Seedborne Pathogenic Fungi that Affect Seedling Quality of Red Angico (Anadenanthera macrocarpa) Trees in Brazil

Internal and external seedborne fungal pathogens of Anadenanthera macrocarpa reduced seedling emergence and the quality of seedlings grown from contaminated seeds. Colletotrichum gloeosporioides, Fusarium lateritium, F. semitectum, Pestalotiopsis sp. and Phomopsis dalbergiae were the only fungi consistently isolated from seed samples collected from afforestation companies, university forestry departments and a Forest Reserve Park. Their frequency was much lower in surface disinfested than in untreated seeds. The temporal dynamics of the pericarp and seed infection on trees used for seed harvest in the Forest Reserve Park showed that colonization by these fungi starts soon after pod and seed formation, and continues to increase to pod maturity. Although the maximum proportion of infected seeds occurred at full maturity, their proportion was also high at physiological maturity. The high external seed infestation appears to occur during on-floor sun drying of the pods and separation of pericarps from seeds by broom sweeping. All five fungi were highly pathogenic to seeds and seedlings, causing seed rot, root rot and reduced height and thriftiness of surviving seedlings. Our results explain the heavy losses suffered by nurserymen due to low quality seedlings. This is the first report of the occurrence of these fungi on this host causing economical losses.