Identification of Growing Media Favorable for the Growth of Pythium aphanidermatum, a Telluric Pathogen of Papaya (Carica papaya L.) in Côte d’Ivoire

Pawpaw (Carica papaya L.) is an economically important plant in Côte d'Ivoire. However, its cultivation is subject to numerous biotic constraints, including root and crown rot, caused by several species of Pythium, Phytophthora, and Rhizoctonia. Of all these fungi, Pythium aphanidermatum is the most dreaded in Ivorian plantations, causing root, crown, trunk, and fruit rot. This causes enormous production losses, reducing farmers’ incomes. The present study was initiated with a view to finding a suitable culture medium for the development of P. aphanidermatum, which is responsible for root and crown rot of papaya trees, through the study of its morphology and biology. To this end, the mycelial growth of P. aphanidermatum was evaluated on different culture media (PDA, V8, CMA and Papaya). The results showed that all these culture media were favorable for the mycelial growth of P. aphanidermatum. However, in terms of propagule production, PDA and V8 culture media were the most favorable. The CMA medium produced fewer propagules than the PDA and V8 media. Papaya culture medium inhibited oospore production. Sporocysts and chlamydospores were observed in all media. The culture medium did not influence the mycelial growth of P. aphanidermatum but rather oospore production.