Effect of temperature on the interaction between Rhizopus stolonifer and Colletotrichum sp., postharvest pathogens of jackfruit (Artocarpus heterophyllus Lam.)

Abstract

Jackfruit (Artocarpus heterophyllus Lam.) is a climacteric fruit whit a high commercial value, but susceptible to decay. The most important pathogens for jackfruit R. stolonifer and C. gloeosporioides may interact in different ways. The objectives of this study were to examine the interaction between three fungal species isolated from jackfruit and describe their behavior and interactions as a function of temperature. Three pathogen isolates from jackfruit rots, cultivated individually or paired at 4 cm in a natural medium were used. The growth rate was evaluated at 13, 25, and 35 °C. The Baranyi-Roberts model was used to obtain the radial growth rate. Differences between the growth rate of each fungus are the reference to determine the type of interaction. The effect of temperature of the unpaired isolates was studied by Rosso-Robinson’s model. The experiment was validated by infecting fresh jackfruit whit a mix of spores of all isolates. Rhizopus stolonifer is capable of rapidly colonizing the Petri dish thus reducing the space for the other fungi. The growth rates of unpaired and paired fungal isolates were statistically different showing that interactions between them exist. Rhizopus intermingling the others at 13 and 25 °C whereas, at the same temperatures, Colletotrichum AhCx-02 dominates AhCx-03. In contrast, dominance patterns of the Colletotrichum AhCx-03 strain were higher at 35 °C.