico. Larvae of Cydia pomonella (Linnaeus, 1758) were discovered on floral cones of Magnolia schiedeana (Schltdl, 1864) near the natural reserve of La Martinica, Veracruz, México. Magnolia represents an unusual host for this moth species, which is known throughout the world as the "codling moth", a serious pest of fruits of Rosaceae, especially apples. The larvae were identified using taxonomic keys, and identification was corroborated using molecular markers. Further sampling resulted in no additional larvae, hence, the observation was probably that of an ovipositional error by the female, and M. schiedeana is not at risk of attack by this important moth pest.
