Diversity and host preference of leaf endophytic fungi in the Iwokrama Forest Reserve, Guyana.

Endophytic fungi were isolated from living symptomless leaves of 12 tree species from two locations in the Iwokrama Forest Reserve, Guyana. Sixty-four fungal morphotaxa were characterized from 2492 cultures, which were derived from a total of 2520 sample units. Species of Colletotrichum, Nodulisporium, Pestalotiopsis and Phomopsis were most frequently isolated. Colonization was greater in samples from the midrib than in those from laminar tissue, and slightly greater at the tip of the lamina compared with the base of the leaf. In contrast to studies in temperate ecosystems, no distinct fungal communities were identified for individual plant species, suggesting that the degree of host preference is low. The implications for estimation of fungal diversity in tropical systems are explored.