Interactions of the main pathogenic fungi of papaya (Carica papaya, L.) as a function of temperature

The temperature effect on the interaction between fungal isolates of papaya was studied. Rhizopus stolonifer, Colletotrichum cobbittiense, Fusarium pernambucarum, and Alternaria arborescens were grown in papaya agar in pairs, one against the other, at 13, 25, and 35 °C. The growth rate for each fungus was compared when grown alone or paired. Four types of interaction were observed: mutual intermingling, mutual antagonism on contact, dominance on contact, and dominance at a distance. At 13 and 35 °C, F. pernambucarum was more competitive whereas at 25 °C R. stolonifer does. In vivo validation showed R. stolonifer was the dominant fungus at 25 °C but coexists with C. cobbittiense forming a second infection. Then, a hierarchy may be established through a growth mechanism to infer which fungi may develop first and damage fruit to prevent postharvest losses. These findings could improve the management of papaya fruit in the postharvest stage.