Pseudopestalotiopsis elaeidis associated with leaf spots on Cycas revoluta in Brazil

Cycas revoluta (Cycadaceae) is commonly cultivated as an ornamental tree in several countries. In April 2015, C. revoluta leaves showing brownish spots with a yellow halo that progressed to leaflet necrosis were observed in Belém, Pará state, Brazil. This study aimed to determine the aetiology of this disease on sago palm in Brazil. Based on DNA sequence-based phylogeny, morphology, and colony characterization, the fungus was identified as Pseudopestalotiopsis elaeidis. To the best of our knowledge, this is the first report of P. elaeidis associated with leaf spots on C. revoluta worldwide.     

Investigations into Encephalartos insect pests and diseases in South Africa and identification of Phytophthora cinnamomi as a pathogen of the Modjadji cycad

South Africa holds the greatest diversity of Encephalartos species globally. In recent years several reports have been received of Encephalartos species in the country dying of unknown causes. The aim of this study was to investigate the presence of, and identify the causal agents of, diseases of Encephalartos species in the Gauteng and Limpopo Provinces of South Africa. Plant material with symptoms and insects were collected from diseased plants in private gardens, commercial nurseries and conservation areas in these regions. Insects collected were identified based on morphology, and microbial isolates based on morphology and DNA sequence data. Insect species identified infesting cultivated cycads included the beetle Amorphocerus talpa, and the scale insects Aonidiella aurantii, Aspidiotus capensis, Chrysomphalus aonidum, Lindingaspis rossi, Pseudaulacaspis cockerelli, Pseudaulacaspis pentagona and Pseudococcus longispinus. Fungal species isolated from diseased plants included species of Diaporthe, Epicoccum, Fusarium, Lasiodiplodia, Neofusicoccum, Peyronellaea, Phoma, Pseudocercospora and Toxicocladosporium. The plant pathogen Phytophthora cinnamomi was identified from E. transvenosus plants in the Modjadji Nature Reserve. Artificial inoculation studies fulfilled Koch's postulates, strongly suggesting that P. cinnamomi is responsible for the deaths of these plants under field conditions.