Use of Penicillium, Colletotrichum and Rhizpus species in organic waste treatment

Tesis (Doctorado en Ciencias en Bioprocesos), Instituto Politécnico Nacional, SEPI, UPIBI, 2009, 1 archivo PDF, (18 páginas), tesis.ipn.m

Tratamientos poscosecha para el control de Conotrachelus dimidiatus (Coleoptera: Curculionidae) en guayaba (Psidium guajava)

Guava (Psidium guajava) is one of the most common fruit trees cultivated in Latin America; however, its production is delimited by different insect pests that affect fruit quality, including the guava weevil Conotrachelus dimidiatus. This study assessed the effects of two post-harvest treatments (hydrothermal and temperature storage) in the control of C. dimidiatus, as well as physicochemical variables of treated guava fruits. The hydrothermal treatment presented mortality of larvae 70 minutes after immersion, while mortality of larvae was observed after the six days of evaluation in the temperature treatment. In both post-harvest treatments, the variables titratable physicochemical acidity and vitamin C did not present significant statistical differences among treatments; whereas, the degrees °Brix and ionic acidity showed significant differences with respect to the control. For the hydrothermal treatment, a decrease in the time of immersion is suggested in order to minimize or void the effects of the treatment tested. Regarding temperature, it was observed that the presence of larvae of C. dimidiatus in fruit leads to a reduction in the sugar content. Hence, more studies are needed to determine ideal temperatures in which the effects of the treatments are minimal or void on the physicochemical properties of guava fruit. These may be considered as an alternative to post-harvest control for this insect.  En América Latina, la guayaba (Psidium guajava) es uno de los principales frutales cultivados, no obstante, su producción es demeritada por diversos insectos plaga, uno de ellos es el picudo de la guayaba Conotrachelus dimidiatus, el cual afecta la calidad de los frutos. En este estudio se evaluó el efecto de dos tratamientos poscosecha (hidrotérmico y temperatura de almacenamiento) en el control de C. dimidiatus y la calidad de algunas variables fisicoquímicas de los frutos de guayaba tratados. En el tratamiento hidrotérmico se presentó mortalidad de larvas a partir de los 70 min de inmersión y en el de temperatura, se observó mortalidad de larvas después de seis días de evaluación. En ambos tratamientos poscosecha, las variables fisicoquímicas acidez titulable y vitamina C, no presentaron diferencias estadísticas significativas entre los tratamientos, mientras que, los grados °Brix y acidez iónica mostraron diferencias significativas respecto al testigo. Para el tratamiento hidrótermico, se sugiere disminuir el tiempo de inmersión para que su efectos sean mínimos o nulos; en cuanto al de temperatura se observó que la presencia de larvas de C. dimidiatus en los frutos ocasiona una reducción en el contenido de azúcares de los mismos. Por lo tanto, se requieren más estudios para determinar las temperaturas óptimas para que los efectos de los tratamientos probados sean mínimos o nulos sobre las propiedades fisicoquímicas de los frutos de guayaba y éstos puedan ser considerados como una alternativa de control poscosecha para este insecto. &nbsp

Postharvest treatments for control of Conotrachelus dimidiatus (Coleoptera: Curculionidae) in guava (Psidium guajava).

Guava (Psidium guajava) is one of the most common fruit trees cultivated in Latin America; however, its production is delimited by different insect pests that affect fruit quality, including the guava weevil Conotrachelus dimidiatus. This study assessed the effects of two post-harvest treatments (hydrothermal and temperature storage) in the control of C. dimidiatus, as well as physicochemical variables of treated guava fruits. The hydrothermal treatment presented mortality of larvae 70 minutes after immersion, while mortality of larvae was observed after the six days of evaluation in the temperature treatment. In both post-harvest treatments, the variables titratable physicochemical acidity and vitamin C did not present significant statistical differences among treatments; whereas, the degrees °Brix and ionic acidity showed significant differences with respect to the control. For the hydrothermal treatment, a decrease in the time of immersion is suggested in order to minimize or void the effects of the treatment tested. Regarding temperature, it was observed that the presence of larvae of C. dimidiatus in fruit leads to a reduction in the sugar content. Hence, more studies are needed to determine ideal temperatures in which the effects of the treatments are minimal or void on the physicochemical properties of guava fruit. These may be considered as an alternative to post-harvest control for this insect