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Coralline red algae from the New Zealand region were investigated in a study focused on documenting regional diversity. We present a multi-gene analysis using sequence data obtained for four genes (nSSU, psaA, psbA, rbcL) from 68 samples. The study revealed cryptic diversity at both genus and species levels, confirming and providing further evidence of problems with current taxonomic concepts in the Corallinophycidae. In addition, a new genus Corallinapetra novaezelandiae gen. et sp. nov. is erected for material from northern New Zealand. Corallinapetra is excluded from all currently recognized families and orders within the Corallinophycidae and thus represents a previously unrecognized lineage within this subclass. We discuss rank in the Corallinophycidae and propose the order Hapalidiales.

In a study of the variation among isolates of Banana streak virus (BSV) in Uganda, 140 sequences were obtained from 49 samples by PCR across the conserved reverse transcriptase/RNaseH region of the genome. Pairwise comparison of these sequences suggested that they represented 15 different species and phylogenetic analyses showed that all species fell into three major clades based on 28% sequence difference. In addition to the Ugandan sequences, clade I also contained BSV species that are known as both integrated sequences and episomal viruses; clade II also contained integrated BSV sequences but which have not previously been identified as episomal viruses. Clade III comprised of Sugarcane bacilliform virus isolates and Ugandan BSV sequences and for which there is no evidence of integration. The possible reasons for the extraordinary levels of virus sequence variation and the potential origins and epidemiology of these viruses causing banana streak disease are discussed.

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Summary Banana streak virus (BSV) is one of the major constraints to banana production in Uganda. To develop a diagnostic technique, 59 samples were taken from 30 farms at 14 locations across Uganda; a further three samples were taken from infector plants for BSV epidemiology experiments. BSV was found in 51 of the field samples and in the three infector plants. The possible variation of the virus was assessed by serology (ISEM and ELISA) using a broad‐spectrum antiserum and by PCR. Virus was poorly detected in many of the samples by serological tests even though other techniques showed its presence. Virus was detected in most samples by PCR with a degenerate primer set on extracted viral DNA and on immune‐captured (1C) or directly bound (DB) virus particles. The epidemiology experiment samples did not give a product with these degenerate primers but did with other primer sets. A diagnostic procedure was developed involving concentrating the virus in sap by polyethylene glycol precipitation followed by 1C‐ or DB‐PCR using a degenerate primer set which detected virus in most samples.

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