First report of Bipolaris oryzae causing leaf spot on Strelitzia nicolai in Florida.
Strelitzia nicolai is native to southern Africa and is known as white bird-of-paradise. It is very common in tropical landscapes and is popular throughout southern California, Florida and Hawaii, USA. In December 2015, plants with a severe leaf spot were found in a commercial nursery located in south Florida. Individual leaf spots were circular to irregular in shape with a light tannish brown centre and a dark brown to black border ranging from 0.2 to 3 cm in diameter. Some leaf spots coalesced and in severe cases covered 75% of the leaf area. Some of the light tannish brown centres of leaf spots had fallen out, giving a "shot hole" appearance, while other spots appeared black due to heavy fungal sporulation. Based on cultural and morphological characteristics, molecular data (sequence analysis of the complete internal transcribed spacer region and the glyceraldehyde-3-phosphate dehydrogenase gene) and pathogenicity tests, the causal agent was identified as B. oryzae [Cochliobolus miyabeanus]. This is thought to be the first report of B. oryzae on S. nicolai. B. oryzae has since been confirmed causing leaf spot on white bird-of-paradise at 3 additional commercial nurseries and a retail garden centre in Florida.