Dry flower disease of Macadamia in Australia caused by Neopestalotiopsis macadamiae sp. nov. and Pestalotiopsis macadamiae sp. nov

Akinsanmi, Olufemi A. and Nisa, Shaheen and Jeff-Ego, Olumdie S. and Shivas, Roger G. and Drenth, Andre (2017) Dry flower disease of Macadamia in Australia caused by Neopestalotiopsis macadamiae sp. nov. and Pestalotiopsis macadamiae sp. nov. Plant Disease, 101 (1). pp. 45-53. ISSN 0191-2917

Abstract

Incidence of dry flower disease of macadamia (Macadamia integrifolia), expressed as blight of the flowers and necrosis and dieback of the rachis, is increasing in Australia. In the 2012–13 production season, incidence of dry flower disease resulted in 10 to 30% yield loss in the affected orchards. Etiology of the disease has not been established. This study was established to characterize the disease and identify the causal pathogen. A survey of the major macadamia-producing regions in Australia revealed dry flower disease symptoms regardless of cultivar or location at all stages of raceme development. Based on colony and conidial morphology, the majority (41%) of fungal isolates obtained from tissue samples were identified as Pestalotiopsis and Neopestalotiopsis spp. The phylogeny of the combined partial sequence of the internal transcribed spacer, β-tubulin, and translation elongation factor 1-α gene loci segregated the isolates into two well-supported clades, independent of location or part of the inflorescence affected. Further morphological examination supported the establishment of two new species, which are formally described as Neopestalotiopsis macadamiae sp. nov. and Pestalotiopsis macadamiae sp. nov. Using spore suspensions of isolates of both species, Koch’s postulates were fulfilled on three macadamia cultivars at all stages of raceme development. To our knowledge, this is the first report of species of Neopestalotiopsis and Pestalotiopsis as causal agents of inflorescence disease in macadamia.


Statistics for USQ ePrint 32433
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version, in accordance with the copyright policy of the publisher.
Faculty / Department / School: No Faculty
Date Deposited: 21 Dec 2017 03:53
Last Modified: 21 Dec 2017 03:53
Uncontrolled Keywords: macadamia; dry flower disease; Neopestalotiopsis macadamiae; Pestalotiopsis macadamiae
Fields of Research : 06 Biological Sciences > 0607 Plant Biology > 060704 Plant Pathology
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970106 Expanding Knowledge in the Biological Sciences
Identification Number or DOI: 10.1094/PDIS-05-16-0630-RE
URI: http://eprints.usq.edu.au/id/eprint/32433

Actions (login required)

View Item Archive Repository Staff Only